16-Bit, Isolated,
Sigma-Delta Modulator
ADuM7704
Data Sheet
FEATURES
FUNCTIONAL BLOCK DIAGRAM
VDD2
VDD1
ADuM7704
LDO
VIN+
VIN–
GAIN
Σ-Δ ADC
CLK
DECODER
CLK
ENCODER
MCLKIN
DATA
ENCODER
DATA
DECODER
MDAT
GND1
GND2
25057-001
5 MHz to 21 MHz master clock input frequency
Offset drift vs. temperature: ±0.25 µV/°C maximum
SNR: 82 dB typical
16 bits, no missing codes
Full-scale analog input voltage range: ±64 mV
ENOB: 13 bits typical
IDD1: 10 mA maximum
On-board digital isolator
Operating temperature range
−40°C to +125°C (16-lead SOIC_W)
−40°C to +105°C (8-lead SOIC_IC)
High isolation common-mode transient immunity:
150 kV/µs minimum, VDD2 = 3.3 V
Wide-body SOICs
16-lead SOIC_W
8-lead SOIC_IC with increased creepage
Safety and regulatory approvals
UL recognition
5700 V rms for 1 minute per UL 1577
CSA Component Acceptance Notice 5A
VDE Certificate of Conformity
DIN V VDE V 0884-10: VIORM = 1270 VPEAK
DIN V VDE V 0884-11: VIORM = 1060 VPEAK (pending)
Figure 1.
APPLICATIONS
Shunt current monitoring
AC motor controls
Power and solar inverters
Wind turbine inverters
Analog-to-digital and optoisolator replacement
GENERAL DESCRIPTION
The ADuM7704 is a high performance, second-order, Σ-Δ
modulator that converts an analog input signal into a high
speed, single-bit data stream, with on-chip digital isolation
based on Analog Devices, Inc., iCoupler® technology. The
device operates from a 4.5 V to 20 V power supply range (VDD1)
and accepts a pseudo differential input signal of ±50 mV
(±64 mV full-scale). The pseudo differential input is ideally
suited to shunt voltage monitoring in high voltage applications
where galvanic isolation is required.
The analog input is continuously sampled by a high performance
analog modulator and converted to a ones density digital output
stream with a data rate of up to 21 MHz. The original information
can be reconstructed with an appropriate sinc3 digital filter to
Rev. 0
achieve an 82 dB signal-to-noise ratio (SNR) at 78.1 kSPS with a
256 decimation rate and a 20 MHz master clock. The serial input
and output operates from a 5 V or a 3.3 V supply (VDD2).
The serial interface is digitally isolated. High speed complementary
metal-oxide semiconductor (CMOS) technology, combined with
monolithic transformer technology, results in the on-chip
isolation providing outstanding performance characteristics,
superior to alternatives such as optocoupler devices. The
ADuM7704 is available in a 16-lead, wide-body SOIC_W with
an operating temperature range of −40°C to +125°C and an 8-lead,
wide-body SOIC_IC with an operating temperature range of
−40°C to +105°C.
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ADuM7704
Data Sheet
TABLE OF CONTENTS
Features .............................................................................................. 1
Pin Configurations and Function Descriptions ............................9
Applications ....................................................................................... 1
Typical Performance Characteristics ........................................... 11
Functional Block Diagram .............................................................. 1
Terminology .................................................................................... 14
General Description ......................................................................... 1
Theory of Operation ...................................................................... 16
Revision History ............................................................................... 2
Circuit Information.................................................................... 16
Specifications..................................................................................... 3
Analog Input ............................................................................... 16
Timing Specifications .................................................................. 4
Applications Information .............................................................. 18
Package Characteristics ............................................................... 5
Current Sensing Applications ................................................... 18
Insulation and Safety Related Specifications ............................ 5
Voltage Sensing Applications .................................................... 18
Regulatory Information ............................................................... 5
Input Filter................................................................................... 18
DIN V VDE V 0884-10 Insulation Characteristics ................. 6
Digital Filter ................................................................................ 19
DIN V VDE V 0884-11 Insulation Characteristics (Pending) 7
Interfacing to ADSP-CM4xx .................................................... 20
Absolute Maximum Ratings............................................................ 8
Grounding and Layout .............................................................. 20
Thermal Resistance ...................................................................... 8
Insulation Lifetime ..................................................................... 20
Insulation Ratings......................................................................... 8
Outline Dimensions ....................................................................... 21
Electrostatic Discharge (ESD) Ratings ...................................... 8
Ordering Guide .......................................................................... 22
ESD Caution .................................................................................. 8
REVISION HISTORY
8/2020—Revision 0: Initial Version
Rev. 0 | Page 2 of 22
Data Sheet
ADuM7704
SPECIFICATIONS
VDD1 = 4.5 V to 20 V, VDD2 = 3 V to 5.5 V, VIN+ = −50 mV to +50 mV, VIN− = 0 V, TA = −40°C to +125°C (16-lead SOIC_W), TA = −40°C to
+105°C (8-lead SOIC_IC), MCLKIN frequency (fMCLKIN) = 20 MHz, tested with a sinc3 filter, and a 256 decimation rate, unless otherwise
noted.
Table 1.
Parameter
STATIC PERFORMANCE
Resolution
Integral Nonlinearity (INL) 1
Differential Nonlinearity (DNL)1
Offset Error1
Min
±8
±0.99
±0.13
±0.18
±0.25
±0.6
±15.6
±2
±5
−64
−50
Input Common-Mode Voltage Range
Dynamic Input Current
LOGIC INPUTS
Input High Voltage (VIH)
Input Low Voltage (VIL)
Input Current (IIN)
Input Capacitance (CIN)
LOGIC OUTPUTS
Output High Voltage (VOH)
Output Low Voltage (VOL)
±2
±0.05
±0.1
±0.1
±0.1
±2.5
Offset Drift vs. VDD1
Gain Error1
Gain Error Drift vs. Temperature1
DC Leakage Current
Input Capacitance
DYNAMIC SPECIFICATIONS
Signal-to-Noise-and-Distortion Ratio (SINAD)1
SNR1
Total Harmonic Distortion (THD)1
Peak Harmonic or Spurious-Free Dynamic
Range Noise (SFDR)1
Effective Number of Bits (ENOB)1
ISOLATION COMMON-MODE TRANSIENT
IMMUNITY (CMTI)1
Static and Dynamic
Max
16
Offset Drift vs. Temperature1
Gain Error Drift vs. VDD1
ANALOG INPUT
Input Voltage Range
Typ
±0.2
±31.3
±4
+64
+50
−0.2 to +0.8
±1
0.05
±0.01
25
±2
Unit
Test Conditions/Comments
Bits
LSB
LSB
mV
mV
µV/°C
µV/°C
µV/V
% FSR
ppm/°C
µV/°C
ppm/V
Filter output truncated to 16 bits
mV
mV
V
µA
µA
µA
pF
76.5
78.6
−78
82
82
−89
−97
dB
dB
dB
dB
12.4
13
Bits
Guaranteed no missed codes to 16 bits
Initial at TA = 25°C
16-lead SOIC_W
8-lead SOIC_IC
Initial at TA = 25°C
Full-scale range
For specified performance
VIN+ = ±50 mV, VIN− = 0 V
VIN+ = 0 V, VIN− = 0 V
VIN+ or VIN− left floating
VIN+ = 1 kHz
Common-mode voltage (|VCM|) = 2 kV
75
150
150
kV/µs
kV/µs
0.7 × VDD2
0.3 × VDD2
±0.6
10
VDD2 − 0.4
VDD2 − 0.2
0.2
0.4
Rev. 0 | Page 3 of 22
VDD2 = 5.5 V
VDD2 = 3.3 V
CMOS with Schmitt trigger
V
V
µA
pF
V
V
Output current (IOUT) = −4 mA
IOUT = 4 mA
ADuM7704
Data Sheet
Parameter
POWER REQUIREMENTS
VDD1
VDD2
VDD1 Current (IDD1)
VDD2 Current (IDD2)
Power Dissipation
1
Min
Typ
Max
Unit
4.5
3
15
20
5.5
10
3
216.5
211
V
V
mA
mA
mW
mW
8.2
2
133
130
Test Conditions/Comments
VIN+ > 64 mV
VDD2 = 4.5 V to 5.5 V
VDD2 = 3 V to 3.6 V
See the Terminology section.
TIMING SPECIFICATIONS
VDD1 = 4.5 V to 20 V, VDD2 = 3 V to 5.5 V, TA = −40°C to +125°C (16-lead SOIC_W), and TA = −40°C to +105°C (8-lead SOIC_IC), unless
otherwise noted. Sample tested during initial release to ensure compliance. It is recommended to read the MDAT pin on the MCLKIN
rising edge.
Table 2.
Parameter
fMCLKIN
tMCLKIN
t1 1
t21
t3
t4
1
Min
5
48
Limit at TMIN, TMAX
Typ
20
50
Max
21
200
16
Unit
MHz
ns
ns
ns
ns
ns
5
0.4 × tMCLKIN
0.4 × tMCLKIN
Description
Master clock input frequency
Master clock input period
Data access time after MCLKIN rising edge
Data hold time after MCLKIN rising edge
Master clock low time
Master clock high time
Defined as the time required from an 80% MCLKIN input level to when the output crosses 0.5 × VDD2, as outlined in Figure 2. Measured with a ±20 µA load and a 25 pF
load capacitance.
Timing Diagram
tMCLKIN
t4
80%
MCLKIN
t1
t2
t3
1SEE NOTE 1 OF TABLE 2 FOR FURTHER DETAILS.
Figure 2. Data Timing Diagram
Rev. 0 | Page 4 of 22
25057-002
0.5 × VDD2 1
MDAT
Data Sheet
ADuM7704
PACKAGE CHARACTERISTICS
Table 3.
Parameter 1
Resistance (Input to Output)
Capacitance (Input to Output)
1
Symbol
RI-O
CI-O
Min
Typ
1012
1
Max
Unit
Ω
pF
Test Conditions/Comments
Frequency = 1 MHz
The device is considered a 2-terminal device. For the 16-lead SOIC_W, Pin 1 to Pin 8 are shorted together and Pin 9 to Pin 16 are shorted together. For the 8-lead
SOIC_IC, Pin 1 to Pin 4 are shorted together and Pin 5 to Pin 8 are shorted together.
INSULATION AND SAFETY RELATED SPECIFICATIONS
Table 4.
Parameter
Input to Output Momentary Withstand Voltage
Minimum External Air Gap (Clearance) 1, 2
16-Lead SOIC_W
8-Lead SOIC_IC
Minimum External Tracking (Creepage)1
16-Lead SOIC_W
8-Lead SOIC_IC
Minimum Internal Gap (Internal Clearance)
Tracking Resistance (Comparative Tracking Index)
Isolation Group
1
2
Symbol
VISO
Value
5700 min
Unit
V rms
Test Conditions/Comments
1 minute duration
L(I01)
7.8 min
mm
L(I01)
8.3 min
mm
Measured from input terminals to output
terminals, shortest distance through air
Measured from input terminals to output
terminals, shortest distance through air
L(I02)
7.8 min
mm
L(I02)
8.3 min
mm
CTI
0.041 min
>600
I
mm
V
Measured from input terminals to output
terminals, shortest distance path along body
Measured from input terminals to output
terminals, shortest distance path along body
Distance through insulation
DIN IEC 112/VDE 0303 Part 1
Material Group (DIN VDE 0110, 1/89, Table I)
In accordance with IEC 60950-1 guidelines for the measurement of creepage and clearance distances for a pollution degree of 2 and altitudes ≤ 2000 m.
Consideration must be given to pad layout to ensure the minimum required distance for clearance is maintained.
REGULATORY INFORMATION
Table 5.
UL
Recognized under 1577 Component
Recognition Program 1
CSA
Approved under CSA Component Acceptance
Notice 5A
5700 V rms Isolation Voltage Single
Protection
Basic insulation per CSA 60950-1-07 and
IEC 60950-1, ADuM7704: 780 V rms (1102 VPEAK),
ADuM7704-8: 830 V rms (1173 VPEAK) maximum
working voltage 3
Reinforced insulation per CSA 60950-1-07 and
IEC 60950-1, ADuM7704: 390 V rms (551 VPEAK),
ADuM7704-8: 415 V rms (586 VPEAK) maximum
working voltage3
Reinforced insulation per IEC 60601-1, 261 V rms
(369 VPEAK) maximum working voltage
1
2
3
VDE
Certified according to DIN V VDE V 0884-10 2,
reinforced insulation, VIORM = 1270 VPEAK,
VIOSM = 8000 VPEAK
Certified according to DIN V VDE V 0884-11,
reinforced insulation, VIORM = 1060 VPEAK,
VIOSM = 8000 VPEAK (pending)
In accordance with UL 1577, each ADuM7704 is proof tested by applying an insulation test voltage ≥ 6840 V rms for 1 sec (current leakage detection limit = 15 µA).
In accordance with DIN V VDE V 0884-10, each ADuM7704 is proof tested by applying an insulation test voltage ≥ 2344 VPEAK for 1 sec (partial discharge detection limit = 5 pC).
Rating is calculated for a pollution degree of 2 and a Material Group III. The ADuM7704 package material is rated by CSA to a comparative tracking index (CTI) of >600 V
and, therefore, Material Group I.
Rev. 0 | Page 5 of 22
ADuM7704
Data Sheet
DIN V VDE V 0884-10 INSULATION CHARACTERISTICS
This isolator is suitable for reinforced electrical isolation only within the safety limit data. Maintenance of the safety data is ensured by
means of protective circuits.
Table 6.
Description
INSTALLATION CLASSIFICATION PER DIN VDE 0110
For Rated Mains Voltage ≤300 V rms
For Rated Mains Voltage ≤450 V rms
For Rated Mains Voltage ≤600 V rms
CLIMATIC CLASSIFICATION
POLLUTION DEGREE (DIN VDE 0110, TABLE 1)
MAXIMUM WORKING INSULATION VOLTAGE
INPUT TO OUTPUT TEST VOLTAGE, METHOD B1
VIORM × 1.875 = VPR, 100% Production Test, tm = 1 Second, Partial Discharge < 5 pC
INPUT TO OUTPUT TEST VOLTAGE, METHOD A
After Environmental Test Subgroup 1
VIORM × 1.6 = VPR, tm = 60 sec, Partial Discharge < 5 pC
After Input and/or Safety Test Subgroup 2/Safety Test Subgroup 3
VIORM × 1.2 = VPR, tm = 60 sec, Partial Discharge < 5 pC
HIGHEST ALLOWABLE OVERVOLTAGE (TRANSIENT OVERVOLTAGE, tTR = 10 sec)
SURGE ISOLATION VOLTAGE
1.2 µs Rise Time, 50 µs, 50% Fall Time
SAFETY LIMITING VALUES (MAXIMUM VALUE ALLOWED IN THE EVENT OF A FAILURE) 1
Case Temperature
Side 1 (PVDD1) and Side 2 (PVDD2) Power Dissipation
16-Lead SOIC_W
8-Lead SOIC_IC
INSULATION RESISTANCE AT TS, VOLTAGE INPUT TO OUTPUT (VIO) = 500 V
Characteristic
Unit
VIORM
I to IV
I to IV
I to IV
40/125/21
2
1270
VPEAK
2344
VPEAK
2032
VPEAK
VIOTM
1524
8000
VPEAK
VPEAK
VIOSM
8000
VPEAK
TS
PSO
150
°C
1.43
1.19
>109
W
W
Ω
VPD(M)
VPR(M)
RIO
See Figure 3.
2.0
16-LEAD SOIC_W
8-LEAD SOIC_IC
1.8
SAFE OPERATING POWER (W)
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
0
50
100
150
AMBIENT TEMPERATURE (°C)
200
25057-003
1
Symbol
Figure 3. Thermal Derating Curve, Dependence of Safety Limiting Values with Case Temperature per DIN V VDE V 0884-10
Rev. 0 | Page 6 of 22
Data Sheet
ADuM7704
DIN V VDE V 0884-11 INSULATION CHARACTERISTICS (PENDING)
This isolator is suitable for reinforced electrical isolation only within the safety limit data. Maintenance of the safety data is ensured by
means of protective circuits.
Table 7.
Description
INSTALLATION CLASSIFICATION PER DIN VDE 0110
For Rated Mains Voltage ≤300 V rms
For Rated Mains Voltage ≤450 V rms
For Rated Mains Voltage ≤600 V rms
CLIMATIC CLASSIFICATION
POLLUTION DEGREE (DIN VDE 0110, TABLE 1)
MAXIMUM WORKING INSULATION VOLTAGE
INPUT TO OUTPUT TEST VOLTAGE, METHOD B1
VIORM × 1.875 = VPR, 100% Production Test, tm = 1 sec, Partial Discharge < 5 pC
INPUT TO OUTPUT TEST VOLTAGE, METHOD A
After Environmental Test Subgroup 1
VIORM × 1.6 = VPR, tm = 60 sec, Partial Discharge < 5 pC
After Input and/or Safety Test Subgroup 2/Safety Test Subgroup 3
VIORM × 1.2 = VPR, tm = 60 sec, Partial Discharge < 5 pC
HIGHEST ALLOWABLE OVERVOLTAGE (TRANSIENT OVERVOLTAGE, tTR = 10 sec)
SURGE ISOLATION VOLTAGE
1.2 µs Rise Time, 50 μs, 50% Fall Time
SAFETY LIMITING VALUES (MAXIMUM VALUE ALLOWED IN THE EVENT OF A FAILURE) 1
Case Temperature
Side 1 (PVDD1) and Side 2 (PVDD2) Power Dissipation
16-Lead SOIC_W
8-Lead SOIC_IC
INSULATION RESISTANCE AT TS, VIO = 500 V
Characteristic
Unit
VIORM
I to IV
I to IV
I to IV
40/125/21
2
1060
VPEAK
1987
VPEAK
1696
VPEAK
VIOTM
1272
8000
VPEAK
VPEAK
VIOSM
8000
VPEAK
TS
PSO
150
°C
1.43
1.19
>109
W
W
Ω
VPD(M)
VPR(M)
RIO
See Figure 4.
2.0
16-LEAD SOIC_W
8-LEAD SOIC_IC
1.8
SAFE OPERATING POWER (W)
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
0
50
100
150
AMBIENT TEMPERATURE (°C)
200
25057-004
1
Symbol
Figure 4. Thermal Derating Curve, Dependence of Safety Limiting Values with Case Temperature per DIN V VDE V 0884-11
Rev. 0 | Page 7 of 22
ADuM7704
Data Sheet
ABSOLUTE MAXIMUM RATINGS
TA = 25°C, unless otherwise noted. All voltages are relative to
their respective GNDx.
Table 8.
Parameter
VDD1 to GND1
VDD2 to GND2
Analog Input Voltage to GND1
Digital Input Voltage to GND2
Digital Output Voltage to GND2
Input Current to Any Pin Except Supplies1
Output Current from Any Pin Except
Supplies
Temperature
Operating Range
Storage Range
Junction
Pb-Free, Soldering
Reflow
Rating
−0.3 V to +23 V
−0.3 V to +6 V
−1 V to +4.3 V
−0.5 V to VDD2 + 0.5 V
−0.5 V to VDD2 + 0.5 V
±10 mA
±10 mA
−40°C to +125°C
−65°C to +150°C
150°C
INSULATION RATINGS
The maximum continuous working voltage refers to the
continuous voltage magnitude imposed across the isolation
barrier. See the Insulation Lifetime section for more details.
Table 10. Maximum Continuous Working Voltage
1129 VPEAK
20 years to 1000 ppm
failure at 1129 VPEAK
(798 V rms, 50 Hz/60 Hz
sine wave)
Reinforced Insulation
AC Voltage
Bipolar Waveform
1060 VPEAK
20 years to 1 ppm failure
at 1060 VPEAK (750 V rms,
50 Hz/60 Hz sine wave)
260°C
1
1
Transient currents of up to 100 mA do not cause silicon controlled rectifier
(SCR) to latch up.
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.
θJA2
105
87.25
Unit
°C/W
°C/W
ELECTROSTATIC DISCHARGE (ESD) RATINGS
The following ESD information is provided for handling of
ESD-sensitive devices in an ESD protected area only.
Human body model (HBM) per ANSI/ESDA/JEDEC JS-001.
Field induced charged device model (FICDM) per
ANSI/ESDA/JEDEC JS-002.
ESD Ratings for ADuM7704
Table 11. ADuM7704, 16-Lead SOIC_W and 8-Lead SOIC_IC
1
2
Thermal impedance simulated values are based on a JEDEC 2S2P thermal
test board. See JEDEC JESD-51.
2
θJA was calculated using the total power and maximum junction
temperature.
Lifetime Conditions
Insulation capability without regard to creepage limitations. Working
voltage may be limited by the PCB creepage when considering rms voltages
for components soldered to a PCB (assumes Material Group I up to
1270 V rms), or package: RI-8-1 package creepage of 8.3 mm, and RW-16
package creepage of 7.8 mm, when considering rms voltages for Material
Group I.
ESD Model
HBM1
FICDM2
Table 9. Thermal Resistance
Package Type1
RI-8-1
RW-16
Insulation
Rating1
Parameter
Basic Insulation
AC Voltage
Bipolar Waveform
Withstand Threshold (V)
±3500
±1500
JESD22-C101, RC network, 1 Ω, and package capacitance.
ESDA/JEDEC JS-001-2011, RC network: 1.5 kΩ and 100 pF.
1
ESD CAUTION
Rev. 0 | Page 8 of 22
Class
3A
C4
Data Sheet
ADuM7704
PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS
NIC1 1
16
GND2
VIN+ 2
15
NIC2
VIN– 3
14
VDD2
NIC1 5
ADuM7704
13
MCLKIN
TOP VIEW
(Not to Scale) 12 NIC2
VDD1 6
11
MDAT
NIC1 7
10
NIC2
GND1 8
9
GND2
NOTES
1. NIC1 = NOT INTERNALLY CONNECTED. THE NIC1 PINS ARE NOT INTERNALLY CONNECTED.
CONNECT THE NIC1 PINS TO VDD1 , EITHER OF THE GND1 PINS, OR LEAVE FLOATING.
2. NIC2 = NOT INTERNALLY CONNECTED. THE NIC2 PINS ARE NOT INTERNALLY CONNECTED.
CONNECT THE NIC2 PINS TO VDD2 , EITHER OF THE GND2 PINS, OR LEAVE FLOATING.
3. CONNECT GND1 BEFORE VDD1 .
25057-005
GND1 4
Figure 5. 16-Lead SOIC_W Pin Configuration
Table 12. 16-Lead SOIC_W Pin Function Descriptions
Pin No.
1, 5, 7
Mnemonic
NIC1
2
3
4, 8
6
VIN+
VIN−
GND1
VDD1
9, 16
10, 12, 15
GND2
NIC2
11
MDAT
13
MCLKIN
14
VDD2
Description
Not Internally Connected. The NIC1 pins are not internally connected. Connect the NIC1 pins to VDD1, either of the
GND1 pins, or leave floating.
Positive Analog Input.
Negative Analog Input.
Ground 1. The GND1 pins are the ground reference point for all circuitry on the isolated side.
Supply Voltage, 4.5 V to 20 V. VDD1 is the supply voltage for the isolated side of the ADuM7704 and is relative to the
GND1 pins. For device operation, connect the supply voltage to NIC1 (Pin 7). Decouple the supply pin to either of
the GND1 pins with a 10 µF capacitor in parallel with a 100 nF capacitor as close to the pin as possible.
Ground 2. The GND2 pins are the ground reference point for all circuitry on the nonisolated side.
Not Internally Connected. The NIC2 pins are not internally connected. Connect the NIC2 pins to VDD2, either of the
GND2 pins, or leave floating.
Serial Data Output. The single-bit modulator output is supplied to MDAT as a serial data stream. MDAT is clocked
out on the rising edge of the MCLKIN input and is valid on the following MCLKIN rising edge.
Master Clock Logic Input. 5 MHz to 21 MHz frequency range. The bit stream from the modulator is propagated on
the rising edge of the MCLKIN.
Supply Voltage, 3 V to 5.5 V. VDD2 is the supply voltage for the nonisolated side and is relative to the GND2 pins.
Decouple this supply to either of the GND2 pins with a 10 µF capacitor in parallel with a 100 nF capacitor as close
to the pin as possible.
Rev. 0 | Page 9 of 22
Data Sheet
VDD1 1
VIN+ 2
VIN– 3
GND1 4
ADuM7704
8
VDD2
7
MCLKIN
TOP VIEW
6 MDAT
(Not to Scale)
5 GND2
25057-006
ADuM7704
Figure 6. 8-Lead SOIC_IC Pin Configuration
Table 13. 8-Lead SOIC_IC Pin Function Descriptions
Pin No.
1
Mnemonic
VDD1
2
3
4
5
6
VIN+
VIN−
GND1
GND2
MDAT
7
MCLKIN
8
VDD2
Description
Supply Voltage, 4.5 V to 20 V. VDD1 is the supply voltage for the isolated side of the ADuM7704 and is relative to GND1.
For device operation, connect the supply voltage to VDD1. Decouple the supply pin to GND1 with a 10 µF capacitor
in parallel with a 100 nF capacitor as close to the GND1 pin and VDD1 pin as possible.
Positive Analog Input.
Negative Analog Input.
Ground 1. GND1 is the ground reference point for all circuitry on the isolated side.
Ground 2. GND2 is the ground reference point for all circuitry on the nonisolated side.
Serial Data Output. The single-bit modulator output is supplied to MDAT as a serial data stream. MDAT is clocked
out on the rising edge of the MCLKIN input and is valid on the following MCLKIN rising edge.
Master Clock Logic Input. 5 MHz to 21 MHz frequency range. The bit stream from the modulator is propagated on
the rising edge of the MCLKIN.
Supply Voltage, 3 V to 5.5 V. VDD2 is the supply voltage for the nonisolated side and is relative to GND2. Decouple
this supply to GND2 with a 10 µF capacitor in parallel with a 100 nF capacitor as close to the GND2 pin and VDD2 pin
as possible.
Rev. 0 | Page 10 of 22
Data Sheet
ADuM7704
TYPICAL PERFORMANCE CHARACTERISTICS
TA = 25°C, VDD1 = 5 V, VDD2 = 5 V, VIN+ = −50 mV to +50 mV, VIN− = 0 V, and fMCLKIN = 20 MHz, using a sinc3 filter with a
256 oversampling ratio (OSR), unless otherwise noted.
0
0
–20
–20
MAGNITUDE (dB)
–60
–80
–100
–60
–80
–100
–120
–120
–140
400
200
600
800
1000
SUPPLY RIPPLE FREQUENCY (kHz)
–160
25057-107
0
0
5000
10000
15000
20000
25000
30000
FREQUENCY (kHz)
Figure 7. Power Supply Rejection Ratio (PSRR) vs. Supply Ripple Frequency
25057-110
PSRR (dB)
SNR = 82.71dB
SINAD = 82.54dB
THD = –96.65dB
–40
–40
–140
fIN = 1kHz
Figure 10. Typical Fast Fourier Transform (FFT)
0
1.0
SHORTED VIN± INPUTS
200mV p-p SINE WAVE ON INPUTS
0.8
–20
0.6
DNL ERROR (LSB)
CMRR (dB)
–40
–60
–80
0.4
0.2
0
–0.2
–0.4
–100
–0.6
–120
10
100
1000
COMMON-MODE RIPPLE FREQUENCY (kHz)
–1.0
25057-108
1
0
10000
20000
30000
40000
50000
60000
50000
60000
CODE
Figure 8. Common-Mode Rejection Ratio (CMRR) vs. Common-Mode Ripple
Frequency
25057-111
–0.8
MCLKIN = 10MHz, SINC3 OSR = 256
MCLKIN = 20MHz, SINC3 OSR = 256
–140
0.1
Figure 11. Typical DNL Error
2.0
88
SINAD 20MHz MCLKIN
SINAD 10MHz MCLKIN
86
1.5
84
1.0
INL ERROR (LSB)
80
78
76
0.5
0.0
–0.5
74
–1.0
72
68
0.1
1
ANALOG INPUT FREQUENCY (kHz)
10
Figure 9. SINAD vs. Analog Input Frequency
–2.0
0
10000
20000
30000
40000
CODE
Figure 12. Typical INL Error
Rev. 0 | Page 11 of 22
25057-112
–1.5
70
25057-109
SINAD (dB)
82
ADuM7704
Data Sheet
14
100
80
11.51
11.226
DEVICE 1
DEVICE 2
DEVICE 3
60
10.237
10
40
OFFSET (µV)
8.627
8
7.107
6
5.57
4.145
2.81
–20
–60
32778
25057-113
32776
32777
32774
32775
32773
32771
32772
32770
32769
32767
32768
32765
CODE
–100
–40
–25
–10
5
20
35
50
65
95
80
110
125
TEMPERATURE (°C)
Figure 13. Histogram of Codes at the Code Center
25057-116
–80
0.616
0.198 0.006
0.041 0.004
32766
32763
32764
32762
0
0
1.752
1.139
0.016 0.384
0.008 0.11
32760
2
20
–40
4
32761
HITS PER CODE (In Thousands)
12
Figure 16. Offset vs. Temperature
100
100
SNR
SINAD
80
DEVICE 1
DEVICE 2
DEVICE 3
60
40
OFFSET (µV)
SNR AND SINAD (dB)
90
80
20
0
–20
–40
70
–60
–10
5
20
35
50
65
80
95
110
125
TEMPERATURE (°C)
25057-114
–25
–100
4.5
7.6
13.8
16.9
20.0
VDD1 (V)
Figure 14. SNR and SINAD vs. Temperature
Figure 17. Offset vs. VDD1
–60
1.0
THD
SFDR
0.8
–70
DEVICE 1
DEVICE 2
DEVICE 3
GAIN ERROR (mV)
0.6
–80
–90
–100
0.4
0.2
0
–0.2
–0.4
–0.6
–110
–120
–40
–25
–10
5
20
35
50
65
80
95
TEMPERATURE (°C)
110
125
Figure 15. THD and SFDR vs. Temperature
–1.0
–40
–25
–10
5
20
35
50
65
80
95
TEMPERATURE (°C)
Figure 18. Gain Error vs. Temperature
Rev. 0 | Page 12 of 22
110
125
25057-118
–0.8
25057-115
THD AND SFDR (dB)
10.7
25057-117
–80
60
–40
ADuM7704
5.0
0.20
4.5
0.15
4.0
0.10
3.5
0.05
3.0
0
–0.05
2.0
1.5
–0.15
1.0
–0.20
0.5
10.7
7.6
13.8
16.9
20.0
VDD1 (V)
–40°C
+25°C
+125°C
–40°C
+25°C
+125°C
2.5
–0.10
–0.25
4.5
MCLKIN = 10MHz,
MCLKIN = 10MHz,
MCLKIN = 10MHz,
MCLKIN = 20MHz,
MCLKIN = 20MHz,
MCLKIN = 20MHz,
0
3
4
3.5
5
4.5
5.5
VDD2 (V)
25057-122
IDD2 (mA)
0.25
25057-119
GAIN ERROR (%FSR)
Data Sheet
Figure 22. IDD2 vs. VDD2 at Various Temperatures and Clock Rates
Figure 19. Gain Error vs. VDD1
5.0
16
MCLKIN = 10MHz,
MCLKIN = 10MHz,
MCLKIN = 10MHz,
MCLKIN = 20MHz,
MCLKIN = 20MHz,
MCLKIN = 20MHz,
14
12
–40°C
+25°C
+125°C
–40°C
+25°C
+125°C
TA = –40°C
TA = 0°C
TA = +25°C
TA = +85°C
TA = +125°C
4.5
DC INPUT
4.0
IDD2 (mA)
IDD1 (mA)
10
8
6
3.5
3.0
4
2.5
13.8
10.7
7.6
16.9
20.0
VDD1 (V)
2.0
–50
25057-120
0
4.5
0
–25
25
50
VIN+ (mV)
25057-123
2
Figure 23. IDD2 vs. VIN+ DC Input at Various Temperatures
Figure 20. IDD1 vs. VDD1 at Various Temperatures and Clock Rates
500
10.0
DC INPUT
9.5
MLCKIN = 10MHz
MLCKIN = 20MHz
DC INPUT
400
9.0
300
200
IIN+ (nA)
8.0
7.5
7.0
100
0
6.5
–100
TA = –40°C
TA = 0°C
TA = +25°C
TA = +85°C
TA = +125°C
5.5
5.0
–50
–25
0
25
VIN+ (mV)
–200
50
Figure 21. IDD1 vs. VIN+ DC Input at Various Temperatures
–300
–50
–30
–10
10
30
VIN+ (mV)
Figure 24. VIN+ Current (IIN+) vs. VIN+ DC Input
Rev. 0 | Page 13 of 22
50
25057-124
6.0
25057-121
IDD1 (mA)
8.5
ADuM7704
Data Sheet
TERMINOLOGY
Differential Nonlinearity (DNL)
DNL is the difference between the measured and the ideal
1 LSB change between any two adjacent codes in the analogto-digital converter (ADC).
Integral Nonlinearity (INL)
INL is the maximum deviation from a straight line passing
through the endpoints of the ADC transfer function. The
endpoints of the transfer function are specified negative full
scale, −50 mV (VIN+ − VIN−), Code 7168 for the 16-bit level, and
specified positive full scale, +50 mV (VIN+ − VIN−), Code 58,368
for the 16-bit level.
Offset Error
Offset error is the deviation of the midscale code (32,768 for
the 16-bit level) from the ideal VIN+ − VIN− (that is, 0 V).
Offset Drift vs. Temperature
The offset drift is calculated using the box method, as shown
by the following equation:
Offset Drift = ((VoltageMAX − VoltageMIN)/TΔ)
where:
VoltageMAX is the maximum offset error point recorded.
VoltageMIN is the minimum offset error point recorded.
TΔ is the difference in temperature between the maximum
and minimum operating range.
Signal-to-Noise-and-Distortion Ratio (SINAD)
SINAD is the measured ratio of signal to noise and distortion at
the output of the ADC. The signal is the rms value of the sine
wave, and noise is the rms sum of all nonfundamental signals
up to half the sampling frequency (fS/2), including harmonics,
but excluding dc.
Signal-to-Noise Ratio (SNR)
SNR is the measured ratio of signal to noise at the output of the
ADC. The signal is the rms amplitude of the fundamental. Noise
is the sum of all nonfundamental signals up to half the sampling
frequency (fS/2), excluding dc.
The ratio is dependent on the number of quantization levels in the
digitization process, that is, the greater the number of levels, the
smaller the quantization noise. The theoretical SNR for an ideal
N-bit converter with a sine wave input is given by
SNR = (6.02N + 1.76) dB
Therefore, for a 12-bit converter, the SNR is 74 dB.
Isolation Common-Mode Transient Immunity (CMTI)
The isolation CMTI specifies the rate of the rise and fall of a
transient pulse applied across the isolation boundary, beyond
which clock or data is corrupted. Both the rate of change and
the absolute common-mode voltage of the pulse are recorded.
The ADuM7704 is tested under both static and dynamic CMTI
conditions. Static testing detects single-bit errors from the device.
Dynamic testing monitors the filtered data output for variations in
noise performance to a randomized application of the CMTI pulse.
Gain Error
The gain error includes both positive full-scale gain error and
negative full-scale gain error. Positive full-scale gain error is the
deviation of the specified positive full-scale code (58,368 for the
16-bit level) from the ideal VIN+ − VIN− (50 mV) after the offset
error is adjusted out. Negative full-scale gain error is the deviation
of the specified negative full-scale code (7168 for the 16-bit level)
from the ideal VIN+ − VIN− (−50 mV) after the offset error is
adjusted out.
Total Harmonic Distortion (THD)
THD is the ratio of the rms sum of the harmonics to the
fundamental. It is defined as
Gain Error Drift vs. Temperature
The gain error drift (GED) is calculated using the box method,
as shown by the following equation:
where:
V2, V3, V4, V5, and V6 are the rms amplitudes of the second
through the sixth harmonics.
V1 is the rms amplitude of the fundamental.
GED (ppm) = ((VoltageMAX − VoltageMIN)/(VoltageFS ×
TΔ)) × 106
where:
VoltageMAX is the maximum gain error point recorded.
VoltageMIN is the minimum gain error point recorded.
VoltageFS is the analog input range full scale.
TΔ is the difference in temperature between the maximum
and minimum operating range.
THD (dB) = 20log
V22 +V32 +V42 +V5 2 +V6 2
V1
Peak Harmonic or Spurious-Free Dynamic Range (SFDR) Noise
Peak harmonic or SFDR noise is defined as the ratio of the rms
value of the next largest component in the ADC output spectrum
(up to fS/2, excluding dc) to the rms value of the fundamental.
Normally, the value of this specification is determined by the
largest harmonic in the spectrum, but for ADCs where the
harmonics are buried in the noise floor, it is a noise peak.
Effective Number of Bits (ENOB)
ENOB is defined by
ENOB = (SINAD − 1.76)/6.02 bits
Rev. 0 | Page 14 of 22
Data Sheet
ADuM7704
Noise Free Code Resolution
Noise free code resolution represents the resolution in bits for
which there is no code flicker. The noise free code resolution for
an N-bit converter is defined as
Noise Free Code Resolution (Bits) = log2(2N/Peak-to-Peak Noise)
The peak-to-peak noise in LSBs is measured with VIN+ = VIN− =
0 V.
Common-Mode Rejection Ratio (CMRR)
CMRR is the ratio of the power in the ADC output at ±50 mV
frequency, f, to the power of a +50 mV p-p sine wave applied to
the common-mode voltage of VIN+ and VIN− of frequency, fS, as
where:
Pf is the power at frequency, f, in the ADC output.
PfS is the power at frequency, fS, in the ADC output.
Power Supply Rejection Ratio (PSRR)
Variations in power supply affect the full-scale transition but
not the linearity of the converter. PSRR is the maximum change
in the specified full-scale (±50 mV) transition point due to a
change in power supply voltage from the nominal value.
CMRR (dB) = 10 log(Pf/PfS)
Rev. 0 | Page 15 of 22
ADuM7704
Data Sheet
THEORY OF OPERATION
CIRCUIT INFORMATION
The ADuM7704 isolated Σ-Δ modulator converts an analog
input signal to a high speed (21 MHz maximum), single-bit data
stream. The time average single-bit data from the modulator is
directly proportional to the input signal. Figure 25 shows a
typical application circuit where the ADuM7704 provides
isolation between the analog input, a current sensing resistor
or shunt, and the digital output, which is then processed by a
digital filter to provide an N-bit word.
ANALOG INPUT
The pseudo differential analog input of the ADuM7704 is
implemented with a switched capacitor circuit. This circuit
implements a second-order modulator stage that digitizes the
input signal to a single-bit output stream. The sample clock
(MCLKIN) provides the clock signal for the conversion process
as well as the output data framing clock. This clock source is
externally supplied to the ADuM7704. The analog input signal
is continuously sampled by the modulator and compared to
an internal voltage reference. A digital stream that accurately
represents the analog input over time appears at the output of
the converter (see Figure 26).
A differential signal of 0 V ideally results in a stream of
alternating 1s and 0s at the MDAT output pin. This output is
high 50% of the time and low 50% of the time. A differential
input of 50 mV produces a stream of 1s and 0s that are high
89.06% of the time. A differential input of −50 mV produces a
stream of 1s and 0s that are high 10.94% of the time.
A differential input of 64 mV ideally results in a stream of all 1s.
A differential input of −64 mV ideally results in a stream of all
0s. The ADuM7704 absolute full-scale range is ±64 mV, and the
specified full-scale performance range is ±50 mV, as shown in
Table 14.
Table 14. Analog Input Range
Analog Input
Positive Full-Scale (+FS) Value
Positive Specified Performance
Zero
Negative Specified Performance
Negative Full-Scale (−FS) Value
FLOATING
POWER SUPPLY
NONISOLATED
5V/3.3V
+400V
GATED
DRIVE
CIRCUIT
10µF 100nF
VDD1
ADuM7704
VDD2
VIN+
Σ-Δ
MOD/
ENCODER
MDAT
MDAT
10Ω
MOTOR
MCLKIN
MCLK
FLOATING
POWER SUPPLY
VDD
SINC3 FILTER*
220pF
10Ω
RSHUNT
Voltage Input (mV)
+64
+50
0
−50
−64
CS
DECODER
SCLK
VIN–
SDAT
220pF
DECODER
100nF
ENCODER
GND1
10µF
GND2
GND
GATED
DRIVE
CIRCUIT
25057-007
*THIS FILTER IS IMPLEMENTED
WITH AN FPGA OR DSP
–400V
Figure 25. Typical Application Circuit
MODULATOR OUTPUT
–FS ANALOG INPUT
ANALOG INPUT
Figure 26. Analog Input vs. Modulator Output
Rev. 0 | Page 16 of 22
25057-008
+FS ANALOG INPUT
Data Sheet
ADuM7704
65535
58368
SPECIFIED RANGE
ADC CODE
To reconstruct the original information, this output must be
digitally filtered and decimated. A sinc3 filter is recommended
because this filter is one order higher than that of the ADuM7704
modulator, which is a second-order modulator. When a
256 decimation rate is used, the resulting 16-bit word rate is
78.1 kSPS, assuming a 20 MHz external clock frequency. See the
Digital Filter section for more detailed information on the sinc
filter implementation. Figure 27 shows the transfer function of
the ADuM7704 relative to the 16-bit output.
7168
–64mV
–50mV
+50mV
ANALOG INPUT
+64mV
Figure 27. Filtered and Decimated 16-Bit Transfer Function
Rev. 0 | Page 17 of 22
25057-009
0
ADuM7704
Data Sheet
APPLICATIONS INFORMATION
CURRENT SENSING APPLICATIONS
90
13-BIT
ENOB
85
80
SINAD (dB)
The ADuM7704 is ideally suited for current sensing applications
where the voltage across a shunt resistor (RSHUNT) is monitored.
The load current flowing through an external shunt resistor
produces a voltage at the input terminals of the ADuM7704.
The ADuM7704 provides isolation between the analog input
from the current sensing resistor and the digital outputs. By
selecting the appropriate shunt resistor value, a variety of
current ranges can be monitored.
fIN = 1kHz
MCLKIN = 20MHz
VDD1 = 5V
VDD2 = 3.3V
TA = 25°C
12-BIT
ENOB
75
70
Choosing RSHUNT
11-BIT
ENOB
The RSHUNT values used in conjunction with the ADuM7704 are
determined by the specific application requirements in terms of
voltage, current, and power. Small resistors minimize power
dissipation, whereas low inductance resistors prevent any
induced voltage spikes, and high tolerance devices reduce
current variations. The final values chosen are a compromise
between low power dissipation and accuracy. Higher value
resistors use the full performance input range of the ADC, thus
achieving maximum SNR performance. Low value resistors
dissipate less power but do not use the full performance input
range. The ADuM7704, however, delivers excellent
performance, even with lower input signal levels, allowing low
value shunt resistors to be used while maintaining system
performance.
To choose a suitable shunt resistor, first determine the current
through the shunt. Calculate the shunt current for a 3-phase
induction motor as
IRMS = PW/(1.73 × V × EF × PF)
where:
IRMS is the motor phase current (A rms).
PW is the motor power (W).
V is the motor supply voltage (V ac).
EF is the motor efficiency (%).
PF is the power efficiency (%).
60
0
10
20
30
40
50
VIN+ (mV)
25057-028
65
Figure 28. SINAD vs. VIN+ AC Input Signal Amplitude
RSHUNT must dissipate the current2 × resistance (I2R) power
losses. If the power dissipation rating of the resistor is exceeded,
the value may drift, or the resistor may be damaged, resulting in
an open circuit. This open circuit can result in a differential
voltage across the terminals of the ADuM7704, in excess of the
absolute maximum ratings. If ISENSE has a large high frequency
component, choose a resistor with low inductance.
VOLTAGE SENSING APPLICATIONS
The ADuM7704 can also be used for isolated voltage
monitoring. For example, in motor control applications, the
device can be used to sense the bus voltage. In applications where
the voltage being monitored exceeds the specified analog input
range of the ADuM7704, a voltage divider network can be used
to reduce the voltage being monitored to the required range.
INPUT FILTER
In a typical use case for directly measuring the voltage across a
shunt resistor, the ADuM7704 can be connected directly across
the shunt resistor with a simple RC low-pass filter on each input.
If the power dissipation in the shunt resistor is too large, the
shunt resistor can be reduced, and less of the ADC input
range can be used. Figure 28 shows the SINAD performance
characteristics and the ENOB of resolution for the ADuM7704
for different input signal amplitudes. The performance of the
ADuM7704 at lower input signal ranges allows smaller shunt
values to be used while still maintaining a high level of
performance and overall system efficiency.
Rev. 0 | Page 18 of 22
C
VIN+
R
ADuM7704
VIN–
R
C
25057-012
To determine the shunt peak sense current (ISENSE), consider the
motor phase current and any overload that may be possible in
the system. When the peak sense current is known, divide the
voltage range of the ADuM7704 (±50 mV) by the peak sense
current to yield a maximum shunt value.
The recommended circuit configuration for driving the
differential inputs to achieve best performance is shown in
Figure 29. An RC low-pass filter is placed on both the analog
input pins. Recommended values for the resistors and capacitors
are 10 Ω and 220 pF, respectively. If possible, equalize the
source impedance on each analog input to minimize offset.
Figure 29. RC Low-Pass Filter Input Network
Data Sheet
ADuM7704
The input filter configuration for the ADuM7704 is not limited
to the low-pass structure shown in Figure 29. The differential RC
filter configuration shown in Figure 30 also achieves excellent
performance. Recommended values for the resistors and
capacitor are 22 Ω and 47 pF, respectively.
VIN+
(
1 1 − Z − DR
H (Z ) =
DR 1 − Z −1
R
C
(
ADuM7704
R
)
N
)
Figure 30. Differential RC Filter Network
DIGITAL FILTER
The output of the ADuM7704 is a continuous digital bit stream.
To reconstruct the original input signal information, this output
bit stream must be digitally filtered and decimated. A sinc filter
is recommended due to simplicity of the filter. A sinc3 filter is
recommended because the filter is one order higher than that of
the ADuM7704 modulator, which is a second-order modulator.
The type of filter selected, the decimation rate, and the modulator
clock used determines the overall system resolution and
throughput rate. The higher the decimation rate, the greater the
system accuracy, as shown in Figure 31. However, there is a
trade-off between accuracy and throughput rate and, therefore,
higher decimation rates result in lower throughput solutions.
Note that for a given bandwidth requirement, a higher MCLKIN
frequency can allow higher decimation rates to be used, resulting
in higher SNR performance.
The throughput rate of the sinc filter is determined by the
modulator clock and the decimation rate selected.
Throughput = MCLK/DR
As the decimation rate increases, the data output size from
the sinc filter increases. The output data size is expressed in
Equation 3. The 16 most significant bits are used to return a
16-bit result.
Data Size = N × log2 DR
SNR (dB)
60
40
1000
25057-125
20
100
Figure 31. SNR vs. Decimation Rate of Sinc3 Filter Order
Table 15. Sinc3 Filter Characteristics for 20 MHz MCLKIN
Decimation Ratio (DR)
32
64
128
256
512
Throughput Rate (kHz)
625
312.5
156.2
78.1
39.1
(3)
For a sinc3 filter, the −3 dB filter response point can be derived
from the filter transfer function, Equation 1, and is 0.262 times
the throughput rate. The filter characteristics for a third-order
sinc filter are summarized in Table 15.
80
DECIMATION RATE
(2)
where MCLK is the modulator clock frequency
100
0
10
(1)
where:
Z is the sample.
DR is the decimation rate.
N is the sinc filter order.
25057-011
VIN–
A sinc3 filter is recommended for the ADuM7704. This filter
can be implemented on a field programmable gate array
(FPGA) or a digital signal processor (DSP). Equation 1
describes the transfer function of a sinc filter.
Output Data Size (Bits)
15
18
21
24
27
Rev. 0 | Page 19 of 22
Filter Response (kHz)
163.7
81.8
40.9
20.4
10.2
ADuM7704
Data Sheet
INTERFACING TO ADSP-CM4xx
The ADSP-CM4xx family of mixed-signal control processors
contains an on-chip sinc filter and clock generation modules for
direct connection to the ADuM7704 MCLKIN and MDAT pins.
The ADSP-CM4xx can process bit streams from four
ADuM7704 devices using a pair of configurable sinc filters for
each bit stream. The primary sinc filter of each pair produces the
filtered and decimated output for the pair. The output can be
decimated to any integer rate between 8 times and 256 times
lower than the input rate. The four secondary sinc filters are low
latency filters with programmable positive and negative
overrange detection comparators that can detect system fault
conditions
Figure 32 shows the typical interface between the ADuM7704
and the ADSP-CM4xx. Additional information on the
configuration of the sinc filter modules in the ADSP-CM4xx
can be found in the AN-1265 Application Note.
PRIMARY
LIMIT
SECONDARY
CONTROL FOR GROUP n
SINC0_CLK0
ADuM77041
1ADDITIONAL
MODULATOR CLOCK n
ADSP-CM40xF1
PINS OMITTED FOR CLARITY
25057-014
MCLKIN
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. In addition
to the testing performed by the regulatory agencies, Analog
Devices carries out an extensive set of evaluations to determine
the lifetime of the insulation structure within the ADuM7704.
Figure 32. Interfacing the ADuM7704 to the ADSP-CM4xx
These tests subjected the ADuM7704 to continuous cross isolation
voltages. To accelerate the occurrence of failures, the selected
test voltages were values exceeding those of normal use. The
time to failure values of these units were recorded and used to
calculate the acceleration factors. These factors were then used
to calculate the time to failure under the normal operating
conditions. The values shown in Table 10 are the lesser of the
following two values:
GROUNDING AND LAYOUT
•
It is recommended to decouple the VDD1 supply with a 10 µF
capacitor in parallel with a 100 nF capacitor to any GND1 pin.
Decouple the VDD2 supply with a 10 µF capacitor in parallel with
a 100 nF capacitor to any GND2 pin. In applications involving
high common-mode transients, ensure that board coupling
across the isolation barrier is minimized. Furthermore, design
the board layout so that any coupling that occurs equally affects
all pins on a given component side. Failure to ensure equal
coupling can cause voltage differentials between pins to exceed
the absolute maximum ratings of the device, thereby leading to
latch-up or permanent damage. Place any decoupling capacitors
used as close to the supply pins as possible.
•
The value that ensures at least a 37.5 year lifetime of
continuous (reinforced) use.
The maximum VDE approved working voltage.
The lifetime of the ADuM7704 is guaranteed using a bipolar
ac waveform, as shown in Figure 33.
Rev. 0 | Page 20 of 22
RATED PEAK VOLTAGE
0V
25057-015
SINC0_D0
INSULATION LIFETIME
Analog Devices performs accelerated life testing using voltage levels
higher than the rated continuous working voltage. Acceleration
factors for several operating conditions are determined. These
factors allow calculation of the time to failure at the actual
working voltage. The values shown in Table 10 summarize the
peak voltage for 37.5 years of (reinforced) service life for a
bipolar, ac operating condition and the maximum VDE
approved working voltages.
SINC PAIR n
MDAT
Minimize series resistance in the analog inputs to avoid any
distortion effects, especially at high temperatures. If possible,
equalize the source impedance on each analog input to minimize
offset. Check for mismatch and thermocouple effects on the analog
input PCB tracks to reduce offset drift.
Figure 33. Bipolar AC Waveform, 50 Hz or 60 Hz
Data Sheet
ADuM7704
OUTLINE DIMENSIONS
10.50 (0.4134)
10.10 (0.3976)
9
16
7.60 (0.2992)
7.40 (0.2913)
1
10.65 (0.4193)
10.00 (0.3937)
8
1.27 (0.0500)
BSC
0.30 (0.0118)
0.10 (0.0039)
COPLANARITY
0.10
0.75 (0.0295)
45°
0.25 (0.0098)
2.65 (0.1043)
2.35 (0.0925)
SEATING
PLANE
0.51 (0.0201)
0.31 (0.0122)
8°
0°
1.27 (0.0500)
0.40 (0.0157)
0.33 (0.0130)
0.20 (0.0079)
03-27-2007-B
COMPLIANT TO JEDEC STANDARDS MS-013-AA
CONTROLLING DIMENSIONS ARE IN MILLIMETERS; INCH DIMENSIONS
(IN PARENTHESES) ARE ROUNDED-OFF MILLIMETER EQUIVALENTS FOR
REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN.
Figure 34. 16-Lead Standard Small Outline Package [SOIC_W]
Wide Body
(RW-16)
Dimensions shown in millimeters and (inches)
6.05
5.85
5.65
8
5
7.60
7.50
7.40
10.51
10.31
10.11
4
2.45
2.35
2.25
0.30
0.20
0.10
COPLANARITY
0.10
2.65
2.50
2.35
1.27 BSC
0.51
0.41
0.31
SEATING
PLANE
0.75
0.50
0.25
1.04
BSC
0.75
0.58
0.40
45°
8°
0°
0.33
0.27
0.20
Figure 35. 8-Lead Standard Small Outline Package, with Increased Creepage [SOIC_IC]
Wide Body
(RI-8-1)
Dimensions shown in millimeters
Rev. 0 | Page 21 of 22
09-17-2014-B
PIN 1
MARK
1
ADuM7704
Data Sheet
ORDERING GUIDE
Model 1, 2
ADuM7704BRWZ
ADuM7704BRWZ-RL
ADuM7704BRWZ-RL7
ADuM7704-8BRIZ
ADuM7704-8BRIZ-RL
ADuM7704-8BRIZ-RL7
EV-ADuM7704-8FMCZ
1
2
Temperature Range
−40°C to +125°C
−40°C to +125°C
−40°C to +125°C
−40°C to +105°C
−40°C to +105°C
−40°C to +105°C
Package Description
16-Lead Standard Small Outline Package [SOIC_W]
16-Lead Standard Small Outline Package [SOIC_W]
16-Lead Standard Small Outline Package [SOIC_W]
8-Lead Standard Small Outline Package, with Increased Creepage [SOIC_IC]
8-Lead Standard Small Outline Package, with Increased Creepage [SOIC_IC]
8-Lead Standard Small Outline Package, with Increased Creepage [SOIC_IC]
Evaluation Board
Z = RoHS Compliant Part.
The EV-ADuM7704-8FMCZ is compatible with the EVAL-SDP-CH1Z high speed controller board.
©2020 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D25057-8/20(0)
Rev. 0 | Page 22 of 22
Package
Option
RW-16
RW-16
RW-16
RI-8-1
RI-8-1
RI-8-1
工商网监
湘ICP备2023018690号
