LTM8022
1A, 36V DC/DC µModule
FEATURES
DESCRIPTION
n
The LTM®8022 is a complete 1A, DC/DC step-down power
supply. Included in the package are the switching controller,
power switches, inductor, and all support components.
Operating over an input voltage range of 3.6V to 36V, the
LTM8022 supports an output voltage range of 0.8V to 10V,
and a switching frequency range of 200kHz to 2.4MHz,
each set by a single resistor. Only the bulk input and output
filter capacitors are needed to finish the design.
n
n
n
n
n
n
n
n
Complete Step-Down Switch Mode Power Supply
Wide Input Voltage Range: 3.6V to 36V
0.8V to 10V Output Voltage
1A Output Current
Adjustable Switching Frequency: 200kHz to 2.4MHz
Current Mode Control
(e4) RoHS Compliant Package with Gold Pad Finish
Programmable Soft-Start
Tiny, Low Profile (11.25mm × 9mm × 2.82mm)
Surface Mount LGA Package
APPLICATIONS
n
n
n
n
n
The low profile package (2.82mm) enables utilization of
unused space on the bottom of PC boards for high density
point of load regulation.
The LTM8022 is packaged in a thermally enhanced, compact
(11.25mm × 9mm) and low profile (2.82mm) overmolded
land grid array (LGA) package suitable for automated
assembly by standard surface mount equipment. The
LTM8022 is RoHS compliant.
Automotive Battery Regulation
Power for Portable Products
Distributed Supply Regulation
Industrial Supplies
Wall Transformer Regulation
L, LT, LTC, LTM, Linear Technology, Burst Mode and the Linear logo are registered trademarks of
Linear Technology Corporation. All other trademarks are the property of their respective owners.
TYPICAL APPLICATION
7VIN to 36VIN , 5V/1A μModule® Regulator
VIN*
7V TO
36V
VIN
100
VOUT
5V
1A
VOUT
LTM8022
AUX
RUN/SS
2.2μF
Efficiency and Power Loss
0.8
VIN = 12V
0.7
90
4.7μF
0.6
EFFICIENCY (%)
BIAS
PG
RT GND SYNC ADJ
70
0.5
EFFICIENCY
POWER
LOSS
60
0.4
0.3
50
29.4k
0.2
93.1k
40
8022 TA01a
*RUNNING VOLTAGE RANGE. PLEASE REFER TO
APPLICATIONS INFORMATION FOR START-UP DETAILS
30
0.001
POWER LOSS (W)
80
SHARE
0.1
0.1
0.01
LOAD CURRENT (A)
1
0
8022 TA01b
8022fd
1
LTM8022
ABSOLUTE MAXIMUM RATINGS
PIN CONFIGURATION
(See Table 3, Pin Assignment)
(Note 1)
VIN, RUN/SS Voltage .................................................40V
ADJ, RT, SHARE, Voltage ............................................5V
VOUT , AUX .................................................................10V
SYNC, PG ..................................................................30V
BIAS ..........................................................................16V
VIN + BIAS .................................................................56V
Internal Operating Temperature..............–40°C to 125°C
Solder Temperature............................................... 250°C
Storage Temperature..............................–55°C to 125°C
GND (BANK 3)
SHARE RT
ADJ
7
6
SYNC
PG
5
RUN/SS
BIAS
4
AUX
3
VOUT
(BANK 2) 2
VIN
(BANK 1)
1
A
B
C
D
E
F
G
H
LGA PACKAGE
50-LEAD (11.25mm s 9mm s 2.82mm)
TJMAX = 125°C, θJA = 23.4°C/W, θJC(BOTTOM) = 9.20°C/W,
θJC(TOP) = 25.10°C/W, θJBOARD = 16°C/W
θ VALUES DETERMINED PER JESD51-9
WEIGHT = 0.93g
ORDER INFORMATION
LEAD FREE FINISH
PART MARKING*
PACKAGE DESCRIPTION
TEMPERATURE RANGE (Note 2)
LTM8022EV#PBF
LTM8022V
50-Pin (11.25mm × 9mm × 2.82mm) LGA
–40°C to 85°C
LTM8022IV#PBF
LTM8022V
50-Pin (11.25mm × 9mm × 2.82mm) LGA
–40°C to 85°C
LTM8022MPV#PBF
LTM8022MPV
50-Pin (11.25mm × 9mm × 2.82mm) LGA
–55°C to 125°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
Consult LTC Marketing for information on non-standard lead based finish parts.
For more information on lead free part marking, go to: http://www.linear.com/leadfree/
This product is only offered in trays. For more information go to: http://linear.com/packaging/
8022fd
2
LTM8022
ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN = 10V, VRUN/SS = 10V, VBIAS = 3V, RT = 60.4kΩ, CIN = 2.2μF, COUT = 4.7μF,
unless otherwise specified. (Note 2)
SYMBOL
PARAMETER
CONDITIONS
MIN
VIN
Input DC Voltage
VOUT
Output DC Voltage
0V < IOUT < 1A, RADJ Open
0V < IOUT < 1A, RADJ = 43.2k
RADJ(MIN)
Minimum Allowable RADJ
(Note 3)
IOUT(MAX)
Continuous Output DC Current
4V < VIN < 36V, COUT = 51μF (Note 4)
IQVIN
VIN Quiescent Current
VRUN/SS = 0.2V, RT = 174k
VBIAS = 3V, Not Switching, RT = 174k (E, I)
VBIAS = 3V, Not Switching, RT = 174k (MP)
VBIAS = 0V, Not Switching, RT = 174k
l
l
IQBIAS
BIAS Quiescent Current
VRUN/SS = 0.2V, RT = 174k
VBIAS = 3V, Not Switching, RT = 174k (E, I)
VBIAS = 3V, Not Switching, RT = 174k (MP)
VBIAS = 0V, Not Switching, RT = 174k
l
l
ΔVOUT/VOUT
Line Regulation
3.6V < VIN < 36V, IOUT = 1A, VOUT = 3.3V
0.1
%
ΔVOUT/VOUT
Load Regulation
VIN = 24V, 0V < IOUT < 1A, VOUT = 3.3V,
COUT = 51μF
0.4
%
VOUT(AC_RMS)
Output Ripple (RMS)
VIN = 24V, IOUT = 1A, VOUT = 3.3V,
COUT = 51μF
10
mV
fSW
Switching Frequency
RT = 113kΩ, COUT = 51μF
325
kHz
ISC(OUT)
Output Short-Circuit Current
VIN = 36V, VOUT = 0V (Note 5)
l
TYP
3.6
36
0.8
10
COUT = 51μF
1
A
0.1
25
25
85
0.5
60
350
120
μA
μA
μA
μA
0.03
50
50
1
0.5
120
200
5
μA
μA
μA
μA
3
765
V
kΩ
0
l
UNITS
V
V
42.2
VADJ
Voltage at ADJ Pin
VBIAS(MIN)
Minimum BIAS Voltage for Proper Operation
IADJ
Current Out of ADJ Pin
ADJ = 1V, COUT = 51μF
2
IRUN/SS
RUN/SS Pin Current
VRUN/SS = 2.5V
5
VIH(RUN/SS)
RUN/SS Input High Voltage
COUT = 51μF
VIL(RUN/SS)
RUN/SS Input Low Voltage
COUT = 51μF
VPG(TH)
PG Threshold
VFB Rising
730
IPGO
PG Leakage
VPG = 30V
0.1
IPG(SINK)
PG Sink Current
VPG = 0.4V
200
VSYNC(IL)
SYNC Low Threshold
fSYNC = 550kHz, COUT = 51μF
0.5
VSYNC(IH)
SYNC High Threshold
fSYNC = 550kHz, COUT = 51μF
ISYNC(BIAS)
SYNC Pin Bias Current
VSYNC = 0V
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2: The LTM8022E is guaranteed to meet performance specifications
from 0°C to 85°C ambient. Specifications over the full –40°C to
85°C ambient operating temperature range are assured by design,
characterization and correlation with statistical process controls. The
LTM8022I is guaranteed to meet specifications over the full –40°C to 85°C
ambient operating temperature range. The LTM8022MP is guaranteed to
MAX
A
790
805
mV
1.9
2.4
V
μA
10
2.5
μA
V
0.2
V
mV
1
800
μA
μA
V
0.7
0.1
V
μA
meet specifications over the full –55°C to 125°C temperature range. Note
that the maximum internal temperature is determined by specific operating
conditions in conjunction with board layout, the rated package thermal
resistance and other environmental factors.
Note 3: Guaranteed by design.
Note 4: COUT = 51μF is composed of a 4.7μF ceramic capacitor and a 47μF
electrolytic.
Note 5: Short circuit current at VIN = 36V is guaranteed by characterization
and correlation. 100% tested at VIN = 10V.
8022fd
3
LTM8022
TYPICAL PERFORMANCE CHARACTERISTICS
Efficiency vs Load (8VOUT)
Efficiency vs Load (5VOUT)
95
Efficiency vs Load (3.3VOUT)
90
90
12VIN
12VIN
90
80
80
EFFICIENCY (%)
36VIN
36VIN
75
80
36VIN
75
70
75
70
65
70
65
60
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
OUTPUT CURRENT (A)
12VIN
24VIN
24VIN
EFFICIENCY (%)
85
5VIN
85
85
24VIN
EFFICIENCY (%)
(TA = 25°C, unless otherwise noted)
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
OUTPUT CURRENT (A)
8022 G01
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
OUTPUT CURRENT (A)
8022 G03
8022 G02
Output Start-up Waveform
VIN = 36V, 3.3VOUT, IOUT = 1A
Output Start-up Waveform
VIN = 36V, 5VOUT, IOUT = 1A
Minimum Required Input Voltage
vs Output Voltage, IOUT = 1A
12
VOUT
2V/DIV
11
10
INPUT VOLTAGE (V)
9
8
7
VOUT
2V/DIV
IIN
0.2A/DIV
IIN
0.2A/DIV
RUN/SS
5V/DIV
RUN/SS
5V/DIV
6
8022 G05
50μs/DIV
8022 G06
50μs/DIV
5
4
3
2
0
2
4
6
8
OUTPUT VOLTAGE (V)
10
8022 G04
Input Current
vs Output Current (8VOUT)
Input Current
vs Output Current (3.3VOUT)
Input Current
vs Output Current (5VOUT)
800
700
500
900
450
800
500
12VIN
400
24VIN
300
200
700
350
300
250
12VIN
200
24VIN
150
100
36VIN
INPUT CURRENT (mA)
600
INPUT CURRENT (mA)
INPUT CURRENT (mA)
400
600
500
300
50
100
0
0
0
200
400
800
600
OUTPUT CURRENT (mA)
1000
8022 G07
12VIN
200
36VIN
100
0
5VIN
400
24VIN
36VIN
0
200
600
800
400
OUTPUT CURRENT (mA)
1000
8022 G08
0
800
200
600
400
OUTPUT CURRENT (mA)
1000
8022 G09
8022fd
4
LTM8022
TYPICAL PERFORMANCE CHARACTERISTICS
3000
14
2800
12
2600
2400
2200
5VOUT
6
1800
2
0
40
30
8VOUT
8
4
20
1000
10
2000
10
1200
LOAD CURRENT (mA)
16
BIAS CURRENT (mA)
OUTPUT CURRENT (mA)
3200
0
Minimum Required Input Voltage
vs Output Load (8VOUT)
BIAS Quiescent Current
vs Load Current
Output Current vs Input Voltage
(Output Short)
1600
(TA = 25°C, unless otherwise noted)
3.3VOUT
600
400
200
25°C
85°C
0
200
0
INPUT VOLTAGE (V)
400
800
600
LOAD CURRENT (mA)
0
1000
10
Minimum Required Input Voltage
vs Output Load (5VOUT)
1200
1000
1000
LOAD CURRENT (mA)
1200
800
600
400
8022 G13
800
600
400
200
25°C
85°C
0
0
10
20
30
INPUT VOLTAGE (V)
25°C
85°C
0
40
0
10
20
30
INPUT VOLTAGE (V)
8022 G14
Temperature Rise vs Load
(3.3VOUT)
15
36VIN
10
12VIN
24VIN
5
Temperature Rise vs Load
(8VOUT)
35
40
30
35
TEMPERATURE RISE (°C)
TEMPERATURE RISE (°C)
TEMPERATURE RISE (°C)
20
25
20
36VIN
15
12VIN
10
24VIN
5
400
600
800
LOAD (mA)
1000
1200
8022 G16
30
25
24VIN
36VIN
20
15
12VIN
10
5
0
0
200
40
8022 G15
Temperature Rise vs Load
(5VOUT)
25
0
40
Minimum Required Input Voltage
vs Output Load (3.3VOUT)
200
0
20
30
INPUT VOLTAGE (V)
8022 G11
8022 G10
LOAD CURRENT (mA)
800
0
200
400
800
600
LOAD (mA)
1000
1200
8022 G17
0
200
400
800
600
LOAD (mA)
1000
1200
8022 G18
8022fd
5
LTM8022
PIN FUNCTIONS
VIN (Bank 1): The VIN pin supplies current to the LTM8022’s
internal regulator and to the internal power switch. This
pin must be locally bypassed with an external, low ESR
capacitor of at least 2.2μF.
VOUT (Bank 2): Power Output Pins. Apply the output filter
capacitor and the output load between these pins and
GND pins.
AUX (Pin F5): Low current voltage source for BIAS. In
many designs, the BIAS pin is simply connected to VOUT.
The AUX pin is internally connected to VOUT and is placed
adjacent to the BIAS pin to ease printed circuit board
routing. Although this pin is internally connected to VOUT ,
do NOT connect this pin to the load. If this pin is not tied
to BIAS, leave it floating. The Application Information
section gives specific information about the BIAS and
AUX connections
BIAS (Pin G5): The BIAS pin connects to the internal power
bus. Connect to a power source greater than 2.4V. If the
output is greater than 2.4V, connect this pin there. If the
output voltage is less, connect this to a voltage source
between 2.4V and 16V. Also, make sure that BIAS + VIN
is less than 56V.
RUN/SS (Pin H5): Tie RUN/SS pin to ground to shut down
the LTM8022. Tie to 2.5V or more for normal operation.
If the shutdown feature is not used, tie this pin to the VIN
pin. RUN/SS also provides a soft-start function; see the
Applications Information section.
RT (Pin G7): The RT pin is used to program the switching
frequency of the LTM8022 by connecting a resistor from
this pin to ground. The Applications Information section of
the data sheet includes a table to determine the resistance
value based on the desired switching frequency. Minimize
capacitance at this pin.
SHARE (Pin F7): Tie this to the SHARE pin of another
LTM8022 when paralleling the outputs. Otherwise, leave
this pin floating.
SYNC (Pin G6): External Clock Synchronization Input.
Ground this pin for low ripple Burst Mode® operation at
low output loads, or connect to a stable voltage source
above 0.7V to disable Burst Mode operation. Do not leave
this pin floating. Tie to a clock source for synchronization.
Clock edges should have rise and fall times faster than
1μs. See Synchronization in the Applications Information
section.
PG (Pin H6): Open Collector Output of an Internal
Comparator. PG remains low until the ADJ pin is within
10% of the final regulation voltage. PG output is valid when
VIN is above 3.6V and RUN/SS is high. If this function is
not used, leave this pin floating.
ADJ (Pin H7): The LTM8022 regulates its ADJ pin to 0.79V.
Connect the adjust resistor from this pin to ground. The
value of RADJ is given by the equation, RADJ = 394.21/
(VOUT – 0.79), where RADJ is in kΩ.
GND (Bank 3): Tie these GND pins to a local ground plane
below the LTM8022 and the circuit components. Return
the feedback divider (RADJ) to this pin.
8022fd
6
LTM8022
BLOCK DIAGRAM
VIN
VOUT
4.7μH
0.1μF
4.7pF
499k
10μF
AUX
BIAS
SHARE
RUN/SS
CURRENT MODE
CONTROLLER
PG
SYNC
GND
RT
ADJ
8022 BD
OPERATION
The LTM8022 is a standalone non-isolated step-down
switching DC/DC power supply. It can deliver up to 1A of
DC output current with only bulk external input and output
capacitors. This module provides a precisely regulated
output voltage programmable via one external resistor
from 0.8VDC to 10VDC . The input voltage range is 3.6V to
36V. Given that the LTM8022 is a step-down converter,
make sure that the input voltage is high enough to support
the desired output voltage and load current. A simplified
Block Diagram is shown above.
The LTM8022 contains a current mode controller, power
switching element, power inductor, power Schottky diode
and a modest amount of input and output capacitance.
The LTM8022 is a fixed frequency PWM regulator. The
switching frequency is set by simply connecting the
appropriate value resistor from the RT pin to GND.
An internal regulator provides power to the control circuitry. The bias regulator normally draws power from the
VIN pin, but if the BIAS pin is connected to an external
voltage higher than 2.4V, bias power will be drawn from
the external source (typically the regulated output voltage).
This improves efficiency. The RUN/SS pin is used to place
the LTM8022 in shutdown, disconnecting the output and
reducing the input current to less than 1μA.
To further optimize efficiency, the LTM8022 automatically
switches to Burst Mode operation in light load situations.
Between bursts, all circuitry associated with controlling the
output switch is shut down reducing the input supply current to 50μA in a typical application. The oscillator reduces
the LTM8022’s operating frequency when the voltage at the
ADJ pin is low. This frequency foldback helps to control
the output current during start-up and overload.
The LTM8022 contains a power good comparator which
trips when the ADJ pin is at 92% of its regulated value.
The PG output is an open-collector transistor that is off
when the output is in regulation, allowing an external
resistor to pull the PG pin high. Power good is valid when
the LTM8022 is enabled and VIN is above 3.6V.
8022fd
7
LTM8022
APPLICATIONS INFORMATION
Table 1. Recommended Component Values and Configuration
VIN*
VOUT
CIN
COUT
RADJ
BIAS
fOPTIMAL(kHz)
3.6V to 36V
0.82V
2.2μF
247μF 1206
13M
≥2.4V,