Three-Channel, Isolated Micropower
Management Unit with Seven Digital Isolators
ADP1031
Data Sheet
TYPICAL APPLICATION CIRCUIT
Wide input supply voltage range: 4.5 V to 60 V
Integrated flyback power switch
Generates isolated, independent bipolar outputs and factory
programmable buck output
VOUT1: 21 V, 24 V or 6 V to 28 V
VOUT2: 5.15 V, 5.0 V, or 3.3 V
VOUT3: −24 V to −5 V
Uses a 1:1 ratio transformer for simplified transformer design
Peak current limiting and OVP for flyback, buck, and
inverting regulators
Precision enable input and power-good output
Adjustable switching frequency via SYNC input
Internal compensation and soft start control per regulator
High speed, low propagation delay, SPI signal isolation
channels
Three, 100 kbps general-purpose isolated data channels
9 mm × 7 mm LFCSP form factor enables small overall
solution size
−40°C to +125°C operating junction temperature range
Conforms to CISPR11 Class B radiated emission limits
Safety and regulatory approvals (pending)
UL recognition: 2500 V rms for 1 minute per UL 1577
CSA Component Acceptance Notice 5A
300 V rms basic insulation between slave, master, and
field power domains (IEC 61010-1, pending)
VDE certificate of conformity
DIN V VDE 0884-10 (VDE 0884-10):2006-12
VIORM = 565 VPEAK
APPLICATIONS
Industrial automation and process control
Instrumentation and data acquisition systems
Data and power isolation
GENERAL DESCRIPTION
The ADP1031 is a high performance, isolated micropower
management unit (PMU) that combines an isolated flyback
dc-to-dc regulator, an inverting dc-to-dc regulator, and a
buck dc-to-dc regulator, providing three isolated power rails.
Additionally, the ADP1031 contains four, high speed, serial
peripheral interface (SPI) isolation channels and three generalpurpose isolators for channel to channel applications where low
power dissipation and small solution size is required.
Rev. A
VINP
4.5V TO 60V
1:1
Tx1
SWP
VINP
CIN
R3
R2
PGNDP
VOUT1
6V TO 28V
D1
RFT1
CFLYBK
RFB1
FB1
SGND2
VOUT1
ADP1031
VOUT2
SW2
CBUCK
L1
VOUT3
–24V TO –5V
PGNDP
GNDP
VOUT3
SLEW
FB3
SW3
ISOLATED GPIO
CHANNELS AND SPI
INTERFACE
RFB3
L2
RFT3
CINV
ISOLATED GPIO
CHANNELS AND SPI
INTERFACE
PWRGD
MVDD
2.3V TO 5.5V
VOUT2
3.3V, 5V, 5.15V
SYNC
EN
SVDD2
R1
SGND2
MVDD
C3
SVDD
1.8V TO 5.5V
SVDD1
C1
MGND
SGND1
C4
16434-101
FEATURES
Figure 1.
Operating over an input voltage range of +4.5 V to +60 V, the
ADP1031 generates isolated output voltages of +6 V to +28 V
(adjustable version) or+ 21 V and +24 V (fixed versions) for
VOUT1, factory programmable voltages of +5.15 V, +5.0 V, or
+3.3 V for VOUT2, and an adjustable output voltages of −24 V to
−5 V for VOUT3.
By default, the ADP1031 flyback regulator operates at a 250 kHz
switching frequency and the buck and inverting regulators operate
at 125 kHz. All three regulators are phase shifted relative to each
other to reduce electromagnetic interference (EMI). The ADP1031
can be driven by an external oscillator in the range of 350 kHz to
750 kHz to ease noise filtering in sensitive applications.
The digital isolators integrated in the ADP1031 use Analog
Devices, Inc., iCoupler® chip scale transformer technology,
optimized for low power and low radiated emissions.
The ADP1031 is available in a 9 mm × 7 mm, 41-lead LFCSP and
is rated for a −40°C to +125°C operating junction temperature
range.
COMPANION PRODUCTS
Analog Output DAC: AD5758
Precision Data Acquisition Subsystem: AD7768-1
Additional companion products on the ADP1031 product page
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ADP1031
Data Sheet
TABLE OF CONTENTS
Features .............................................................................................. 1
Buck Regulator ........................................................................... 25
Applications ....................................................................................... 1
Inverting Regulator .................................................................... 26
General Description ......................................................................... 1
Power Good ................................................................................ 26
Typical Application Circuit ............................................................. 1
Power-Up Sequence ................................................................... 26
Companion Products ....................................................................... 1
Oscillator and Synchronization ................................................ 26
Revision History ............................................................................... 2
Thermal Shutdown .................................................................... 27
Specifications..................................................................................... 3
Data Isolation .............................................................................. 27
Regulatory Information ............................................................... 7
Applications Information .............................................................. 29
Electromagnectic Compatibility................................................. 8
Component Selection ................................................................ 29
Insulation and Safety Related Specifications ............................ 8
Flyback Regulator Components Selection .............................. 30
DIN V VDE 0884-10 (VDE V 0884-10) Insulation
Characteristics .............................................................................. 9
Buck Regulator Components Selection ................................... 33
Absolute Maximum Ratings.......................................................... 10
Insulation Lifetime ..................................................................... 34
Thermal Resistance .................................................................... 10
Thermal Analysis ....................................................................... 35
ESD Caution ................................................................................ 10
Typical Application Circuit ....................................................... 36
Pin Configuration and Function Descriptions ........................... 11
PCB Layout Considerations .......................................................... 37
Typical Performance Characteristics ........................................... 13
Outline Dimensions ....................................................................... 38
Theory of Operation ...................................................................... 23
Ordering Guide .......................................................................... 38
Inverting Regulator Component Selection ............................. 33
Flyback Regulator ....................................................................... 24
REVISION HISTORY
12/2019—Rev. 0 to Rev. A
Changes Table 9 .............................................................................. 11
Changes to Figure 48 and Figure 51 ............................................. 20
Changes to Figure 52 to Figure 57 ................................................ 21
Changes to Figure 58 to Figure 63 ................................................ 22
Changes to Insulation Lifetime Section ....................................... 34
Added Surface Tracking Section, Insulation Wear Out Section,
Equation 1 and Equation 2; Renumbered Sequentially, Calculation
and Use of Parameters Example Section, and Figure 75;
Renumbered Sequentially ............................................................. 35
Changes to Figure 76...................................................................... 36
Updated Outline Dimensions ....................................................... 38
Changes to Ordering Guide .......................................................... 38
1/2019—Revision 0: Initial Version
Rev. A | Page 2 of 38
Data Sheet
ADP1031
SPECIFICATIONS
VINP voltage (VINP) = 24 V, MVDD voltage (VMVDD) = 3.3 V, SVDDx voltage (VSVDDx) = 3.3 V, VOUT1 voltage (VOUT1) = 24 V, VOUT2
voltage (VOUT2) = 5.15 V, VOUT3 voltage (VOUT3) = −15 V, and TA = 25°C for typical specifications. Minimum and maximum specification
apply over the entire operating range of 4.5 V ≤ VINP ≤ 60 V, 2.3 V ≤ VMVDD ≤ 5.5 V, 1.8 V ≤ VSVDDx ≤ 5.5 V, and −40°C ≤ TJ ≤ +125°C,
unless otherwise noted.
Table 1.
Parameter
INPUT SUPPLY VOLTAGE RANGE
VINP
MVDD
SVDDx
OUTPUT POWER AND EFFICIENCY
Total Output Power
Symbol
Min
VINP
VMVDD
VSVDDx
4.5
2.3
1.8
SPI Low Power Mode
SVDD1
SPI Active Mode
SPI Low Power Mode
SVDD2
UVLO
VINP
Rising Threshold
Falling Threshold
Hysteresis
MVDD
Rising Threshold
Falling Threshold
Hysteresis
Unit
60
5.5
5.5
V
V
V
Test Conditions/Comments
Applies to SVDD1 and SVDD2
Transformer = 750316743
VOUT1 current (IOUT1) = 70 mA,
VOUT2 current (IOUT2) = 7 mA,
VOUT3 current (IOUT3) = −0.3 mA
IOUT1 = 20 mA, IOUT2 = 7 mA,
IOUT3 = −0.3 mA
IOUT1 = 70 mA, IOUT2 = 7 mA,
IOUT3 = −0.3 mA
IOUT1 = 20 mA, IOUT2 = 7 mA,
IOUT3 = −0.3 mA
IOUT1 = 70 mA, IOUT2 = 7 mA,
IOUT3 = −0.3 mA
IOUT1 = 20 mA, IOUT2 = 7 mA,
IOUT3 = −0.3 mA
mW
520
mW
88.8
%
84.8
%
216.5
mW
93.1
mW
IQ_VINP
1.77
mA
ISHDN_VINP
125
175
µA
Normal operation, VOUT1,
VOUT2, VOUT3 = no load
EN voltage (VEN) = 0 V
IQ_MVDD (SPI_ACTIVE)
4.1
9.2
1.6
1.6
6.5
14
2.5
2.5
mA
mA
mA
mA
VIx 1 = logic low, MSS = logic low
VIx1 = logic high, MSS = logic low
VIx1 = logic low, MSS = logic high
VIx1 = logic high, MSS = logic high
1.8
5.7
1.8
1.8
39
2
2.7
8.6
2.7
2.7
85
2.5
mA
mA
mA
mA
µA
mA
VIx1 = logic low, SSS = logic low
VIx1 = logic high, SSS = logic low
VIx1 = logic low, SSS = logic high
VIx1 = logic high, SSS = logic high
VIx1 = logic low
VIx1 = logic high
4.49
4.29
4.44
4.34
100
V
V
mV
2.28
1.9
2.14
2
140
V
V
mV
Power Dissipation
Shutdown Current
MVDD
SPI Active Mode
Max
1720
Efficiency
QUIESCENT CURRENT
VINP
Operating Current
Typ
IQ_MVDD (SPI_LOWPWR)
IQ_SVDD1 (SPI_ACTIVE)
IQ_SVDD1 (SPI_LOWPWR)
IQ_SVDD2
Relative to PGNDP
VUVLO_FLYBACK (RISE)
VUVLO_FLYBACK (FALL)
Relative to MGND
VUVLO_MVDD (RISE)
VUVLO_MVDD (FALL)
Rev. A | Page 3 of 38
ADP1031
Parameter
THERMAL SHUTDOWN
Threshold
Hysteresis
PRECISION ENABLE
Rising Input Threshold
Input Hysteresis
Leakage Current
POWER GOOD
Power-Good Threshold
Flyback Regulator
Lower Limit
Upper Limit
Buck Regulator
Lower Limit
Upper Limit
Inverting Regulator
Lower Limit
Upper Limit
Glitch Rejection
Output Voltage
Logic High
Logic Low
SLEW
Voltage Level Threshold
Slow Slew Rate
Normal Slew Rate
Input Current
Slow Slew Rate
Normal Slew Rate
Fast Slew Rate
CLOCK SYNCHRONIZATION
SYNC Input
Input Clock
Range
Minimum On Pulse Width
Minimum Off Pulse Width
High Logic
Low Logic
Leakage Current
FLYBACK REGULATOR
Output Voltage Range
Data Sheet
Symbol
Min
TSHDN
THYS
VEN_RISING
VEN_HYST
Max
150
15
1.10
Unit
1.135
100
0.03
1.20
0.5
V
mV
µA
87.5
90
92.5
%
VPG_FYLBACK_UL
107.5
110
112.5
%
VPG_BUCK_LL
VPG_BUCK_UL
87.5
107.5
90
110
92.5
112.5
%
%
VPG_INVERTER_LL
VPG_INVERTER_UL
87.5
107.5
90
110
1.36
92.5
112.5
%
%
µs
VPWRGD_OH
VMVDD −
0.4
VPWRGD_OL
−1
V
IPWRGD = 1 mA
0.8
V
V
VOUT1 (ADJ)
µA
µA
µA
Slew voltage (VSLEW) = 0 V to 0.8 V
VSLEW = 2 V to VINP
SLEW pin not connected
0.4
1
kHz
ns
ns
V
V
µA
SYNC voltage (VSYNC) = VSVDDx
28
V
+1.5
V
V
%
750
0.005
6
24
21
−1.5
Rev. A | Page 4 of 38
Glitch of ±15% of the typical
output
0.4
10
+1
350
100
150
1.3
Fixed and adjustable output
versions
Fixed and adjustable output
versions
PWRGD current (IPWRGD) = −1 mA
−10
fSYNC
tSYNC_MIN_ON
tSYNC_MIN_OFF
VH (SYNC)
VL (SYNC)
VEN = VINP
V
2
−1
Test Conditions/Comments
°C
°C
VPG_FLYBACK_LL
VOUT1 (FIXED)
VOUT1 (FIXED)
Output Voltage Accuracy
Typ
ADP1031ACPZ-1,
ADP1031ACPZ-2, and
ADP1031ACPZ-3
ADP1031ACPZ-4
ADP1031ACPZ-5
Fixed output options
Data Sheet
Parameter
Feedback Voltage
Feedback Voltage Accuracy
Feedback Bias Current
Load Regulation
ADP1031
IFB1
(ΔVFB1/VFB1)/ΔIOUT1
−0.0005
Unit
V
%
µA
%/mA
Line Regulation
(ΔVOUT1/VOUT1)/ΔVINP
0.0003
%/V
Power Field Effect Transistor (FET)
On Resistance
Current-Limit Threshold
SWP Leakage Current
SWP Capacitance
Switching Frequency
RON (FLYBACK)
3
Ω
CSWP
fSW (FLYBACK)
235
Minimum On Time
Minimum Off Time
Soft Start Timer
Severe Overvoltage Threshold
tSS (FLYBACK)
SOVPFLYBACK
29.4
Severe Overvoltage Hysteresis
BUCK REGULATOR
Output Voltage
Symbol
VFB1
Min
−1.5
ILIM (FLYBACK)
280
Current-Limit Threshold
SW2 Leakage Current
P Type Metal-Oxide Semiconductor
(PMOS)
N Type Metal-Oxide Semiconductor
(NMOS)
Switching Frequency
Minimum On Time
Soft Start Timer
Active Pull-Down Resistor
INVERTING REGULATOR
Output Voltage Range
Feedback Voltage
Feedback Voltage Accuracy
Feedback Bias Current
Load Regulation
Line Regulation
Power FET On Resistance
Max
+1.5
0.05
300
0.03
50
250
fSYNC/2
425
220
8
30
320
0.5
265
30.6
mA
µA
pF
kHz
kHz
ns
ns
ms
V
Test Conditions/Comments
Adjustable output options
IOUT1 = 4 mA to 24 mA,
IOUT2 = 10 mA, IOUT3 = −1 mA
VINP = 16 V to 32 V, IOUT1 = 20 mA,
IOUT2 = 10 mA, IOUT3 = −1 mA
SWP current (ISWP) = 100 mA
SWP voltage (VSWP) = 60 V
SYNC = low or high
SYNC = external clock
Flyback regulator stops switching
until the overvoltage is removed
SOVPFLYBACK_HYST
500
mV
VOUT2
5.15
V
5.0
3.3
+1.5
V
V
%
−0.0005
0.0004
1
2.5
300
320
%/mA
%/V
Ω
Ω
mA
0.03
0.5
µA
VSW2 = 0 V
0.03
0.5
µA
VSW2 = 28 V
125
fSYNC/4
200
8
1.7
132.5
kHz
kHz
ns
ms
kΩ
SYNC = low or high
SYNC = external clock
Output Voltage Accuracy
Load Regulation
Line Regulation
Power FET On Resistance
Typ
0.8
−1.5
(ΔVOUT2/VOUT2)/ΔIOUT2
(ΔVOUT2/VOUT2)/ΔVOUT1
RON_NFET (BUCK)
RON_PFET (BUCK)
ILIM (BUCK)
fSW (BUCK)
280
117.5
tSS (BUCK)
RPD (BUCK)
VOUT3
VFB3
−24
−5
IFB3
(ΔVFB3/VFB3)/ΔIOUT3
−0.01
V
V
%
µA
%/mA
(ΔVOUT3/VOUT3)/ΔVOUT1
RON_NFET (INVERTER)
RON_PFET (INVERTER)
0.0005
1.45
2.2
%/V
Ω
Ω
0.8
−1.5
+1.5
0.05
Rev. A | Page 5 of 38
ADP1031ACPZ-1,
ADP1031ACPZ-4, and
ADP1031ACPZ-5
ADP1031ACPZ-2
ADP1031ACPZ-3
IOUT2 = 10 mA, applies to all
models
IOUT2 = 2 mA to 50 mA
VOUT1 = 6 V to 28 V, IOUT2 = 7 mA
SW2 current (ISW2) = 100 mA
ISW2 = 100 mA
1.23 V < VOUT1 < 4.5 V
In reference to VOUT3
Adjustable output option
IOUT3 = 1 mA to 15 mA
VOUT1 = 6 V to 28 V, IOUT3 = −15 mA
SW3 current (ISW3) = 100 mA
ISW3 = 100 mA
ADP1031
Parameter
Current-Limit Threshold
SW3 Leakage Current
PMOS
NMOS
Switching Frequency
Minimum On Time
Soft Start Timer
Active Pull-Down Resistor
ISOLATORS, DC SPECIFICATIONS
MCK, MSS, MO, SO, MGPI1, MGPI2, SGPI3
Input Threshold
Logic High
Logic Low
Input Current
SCK, SSS, SI, MI
Output Voltage
Logic High
Logic Low
Data Sheet
Symbol
ILIM (INVERTER)
fSW (INVERTER)
Min
280
117.5
tSS (INVERTER)
RPD (INVERTER)
VIH
Typ
300
Max
320
Unit
mA
Test Conditions/Comments
0.03
0.03
125
fSYNC/4
178
8
350
0.5
0.5
132.5
µA
µA
kHz
kHz
ns
ms
Ω
VSW3 = −24 V
VSW3 = 24 V
SYNC = low or high
SYNC = external clock
V
VxVDD = VMVDD or VSVDDx
V
VxVDD = VMVDD or VSVDDx
µA
0 V ≤ VINPUT ≤ VxVDD
V
IOx 2 = −20 µA, VIx = VIxH 3
V
IOx2 = −2 mA, VIx = VIxH3
V
V
IOx2 = 20 µA, VIx = VIxL 4
IOx2 = 2 mA, VIx = VIxL4
V
IOx2 = −20 µA, VIx = VIxH3
V
IOx2 = −500 µA, VIx = VIxH3
0.7 ×
VxVDD
0.3 ×
VxVDD
+1
VIL
II
−1
VOH
VxVDD −
0.1
VxVDD −
0.4
VOL
0.15
SGPO1, SGPO2, MGPO3
Output Voltage
Logic High
Logic Low
VOH
ISOLATORS, SWITCHING SPECIFICATION
MCK, MSS, MO, SO
SPI Clock Rate
VxVDD −
0.1
VxVDD −
0.4
VOL
SCK, SI, MI
Tristate Leakage
0.15
0.1
0.4
V
V
IOx2 = 20 µA, VIx = VIxL4
IOx2 = 500 µA, VIx = VIxL4
0.01
0.01
1
1
µA
µA
MSS = logic high
VOx 5 = VxVDD
16.6
MHz
100
125
ns
0.25
6.5
ns
ns
0.5
0.5
5.5
4
ns
ns
−1
−1
SPIMCK
Latency
Input Pulse Width
Input Pulse Width Distortion
Channel Matching
Codirectional
Opposing Direction
tPW
tPWD
tPSKCD
tPSKOD
0.1
0.4
1.23 V < VOUT1 < 4.5 V
17
Rev. A | Page 6 of 38
Delay from MSS going low
to the first data out is valid
Within PWD limit
|tPLH − tPHL|
Data Sheet
ADP1031
Parameter
Propagation Delay
Symbol
tPHL, tPLH
Min
Jitter
Typ
Max
Unit
7
7
7
8.5
620
100
11
12
15
12
ns
ns
ns
ns
ps p-p
ps
rms
ps p-p
ps
rms
ps p-p
ps
rms
ps p-p
ps
rms
440
80
290
60
410
110
MGPI1, MGPI2, SGPI3
Data Rate
Input Pulse Width
Propagation Delay
Jitter
ISOLATORS AC SPECIFICATIONS
General-Purpose Input/Output (GPIO)
Output Rise Time/Fall Time
SPI
Output Rise Time/Fall Time
Common-Mode Transient Immunity 6
100
tPW
tPHL, tPLH
10
14
19.5
Test Conditions/Comments
50% input to 50% output
VMVDD = 5 V, VSVDD1 = 5 V
VMVDD = 3.3V, VSVDD1 = 5 V
VMVDD = 3.3 V, VSVDD1 = 3.3 V
VMVDD = 2.3 V, VSVDD1 = 1.8 V
VMVDD = 5 V, VSVDD1 = 5 V
VMVDD = 5 V, VSVDD1 = 5 V
VMVDD = 3.3 V, VSVDD1 = 5 V
VMVDD = 3.3 V, VSVDD1 = 5 V
VMVDD = 3.3 V, VSVDD1 = 3.3 V
VMVDD = 3.3 V, VSVDD1 = 3.3 V
VMVDD = 2.3 V, VSVDD1 = 1.8 V
VMVDD = 2.3 V, VSVDD1 = 1.8 V
kbps
µs
µs
µs
Within PWD limit
50% input to 50% output
tR/tF
2.5
ns
10% to 90%
tR/tF
|CM|
2
100
ns
kV/µs
10% to 90%
VIx is the Channel x logic input, where Channel x can be MCK, MO, SO, MGPI1, MGPI2, or MGPI3.
IOx is the output current of the pin.
3
VIxH is the input side, logic high.
4
VIxL is the input side, logic low.
5
VOx is the voltage where the output is pulled.
6
|CM| is the maximum common-mode voltage slew rate that can be sustained while maintaining VOUT > 0.8 MVDD and/or SVDDx. The common-mode voltage slew
rates apply to both rising and falling common-mode voltage edges.
1
2
REGULATORY INFORMATION
See Table 8 and the Insulation Lifetime section for the recommended maximum working voltages for specific cross isolation waveforms
and insulation levels.
Table 2. Safety Certifications
UL (Pending)
Recognized Under UL 1577
Component Recognition Program
CSA (Pending)
Approved under CSA Component Acceptance Notice 5A
VDE (Pending)
Certified according to DIN V VDE V
0884-10 (VDE V 0884-10):2006-12
2500 V rms Single Protection
CSA 60950-1-07+A1+A2 and IEC 60950-1, second edition,
+A1+A2: basic insulation at 300 V rms (424 VPEAK)
Basic insulation, 565 VPEAK
CSA 61010-1-12 and IEC 61010-1 third edition: basic
insulation at 300 V rms mains, 300 V rms (424 VPEAK) secondary
Rev. A | Page 7 of 38
ADP1031
Data Sheet
ELECTROMAGNECTIC COMPATIBILITY
Table 3.
Regulatory Body
SGS-CCSR
Standard
CISPR11 Class B
Comment
Tested using the system board with the AD5758
INSULATION AND SAFETY RELATED SPECIFICATIONS
Table 4.
Parameter
Rated Dielectric Insulation Voltage
Minimum External Air Gap (Clearance)
Field Power Domain to Master Domain
Value
2500
Unit
V rms
Test Conditions/Comments
1-minute duration
2.15
mm min
Field Power Domain to Slave Domain
2.15
mm min
Master Domain to Slave Domain
2.15
mm min
Measured from field power pins and pads to master
pins and pads, shortest distance through air
Measured from field power pins and pads to slave
pins and pads, shortest distance through air
Measured from master pins and pads to slave pins
and pads, shortest distance through air
Minimum External Tracking (Creepage)
Field Power Domain to Master Domain
2.15
mm min
Field Power Domain to Slave Domain
2.15
mm min
Master Domain to Slave Domain
2.15
mm min
18
>400
II
µm min
V
Minimum Internal Gap (Internal Clearance)
Tracking Resistance (Comparative Tracking Index)
Material Group
Symbol
CTI
Rev. A | Page 8 of 38
Measured from field power pins and pads to master
pins and pads, shortest distance path along body
Measured from field power pins and pads to slave
pins and pads, shortest distance path along body
Measured from master pins and pads to slave pins
and pads, shortest distance path along body
Insulation distance through insulation
DIN IEC 112/VDE 0303, Part 1
Material group (DIN VDE 0110, 1/89, Table 1)
Data Sheet
ADP1031
DIN V VDE 0884-10 (VDE V 0884-10) INSULATION CHARACTERISTICS
Table 5.
Description
Installation Classification per DIN VDE 0110
For Rated Mains Voltage ≤ 150 V rms
For Rated Mains Voltage ≤ 300 V rms
For Rated Mains Voltage ≤ 400 V rms
Climatic Classification
Pollution Degree per DIN VDE 0110, Table 1
Maximum Working Insulation Voltage
Input to Output Test Voltage, Method B1
Test Conditions/Comments
VIORM × 1.875 = Vpd (m), 100% production test,
tini = tm = 1 sec, partial discharge < 5 pC
Input to Output Test Voltage, Method A
After Environmental Tests Subgroup 1
After Input and/or Safety Test Subgroup 2 and
Subgroup 3
Highest Allowable Overvoltage
Surge Isolation Voltage
Safety Limiting Values
Maximum Junction Temperature
Total Power Dissipation at 25°C
Insulation Resistance at TS
VIORM × 1.5 = Vpd (m), tini = 60 sec, tm = 10 sec,
partial discharge < 5 pC
VIORM × 1.2 = Vpd (m), tini = 60 sec, tm = 10 sec,
partial discharge < 5 pC
VPEAK = 12.8 kV, 1.2 µs rise time, 50 µs,
50% fall time
Maximum value allowed in the event of a
failure (see Figure 2)
VIO = 500 V
Symbol
Characteristic
Unit
VIORM
Vpd (m)
I to III
I to II
I to I
40/105/21
2
565
1060
VPEAK
VPEAK
Vpd (m)
847
VPEAK
678
VPEAK
VIOTM
VIOSM
3537
4000
VPEAK
VPEAK
TS
PS
RS
150
2.48
>109
°C
W
Ω
3.0
SAFE LIMITING POWER (W)
2.5
2.0
1.5
1.0
0
0
50
100
150
AMBIENT TEMPERATURE (°C)
200
16434-102
0.5
Figure 2. Thermal Derating Curve, Dependence of Safety Limiting Values with Ambient Temperature per DIN V VDE V 0884-10
Rev. A | Page 9 of 38
ADP1031
Data Sheet
ABSOLUTE MAXIMUM RATINGS
Table 6.
Parameter
VINP to PGNDP
SWP to VINP
SLEW to GNDP
EN to GNDP
VOUT1 to SGND2
FB1 to SGND2
VOUT1 to VOUT3
SW2 to SGND2
VOUT2 to SGND2
SW3 to SGND2
VOUT3 to SGND2
FB3 to VOUT3
SVDD1 to SGND1
SVDD2 to SGND2
SSS, SCK, SI, SO to SGND1
SGPO1, SGPO2, SGPI3 to SGND2
SYNC to SGND2
MVDD to MGND
MSS, MCK, MO, MI to MGND
MGPI1, MGPI2, MGPO3 to MGND
PWRGD to MGND
Common-Mode Transients
Operating Junction Temperature
Range1
Storage Temperature Range
Lead Temperature
Soldering Conditions
1
Rating
61 V
VINP + 70 V or 110 V,
whichever is lower
−0.3 V to VINP + 0.3 V
−0.3 V to +61 V
35 V
−0.3 V to VOUT1 + 0.3 V
61 V
−0.3 V to VOUT1 + 0.3 V
6V
VOUT3 − 0.3 V to
VOUT1 + 0.3 V
−26 V to +0.3 V
+3.3 V to −0.3 V
6.0 V
6.0 V
−0.3 V to SVDD1 + 0.3 V
−0.3 V to SVDD2 + 0.3 V
−0.3 V to +6 V
6.0 V
−0.3 V to MVDD + 0.3 V
−0.3 V to MVDD + 0.3 V
−0.3 V to MVDD + 0.3 V
±100 kV/µs
−40°C to +125°C
−65°C to +150°C
JEDEC industry standard
JEDEC J-STD-020
Stresses at or above those listed under Absolute Maximum
Ratings may cause permanent damage to the product. This is a
stress rating only; functional operation of the product at these
or any other conditions above those indicated in the operational
section of this specification is not implied. Operation beyond
the maximum operating conditions for extended periods may
affect product reliability.
THERMAL RESISTANCE
Thermal performance is directly linked to printed circuit board
(PCB) design and operating environment. Close attention to
PCB thermal design is required.
θJA is the natural convection, junction to ambient thermal
resistance measured in a one cubic foot sealed enclosure. θJC
is measured at the top of the package and is independent of the
PCB. The ΨJT value is appropriate for calculating junction to
case temperature in the application.
Table 7. Thermal Resistance
Package Type1, 2, 3, 4
CP-41-1
θJA
50.4
θJC
33.1
ΨJT
25
Unit
°C/W
9 mm × 7 mm LFCSP with omitted pins for isolation purposes.
Thermal impedance simulated values are based on a JEDEC 2S2P thermal
test board with 19 thermal vias. See JEDEC JESD-51.
3
Case temperature was measured at the center of the package.
4
Board temperature was measured near Pin 1.
1
2
ESD CAUTION
Power dissipated on chip must be derated to keep the junction temperature
below 125°C.
Table 8. Maximum Continuous Working Voltage1
Parameter
60 Hz AC Voltage
DC Voltage
1
2
3
Value
300 V rms
424 VPEAK
Constraint
20-year lifetime at 0.1% failure rate, zero average voltage
Limited by the creepage of the package, Pollution Degree 2, Material Group II2, 3
See the Insulation Lifetime section for more details.
Other pollution degree and material group requirements yield a different limit.
Some system level standards allow components to use the printed wiring board (PWB) creepage values. The supported dc voltage may be higher for those standards.
Rev. A | Page 10 of 38
Data Sheet
ADP1031
MI 1
MSS 2
MGND 3
33 GNDP
32 SLEW
31 EN
41
40
39
38
37
36
35
34
MO
MCK
MVDD
MGPO3
MGPI2
MGPI1
PWRGD
MGND
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
M
FP
EPGNDM
EPGNDP
30 VINP
29 SWP
28 PGNDP
ADP1031
TOP VIEW
(Not to Scale)
4
5
6
7
EPGND2
S
27
26
25
24
SGND2
DNC
DNC
DNC
NOTES
1. DNC = DO NOT CONNECT. DO NOT CONNECT TO THIS PIN.
2. EPGNDP IS INTERNALLY CONNECTED TO PGNDP,
EPGNDM IS INTERNALLY CONNECTED TO MGND,
AND EPGND2 IS INTERNALLY CONNECTED TO SGND.
16434-002
SI
SCK
SVDD1
FB3
VOUT3
SW3
SYNC
VOUT2
SGND2
SW2
VOUT1
FB1
SVDD2
SGPI3
SGPO2
SGPO1
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
SGND2
SGND1
SSS
SO
Figure 3. Pin Configuration
Table 9. Pin Function Descriptions
Pin No.
1
Mnemonic
MI
Isolation Domain
Master
Direction
Output
2
MSS
Master
Input
3
4
5
6
MGND
SGND2
SGND1
SSS
Master
Slave
Slave
Slave
Return
Return
Return
Output
7
SO
Slave
Input
8
SI
Slave
Output
9
SCK
Slave
Output
10
SVDD1
Slave
Power
11
12
13
14
FB3
VOUT3
SW3
SYNC
Slave
Slave
Slave
Slave
Not applicable
Power
Not applicable
Input
15
16
VOUT2
SGND2
Slave
Slave
Power
Return
17
18
SW2
VOUT1
Slave
Slave
Not applicable
Power
19
20
FB1
SVDD2
Slave
Slave
Power
Description
SPI Data Output from the Slave MI and SO Line. This pin is paired with SO.
On the slave domain, SO drives this pin.
SPI Slave Select Input from the Master Controller. This pin is paired with SSS.
On the slave domain, this pin drives SSS. This signal uses an active low logic.
Master Domain Signal Ground Connection.
Slave Domain Ground Connection. This pin can be left unconnected.
Slave Domain SPI Isolator Ground.
SPI Slave Select Output. This pin is paired with MSS. On the master
domain, MSS drives this pin.
SPI Data Input Going to the Master MI and SO Line. This pin is paired with
MI. On the master domain, this pin drives MI.
SPI Data Output from the Master MO and SI Line. This pin is paired with
MO. On the master domain, MO drives this pin.
SPI Clock Output from the Master. This pin is paired with MCK. On the
master domain, MCK drives this pin.
SPI Isolator Power Supply. Connect a 100 nF decoupling capacitor from
SVDD1 to SGND1.
Inverting Regulator Feedback Pin.
Inverting Regulator Output and Overvoltage Sense.
Inverting Regulator Switch Node.
SYNC Pin. To synchronize the switching frequency, connect the SYNC pin
to an external clock at twice the required switching frequency. Do not
leave this pin floating. Connect a 100 kΩ pull-down resistor to SGND2.
Buck Regulator Output Feedback.
Slave Power Ground. Ground return for inverting and buck regulator
output capacitors.
Buck Regulator Switch Node.
Flyback Regulator Output and Overvoltage Sense. This pin is the input to
the buck and inverting regulators.
Feedback Node for the Flyback Regulator.
GPIO Isolators Power Supply. Connect a 100 nF decoupling capacitor from
SVDD2 to SGND2.
Rev. A | Page 11 of 38
ADP1031
Data Sheet
Pin No.
21
22
23
24
25
26
27
28
29
30
Mnemonic
SGPI3
SGPO2
SGPO1
DNC
DNC
DNC
SGND2
PGNDP
SWP
VINP
Isolation Domain
Slave
Slave
Slave
Slave
Slave
Slave
Slave
Field power
Field power
Field power
Direction
Input
Output
Output
Not applicable
Not applicable
Not applicable
Return
Return
Not applicable
Power
31
EN
Field power
Input
32
SLEW
Field power
Input
33
34
35
GNDP
MGND
PWRGD
Field power
Master
Master
Return
Return
Return
36
37
38
39
MGPI1
MGPI2
MGPO3
MVDD
Master
Master
Master
Master
Input
Input
Output
Power
40
MCK
Master
Input
41
MO
Master
Input
EPGNDP
EPGNDM
EPGND2
Field power
Master
Slave
Return
Return
Return
Description
General-Purpose Input 3. This pin is paired with MGPO3.
General-Purpose Output 2. This pin is paired with MGPI2.
General-Purpose Output 1. This pin is paired with MGPI1.
Do Not Connect. Do not connect to this pin.
Do Not Connect. Do not connect to this pin.
Do Not Connect. Do not connect to this pin.
Slave Domain Ground Connection. This pin can be left unconnected.
Ground Return for Flyback Regulator Power Supply.
Flyback Regulator Switching Node. Primary side transformer connection.
Flyback Regulator Supply Voltage. Connect a minimum of 3.3 µF capacitor
from VINP to PGNDP.
Precision Enable. Compare the EN pin to an internal precision reference to
enable the flyback regulator output.
Flyback Regulator Slew Rate Control. The SLEW pin sets the slew rate for
the SWP driver. For the fastest slew rate (best efficiency), leave the SLEW
pin open. For the normal slew rate, connect the SLEW pin to VINP. For the
slowest slew rate (best EMI performance), connect the SLEW pin to GNDP.
Field Power Signal Ground Connection.
Master Domain Power Ground Connection.
Power Good. This pin indicates when the secondary side supplies are
within their programmed range.
General-Purpose Input 1. This pin is paired with SGPO1.
General-Purpose Input 2. This pin is paired with SGPO2.
General-Purpose Output 3. This pin is paired with SGPI3.
Master Domain Power. Connect a 100 nF decoupling capacitor from
MVDD to MGND.
SPI Clock Input from the Master Controller. Paired with SCK. On the slave
domain, this pin drives SCK.
SPI Data Input Going to Slave MO and SI Line. Paired with SI. On the slave
domain, this pin drives SI.
PGNDP Exposed Pad. This pad is internally connected to PGNDP.
MGND Exposed Pad. This pad is internally connected to MGND.
SGND Exposed Pad. This pad is internally connected to SGND.
Rev. A | Page 12 of 38
Data Sheet
ADP1031
TYPICAL PERFORMANCE CHARACTERISTICS
100
450
POWER DISSIPATION (mW)
90
70
60
VINP = 5V
VINP = 12V
VINP = 18V
VINP = 24V
VINP = 32V
VINP = 60V
10
20
30
40
50
60
70
80
90
100
Figure 4. Overall Efficiency at Various Input Voltages, TA = +25°C,
VOUT1 = +24 V, VOUT2 = +5.15 V, IOUT2 = +7 mA, VOUT3 = −15 V, IOUT3 = −0.3 mA,
Using a Würth Elektronik 750316743 Transformer
0
POWER DISSIPATION (mW)
60
50
VINP = 5V
VINP = 12V
VINP = 18V
VINP = 24V
VINP = 32V
VINP = 60V
0
10
20
30
40
50
60
70
80
90
100
IOUT1 (mA)
Figure 5. Overall Efficiency at Various Input Voltages, TA = +25°C, VOUT1 =
+21 V, VOUT2 = +5.15 V, IOUT2 = +7 mA, VOUT3 = −15 V, IOUT3 = −0.3 mA, Using a
Würth Elektronik 750316743 Transformer
350
70
60
50
40
50
VOUT1 = 21V (–40°C)
VOUT1 = 21V (+25°C)
VOUT1 = 21V (+125°C)
60
IOUT1 (mA)
70
80
90
100
90
100
150
100
0
10
20
30
40
50
60
70
80
90
100
VOUT1 = 24V (–40°C)
VOUT1 = 24V (+25°C)
VOUT1 = 24V (+125°C)
VOUT1 = 21V (–40°C)
VOUT1 = 21V (+25°C)
VOUT1 = 21V (+125°C)
350
300
250
200
150
100
50
0
16434-005
30
80
Figure 8. Power Dissipation at Various Input Voltages, TA = +25°C,
VOUT1 = +21 V, VOUT2 = +5.15 V, IOUT2 = +7 mA, VOUT3 = −15 V, IOUT3 = −0.3 mA,
Using a Würth Elektronik 750316743 Transformer
POWER DISSIPATION (mW)
80
20
70
IOUT1 (mA)
90
10
60
200
400
0
50
250
450
VOUT1 = 24V (–40°C)
VOUT1 = 24V (+25°C)
VOUT1 = 24V (+125°C)
40
300
0
100
40
30
50
16434-004
40
20
VINP = 5V
VINP = 12V
VINP = 18V
VINP = 24V
VINP = 32V
VINP = 60V
400
70
10
Figure 7. Power Dissipation at Various Input Voltages, TA = +25°C,
VOUT1 = +24 V, VOUT2 = +5.15 V, IOUT2 = +7 mA, VOUT3 = −15 V, IOUT3 = −0.3 mA, T
Using a Würth Elektronik 750316743 Transformer
450
80
EFFICIENCY (%)
100
IOUT1 (mA)
90
EFFICIENCY (%)
150
0
100
30
200
50
IOUT1 (mA)
30
250
16434-006
0
300
16434-007
40
350
Figure 6. Overall Efficiency across Temperature, VINP = +24 V, VOUT1 = +21 V and
VOUT1 = +24 V, VOUT2 = +5.15 V, IOUT2 = +7 mA, VOUT3 = −15 V, IOUT3 = −0.3 mA,
Using a Würth Elektronik 750316743 Transformer
0
10
20
30
40
50
60
IOUT1 (mA)
70
80
90
100
16434-008
50
16434-003
EFFICIENCY (%)
80
30
VINP = 5V
VINP = 12V
VINP = 18V
VINP = 24V
VINP = 32V
VINP = 60V
400
Figure 9. Power Dissipation across Temperature, VINP = +24 V, VOUT1 = +21 V and
VOUT1 = +24 V, VOUT2 = +5.15 V, IOUT2 = +7 mA, VOUT3 = −15 V, IOUT3 = −0.3 mA,
Using a Würth Elektronik 750316743 Transformer
Rev. A | Page 13 of 38
ADP1031
Data Sheet
450
100
POWER DISSIPATION (mW)
90
70
60
BS64042CS
YA9293-AL
LPD5030-154MRB
750316743
750316566
WA8478-BE
0
10
20
30
40
50
60
70
80
90
100
Figure 10. Overall Efficiency using Various Transformers, TA = +25°C,
VINP = +24 V, VOUT1 = +24 V, VOUT2 = +5.15 V, IOUT2 = +7 mA, VOUT3 = −15 V,
IOUT3 = −0.3 mA
200
150
100
0
0
10
POWER DISSIPATION (mW)
90
60
50
BS64042CS
YA9293-AL
LPD5030-154MRB
750316743
750316566
WA8478-BE
0
10
20
30
40
50
60
70
80
90
100
IOUT1 (mA)
Figure 11. Overall Efficiency using Various Transformers, TA = +125°C,
VINP = +24 V, VOUT1 = +24 V, VOUT2 = +5.15 V, IOUT2 = +7 mA, VOUT3 = −15 V,
IOUT3 = −0.3 mA
350
4
0
80
90
100
200
150
100
0
10
20
30
40
60
50
70
80
90
IOUT1 (mA)
100
Figure 14. Power Dissipation using Various Transformers, TA = +125°C,
VINP = +24 V, VOUT1 = +24 V, VOUT2 = +5.15 V, IOUT2 = +7 mA, VOUT3 = −15 V,
IOUT3 = −0.3 mA
VEN
VINP
VOUT1
2
VOUT2
3
VOUT3
4
0
PWRGD
CH1 10.0V
CH3 5.0V
B
B
W
W
CH2 10.0V
CH4 10.0V
B
B
W
W
M4.00ms A CH1
T
14.000ms
3.60mA
VOUT1
VOUT2
VOUT3
PWRGD
CH1 5.00V
CH3 2.00V
Figure 12. Power-Up Sequence at VINP Rising, TA = +25°C, VINP = +24 V,
VOUT1 = +24 V, IOUT1 = +20 mA, VOUT2 = +5.15 V, IOUT2 = +7 mA, VOUT3 = −15 V,
IOUT3 = −0.3 mA
B
B
W
W
CH2 10.0V
CH4 10.0V
B
B
W
W
M4.00ms A CH1
T
12.0000ms
3.20V
16434-014
3
70
250
0
16434-011
2
60
300
1
1
50
50
16434-010
40
40
BS64042CS
YA9293-AL
LPD5030-154MRB
750316743
750316566
WA8478-BE
400
70
30
Figure 13. Power Dissipation using Various Transformers, TA = +25°C,
VINP = +24 V, VOUT1 = +24 V, VOUT2 = +5.15 V, IOUT2 = +7 mA, VOUT3 = −15 V,
IOUT3 = −0.3 mA
450
80
20
IOUT1 (mA)
100
EFFICIENCY (%)
250
50
IOUT1 (mA)
30
300
16434-012
40
350
16434-013
50
16434-009
EFFICIENCY (%)
80
30
BS64042CS
YA9293-AL
LPD5030-154MRB
750316743
750316566
WA8478-BE
400
Figure 15. Power-Up Sequence at EN Rising, TA = +25°C, VINP = +24 V,
VOUT1 = +24 V, IOUT1 = +20 mA, VOUT2 = +5.15 V, IOUT2 = +7 mA, VOUT3 = −15 V,
IOUT3 = −0.3 mA
Rev. A | Page 14 of 38
Data Sheet
ADP1031
VEN
1
VOUT1
VOUT3
PWRGD
CH1 5.00V
CH3 2.00V
B
B
W
W
CH2 10.0V
CH4 10.0V
M4.00ms A CH1
T
12.0000ms
B
W
B
W
3.20V
16434-015
0
CH1 5.00V BW CH2 10.0V
CH3 50.0mA BW
Figure 16. Shutdown Sequence, TA = +25°C, VINP = +24 V, VOUT1 = +24 V,
IOUT1 = +20 mA, VOUT2 = +5.15 V, IOUT2 = +7 mA, VOUT3 = −15 V, IOUT3 = −0.3 mA
1.5
–40°C
+25°C
+125°C
VARIATION FROM NOMINAL (%)
1.0
0.5
0
–0.5
–1.0
0
10
20
30
40
50
60
70
80
90
100
IOUT1 (mA)
0.2
–0.5
–1.0
0
0.5
10
20
30
40
50
60
70
80
90
100
VINP = 5V
VINP = 12V
VINP = 18V
VINP = 24V
VINP = 32V
VINP = 60V
0.4
0.1
0
–0.1
–0.2
–0.3
–0.4
0.3
0.2
0.1
0
–0.1
–0.2
–0.3
–0.4
0
10
20
30
40
50
60
IOUT1 (mA)
70
80
90
100
–0.5
16434-017
–0.5
0
IOUT1 (mA)
VARIATION FROM NOMINAL (%)
0.3
0.5
Figure 20. Flyback Regulator Load Regulation Across Temperature,
VINP = 24 V, VOUT1 = 21 V, Nominal = VOUT1 at 20 mA Load
VINP = 5V
VINP = 12V
VINP = 18V
VINP = 24V
VINP = 32V
VINP = 60V
0.4
3.20V
–40°C
+25°C
+125°C
1.0
–1.5
Figure 17. Flyback Regulator Load Regulation Across Temperature,
VINP = 24 V, VOUT1 = 24 V, Nominal = VOUT1 at 20 mA Load
0.5
W
Figure 18. Flyback Regulator Load Regulation at Various Input Voltages,
TA = 25°C, VOUT1 = 24 V, Nominal = VOUT1 at 20 mA Load
0
10
20
30
40
50
60
IOUT1 (mA)
70
80
90
100
16434-020
–1.5
M4.00ms A CH1
T
8.0400ms
B
Figure 19. Inrush Current, TA = +25°C, VINP = +24 V, VOUT1 = +24 V,
IOUT1 = +20 mA, VOUT2 = +5.15 V, IOUT2 = +7 mA, VOUT3 = −15 V, IOUT3 = −0.3 mA
16434-016
VARIATION FROM NOMINAL (%)
1.5
ISWP
3
16434-018
4
16434-019
2
VARIATION FROM NOMINAL (%)
VOUT1
2
VOUT2
3
VEN
1
Figure 21. Flyback Regulator Load Regulation at Various Input Voltages,
TA = 25°C, VOUT1 = 21 V, Nominal = VOUT1 at 20 mA Load
Rev. A | Page 15 of 38
ADP1031
1.5
–40°C
+25°C
+125°C
0.5
0
–0.5
–1.0
0
20
10
40
30
60
50
VINP (V)
VOUT1
VOUT1
VOUT1
VOUT1
VOUT1
160
0
–0.5
–1.0
100
= 6V
= 15V
= 21V
= 24V
= 28V
30
40
50
60
–40°C
+25°C
+105°C
90
80
70
100
80
60
60
50
40
30
40
20
20
10
10
15
20
25
30
35
40
45
50
0
16434-022
5
VINP (V)
Figure 23. Flyback Regulator Maximum Output Current at
Various Output Voltage, TA = 25°C, Using a Würth Elektronik 750316743
Transformer, Based on Target of 70% ILIM (FLYBACK)
1
20
Figure 25. Flyback Regulator Line Regulation Across Temperature,
VOUT1 = 21 V, IOUT1 = 20 mA, Nominal = VOUT1 with VINP = 24 V
120
0
10
0
VINP (V)
IOUT1 (MAX) (mA)
IOUT1 (MAX) (mA)
140
0.5
–1.5
Figure 22. Flyback Regulator Line Regulation Across Temperature,
VOUT1 = 24 V, IOUT1 = 20 mA, Nominal = VOUT1 with VINP = 24 V
180
1.0
5
10
15
20
25
30
VINP (V)
35
40
45
50
16434-025
–1.5
–40°C
+25°C
+125°C
16434-024
VARIATION FROM NOMINAL (%)
1.0
16434-021
VARIATION FROM NOMINAL (%)
1.5
Data Sheet
Figure 26. Flyback Regulator Maximum Output Current across Temperature,
VOUT1 = 24 V, Using a Würth Elektronik 750316743 Transformer, Based on
Target of 70% ILIM (FLYBACK)
VOUT1
1
VOUT1
ISWP
2
2
ISWP
VSWP
B
W
CH2 20.0mA BW 4.00µs
A CH3
T 50.10%
48.0V
16434-124
CH1 20.0mV
CH3 50.0V BW
VSWP
CH1 20.0mV
CH3 20.0V BW
Figure 24. Flyback Regulator Pulse Skipping Operation Showing Inductor
Current (ISWP), Switch Node Voltage, and Output Ripple, TA = 25°C, VINP = 48 V,
VOUT1 = 24 V, IOUT1 = 1 mA
B
W
CH2 50.0mA BW 1.00µs
A CH3
T 50.10%
48.0V
16434-127
3
3
Figure 27. Flyback Regulator Discontinuous Conduction Mode Operation
Showing ISWP, Switch Node Voltage, and Output Ripple, TA = 25°C, VINP = 24 V,
VOUT1 = 24 V, IOUT1 = 10 mA
Rev. A | Page 16 of 38
Data Sheet
1
ADP1031
VOUT1
1
2
VEN
VOUT1
ISWP
2
3
ISWP
VSWP
VSWP
CH1 50.0mV
CH3 20.0V BW
B
W
CH2 100mA
B
W
1.00µs
A CH3
T 50.10%
48.0V
CH1 5.00V
CH3 200mA
Figure 28. Flyback Regulator Continuous Conduction Mode Operation
Showing ISWP, Switch Node Voltage, and Output Ripple, TA = 25°C, VINP = 24 V,
VOUT1 = 24 V, IOUT1 = 50 mA
2
W
W
CH2 10.0V
CH4 20.0V
M1.00ms
A CH1
T
2.01000ms
B
W
B
W
3.20V
Figure 31. Flyback Regulator Short-Circuit Current Limit During Startup,
VINP = 24 V, VOUT1 = SGND2, TA = 25°C
IOUT1
VINP
1
B
B
16434-030
4
16434-128
3
1
VOUT1
2
VOUT1
VSWP
VSWP
3
CH2 2.00V
B
W
B
M4.00ms A CH1
T
11.929ms
B
W
W
15.4V
CH1 20.0mA BW CH2 2.00V
CH3 20.0V BW
Figure 29. Flyback Regulator Line Transient Response, VINP = 6 V to 20 V Step,
VOUT1 = 24 V, IOUT1 = 20 mA, TA = 25°C
B
W
M4.00ms A CH1
T
11.9000ms
16.8mA
16434-031
CH1 10.0V
CH3 20.0V
16434-028
3
Figure 32. Flyback Regulator Load Transient Response, VINP = 24 V,
VOUT1 = 24 V, IOUT1 = 1 mA to 20 mA Step, TA = 25°C
VINP
1
VOUT1
2
2
VSWP
IOUT1
VOUT1
VSWP
1
3
B
W
B
CH2 200mV
W
B
W
M4.00ms A CH1
T
11.9290ms
6.64V
CH1 50.0mA
CH3 50.0V
Figure 30. Flyback Regulator Line Transient Response, VINP = 6 V to 7 V Step,
VOUT1 = 24 V, IOUT1 = 20 mA, TA = 25°C
Rev. A | Page 17 of 38
B
B
W
W
CH2 2.00V
B
W
M4.00ms A CH1
T
11.9000ms
35.0mA
16434-032
CH1 1.00V
CH3 20.0V
16434-029
3
Figure 33. Flyback Regulator Load Transient Response, VINP = 32 V,
VOUT1 = 24 V, IOUT1 = 1 mA to 50 mA Step, TA = 25°C
ADP1031
1.5
DEVIATION FROM NOMINAL (%)
1.0
0.5
0
–0.5
–1.0
–1.5
0
10
20
30
50
40
IOUT2 (mA)
1.0
0.5
0
–0.5
–1.0
–1.5
5
10
15
20
25
30
VOUT1 (V)
Figure 34. Buck Regulator Load Regulation Across Temperature, VOUT1 = 24 V,
VOUT2 = 5.15 V, Nominal = VOUT2 at 10 mA IOUT2
1
–40°C
+25°C
+125°C
16434-137
–40°C
+25°C
+125°C
16434-134
DEVIATION FROM NOMINAL (%)
1.5
Data Sheet
Figure 37. Buck Regulator Line Regulation Across Temperature,
VOUT2 = 5.15 V, IOUT2 = 7 mA, Nominal = VOUT2 at 24 VOUT1
VOUT2
VOUT2
1
ISW2
2
VSW2
3
CH1 10.0mV Ω BW CH2 20.0mA BW
CH3 10.0V BW
M10.0µs A CH3
T
700.000ns
20.4V
16434-034
3
CH1 50.0mV Ω BW CH2 100mA
CH3 10.0V BW
Figure 35. Buck Regulator Pulse Skipping Operation Showing Inductor
Current 2 (IL2), Switch Node Voltage, and Output Ripple, TA = 25°C, VOUT1 =
24 V, VOUT2 = 5.15 V, IOUT2 = 0.3 mA
1
2
VSW2
B
W
M2.00µs A CH3
T
–40.000ns
3.80V
16434-037
2
ISW2
Figure 38. Buck Regulator Discontinuous Conduction Mode Operation
Showing IL2, Switch Node Voltage, and Output Ripple, TA = 25°C, VOUT1 = 21 V,
VOUT2 = 5.15 V, IOUT2 = 50 mA
VOUT2
1
ISW2
2
VOUT2
ISW2
VSW2
CH1 20.0mV Ω BW CH2 50.0mA BW
CH3 10.0V BW
M2.00µs A CH3
T
40.0000ns
16.0V
16434-035
3
VSW2
CH1 1.00V Ω BW
CH3 10.0V BW
Figure 36. Buck Regulator Discontinuous Conduction Mode Operation
Showing IL2, Switch Node Voltage, and Output Ripple, TA = 25°C, VOUT1 = 21 V,
VOUT2 = 5.15 V, IOUT2 = 7 mA
CH2 200mA
B
W
M200µs A CH2
T
595.000µs
164mA
16434-038
3
Figure 39. Buck Regulator Short-Circuit Current Limit During Startup,
VOUT1 = 24 V, VOUT2 = SGND2, TA = 25°C
Rev. A | Page 18 of 38
Data Sheet
ADP1031
IOUT2
IOUT2
1
1
VOUT2
2
VOUT2
2
VSW2
VSW2
W
M2.00ms A CH1
T
5.92000ms
4.30mA
CH1 5.00mA BW CH2 500mV
CH3 10.0V BW
DEVIATION FROM NOMINAL (%)
0.5
0
–0.5
–1.0
–1.5
0
5
10
15
20
25
30
IOUT3 (mA)
4.30mA
0.5
0
–0.5
–1.0
5
10
15
20
25
30
VOUT1 (V)
Figure 44. Inverting Regulator Line Regulation Across Temperature,
VOUT3 = −15 V, IOUT3 = −7 mA, Nominal = VOUT3 at +24 VOUT1
Figure 41. Inverting Regulator Load Regulation Across Temperature,
VOUT1 = +24 V, VOUT3 = −15 V, Nominal = VOUT3 at −7 mA IOUT3
1
M2.00ms A CH1
T
5.92000ms
–40°C
+25°C
+125°C
1.0
–1.5
16434-142
DEVIATION FROM NOMINAL (%)
1.5
–40°C
+25°C
+125°C
1.0
W
Figure 43. Buck Regulator Load Transient Response, VOUT1 = 21 V,
VOUT2 = 5.15 V, IOUT2 = 0.3 mA to 7 mA Step, TA = 25°C
Figure 40. Buck Regulator Load Transient Response, VOUT1 = 24 V,
VOUT2 = 5.15 V, IOUT2 = 0.3 mA to 7 mA Step, TA = 25°C
1.5
B
16434-145
B
16434-042
CH1 5.00mA BW CH2 500mV
CH3 10.0V BW
16434-043
3
3
VOUT3
VOUT3
1
2
ISW3
ISW3
2
VSW3
B
W
M10.0µs A CH2
T
595.000µs
36.0mA
CH1 20mV BW CH2 100mA
CH3 10.0V BW
Figure 42. Inverting Regulator Pulse Skipping Operation Showing Inductor
Current (IL3), Switch Node Voltage, and Output Ripple, TA = +25°C,
VOUT1 = +24 V, VOUT3 = −6 V, IOUT3 = −0.3 mA
B
W
M2.00µs A CH2
T
595.000µs
36.0mA
16434-046
CH1 10mV BW CH2 20.0mA
CH3 10.0V BW
16434-045
3
3
VSW3
Figure 45. Inverting Regulator Discontinuous Conduction Operation
Showing IL3, Switch Node Voltage, and Output Ripple, TA = +25°C, VOUT1 =
+24 V, VOUT3 = −15 V, IOUT3 = −7 mA
Rev. A | Page 19 of 38
ADP1031
Data Sheet
VOUT3
1
ISW3
2
VOUT3
1
ISW3
2
VSW3
VSW3
CH1 50mV BW CH2 100mA
CH3 10.0V BW
B
W
M2.00µs
A CH2
T
595.000µs
36.0mA
16434-048
3
CH1 1.00V BW CH2 200mA
CH3 10.0V BW
Figure 46. Inverting Regulator Discontinuous Conduction Operation
Showing IL3, Switch Node Voltage, and Output Ripple, TA = +25°C,
VOUT1 = +24 V, VOUT3 = −15 V, IOUT3 = −20 mA
M200µs
A CH2
T
698.000µs
60.0mA
IOUT3
1
VOUT3
2
W
Figure 49. Inverting Regulator Short-Circuit Current Limit During Startup,
VOUT1 = +24 V, VOUT3 = SGND2, TA = +25°C
IOUT3
1
B
16434-049
3
VOUT3
2
VSW3
VSW3
B
B
W
CH2 200mV
B
W
W
M2.00ms A CH1
T
6.0100ms
4.40mA
16434-151
CH1 5.00mA
CH3 20.0V
CH1 5.00mA
CH3 20.0V
Figure 47. Inverting Regulator Load Transient Response, VOUT1 = +24 V,
VOUT3 = −15 V, IOUT2 = −0.3 mA to −7 mA Step, TA = +25°C
10
VMVDD = 2.5V, VSVDD1 = 1.8V
VMVDD = 3.3V, VSVDD1 = 3.3V
VMVDD = 5.0V, VSVDD1 = 5.0V
8
8
6
6
4
2
CH2 500mV
B
W
M2.00ms A CH1
T
6.0100ms
4.40mA
VMVDD = 2.5V,
VMVDD = 3.3V,
VMVDD = 5.0V,
VSVDD1 = 1.8V
VSVDD1 = 3.3V
VSVDD1 = 5.0V
4
0
10
20
30
40
50
60
DATA RATE (Mbps)
70
80
90
100
0
0
10
20
30
40
50
60
DATA RATE (Mbps)
Figure 48. MVDD Supply Current (IMVDD) per SPI Input vs. Data Rate at Various
Supply Voltages, MSS Is Low, Clock Signal Applied on Single SPI Channel,
Other Input Channels Tied Low
70
80
90
100
16434-256
2
16434-253
0
W
W
Figure 50. Inverting Regulator Load Transient Response, VOUT1 = +6 V,
VOUT3 = −15 V, IOUT2 = −0.3 mA to −7 mA Step, TA = +25°C
ISVDD1 (mA)
IMVDD (mA)
10
B
B
16434-154
3
3
Figure 51. SVDD1 Supply Current (ISVDD1) per SPI Input vs. Data Rate at
Various Supply Voltages, SSS Is Low, Clock Signal Applied on Single SPI
Channel, Other Input Channels Tied Low
Rev. A | Page 20 of 38
Data Sheet
14
12
10
10
ISVDD1 (mA)
12
8
6
8
6
4
4
2
2
0
0
10
20
30
40
50
VMVDD = 2.5V, VSVDD1 = 1.8V
VMVDD = 3.3V, VSVDD1 = 3.3V
VMVDD = 5.0V, VSVDD1 = 5.0V
14
60
70
80
90
100
DATA RATE (Mbps)
0
16434-254
IMVDD (mA)
16
VMVDD = 2.5V, VSVDD1 = 1.8V
VMVDD = 3.3V, VSVDD1 = 3.3V
VMVDD = 5.0V, VSVDD1 = 5.0V
0
10
20
30
40
50
60
70
80
90
100
DATA RATE (Mbps)
Figure 52. IMVDD per SPI Output vs. Data Rate at Various Supply Voltages, MSS
Is Low, Clock Signal Applied on Single SPI Channel, Other Input Channels
Tied Low
16434-257
16
ADP1031
Figure 55. ISVDD1 vs. Data Rate at Various Supply Voltages, SSS Is Low, Clock
Signal Applied on Single SPI Channel, Other Input Channels Tied Low
10
VMVDD = 2.5V, VSVDD1 = 1.8V
VMVDD = 3.3V, VSVDD1 = 3.3V
VMVDD = 5.0V, VSVDD1 = 5.0V
VMVDD = 2.5V, VSVDD1 = 1.8V
VMVDD = 3.3V, VSVDD1 = 3.3V
VMVDD = 5.0V, VSVDD1 = 5.0V
IMVDD (mA)
ISVDD1 (mA)
8
6
4
–25
0
25
50
75
100
125
TEMPERATURE (°C)
0
–50
16434-258
–50
Figure 53. IMVDD vs. Temperature at Various Supply Voltages, MSS Is Low,
Data Rate = 10 Mbps on All SPI Channels
–25
0
25
50
75
100
125
TEMPERATURE (°C)
16434-261
2
Figure 56. ISVDD1 vs. Temperature at Various Supply Voltages, SSS Is Low, Data
Rate = 10 Mbps on All SPI Channels
VMVDD = 2.5V, VSVDD1 = 1.8V
VMVDD = 3.3V, VSVDD1 = 3.3V
VMVDD = 5.0V, VSVDD1 = 5.0V
–25
0
25
50
TEMPERATURE (°C)
75
100
125
Figure 54. SPI Channels Propagation Delay (tPLH) vs. Temperature at Various
Supply Voltages
–50
–25
0
25
50
TEMPERATURE (°C)
75
100
125
16434-162
–50
16434-159
PROPAGATION DELAY, tPLH (ns)
PROPAGATION DELAY, tPHL (ns)
VMVDD = 2.5V, VSVDD1 = 1.8V
VMVDD = 3.3V, VSVDD1 = 3.3V
VMVDD = 5.0V, VSVDD1 = 5.0V
Figure 57. SPI Channels Propagation Delay (tPLH) vs. Temperature at Various
Supply Voltages
Rev. A | Page 21 of 38
ADP1031
4.0
Data Sheet
VMVDD = 2.5V, VSVDD2 = 1.8V
VMVDD = 3.3V, VSVDD2 = 3.3V
VMVDD = 5.0V, VSVDD2 = 5.0V
VMVDD = 2.5V, VSVDD2 = 1.8V
VMVDD = 3.3V, VSVDD2 = 3.3V
VMVDD = 5.0V, VSVDD2 = 5.0V
3.5
2.5
ISVDD2 (µA)
IMVDD (mA)
3.0
2.0
1.5
1.0
0
40
20
60
80
100
DATA RATE (kbps)
Figure 58. IMVDD vs. Data Rate on All GPIO Channels at Various Supply
Voltages, MSS Is High
4.0
3.5
0
20
40
60
DATA RATE (kbps)
80
100
16434-163
0
16434-260
0.5
Figure 61. SVDD2 Supply Current (ISVDD2) vs. Data Rate on All GPIO Channels
at Various Supply Voltages, MSS Is High
VMVDD = 2.5V, VSVDD2 = 1.8V
VMVDD = 3.3V, VSVDD2 = 3.3V
VMVDD = 5.0V, VSVDD2 = 5.0V
VMVDD = 2.5V, VSVDD2 = 1.8V
VMVDD = 3.3V, VSVDD2 = 3.3V
VMVDD = 5.0V, VSVDD2 = 5.0V
2.5
ISVDD2 (µA)
IMVDD (mA)
3.0
2.0
1.5
1.0
0
25
50
75
100
125
TEMPERATURE (°C)
Figure 59. IMVDD vs. Temperature at Various Supply Voltages, MSS Is Low,
Data Rate = 40 kbps on All GPIO Channels
10
10
9
7
6
5
4
3
2
25
50
75
100
125
VMVDD = 2.5V, VSVDD2 = 1.8V
VMVDD = 3.3V, VSVDD2 = 3.3V
VMVDD = 5.0V, VSVDD2 = 5.0V
8
7
6
5
4
3
2
1
1
–25
0
25
50
TEMPERATURE (°C)
75
100
125
0
–50
16434-265
0
–50
0
Figure 62. ISVDD2 vs. Temperature at Various Supply Voltages, SSS Is Low, Data
Rate = 40 kbps on All GPIO Channels
VSVDD2 = 1.8V
VSVDD2 = 3.3V
VSVDD2 = 5.0V
8
–25
TEMPERATURE (°C)
PROPAGATION DELAY, tPHL (µs)
PROPAGATION DELAY, tPLH (µs)
9
V MVDD = 2.5V,
V MVDD = 3.3V,
V MVDD = 5.0V,
–50
16434-166
–25
Figure 60. GPIO Channels Propagation Delay (tPLH) vs. Temperature at
Various Supply Voltages
–25
0
25
50
TEMPERATURE (°C)
75
100
125
16434-267
0
–50
16434-264
0.5
Figure 63. GPIO Channels Propagation Delay (tPHL) vs. Temperature at
Various Supply Voltages
Rev. A | Page 22 of 38
Data Sheet
ADP1031
THEORY OF OPERATION
isolators in a 41-lead LFCSP package for channel to channel
isolated applications where power dissipation and board space
are at a premium.
The ADP1031 is a high performance, isolated micro PMU that
combines an isolated flyback regulator, an inverting regulator,
and a buck regulator, providing three isolated power rails.
Additionally, the ADP1031 includes seven low power digital
D1
VOUT1
RFT1
Tx1
1:1
RFB1
SWP
FB1
FLYBACK
CONTROLLER
VINP
FEEDBACK AND
OVER VOLTAGE
CONTROL
VOUT1
PG1
SYNC
÷2 PLL
VINP
R5
R6
HIGH
EFFICIENCY
BUCK
GNDP
PGNDP
L1
SW3
INVERTING
SWITCHING
REGULATOR
C1
CBUCK
SW2
PG2
SLEW
MVDD
VOUT2
VOUT2
÷2
EN
MVDD
RFT3
FB3
VOUT3
PG3
MGND
L2
PWRGD
CINV
RFB3
VOUT3
SVDD2
SVDD2
SGND2
C3
PWRGD
MGPO3
MGPI2
CONTROL
BLOCK
CONTROL
BLOCK
SGPI3
SGPO2
SGPO1
MGPI1
SVDD1
SVDD1
MSS
ENCODE
DECODE
SSS
MCK
ENCODE
DECODE
SCK
MO
ENCODE
DECODE
SI
MI
DECODE
ENCODE
C4
SO
SGND1
MGND
NOTES
1. CFLYBK IS THE FLYBACK REGULATOR OUTPUT CAPACITOR VALUE.
2. CBUCK IS THE BUCK REGULATOR OUTPUT CAPACITOR VALUE.
3. CINV IS THE INVERTING REGULATOR OUTPUT CAPACITOR VALUE.
Figure 64. Simplified Block Diagram
Rev. A | Page 23 of 38
16434-268
CIN
CFLYBK
ADP1031
Data Sheet
FLYBACK REGULATOR
Flyback Undervoltage Lockout (UVLO)
Flyback Regulator Operation
The UVLO circuitry monitors the VINP pin voltage level. If the
input voltage drops below the VUVLO_FLYBACK (FALL) threshold, the
flyback regulator turns off. After the VINP pin voltage rises
above the VUVLO_FLYBACK (RISE) threshold, the soft start period
initiates, and the flyback regulator enables.
Traditionally, in an isolated flyback regulator, a discrete optocoupler is used in the feedback path to transmit the signal from
the secondary side to the primary side. However, the current
transfer ratio (CTR) of the optocouplers degrades over time and
over temperature. Therefore, the optocoupler must be replaced
every 5 years to 10 years. The ADP1031 eliminates the use of an
optocoupler and the associated problems by integrating Analog
Devices iCoupler technology for feedback, thus reducing system
cost, PCB area, and complexity while improving system
reliability without the issue of CTR degradation.
A flyback transformer with a single primary and secondary
winding is used. This configuration is possible because iCoupler
technology is used to send an isolated control signal to the
primary side controller so that a primary sense winding is not
required. In addition, because the secondary and tertiary rails
are generated using high efficiency switching regulators, extra
secondary windings are not required. This approach offers a
number of advantages over an alternative multiwinding
solution, such as the following:
•
•
•
•
A smaller transformer solution size due to a lower number
of turns required on the core and a fewer number of pins.
Each output can be independently set—the multitap
approach requires a custom multitap transformer for
different output voltage combinations.
Outputs are more accurate because the outputs do not rely
on the discrete ratios between the transformer windings.
Output accuracy is unaffected by load changes on each rail.
Power Saving Mode (PSM)
During light load operation, the regulators can skip pulses to
maintain output voltage regulation. Therefore, no minimum
load is required. Skipping pulses increases the device efficiency
but results in larger output ripple.
Flyback Regulator Precision Enable Control
The flyback regulator in the ADP1031 features a precision
enable circuit with an accurate reference voltage. If the voltage
at the EN pin rises above the VEN_RISING threshold, the flyback
regulator soft start period initiates, and the regulator enables.
If the EN pin voltage falls below the VEN_RISING − VEN_HYST
threshold, the flyback regulator turns off.
Flyback Regulator Soft Start
The flyback regulator includes a soft start function that limits
the inrush current from the supply and ramps up the output
voltage in a controlled manner. The flyback regulator soft start
period initiates when the voltage at the EN pin rises above the
VEN_RISING threshold.
Flyback Slew Rate Control
The flyback regulator employs programmable output driver slew
rate control circuitry. This circuitry adjusts the slew rate of the
switching node as shown in Figure 65, where lower EMI and
reduced ringing can be achieved at slightly lower efficiency
operation and vice versa. To program the slew rate, connect the
SLEW pin to the VINP pin for normal mode, to the GNDP pin
for slow mode, or leave it open for fast mode.
Note that slew rate control causes a trade-off between efficiency
and low EMI.
FASTEST
SLOWEST
16434-051
The flyback regulator in the ADP1031 generates an isolated
output supply rail that can be programmed from 6 V to 28 V
for the adjustable output version or 21 V and 24 V for the
factory programmable fixed output versions. The flyback
regulator adopts current mode control, resulting in a fast inner
current controlled loop that regulates the peak inductor current
and a slower outer loop via an isolated iCoupler channel that
adjusts the current controlled loop to define a regulated output
voltage. When the high voltage switch is on, the diode on the
secondary side of the transformer is reverse biased, which
causes an increase in the current in the primary inductance of
the transformer and is stored as energy. When the switch turns
off, the diode becomes forward biased and energy stored in the
transformer is transferred to the load.
Figure 65. Switching Node at Various Slew Rate Settings
Table 10. Slew Rate Settings
SLEW Pin
Connection
GNDP
VINP
Unconnected
Rev. A | Page 24 of 38
Slew Rate
Slow
Normal
Fast
Comment
Lowest EMI
Optimized efficiency and EMI
Highest efficiency
Data Sheet
ADP1031
Flyback Regulator Overcurrent Protection
Buck Regulator UVLO
The flyback regulator features a current-limit function that senses
the forward current in the switching metal-oxide semiconductor
field effect transistor (MOSFET) on a cycle by cycle basis. If the
current exceeds the ILIM (FLYBACK) threshold, the switch turns off.
The step-down regulator of theADP1031 features an internal
undervoltage lockout circuit that monitors the input voltage to
the regulator or VOUT1. If the voltage at VOUT1 drops below
the internal threshold level of 4.5 V, the regulator turns off. If
the output at VOUT1 rises above the internal threshold, the
regulator soft start period initiates, and the regulator enables.
Flyback Regulator Overvoltage Protection
The flyback regulator of the ADP1031 implements a number of
OVP methods to detect and prevent an overvoltage condition
on the flyback regulator output, such as the following:
•
•
•
If the voltage on the FB1 pin exceeds VFB1 by 10% for the
adjustable output version, or the VOUT1 pin exceeds the
factory programmed VOUT1 by 10% for the fixed output
version, an OVP fault will be detected, which prevents the
flyback regulator switch from turning on. The flyback
regulator primary switch stays off until the OVP condition
is no longer present.
If communication across the isolation barrier from the
secondary controller to the primary controller fails, the
flyback regulator shuts down and a new soft start power-up
cycle initiates.
If the voltage on the output of the flyback regulator exceeds
the severe overvoltage threshold (SOVPFLYBACK), the primary
controller does not turn on the primary side switch. The
flyback regulator primary switch stays off until the voltage on
the VOUT1 pin falls below the SOVPFLYBACK − SOVPFLYBACK_HYST
threshold.
BUCK REGULATOR
Buck Regulator Operation
The step-down, dc-to-dc (or buck) regulator in the ADP1031
uses a current mode controlled scheme, operating at a fixed
frequency set by an internal oscillator. Current mode uses a fast
inner current-controlled loop to regulate peak inductor current
and a slower outer loop to adjust the current loop to regulate
the output voltage. At the start of each oscillator cycle, the highside MOSFET switch turns on, applying the input voltage to one
end of the inductor, which normally causes the buck regulator
inductor current (IL_BUCK) to increase until the current sense
signal crosses the peak inductor current threshold that turns
off the MOSFET switch. The error amplifier output sets this
threshold. During the high-side MOSFET off time, the inductor
current declines through the low-side MOSFET switch until
either the next oscillator clock pulse starts a new cycle that results
in continuous conduction mode (CCM) operation, or the inductor
current reaches zero, the low-side MOSFET switch is turned off,
and the control system waits for the next oscillator clock pulse
to start a new cycle, resulting in discontinuous mode (DCM)
operation. Under light load conditions, the regulator can skip
pulses to maintain regulation and increase power conversion
efficiency.
Buck Regulator Soft Start
The step-down regulator in the ADP1031 includes soft start
circuitry that ramps the output voltage in a controlled manner
during start-up, thereby limiting the inrush current.
Buck Regulator Current-Limit Protection
The step-down regulator in the ADP1031 includes a currentlimit protection circuit to limit the amount of forward current
through the high-side MOSFET switch. The inductor peak
current is monitored cycle by cycle to detect an overload
condition. When the overload condition occurs, the currentlimit protection limits the peak inductor current to ILIM (BUCK),
resulting in a drop in the output voltage.
Buck Regulator OVP
The step-down regulator of the ADP1031 features an OVP
circuit that monitors the output voltage. If the voltage on the
VOUT2 pin exceeds the nominal output voltage by 10%, the
step-down, dc-to-dc regulator stops switching until the voltage
falls below the threshold again.
Buck Regulator Active Pull-Down Resistor
The buck regulator has an active pull-down resistor that
discharges the output capacitor when the output of VOUT1
is between 1.23 V and 4.5 V. The pull-down resistor connects
between VOUT2 and SGND2.
Rev. A | Page 25 of 38
ADP1031
Data Sheet
INVERTING REGULATOR
POWER GOOD
Inverting Regulator Operation
The ADP1031 provides a push pull, power-good output to
indicate when the three isolated output voltage rails are valid.
The PWRGD pin pulls high when the voltages on the three
supplies are within the respective power-good threshold limits.
The inverting, dc-to-dc regulator in the ADP1031 uses a current
mode controlled scheme, operating at a fixed frequency set by
an internal oscillator. Current mode uses a fast inner current
controlled loop to regulate the peak inductor current and a slower
outer loop to adjust the current loop to regulate the output voltage.
At the start of each oscillator cycle, the high-side MOSFET switch
turns on, applying the input voltage to one end of the inductor,
which normally causes the inverting regulator inductor current
(IINV_INDUCTOR) to increase until the current sense signal crosses
the peak inductor current threshold that turns off the MOSFET
switch. The error amplifier output sets this threshold. During the
high-side MOSFET off time, the inductor current declines through
the low-side MOSFET switch until either the next oscillator
clock pulse starts a new cycle, which results in CCM operation, or
the inductor current reaches zero, the low-side MOSFET switch
is turned off, and the control system waits for the next oscillator
clock pulse to start a new cycle, resulting in DCM operation.
Under light load conditions, the regulator can skip pulses to
maintain regulation and increase power conversion efficiency.
POWER-UP SEQUENCE
The power-up sequence is as follows (see Figure 66):
1. The flyback regulator powers up first (see 1 in Figure 66).
2. When VOUT1 rises above the lower power-good threshold
(VPG_FLYBACK_LL), the buck regulator turns on (see 2 in Figure 66).
3. When the buck regulator output (VOUT2) rises above the
lower power-good threshold (VPG_BUCK_LL), the inverting
regulator turns on (see 3 in Figure 66).
4. PWRGD is driven high when the inverting regulator output
(VOUT3) is below the power-good threshold,
VPG_INVERTER_LL (see 4 in Figure 66).
5. If any of the three analog supplies move outside the powergood threshold ranges, PWRGD drives low after a short
deglitch delay (see 5 in Figure 66).
VOUT1
VPG_FLYBACK_U L
Inverting Regulator UVLO
VPG_FLYBACK_L L
The inverting, dc-to-dc regulator of the ADP1031 features an
internal UVLO circuit that monitors the input voltage to the
regulator or VOUT1. If the voltage at VOUT1 drops below the
internal threshold level of 4.5 V, the regulator turns off. If the
output of VOUT1 rises above the internal threshold, the
regulator soft start period initiates, and the regulator enables.
VINP
2
VOUT2
VPG_BUCK_LL
1
3
0V
Inverting Regulator Soft Start
VOUT3
The inverting, dc-to-dc regulator in the ADP1031 includes soft
start circuitry that ramps the output voltage in a controlled
manner during startup, thereby limiting the inrush current.
VPG_INVERTER_L L
Inverting Regulator Current-Limit Protection
4
HIGH
PWRGD
16434-052
The inverting, dc-to-dc regulator in the ADP1031 includes a
current-limit protection circuit to limit the amount of forward
current through the high-side MOSFET switch. The inductor peak
current is monitored cycle by cycle to detect an overload condition.
When the overload condition occurs, the current-limit protection
limits the peak inductor current to ILIM (INVERTER), resulting in a
drop in the output voltage.
5
LOW
Figure 66. Power-Up Sequencing and PWRGD
OSCILLATOR AND SYNCHRONIZATION
Inverting Regulator Active Pull-Down Resistor
A phase-locked loop (PLL)-based oscillator generates the internal
clock for the flyback, buck, and inverter regulators and offers an
internally generated frequency or external clock synchronization.
Connect the SYNC pin as describe in Table 11 to configure the
switching frequency. For external synchronization, connect the
SYNC pin to a suitable clock source. The PLL locks to an input
clock within the range specified by fSYNC.
Table 11. Sync Pin Functionality
The inverting regulator has an active pull-down resistor that
discharges the output capacitor when the output of VOUT1 is
between 1.23 V and 4.5 V. The pull-down resistor connects
between VOUT3 and SGND2.
SYNC Pin State, fSYNC
Low or High
350 kHz to 750 kHz
Inverting Regulator OVP
The inverting, dc-to-dc regulator of the ADP1031 features an
OVP circuit that monitors the voltage on the FB3 pin. If the
voltage on this pin falls below VFB3 by 10%, the inverting regulator
stops switching until the voltage rises above the threshold again.
Rev. A | Page 26 of 38
Switching Frequency (fSW)
Flyback
Buck
Inverter
250 kHz
125 kHz 125 kHz
fSYNC ÷ 2
fSYNC ÷ 4 fSYNC ÷ 4
Data Sheet
ADP1031
THERMAL SHUTDOWN
The datapaths are SPI mode agnostic. The CLK and MO/SI SPI
datapaths are optimized for propagation delay and channel to
channel matching. The MI/SO SPI datapath is optimized for
propagation delay. The device does not synchronize to the clock
channels. Therefore, there are no constraints on the clock
polarity or timing with respect to the data lines.
If the ADP1031 junction temperature rises above TSHDN, the
thermal shutdown circuit turns the flyback regulator off.
Extreme junction temperatures can be the result of prolonged
high current operation, poor circuit board design, and/or high
ambient temperatures. When thermal shutdown occurs, hysteresis
is included so that the ADP1031 does not return to operation until
the on-chip temperature drops below TSHDN − THYS. When resuming
from thermal shutdown, the ADP1031 performs a soft start.
DATA ISOLATION
High Speed SPI Channels
The ADP1031 has four high speed channels. The first three, CLK,
MI/SO, and MO/SI (the slash indicates the connection of the input
and output forming a datapath across the isolator that corresponds to
an SPI bus signal) are optimized for low propagation delay.
With a maximum propagation delay of 15 ns, the ADP1031
supports read and write clock rates up to 16.6 MHz in the standard
4-wire SPI. However, the total round trip delay of the system
determines the maximum clock rate and is less than that value.
The relationship between the SPI signal paths, the ADP1031 pin
mnemonics, and the data directions are detailed in Table 12.
Table 12. Correspondence of the Pin Mnemonics to the SPI
Signal Path Names
SPI Signal Path
CLK
MO/SI
MI/SO
SS
Master Side
MCK
MO
MI
MSS
Data Direction
→
→
←
→
MSS
ENCODE
DECODE
SSS
MCK
ENCODE
DECODE
SCK
MO
ENCODE
DECODE
SI
MI
DECODE
ENCODE
SO
Slave Side
SCK
SI
SO
SSS
16434-053
SS (slave select bar) is an active low signal. To save power in a
multichannel system, SS puts the other SPI isolator channels in
a low power state when the channels are not in use (SS = high),
and these channels are only active when required, which is
when SS is low. The clock and data channels are gated to the SS
as shown in Figure 67. However, this power saving mode adds
100 ns of latency. This latency is the time required for the internal
circuitry to wake up from the low power state and to start
transmitting data to the isolation barrier. Conversely, the
latency is the delay from the falling edge of MSS to the first
clock edge or data edge that appears on the slave side, as shown
in Figure 68.
Figure 67. iCoupler Gating
SPI
ACTIVATION
(LATENCY)
SPI TRANSMIT
MSS
SSS
tP1
tPW
tP2
MCK, MO, SO
tP3
SCK, SI, MI
LATENCY = MSS FALLING EDGE TO SCK, SI, MI STARTS SENDING DATA (EXIT TO HIGH IMPEDANCE MODE).
t PW = MCK, MO, SO PULSE WIDTH.
t P1 = MSS TO SSS PROPAGATION DELAY.
t P2 = MCK TO SCK, MO TO SI, SO TO MI PROPAGATION DELAY.
t P3 = MSS RISING EDGE TO SCK, SI, MI RETURN TO HIGH IMPEDANCE STATE. SAME AS t P1.
Figure 68. SPI Isolators Timing Diagram
Rev. A | Page 27 of 38
16434-054
HIGH IMPEDANCE
ADD A PULL HIGH OR PULL LOW RESISTOR
TO HAVE A KNOWN STATE WHEN MSS IS HIGH.
ADP1031
Data Sheet
MSS
MSS1
SCK
MCK
MCK
MO
MO
CHANNEL 1
SI
SO
MI
MI
The MI, SCK, and SI outputs are also tristated when MSS is
high (see Table 13) to allow a more flexible design and to avoid
the requirement for external multiplexing of MI in a multichannel
system. Figure 69 shows how the SPI busses from multiple
ADP1031 devices can be connected together.
SSS
Table 13. SPI MSS Gating
MSS2
MSS
SSS
Parameter
MSS High
MSS Low
MCK
SCK
SSS
High
Low
SCK
Tristate
MCK
SI
Tristate
MO
MI
Tristate
SO
MO
CHANNEL 2
SO
MI
MCK
MO
CHANNEL 3
MI
GPIO Data Channels
SO
The general-purpose data channels are provided as space-saving
isolated datapaths where timing is not critical. The dc value of
all low speed general-purpose inputs, on a given side of the
device, are sampled simultaneously, packetized, and shifted
across a single isolation coil. The process is then reversed by
reading the inputs on the opposite side of the device, packetizing
the inputs and sending these inputs back for similar processing.
Because of the sampled nature of this process, the generalpurpose data channels exhibit a sampling uncertainty that
resembles 19.5 µs peak jitter.
SCK
MCK
MO
SI
SSS
MSS
MSS4
SCK
Connect a pull-up or pull-down resistor to MI, SCK, and SI to
pull these pins to the desired logic state when MSS is high.
SSS
MSS
MSS3
SI
CHANNEL 4
SI
SO
16434-055
MI
TO CHANNEL 5
THROUGH
CHANNEL 8
For proper operation of the GPIO channels, refer to Table 14.
Power both MVDD and SVDD2 within the specified input
voltage range for these pins.
Figure 69. Multichannel SPI Muxing Scheme
Table 14. Truth Table for GPIO Channels
MVDD State
Unpowered
Powered
Powered
Powered
Powered
SVDD2 State
Powered
Unpowered
Powered
Powered
Powered to Unpowered
xGPIx
Don’t care
Don’t care
High
Low
Don’t care
MGPOx
Low
Low
High
Low
Hold
SGPOx
Low
Low
High
Low
Low
Powered to Unpowered
Powered
Don’t care
Low
Hold
Rev. A | Page 28 of 38
Test Conditions/Comments
During startup
During startup
Normal operation
Normal operation
Hold means that the current state
of the outputs are preserved
Hold means that the current state
of the outputs are preserved
Data Sheet
ADP1031
APPLICATIONS INFORMATION
COMPONENT SELECTION
As with the flyback regulator, calculate the value of the top
resistor for the target VOUT3 by the following equation:
Feedback Resistors
The ADP1031 provides an adjustable output voltage for both
flyback and inverting regulators. An external resistor divider
sets the output voltage where the divider output must equal the
appropriate feedback reference voltage, VFB1 or VFB3. To limit the
output voltage accuracy degradation due to the feedback bias
current, ensure that the current through the divider is at least
10 times IFB1 or IFB3. The recommended RFB1 and RFB3 values are
in the range of 50 kΩ to 250 kΩ to minimize the output voltage
error due to the bias current and to lessen the power dissipation
across the feedback resistors. The external feedback resistors are
not required for the fixed output versions because the feedback
resistors are already inside the chip.
RFT1
Tx1
SWP
VINP
VOUT1
6V TO 28V
D1
RFB1
SGND2
VOUT1
FB1
FLYBACK
Set the positive output for the flyback regulator by
VOUT1 = VFB1 × (1 + (RFT1/RFB1))
where:
VOUT1 is the flyback output voltage.
VFB1 is the flyback feedback voltage.
RFT1 is the feedback resistor from VOUT1 to FB1.
RFB1 is the feedback resistor from FB1 to SGND2.
Conversely, calculate the value of the top resistor for the target
VOUT1 by:
RFT1 = RFB1 × ((VOUT1/VFB1) − 1)
VOUT3
–24V TO –5V
FB3
SW3
RFB3
L2
100µH
RFT3
CINV
4.7µF
SGND2
16434-074
INVERTER
Desired
Output
Voltage (V)
±6
±9
±12
±15
±24
+28
RFT1/RFT3
(MΩ)
0.715
1.24
1.54
2.15
3.48
3.4
Flyback/Inverting Regulator
RFB1/RFB3
Calculated Output
(kΩ)
Voltage (V)
110
±6.000
121
±8.998
110
±12.000
121
±15.015
120
±24.000
100
+28.000
Capacitor Selection
Ceramic capacitors are manufactured with a variety of
dielectrics, each with a different behavior over temperature and
applied voltage. Capacitors must have a dielectric adequate to
ensure the minimum capacitance over the necessary temperature
range and dc bias conditions. X5R or X7R dielectrics with
voltage ratings of 25 V to 50 V (depending on output) are
recommended for best performance. Y5V and Z5U dielectrics
are not recommended for use with any dc-to-dc converter
because of their poor temperature and dc bias characteristics.
Figure 70. Flyback Regulator Output Voltage Setting
VOUT3
Table 15. Recommended Feedback Resistor Values
Higher output capacitor values reduce the output voltage ripple
and improve the load transient response. When choosing this
value, it is also important to account for the loss of capacitance
due to the output voltage dc bias.
CFLYBK
4.7µF
16434-073
1:1
VINP
RFT3 = RFB3 × ((VOUT3/VFB3) − 1)
Figure 71. Inverting Regulator Output Voltage Setting
Set the negative output for the inverting regulator by
VOUT3 = VFB3 × (1 + (RFT3/RFB3))
where:
VOUT3 is the inverting regulator output voltage (negative sign
disregarded).
VFB3 is the inverting regulator feedback voltage in reference to
VOUT3.
RFT3 is the feedback resistor from FB3 to SGND2.
RFB3 is the feedback resistor from VOUT3 to FB3.
Calculate the worst case capacitance accounting for capacitor
variation over temperature, component tolerance, and voltage
using the following equation:
CEFFECTIVE = CNOMINAL × (1 − TEMPCO) × (1 − DCBIASCO) ×
(1 − Tolerance)
where:
CEFFECTIVE is the effective capacitance at the operating voltage.
CNOMINAL is the nominal capacitance shown in this data sheet.
TEMPCO is the worst case capacitor temperature coefficient.
DCBIASCO is the dc bias derating at the output voltage.
Tolerance is the worst case component tolerance.
To guarantee the performance of the device, it is imperative to
evaluate the effects of dc bias, temperature, and tolerances on
the behavior of the capacitors for each application.
Capacitors with lower effective series resistance (ESR) and
effective series inductance (ESL) are preferred to minimize
voltage ripple.
Rev. A | Page 29 of 38
ADP1031
Data Sheet
FLYBACK REGULATOR COMPONENTS SELECTION
Primary Inductance
Input Capacitor
The ADP1031 operates with a transformer with an inductance
in the 80 µH to 560 µH range. However, it is recommended to
choose an inductance value that results in the flyback output voltage
(VOUT1) divided by the transformer primary inductance being
less than or equal to 140,000 to maintain control loop stability.
VOUT1/LPRI ≤ 140,000
where:
VOUT1 is the flyback regulator output voltage.
LPRI is the primary side inductance of the transformer.
An input capacitor must be placed between the VINP pin and
ground. Ceramic capacitors greater than or equal to 3.3 µF over
temperature and voltage are recommended. The input capacitor
reduces the input voltage ripple caused by the switching current.
Place the input capacitor as close as possible to the VINP and
PGNDP pins to reduce input voltage spikes. The voltage rating of
the input capacitor must be greater than the maximum input
voltage.
Output Capacitor
Higher output capacitor values reduce the output voltage ripple
and improve load transient response. When choosing this value,
it is also important to account for the loss of capacitance due to
the output voltage dc bias. A 4.7 µF capacitor is recommended
as a balance between performance and size.
Ripple Current vs. Capacitor Value
The output capacitor value must be chosen to minimize the
output voltage ripple while considering the increase in size and
cost of a larger capacitor. Use the following equation to calculate
the output capacitance:
COUT = (LPRI × ISWP2)/(2 × VOUT1 × ΔVOUT1)
where:
COUT is the capacitance of the flyback output capacitor.
LPRI is the primary inductance of the transformer.
ISWP is the peak switch current.
VOUT1 is the flyback regulator output voltage.
ΔVOUT1 is the allowable flyback regulator output ripple.
Schottky Diode
A Schottky diode with low junction capacitance is recommended
for D1. At higher output voltages and especially at higher
switching frequencies, the junction capacitance is a significant
contributor to efficiency. Choose an output diode with a
forward current rating (IF) that is greater than the maximum
load requirement and with a reverse voltage rating (VR) that is
greater than the summation of the maximum supply voltage
(VINP (MAX)) and the maximum output voltage (VOUT1 (MAX)).
Transformer
The transformer used with the ADP1031 is an important
component within the system, in terms of efficiency and maximum
output power capability. Analog Devices worked with a number of
leading magnetic component suppliers to develop a number of
transformer designs for use with the ADP1031. These designs are
listed in Table 16. A number of factors must be taken into account
when designing a transformer for use with the ADP1031.
Turn Ratio
The ADP1031 requires the use of a transformer with a primary
to secondary turn ratio of 1:1 to start up properly.
Using a transformer at the lower end of the inductance range may
result in a smaller transformer but also reduces the output power
capabilities due to larger ac ripple current through the transformer.
Conversely, operating at higher inductance can result in higher
output power at the expense of a potentially larger transformer.
Flyback Transformer Saturation Current
Do not exceed the saturation current of the transformer in
operation or this may lead to much higher losses and overall
lower system efficiency. Choose a transformer with a saturation
current rating that is greater than the expected peak switch
current (ISWP) across line and load conditions.
Series Winding Resistance
In power loss sensitive applications, keep the series resistance
of the primary and secondary windings as low as possible to
improve overall efficiency.
Leakage Inductance and Clamping Circuits
When choosing a transformer to operate with the ADP1031,
minimize transformer leakage inductance. Leakage inductance
causes a voltage spike to appear on the SWP node when the
flyback regulator switch is off due to energy storage in the
leakage inductance that is not transferred to the output. The
voltage spike is more prominent at higher load currents and
increases with higher leakage inductance. It is important to
keep the voltage spikes lower than the voltage rating of the
flyback switch that drives the SWP pin. Margin must be built
in to any design to avoid exceeding this limit if no clamp or
snubber circuit is used to protect the flyback switch.
To estimate the leading voltage spike at the SWP pin when the
switch turns off, use the following equation:
VPEAK = IPEAK × (LLEAK/(CP + CSWP))1/2 + VINP + VOUT1 + VD
where:
VPEAK is the voltage spike amplitude.
IPEAK is the peak current on the flyback switch.
LLEAK is the leakage inductance of the transformer.
CP is the parasitic capacitance of the transformer.
CSWP is the capacitance on the flyback switch.
VINP is the input supply voltage.
VOUT1 is the output voltage of the flyback regulator.
VD is the forward voltage drop across the rectifier diode.
A snubber or clamp circuit can protect the flyback switch for
cases where the leakage inductance is too high for application
conditions. Two common types of clamping circuit are the
Rev. A | Page 30 of 38
Data Sheet
ADP1031
Tx1
1:1
VINP
D1
VOUT1
VCLAMP
VINP (MAX)
Figure 74. Clamping Waveform
Use the following equation to calculate the value of the
clamping resistor for a given VCLAMP value:
where:
RCLAMP is the value of the clamping resistor.
VCLAMP is the clamping voltage.
VOUT1 is the output voltage of the flyback regulator.
LLEAK is the leakage inductance of the transformer.
IPEAK is the peak current on the flyback switch.
fSW is the switching frequency of the flyback regulator.
LLEAK
SWP
16434-276
To calculate the power dissipation across the snubber resistor,
use the following equation:
PRCLAMP = (VCLAMP)2/(RCLAMP)
Figure 72. Resistor, Capacitor, Diode Clamp
Tx1
1:1
VINP
ZCLAMP
VOUT1 (MAX) + VINP (MAX)
RCLAMP = (2 × VCLAMP × (VCLAMP − VOUT1))/(LLEAK × IPEAK2 × fSW)
RCLAMP CCLAMP L
PRI
DCLAMP
SWPVMAX
16434-278
resistor, capacitor, diode clamp shown in Figure 72 and the diode
Zener diode clamp shown in Figure 73. The resistor, capacitor,
diode clamp quickly dampens the voltage spike and provides
improved EMI performance, and the diode Zener diode clamp
can be used when the clamping level must be consistent and well
defined. The diode Zener diode clamp has slightly higher power
efficiency over the resistor, capacitor, diode clamp. However, the
cost of the diode Zener diode clamp solution is typically higher
than the resistor, capacitor, diode solution.
D1
where PRCLAMP is the power dissipation across RCLAMP. Choose
RCLAMP with power rating of about twice this value to have
margin.
VOUT1
LPRI
Clamping Capacitor
DCLAMP
The clamping capacitor (CCLAMP) is used to minimize the voltage
ripple level (VRIPPLE) superimposed in VCLAMP. Calculate the
clamping capacitor by using the following equation for the
desired VRIPPLE level and the calculated RCLAMP:
LLEAK
SWP
16434-277
CCLAMP = VCLAMP/(VRIPPLE × fSW × RCLAMP)
Figure 73. Diode Zener Diode Clamp
Clamping Resistor
To calculate the clamping resistor (RCLAMP) value, the clamping
voltage (VCLAMP) must be determined. The clamping voltage is
the voltage on which any voltage spike that occurs on the
flyback switch is clamped. Choose a clamping voltage (VCLAMP)
that provides sufficient margin between the SWP maximum
voltage rating (SWPVMAX) specified in the Absolute Maximum
Ratings section and that also is greater than the summation of
the maximum input supply (VINP (MAX)) and the maximum flyback
output voltage (VOUT1 (MAX)) of the application as given by
where:
CCLAMP is the value of the clamping capacitor.
VCLAMP is the clamping voltage.
VRIPPLE is the voltage ripple superimposed in VCLAMP. A VRIPPLE of
about 5% to 10% of VCLAMP is reasonable.
fSW is the switching frequency of the flyback regulator.
RCLAMP is the value of the clamping resistor.
Clamping Diode
Schottky diodes are typically the best choice. However, fast
recovery diodes can also be used. The diode reverse voltage
rating must be higher than the maximum SWP pin voltage
rating.
SWPVMAX > VINP (MAX) + VCLAMP > VINP (MAX) + VOUT1 (MAX)
Rev. A | Page 31 of 38
ADP1031
Data Sheet
Diode Zener Diode Clamp
Maximum Output Current Calculation
A Zener diode can replace the resistor, capacitor (RC) network
on the resistor, capacitor, diode clamp when the clamping level
must be consistent and well defined. Choose the Zener diode
breakdown voltage to balance power loss and switch voltage
protection. Calculate the Zener voltage by using the following
equation:
The maximum output power and current that can be achieved
from the flyback output depends on a number of variables within
the regulator. These variables include the transformer choice,
the operating frequency, and the rectifier diode choice. The
flyback regulator output is the supply to the buck regulator that
drives VOUT2 and the inverting regulator that drives VOUT3.
Determine the maximum output power capability by
VZENER (MAX) ≤ SWPVMAX − VINP (MAX)
where:
VZENER (MAX) is the maximum Zener diode breakdown voltage or
the Zener voltage, which can be the same as the clamping
voltage, VCLAMP.
SWPVMAX is the absolute maximum rating of the SWP pin.
VINP (MAX) is the maximum input supply voltage.
The power loss in the clamp determines the power requirement
for the Zener diode. Use the following equation to calculate the
Zener diode power dissipation:
PZENER = (VZENER × LLEAK × IPEAK2 × fSW)/(2 × (VZENER − VOUT1))
where:
PZENER is the Zener diode power dissipation. Choose a Zener
diode with power rating higher than the calculated value.
VZENER is the Zener diode breakdown voltage or the Zener voltage.
LLEAK is the leakage inductance of the transformer.
IPEAK is the peak current on the flyback switch.
fSW is the switching frequency of the flyback regulator.
VOUT1 is the output voltage of the flyback regulator.
Ripple Current (IAC) vs. Inductance
Calculate the ripple current by first determining the duty cycle
in continuous conduction mode.
PVOUT1 (MAX) = 0.5 × (IPEAK2 − (IPEAK − IAC/2)2) × LPRI × fSW × η
where:
PVOUT1 (MAX) is the maximum output power from VOUT1.
IPEAK is the peak current on the flyback switch.
IAC is the ripple current through the primary side of the
transformer and flyback switch.
LPRI is the primary side inductance of the transformer.
fSW is the switching frequency of the flyback regulator.
η is the expected efficiency of the flyback regulator.
The lower limit of the flyback current-limit threshold, ILIM (FLYBACK),
limits the maximum IPEAK. However, it is not recommended to
operate at this level to avoid unwanted current-limit events due
to variation in transformer inductance, efficiency, flyback
switching frequency, and rectifier diode forward voltage drop. If
the load on the flyback causes the current limit to trip, the
output voltage may not regulate as expected. It is recommended
to choose a peak operating current with built in margin for the
variations mentioned or to calculate the maximum output power
or output load using the worst case transformer inductance,
efficiency, diode forward voltage drop, and flyback switching
frequency.
Calculate the maximum load current on VOUT1 by
IVOUT1 (MAX) = PVOUT1 (MAX)/VOUT1
DCCM = (VOUT1 + VD)/(VOUT1 + VD + VINP)
where:
IVOUT1 (MAX) is the maximum output current from VOUT1.
PVOUT1 (MAX) is the maximum output power from VOUT1.
VOUT1 is the output voltage of the flyback regulator.
where:
DCCM is the duty cycle of the flyback switch.
VOUT1 is the output voltage of the flyback regulator.
VD is the forward voltage drop across the rectifier diode.
VINP is the input supply voltage.
Then, from the duty cycle, calculate the IAC in the flyback switch
and transformer primary.
IAC = (VINP × DCCM)/(fSW × LPRI)
where:
IAC is the ripple current through the primary side of the
transformer and flyback switch.
VINP is the input supply voltage.
DCCM is the duty cycle of the flyback switch.
fSW is the switching frequency of the flyback regulator.
LPRI is the primary side inductance of the transformer.
Rev. A | Page 32 of 38
Data Sheet
ADP1031
BUCK REGULATOR COMPONENTS SELECTION
Inductor
The value of the inductor for the ADP1031 buck regulator
affects the efficiency and the output voltage ripple. Larger value
inductors typically improve efficiency. However, for a given
package size, as load increases, the dc resistance (DCR) and core
losses eventually have an increasing negative impact on efficiency.
Using a smaller value inductor reduces output voltage ripple but
can decrease the overall efficiency due to increased switching
losses.
Output Capacitor
The output capacitor selection affects the output ripple voltage,
load step transient, and the loop stability of the regulator. A 4.7 µF
capacitor is recommended as a balance between performance and
size, but a larger capacitor can be used to reduce output ripple.
INVERTING REGULATOR COMPONENT SELECTION
Inductor
The value of the inductor for the ADP1031 inverting regulator
affects the efficiency and output voltage ripple. Larger value
inductors typically improve efficiency. However, for a given
package size, as load increases, the DCR and core losses
eventually have an increasing negative impact on efficiency. Using
a smaller value inductor reduces output voltage ripple but can
decrease the overall efficiency due to increased switching losses.
Output Capacitor
The output capacitor selection affects the output ripple voltage,
load step transient, and the loop stability of the regulator. A
minimum of 4.7 µF capacitor is recommended to maintain
stability across VOUT1 and output load.
Inverting Regulator Stability
The ADP1031 inverting regulator uses internal compensation
and operates with an inductance of 100 µH and a typical
capacitance of 4.7 µF. Using different component values may
result in instability of VOUT3, particularly if lower capacitance
and smaller inductor values are used. Consult the factory for
guidance. Operating the inverter with the recommended inductor
and output capacitor, the output is stable from no load to a
15 mA load for any output from −24 V to −5 V. When
increasing the load beyond 15 mA, it is recommended to use a
larger output capacitor to stabilize the feedback loop,
particularly for lower output voltages.
Table 16. Transformer Selection
Primary
Part Number
750316743
750316566
WA8478-BE
YA9293-AL
BS64042CS
LPD5030-154MRB
Manufacturer
Würth Elektronik
Würth Elektronik
Coilcraft
Coilcraft
Bourns
Coilcraft
Turns
Ratio1
1:1
1:1
1:1
1:1
1:1
1:1
Inductance
(µH)
280
150
275
300
270
150
Resistance
(Ω)
1.1
1.65
1.2
1.15
1.4
2.43
Saturation
Current2
(mA)
250
220
150
250
400
430
Isolation
Voltage3
(V rms)
2000
2000
2250
2250
2200
Not
applicable
Isolation
Type
Basic
Basic
Basic
Reinforced
Basic
Functional
Size, Length ×
Width × Height,
(mm)
8.26 × 8.6 × 9.65
7.0 × 6.91 × 7.8
7.25 × 7.85 × 7.0
10 × 12.07 × 5.97
10.5 × 9.8 × 11.0
4.8 × 4.8 × 2.9
Turns ratio between the primary and secondary coils.
20% drop from initial.
3
1 minute duration.
1
2
Table 17. Buck Regulator and Inverting Regulator Recommended Inductors
Part Number
744043101
XFL3012-104MEB
LQH3NPN101MMEL
SRN3015-101M
SRU2016-101Y
XFL2006-104MEB
1
Manufacturer
Würth Elektronik
Coilcraft
Murata
Bourns
Bourns
Coilcraft
Inductance (µH)
100
100
100
100
100
100
DC Resistance (Ω)
0.55
2.63
1.59
2.92
4.9
11.1
30% drop in inductance.
Rev. A | Page 33 of 38
Saturation Current1 (mA)
290
280
260
270
150
115
Size, Length × Width ×
Height, (mm)
4.8 × 4.8 × 2.8
3.2 × 3.2 × 1.3
3 × 3 × 1.4
3 × 3 × 1.5
2.8 × 2.8 × 1.65
2 × 2 × 0.6
ADP1031
Data Sheet
INSULATION LIFETIME
Surface Tracking
Surface tracking is addressed in electrical safety standards by
setting a minimum surface creepage based on the working voltage,
the environmental conditions, and the properties of the insulation
material. Safety agencies perform characterization testing on the
surface insulation of components that allows the components to be
categorized in different material groups. Lower material group
ratings are more resistant to surface tracking. Therefore, lower
material group ratings provide adequate lifetime with smaller
creepage. The minimum creepage for a given working voltage and
material group is determined in each system level standard and is
based on the total rms voltage across the isolation, pollution
degree, and material group. The material group and creepage
for the ADP1031 isolators are shown in Table 4.
VRMS 2 − VDC 2
(2)
V=
AC RMS
where:
VRMS is the total rms working voltage.
VAC RMS is the time varying portion of the working voltage.
VDC is the dc offset of the working voltage.
Calculation and Use of Parameters Example
The following example frequently arises in power conversion
applications. Assume that the line voltage on one side of the
isolation is 240 V ac rms and a 400 V dc bus voltage is present
on the other side of the isolation barrier. The isolator material is
polyimide. To establish the critical voltages in determining the
creepage, clearance, and lifetime of a device, see Figure 75 and
the following equations.
VAC RMS
VRMS
VPEAK
Insulation Wear Out
VDC
TIME
The lifetime of insulation is determined by thickness, material
properties, and the voltage stress applied. It is important to
verify that the product lifetime is adequate at the application
working voltage. The working voltage supported by an isolator for
wear out may not be the same as the working voltage supported
for tracking. The working voltage applicable to tracking is
specified in most standards.
Testing and modeling have shown that the primary driver of
long-term degradation is displacement current in the polyimide
insulation. This displacement current causes incremental damage
to the insulation. The stress on the insulation can be broken down
into broad categories: dc stress and ac component time varying
voltage stress. DC stress causes very little insulation wear out
because there is no displacement current. AC component time
varying voltage stress causes insulation wear out.
The ratings in certification documents are usually based on
60 Hz sinusoidal stress because this reflects isolation from line
voltage. However, many practical applications have combinations
of 60 Hz ac and dc across the barrier as shown in Equation 1.
Because only the ac portion of the stress causes wear out, the
equation can be rearranged to solve for the ac rms voltage, as
shown in Equation 2. For insulation wear out with the polyimide
materials, the ac rms voltage determines the product lifetime.
Figure 75. Critical Voltage Example
The working voltage across the barrier from Equation 1 is
VRMS = VAC RMS 2 + VDC 2
VRMS = 240 2 + 400 2
VRMS = 466 V
This VRMS value is the working voltage and is used together with
the material group and pollution degree when looking up the
creepage required by a system standard.
To determine if the lifetime is adequate, obtain the time varying
portion of the working voltage. To obtain the ac rms voltage,
use Equation 2.
V=
AC RMS
VRMS 2 − VDC 2
VAC RMS = 466 2 − 400 2
VAC RMS = 240 V rms
In this case, the ac rms voltage is simply the line voltage of
240 V rms. This calculation is more relevant when the waveform is
not sinusoidal. The value is compared to the limits for working
voltage in Table 8 for the expected lifetime, which is less than a
Rev. A | Page 34 of 38
16434-375
The two types of insulation degradation of primary interest are
breakdown along surfaces exposed to the air and insulation wear
out. Surface breakdown is the phenomenon of surface tracking
and the primary determinant of surface creepage requirements
in system level standards. Insulation wear out is the phenomenon
where charge injection or displacement currents inside the
insulation material cause long-term insulation degradation.
(1)
or
ISOLATION VOLTAGE
All insulation structures eventually break down when subjected to
voltage stress over a sufficiently long period. The rate of insulation
degradation is dependent on the characteristics of the voltage
waveform applied across the insulation as well as on the materials
and material interfaces.
VRMS = VAC RMS 2 + VDC 2
Data Sheet
ADP1031
60 Hz sine wave, and it is well within the limit for a 20-year
service life.
The dc working voltage limit is set by the creepage of the
package as specified in IEC 60664-1. This value can differ for
specific system level standards.
THERMAL ANALYSIS
For the purpose of thermal analysis, the ADP1031 die are
treated as a thermal unit, with the highest junction temperature
reflected in the θJA values from Table 7. The value of θJA is based
on measurements taken with the devices mounted on a JEDEC
standard, 4-layer board with fine width traces and still air.
Under normal operating conditions, the ADP1031 operates at
a full load across the full temperature range without derating
the output current. However, following the recommendations
in the PCB Layout Considerations section decreases thermal
resistance to the PCB, allowing increased thermal margins in
high ambient temperatures. Each switching regulator in the
ADP1031 has a thermal shutdown circuit that turns off the dcto-dc converter and the outputs when a die temperature of
approximately 150°C is reached. When the die cools below
approximately 135°C, the ADP1031 dc-to-dc converter outputs
turn on again.
Rev. A | Page 35 of 38
ADP1031
Data Sheet
TYPICAL APPLICATION CIRCUIT
D1
1:1 BAT46W-7-F
+24V
VINP
SWP
CFLYBK
10µF
120kΩ
FB1
SGND2
VOUT1
VINP
3.4MΩ
CIN
4.7µF
232kΩ
PGNDP
SW2
PGNDP
VOUT3
GNDP
FB3
SLEW
SW3
MVDD
100kΩ
PGOOD
FAULT
LDAC
ADuCM3029
RESET
SYNC
PWRGD
MGPO3
MGPI2
SGPI3
MGND
SGPO2
CS
CLK
MOSI
MISO
GND
MGND
SGND2
SVDD1
MVDD
SGND1
MSS
SSS
SCK
MCK
SI
MO
MI
MGND
–12V
110kΩ
1.54MΩ
CINV
10µF
L2
100µH
100kΩ
PGND
100nF
SGPO1
SVDD2
MVDD
L1
100µH
CBUCK
10µF
ADP1031
MGPI1
100nF
VBAT
+5.15V
VOUT2
EN
100nF
100nF
100kΩ
CLKOUT
100kΩ
100nF
100nF
AVSS
47µH
100nF
AVDD2
AVDD1 SW+
VLOGIC
SCLK
SDI
+VSENSE
CCOMP
FAULT
–VSENSE
LDAC
RESET
DGND AD1 AD0 REFOUT REFIN
RA
RB
13.7kΩ
DGND
HART SIGNAL
Figure 76. Typical Application Circuit for the ADP1031 Using the AD5758
Rev. A | Page 36 of 38
1kΩ
VIOUT
AD5758
SDO
100kΩ
VDPC+
VLDO
SYNC
SO
2.2µF
RLOAD
1kΩ
CHART AGND
AGND
16434-059
Tx1
750316743
3.48MΩ
Data Sheet
ADP1031
•
•
•
•
•
•
Keep the input bypass capacitor, CIN, close to the VINP pin
and the PGNDP pin.
Keep the high current switching paths as short as possible.
These paths include the connections between the
following:
• CIN, VINP, the primary winding of the transformer,
and PGNDP
• VOUT1, CFLYBK, Diode 1 (D1), the secondary winding
of the transformer, and SGND2
• VOUT2, SW2, Inductance 1 (L1), CBUCK, and SGND2
• VOUT3, SW3, Inductance 2 (L2), CINV, and SGND2
Keep high current traces as short and wide as possible to
minimize parasitic series inductance, which causes spiking
and EMI.
Avoid routing high impedance traces near any node
connected to the SWP, SW2, and SW3 pins or near the L1
and L2 inductors or the T1 transformer to prevent radiated
switching noise injection.
Place the feedback resistors as close to the FB1 and FB3
pins as possible to prevent high frequency switching noise
injection.
To minimize EMI, place the MVDD decoupling capacitor
(C1) as close to the MVDD pin (Pin 39) and the MGND pin
(Pin 3).
•
To minimize EMI, place the SVDD1 decoupling capacitor
(C3) as close to the SVDD1 pin (Pin 10) and the SGND1
pin (Pin 5), and place the SVDD2 decoupling capacitor
(C7) as close to the SVDD2 pin (Pin 20) and the SGND2
pin (Pin 16).
Figure 77 shows a suggested top layer layout for the ADP1031.
Rev. A | Page 37 of 38
18.8mm
T1
D1
R9
R10
VINP
VOUT1
PGNDP
L1
CIN
U1
C7
C3
MVDD
CFLYBK
VOUT2
L2
CBUCK
VOUT3
C1
CINV
23mm
To achieve optimum efficiency, proper regulation, strong
stability, and low noise, a well designed PCB layout is required.
Follow these guidelines when designing PCBs:
R7
R8
Figure 77. Suggested Top Layer Layout
16434-060
PCB LAYOUT CONSIDERATIONS
ADP1031
Data Sheet
OUTLINE DIMENSIONS
0.50
BSC
7.10
7.00
6.90
TOP VIEW
31
PKG-005383
SEATING
PLANE
0.30
0.25
0.20
0.35
0.30
0.25
41
1
*EXPOSED
PAD
*EXPOSED
PAD
2.75
BSC
2.15
MIN
2.14
2.04
1.94
*EXPOSED
PAD
0.45
0.40
0.35
(Pins 8-41)
SIDE VIEW
3.88
3.78
3.68
30
24
1.00
0.95
0.90
2.15
MIN
1.72
1.62
1.52
0.05 MAX
0.02 NOM
COPLANARITY
0.08
0.203 REF
23
BOTTOM VIEW
7.70
7.60
7.50
8
7
3.75
BSC
1.46
1.36
1.26
0.435
0.385
0.335
(Pins 1-7)
* FOR PROPER CONNECTION OF
THE EXPOSED PAD, REFER TO
THE PIN CONFIGURATION AND
FUNCTION DESCRIPTIONS
SECTION OF THIS DATA SHEET.
09-05-2019-D
9.10
9.00
8.90
PIN 1
INDICATOR
AREA
Figure 78. 41-Lead Lead Frame Chip Scale Package [LFCSP]
9 mm × 7 mm Body and 0.95 mm Package Height
(CP-41-1)
Dimensions shown in millimeters
ORDERING GUIDE
Model 1
ADP1031ACPZ-1-R7
ADP1031ACPZ-2-R7
ADP1031ACPZ-3-R7
ADP1031ACPZ-4-R7
ADP1031ACPZ-5-R7
ADP1031CP-1-EVALZ
ADP1031CP-2-EVALZ
ADP1031CP-3-EVALZ
ADP1031CP-4-EVALZ
ADP1031CP-5-EVALZ
1
2
VOUT1 2
Adjustable
Adjustable
Adjustable
24 V
21 V
Adjustable
Adjustable
Adjustable
24 V
21 V
VOUT2
5.15 V
5V
3.3 V
5.15 V
5.15 V
5.15 V
5V
3.3 V
5.15 V
5.15 V
VOUT3
Adjustable
Adjustable
Adjustable
Adjustable
Adjustable
Adjustable
Adjustable
Adjustable
Adjustable
Adjustable
Temperature
Range
−40°C to +125°C
−40°C to +125°C
−40°C to +125°C
−40°C to +125°C
−40°C to +125°C
Package Description
41-Lead LFCSP
41-Lead LFCSP
41-Lead LFCSP
41-Lead LFCSP
41-Lead LFCSP
Evaluation Board for the ADP1031ACPZ-1
Evaluation Board for the ADP1031ACPZ-2
Evaluation Board for the ADP1031ACPZ-3
Evaluation Board for the ADP1031ACPZ-4
Evaluation Board for the ADP1031ACPZ-5
Z = RoHS Compliant Part.
For other VOUT1 voltage options, contact Analog Devices local sales representatives for additional information.
©2019 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D16434-0-12/19(A)
Rev. A | Page 38 of 38
Package
Option
CP-41-1
CP-41-1
CP-41-1
CP-41-1
CP-41-1