LINER LTM8001 36vin, 5a module regulator with 5-output configurable ldo array Datasheet

LTM8001
36VIN, 5A µModule
Regulator with 5-Output
Configurable LDO Array
Features
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Description
Complete Step-Down Switch Mode Power Supply
with Configurable Array of Five LDOs
Step-Down Switching Power Supply
– Adjustable 10% Accurate Output Current Limit
–Constant-Current, Constant-Voltage Operation
– Wide Input Voltage Range: 6V to 36V
– 1.2V to 24V Output Voltage
Configurable Output LDO Array
– Five 1.1A Parallelable Outputs
– Outputs Adjustable from 0V to 24V
– Low Output Noise: 90μVRMS (100Hz to 1MHz)
15mm × 15mm × 3.42mm Surface Mount
BGA Package
The LTM®8001 is a 36VIN, 5A step-down μModule® regulator with a 5-output configurable LDO array. Operating
over an input voltage range of 6V to 36V, the LTM8001
buck regulator supports an output voltage range of 1.2V
to 24V. Following the buck regulator is an array of five
1.1A linear regulators whose outputs may be connected
in parallel to accommodate a wide variety of load combinations. Three of these LDOs are tied to the output of the
buck regulator, while the other two are tied together to an
undedicated input.
The low profile package (3.42mm) enables utilization of
unused space on the bottom of PC boards for high density
point of load regulation. The LTM8001 is packaged in a
thermally enhanced, compact (15mm × 15mm) and low
profile (3.42mm) overmolded ball grid array (BGA) package suitable for automated assembly by standard surface
mount equipment. The LTM8001 is available with SnPb
(BGA) or RoHS compliant terminal finish.
Applications
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FPGA, DSP, ASIC and Microprocessor Supplies
Servers and Storage Devices
RF Transceivers
L, LT, LTC, LTM, µModule, Linear Technology and the Linear logo are registered trademarks of
Linear Technology Corporation. All other trademarks are the property of their respective owners.
Protected by U.S. Patents, including 7199560, 7321203.
Typical Application
5A Output DC/DC µModule Converter
VIN45
VIN
6V TO 36V
10µF
3.3V
VIN0
510k
RUN
BIAS123
BIAS45 LTM8001
COMP
SS
VREF
ILIM
SYNC
GND
1.8V
1A
1.2V
1A
VOUT0
LDO 1
VOUT1
SET1
1.1V
1.5A
VOUT2
STEP-DOWN LDO 2 SET2
SWITCHING
V
REGULATOR LDO 3 OUT3
SET3
LDO 4
VOUT5
FBO LDO 5 SET5
RT
118k
19.6k
0.9V
1.5A
VOUT4
SET4
4.7µF
4.7µF
2.2µF
45.3k
54.9k
121k
350kHz
470µF
+
100µF
8001 TA01
8001fc
For more information www.linear.com/LTM8001
1
LTM8001
Absolute Maximum Ratings
Pin Configuration
(Note 1)
TOP VIEW
VOUT4 SET4 VOUT3 SET3 SET2 VOUT2
VIN0............................................................................40V
VIN45, BIAS45............................................................25V
BIAS123.....................................................................25V
FB0, RT, COMP, ILIM, VREF..........................................3V
VOUT0-5......................................................................25V
RUN, SYNC, SS............................................................6V
SET1-5 (Relative to VOUT1-5, Respectively).............±0.3V
Current Into SET1-5.............................................. ±10mA
Current Into RUN Pin.............................................100µA
Maximum Junction Temperature (Notes 2, 3)........ 125°C
Peak Solder Reflow Body Temperature.................. 245°C
Storage Temperature.............................. –55°C to 125°C
11
VOUT5
10
SET5
9
BIAS123
8
VOUT1
VREF
BIAS45
SYNC
7
VIN45
BANK 3 6
GND
ILIM
RT
COMP
BANK 2
5
VOUT0
BANK 4 4
SET1
SS
FBO
RUN
3
VIN0
BANK 1
2
1
A
B
C
D
E
F
G H
J
K
L
BGA PACKAGE
121 PADS (15mm × 15mm × 3.42mm)
TJMAX = 125°C, θJA = 16.1°C/W, θJCbottom = 5.99°C/W, θJCtop = 13.4°C/W, θJB = 4.98°C/W
θ VALUES DETERMINED PER JEDEC 51-9, 51-12
WEIGHT = 1.8 GRAMS
Order Information
PART MARKING*
PART NUMBER
PAD OR BALL FINISH
LTM8001EY#PBF
SAC305 (RoHS)
DEVICE
FINISH CODE
PACKAGE
TYPE
MSL
RATING
LTM8001Y
e1
BGA
3
TEMPERATURE RANGE
(SEE NOTE 2)
–40°C to 125°C
LTM8001IY#PBF
SAC305 (RoHS)
LTM8001Y
e1
BGA
3
–40°C to 125°C
LTM8001IY
SnPb (63/37)
LTM8001Y
e0
BGA
3
–40°C to 125°C
LTM8001MPY#PBF
SAC305 (RoHS)
LTM8001Y
e1
BGA
3
–55°C to 125°C
LTM8001MPY
SnPb (63/37)
LTM8001Y
e0
BGA
3
–55°C to 125°C
Consult Marketing for parts specified with wider operating temperature
ranges. *Device temperature grade is indicated by a label on the shipping
container. Pad or ball finish code is per IPC/JEDEC J-STD-609.
• Recommended LGA and BGA PCB Assembly and Manufacturing
Procedures:
www.linear.com/umodule/pcbassembly
• Terminal Finish Part Marking:
www.linear.com/leadfree
• LGA and BGA Package and Tray Drawings:
www.linear.com/packaging
2
8001fc
For more information www.linear.com/LTM8001
LTM8001
Electrical Characteristics
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. RUN = 3V unless otherwise noted (Note 3).
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Buck Regulator
Minimum VIN0 Input Voltage
6
l
VOUT0 Output DC Voltage
0A < IOUT ≤ 3A, RFB0 Open
0A < IOUT ≤ 3A; RFB0 = 536Ω
VOUT0 Output DC Current
6V < VIN0 < 36V, VOUT = 3.3V
Quiescent Current Into VIN0
RUN = 0V
No Load
0.1
26
1.2
24
0
V
V
V
5
A
1
40
µA
mA
VOUT0 Line Regulation
6V < VIN0 < 36V, IOUT = 1A
±0.5
%
VOUT0 Load Regulation
VIN0 = 24V, 0A < IOUT < 5A
±1.2
%
VOUT0 RMS Voltage Ripple
VIN0 = 24V, IOUT = 5A
10
mV
Switching Frequency
RT = 39.2k
RT = 200k
1000
200
kHz
kHz
Voltage at FB0 Pin
l
1.15
Internal FBO Resistor
RUN Pin Current
1.19
1.21
10
RUN = 1.45V
V
kΩ
5.5
µA
RUN Threshold Voltage (Falling)
1.49
1.61
V
RUN Threshold Voltage (Rising)
1.63
1.75
V
ILIM Control Range
0
ILIM Pin Current
1.5
100
ILIM Current Limit Accuracy
ILIM = 1.5V
ILIM = 0.75V
5.1
2.5
VREF Voltage
0.5mA Load
1.9
SYNC Input Low Threshold
fSYNC = 500kHz
0.8
SYNC Input High Threshold
fSYNC = 500kHz
SYNC Input Current
SYNC = 0V
SYNC = 2V
SS Pin Current
2
V
nA
6.4
3.4
A
A
2.1
V
11
µA
V
–0.1
1.2
V
0.1
µA
µA
10.15
10.20
µA
µA
4
6.5
mV
mV
11
nA
LDO Array
SET1-5 Pin Current
VOUTx – SETx Offset Voltage
BIAS123 = BIAS45 = 2V, SETx = 0V, IOUT1-5 = 1mA
l
9.85
9.80
l
–4
–6.5
BIAS123 = BIAS45 = 2V, SETx = 0V, IOUT1-5 = 1mA
Line Regulation for SET Current
1V < VOUT0 = VIN45 < 22V, IOUTx = 1mA (Note 4)
Line Regulation for VOUT1-5
1V < VOUT0 = VIN45 < 22V, IOUTx = 1mA (Note 4)
10
10
l
0.25
mV
Load Regulation for SETx Current
IOUT1-5 = 1mA to 1.1A
25
nA
Load Regulation for VOUT1-5
IOUT1-5 = 1mA to 1.1A
l
34
52
mV
mV
Minimum Load Current for VOUT1-5 (Note 4)
VOUT0 = VIN45 = BIAS123 = BIAS45 = 10V
VOUT0 = VIN45 = BIAS123 = BIAS45 = 22V
l
l
500
1
µA
mA
BIAS123, BIAS45 Dropout Voltage
IOUT1-5 = 100mA
IOUT1-5 = 1.1A
l
1.6
V
V
VOUT0 to VOUT1-3 and VIN45 to VOUT4-5 Dropout IOUT1-5 = 100mA
Voltage
IOUT1-5 = 1.1A
l
500
mV
mV
1.2
100
8001fc
For more information www.linear.com/LTM8001
3
LTM8001
Electrical Characteristics
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. RUN = 3V unless otherwise noted (Note 3).
PARAMETER
CONDITIONS
Maximum VOUT0 to VOUT1-3 and VIN45 to
VOUT4-5 Differential Voltage (Note 5)
IOUT1-5 = 750mA
IOUT1-5 = 310mA
IOUT1-5 = 125mA
BIAS123, BIAS45 Pin Current
IOUT1-5 = 100mA
IOUT1-5 = 1.1A
MIN
TYP
MAX
l
UNITS
10
15
22
V
V
V
6
30
mA
mA
VOUT1-5 Current Limit (Note 5)
VOUT1-5 = –0.1V
1.3
A
VOUT1-5 RMS Output Noise
VOUT1-5 = 1V, IOUT1-5 = 1.1A, 100Hz to 1MHz
90
µVRMS
–40°C to 125°C internal operating temperature range. The LTM8001MP
is guaranteed to meet specifications over the full –55°C to 125°C internal
operating 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 4: No minimum load is required if the respective linear regulator is
off, such as when VOUT0 = 0V, VIN45 = 0V, BIAS123 = 0V or BIAS45 = 0V.
Note 5: The current limit may decrease to zero at input-to-output
differential voltages greater than 22V. Operation at voltages for VOUT0,
VIN45, BIAS123 and BIAS45 is allowed up to a maximum of 25V as long
as the difference between the linear regulator input and output voltage
is below the specified differential voltage. Line and load regulation
specifications are not applicable when the device is in current limit.
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: This μModule regulator includes overtemperature protection that
is intended to protect the device during momentary overload conditions.
Junction temperature will exceed 125°C when overtemperature protection
is active. Continuous operation above the specified maximum operating
junction temperature may impair device reliability.
Note 3: The LTM8001E is guaranteed to meet performance specifications
from 0°C to 125°C internal. Specifications over the full –40°C to
125°C internal operating temperature range are assured by design,
characterization and correlation with statistical process controls. The
LTM8001I is guaranteed to meet specifications over the full
Typical Performance Characteristics
(TA = 25°C unless otherwise noted. Configured per Table 1, where applicable.)
Efficiency vs Output Current,
VOUT0 = 3.3V
100
85
90
95
80
85
90
75
70
80
75
70
VINO = 12V
VINO = 24V
VINO = 36V
60
55
EFFICIENCY (%)
95
65
0
1
2
3
4
5
60
VINO = 12V
VINO = 24V
VINO = 36V
80
0
1
2
3
5
4
VINO = 12V
VINO = 24V
VINO = 36V
70
VOUT0 CURRENT (A)
8001 G01
85
75
65
VOUT0 CURRENT (A)
4
Efficiency vs Output Current,
VOUT0 = 5V
90
EFFICIENCY (%)
EFFICIENCY (%)
Efficiency vs Output Current,
VOUT0 = 2.5V
65
0
1
2
3
4
5
VOUT0 CURRENT (A)
8001 G02
8001 G03
8001fc
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LTM8001
Typical Performance Characteristics
(TA = 25°C unless otherwise noted. Configured per Table 1, where applicable.)
Efficiency vs Output Current,
VOUT0 = 12V
100
95
95
90
90
85
80
70
0
1
2
3
95
80
70
VINO = 24V
VINO = 36V
0
1
2
3
1.5
100
85
1.8
VINO = 12V
VINO = 24V
VINO = 36V
4
1.4
0.9
0.6
0
5
0
1
3
VOUT0 CURRENT (A)
2
4
0.5
5
8001 G10
0
1
3
2
VOUT0 CURRENT (A)
8001 G09
2.5
INPUT CURRENT (A)
3.0
2.5
2.0
1.5
0
2.0
1.5
1.0
0.5
0
1
2
3
VOUT0 CURRENT (A)
5
4
3.0
0.5
4
0.6
Input Current vs Output Current,
VOUT0 = 12V
1.0
3
VOUT0 CURRENT (A)
0.8
0
5
VINO = 12V
VINO = 24V
VINO = 36V
3.5
INPUT CURRENT (A)
INPUT CURRENT (A)
4.0
1.0
2
1.0
Input Current vs Output Current,
VOUT0 = 8V
VINO = 12V
VINO = 24V
VINO = 36V
1
1.2
8001 G08
Input Current vs Output Current,
VOUT0 = 5V
0
5
0.2
1.5
0
4
0.4
8001 G07
2.0
3
2
VOUT0 CURRENT (A)
VINO = 12V
VINO = 24V
VINO = 36V
1.6
0.3
VINO = 28V
VINO = 36V
3
VOUT0 CURRENT (A)
1
Input Current vs Output Current,
VOUT0 = 3.3V
INPUT CURRENT (A)
INPUT CURRENT (A)
EFFICIENCY (%)
90
2
0
8001 G06
Input Current vs Output Current,
VOUT0 = 2.5V
1.2
95
1
VINO = 28V
VINO = 36V
8001 G05
Efficiency vs Output Current,
VOUT0 = 24V
2.5
75
5
4
8001 G04
0
85
VOUT0 CURRENT (A)
VOUT0 CURRENT (A)
80
90
80
75
5
4
100
85
VINO = 12V
VINO = 24V
VINO = 36V
75
Efficiency vs Output Current,
VOUT0 = 18V
EFFICIENCY (%)
100
EFFICIENCY (%)
EFFICIENCY (%)
Efficiency vs Output Current,
VOUT0 = 8V
4
5
0
VINO = 24V
VINO = 36V
0
1
2
3
4
5
VOUT0 CURRENT (A)
8001 G11
8001 G12
8001fc
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5
LTM8001
Typical Performance Characteristics
(TA = 25°C unless otherwise noted. Configured per Table 1, where applicable.)
Input Current vs Output Current,
VOUT0 = 24V
4.0
5.0
3.5
4.5
7
2.0
1.5
1.0
MINIMUM VIN0 VOLTAGE (V)
2.5
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
VINO = 28V
VINO = 36V
0
1
2
3
VOUT0 CURRENT (A)
4
VINO = 28V
VINO = 36V
0.5
0
5
0
1
3
VOUT0 CURRENT (A)
2
4
2
3
9.75
0
1
VOUT0 CURRENT (A)
2
3
13.80
13.75
13.70
13.65
19.65
25.95
25.90
25.85
25.70
25.65
4
5
VOUT0 CURRENT (A)
8001 G19
25.55
2.5
2.0
1.5
1.0
0.5
25.60
3
5
4
3.0
26.00
OUTPUT VOLTAGE (V)
MINIMUM VIN0 VOLTAGE (V)
19.66
3
3.5
25.75
2
2
Output Voltage vs Output Current,
VOUT0 = 2.5V
25.80
19.67
1
1
8001 G18
26.05
0
0
VOUT0 CURRENT (A)
26.10
19.70
MINIMUM VIN0 VOLTAGE (V)
13.85
Minimum VIN0 vs Output Current,
VOUT0 = 24V
19.71
5
4
8001 G17
Minimum VIN0 vs Output Current,
VOUT0 = 18V
6
5
4
8001 G16
19.68
3
13.90
VOUT0 CURRENT (A)
19.69
2
13.95
9.80
9.70
5
4
1
Minimum VIN0 vs Output Current,
VOUT0 = 12V
MINIMUM VIN0 VOLTAGE (V)
MINIMUM VIN0 VOLTAGE (V)
MINIMUM VIN0 VOLTAGE (V)
6.70
0
8001 G1
9.85
6.75
19.64
4
5
Minimum VIN0 vs Output Current,
VOUT0 = 8V
6.80
1
5
8001 G14
Minimum VIN0 vs Output Current,
VOUT0 = 5V
0
6
VOUT0 CURRENT (A)
8001 G13
6.65
Minimum VIN0 vs Output Current,
VOUT0 = 3.3V and Below
4.0
3.0
INPUT CURRENT (A)
INPUT CURRENT (A)
Input Current vs Output Current,
VOUT0 = 18V
0
1
3
VOUT0 CURRENT (A)
2
5
4
0
–10
–5
0
5
10
LOAD CURRENT (A)
8001 G20
8001 G21
8001fc
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LTM8001
Typical Performance Characteristics
(TA = 25°C unless otherwise noted. Configured per Table 1, where applicable.)
600
4
500
2
0
–2
–4
0
0.25
1
0.75
0.5
ILIM VOLTAGE (V)
1.25
0
12
18
24
VIN0 VOLTAGE (V)
6
30
0
36
0
1
2
3
VOUT0 CURRENT (A)
5
4
Temperature Rise vs VOUT0 Current,
Buck Regulator, VOUT0 = 5V
Temperature Rise vs VOUT0 Current,
Buck Regulator, VOUT0 = 8V
70
80
70
20
12VIN
24VIN
36VIN
0
1
2
3
VOUT0 CURRENT (A)
50
40
30
20
12VIN
24VIN
36VIN
10
0
5
4
TEMPERATURE RISE (°C)
60
TEMPERATURE RISE (°C)
TEMPERATURE RISE (°C)
12VIN
24VIN
36VIN
10
Temperature Rise vs VOUT0 Current,
Buck Regulator, VOUT0 = 3.3V
10
0
1
2
3
50
40
30
20
12VIN
24VIN
36VIN
10
0
5
4
60
0
1
VOUT0 CURRENT (A)
2
3
VOUT0 CURRENT (A)
4
5
8001 G25
8001 G26
8001 G27
Temperature Rise vs VOUT0 Current,
Buck Regulator, VOUT0 = 12V
Temperature Rise vs VOUT0 Current,
Buck Regulator, VOUT0 = 18V
Temperature Rise vs VOUT0 Current,
Buck Regulator, VOUT0 = 24V
120
90
100
90
100
80
TEMPERATURE RISE (°C)
TEMPERATURE RISE (°C)
20
8001 G24
30
70
60
50
40
30
20
0
1
3
VOUT0 CURRENT (A)
2
4
80
60
40
20
24VIN
36VIN
10
0
200
30
8001 G23
40
100
300
40
8001 G22
50
0
400
0
1.5
Temperature Rise vs VOUT0 Current,
Buck Regulator, VOUT0 = 2.5V
50
TEMPERATURE RISE (°C)
60
60
100
–6
–8
VIN0 Input Current vs Voltage,
VOUT0 Shorted
TEMPERATURE RISE (°C)
6
VIN0 INPUT CURRENT (mA)
MAXIMUM CURRENT (A)
ILIM Voltage vs Maximum IOUT0
Output Current
5
8001 G28
0
28VIN
36VIN
0
1
2
3
VOUT0 CURRENT (A)
70
36VIN
60
50
40
30
20
10
5
4
80
8001 G29
0
0
1
3
2
VOUT0 CURRENT (A)
4
5
8001 G30
8001fc
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7
LTM8001
Typical Performance Characteristics
(TA = 25°C unless otherwise noted. Configured per Table 1, where applicable.)
LDO VBIAS-to-Output Dropout
Voltage vs Output Current
350
300
250
200
150
100
50
0
0
200
400
800
600
OUTPUT CURRENT (mA)
1.52
1600
1.50
1400
1.48
1.46
1.44
1.42
1.40
1.38
0
200
400
800
600
OUTPUT CURRENT (mA)
8001 G31
800
600
400
0
1000
0
20
10
30
INPUT-TO-OUTPUT DIFFERENTIAL (V)
120
LDO
INPUT-TO-OUTPUT
DIFFERENTIAL
VOLTAGE
80
0.5V
1.6V
2.4V
4V
7V
9.5V
11.9V
60
40
20
0
500
1000
LDO OUTPUT CURRENT (mA)
100
TEMPERATURE RISE (°C)
100
LDO
INPUT-TO-OUTPUT
DIFFERENTIAL
VOLTAGE
80
0.5V
0.9V
2V
4V
7V
8.7V
11.9V
60
40
20
0
1500
0
1
2
3
4
TOTAL LDO OUTPUT CURRENT (A)
8001 G34
100
90
90
80
80
RIPPLE REJECTION (dB)
RIPPLE REJECTION (dB)
LDO Input Voltage Ripple Rejection
(VOUT4 = 2.5V, VBIAS45 = 4.5V,
VIN45 = 3.5V)
100
70
60
50
40
30
20
70
60
50
40
30
20
ILOAD = 100mA
ILOAD = 1.1A
10
10
102
103
104
FREQUENCY (Hz)
ILOAD = 100mA
ILOAD = 1.1A
10
105
106
0
10
102
8001 G36
8
5
8001 G35
LDO Input Voltage Ripple Rejection
(VOUT4 = 2.5V,
VIN45 = VBIAS45 = 4.5V)
0
40
8001 G33
LDO Temperature Rise vs LDO
Output Current (VIN = 24V,
VOUT0 = 12V, 5 LDOs in Parallel)
120
TEMPERATURE RISE (°C)
1000
8001 G32
LDO Temperature Rise vs LDO
Output Current (VIN = 24V,
VOUT0 = 12V, 1 LDO Powered)
0
1200
200
1.36
1.34
1000
LDO Current Limit vs Input-toOutput Differential Voltage
LDO CURRENT LIMIT (mA)
400
BIAS-TO-OUTPUT DROPOUT VOLTAGE (V)
INPUT-TO-OUTPUT DROPOUT VOLTAGE (mV)
LDO Input-to-Output Dropout
Voltage vs Output Current
103
104
FREQUENCY (Hz)
105
106
8001 G37
8001fc
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LTM8001
Typical Performance Characteristics
(TA = 25°C unless otherwise noted. Configured per Table 1, where applicable.)
LDO VBIAS Ripple Rejection
(VOUT4 = 2.5V, VBIAS45 = 4.5V,
VIN45 = 3.5V)
LDO Output Ripple
100
90
RIPPLE REJECTION (dB)
80
1mV/DIV
70
60
50
40
30
20
ILOAD = 100mA
ILOAD = 1.1A
10
0
10
102
103
104
FREQUENCY (Hz)
105
106
2µs/DIV
VOUT = 1.2V AT 700mA
COUT1 = 22µF
CSET1 = 1nF
VIN = 12V
VOUT0 = 1.8V LOADED TO
A TOTAL CURRENT OF 5A
100MHz BW
8001 G39
8001 G38
Pin Functions
VIN0 (Bank 1): The VIN0 bank supplies current to the
LTM8001’s internal regulator and to the internal power
switches. This pin must be locally bypassed with an external, low ESR capacitor; see Table 1 for recommended
values.
BIAS123 (Pin B8): This pin is the supply pin for the
control circuitry of the LDOs connected to VOUT1-VOUT3.
For the LDOs to regulate, this voltage must be more than
1.2V to 1.6V greater than the output voltage (see Dropout
specifications).
GND (Bank 2): Tie these GND pins to a local ground plane
below the LTM8001 and the circuit components. In most
applications, the bulk of the heat flow out of the LTM8001
is through these pads, so the printed circuit design has a
large impact on the thermal performance of the part. See
the PCB Layout and Thermal Considerations sections for
more details. Return the feedback divider (RFB0) to this net.
SS (Pin K4): The Soft-Start Pin. Place an external capacitor
to ground to limit the regulated current during start-up
conditions. The soft-start pin has an 11μA charging current.
VIN45 (Bank 3): Input to the LDOs connected to VOUT4 and
VOUT5. It must be locally bypassed with a low ESR capacitor.
VOUT0 (Bank 4): Switching Power Converter Output Pins.
Apply the output filter capacitor and the output load between
these pins and the GND pins. In most cases, an output
capacitance made up of a combination of ceramic and electrolytic capacitors yields the optimal volumetric solution.
BIAS45 (Pin A8): This pin is the supply pin for the control
circuitry of the LDOs connected to VOUT4 and VOUT5. For
the LDOs to regulate, this voltage must be more than
1.2V to 1.6V greater than the output voltage (see Dropout
specifications).
SYNC (Pin K7): Frequency Synchronization Pin. This pin
allows the switching frequency to be synchronized to
an external clock. The RT resistor should be chosen to
operate the internal clock at 20% slower than the SYNC
pulse frequency. This pin should be grounded when not
in use. Do not leave this pin floating. When laying out the
board, avoid noise coupling to or from the SYNC trace.
See the Switching Frequency Synchronization section in
Applications Information.
VREF (Pin K8): Buffered 2V Reference Capable of 0.5mA
Drive.
RUN (Pin L4): The RUN pin acts as an enable pin and
turns on the internal circuitry. The pin does not have any
pull up or pull down, requiring a voltage bias for normal
part operation. The RUN pin is internally clamped, so it
may be pulled up to a voltage source that is higher than
8001fc
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9
LTM8001
Pin Functions
the absolute maximum voltage rating of 6V through a
resistor, provided the pin current does not exceed 100µA.
20% lower than the SYNC pulse frequency. Do not leave
this pin open.
FB0 (Pin L5): The LTM8001 regulates its FB0 pin to 1.19V.
Connect the adjust resistor from this pin to ground. The
value of RFB0 is given by the equation:
ILIM (Pin L8): The ILIM pin reduces the maximum regulated
output current of the LTM8001. The maximum control voltage range is 1.5V. ILIM voltages above 1.5V have little or
no effect. If this function is not used, tie this pin to VREF.
RFBO =
11.9
VOUT – 1.19
where RFB0 is in kΩ.
COMP (Pin L6): Compensation Pin. This pin is generally
not used. The LTM8001 is internally compensated, but
some rare situations may arise that require a modification to the control loop. This pin connects directly to the
input PWM comparator of the LTM8001. In most cases,
no adjustment is necessary. If this function is not used,
leave this pin open.
RT (Pin L7): The RT pin is used to program the switching frequency of the LTM8001 by connecting a resistor
from this pin to ground. The Applications Information
section of the data sheet includes a table to determine the
recommended resistance value and switching frequency.
When using the SYNC function, set the frequency to be
SET1, SET2, SET3, SET4, SET5 (Pins L9, H11, G11, D11,
A9): These pins set the regulation point for each LDO. A
fixed current of 10μA flows out of this pin through a single
external resistor, which programs the output voltage of
the device. Output voltage range is zero to the absolute
maximum rated output voltage. The transient performance
can be improved by adding a small capacitor from the
SET pin to ground.
VOUT1 (Pins L10, L11), VOUT2 (Pins J11, K11), VOUT3 (Pins
E11, F11), VOUT4 (Pins B11, C11), VOUT5 (Pins A10, A11):
These are the power outputs of the individual LDOs. There
must be a minimum load current of 1mA or the output may
not regulate. The internal LDOs are rated for positive voltages between their inputs and outputs. Avoid applications
where the internal LDOs can experience a negative voltage,
even during start-up and turn-off transients
Block Diagram
2.2µH
VIN0
0.2µF
RSENSE
VOUT0
10k
2.2µF
VOUT1
1.1A LDO
SET1
VOUT2
1.1A LDO
SET2
VOUT3
RUN
1.1A LDO
SET3
SS
SYNC
VREF
CURRENT
MODE
CONTROLLER
VIN0
VOUT4
INTERNAL
REGULATOR
1.1A LDO
SET4
VOUT5
ILIM
1.1A LDO
COMP
GND
RT
FB0
BIAS123
SET5
BIAS45 VIN45
8001 BD
10
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LTM8001
Operation
The LTM8001 consists of two major parts: the first is a
standalone nonisolated step-down switching DC/DC power
converter that can deliver up to 5A of output current. The
second part is an array of five parallelable 1.1A LDOs. The
DC/DC converter provides a precisely regulated output
voltage programmable via one external resistor from 1.2V
to 24V. The input voltage range is 6V to 36V. Given that it
is a step-down converter, make sure that the input voltage is high enough to support the desired output voltage
and load current. The linear regulator array consists of
five low drop-out regulators, of which three inputs are
dedicated to the buck converter’s output (VOUT0) and two
tie to an undedicated input (VIN45). Each individual linear
regulator may be set to a unique voltage through its SET
pin, or may be paralleled with other LDOs by tying their
respective SET and VOUT pins together.
current can be used with a resistor between RUN and VIN0
to set hysteresis. Please refer to the UVLO and Shutdown
section in the Applications Information for further details.
During start-up, the SS pin is held low until the part is
enabled, after which the capacitor at the soft-start pin is
charged with an 11μA current source.
The LTM8001 is equipped with thermal shutdown circuitry
to protect the device during momentary overload conditions. It is set above the 125°C absolute maximum internal
temperature rating to avoid interfering with normal specified operation, so internal device temperatures will exceed
the absolute maximum rating when the overtemperature
protection is active. Thus, continuous or repeated activation of the thermal shutdown may impair device reliability.
During thermal shutdown, all switching is terminated and
the SS pin is driven low.
The LTM8001 step-down switching converter utilizes fixed
frequency, average current mode control to accurately
regulate the output current. This results in a constantvoltage, constant-current output characteristic, making
the LTM8001’s step-down regulator well suited for many
supercapacitor and battery charging applications. As shown
in the Typical Performance Characteristics, the current limit
works in both directions. The control loop will regulate the
current in the internal inductor. Once the VOUT0 output has
reached the regulation voltage determined by the resistor
from the FBO pin to ground, the voltage regulation loop will
reduce the output current and maintain the output voltage.
The ILIM input may be used to set the maximum allowable
current output of the LTM8001. The analog control range
of the ILIM pin is from 0V to 1.5V. If the ILIM pin is raised
above 1.5V, there is little or no effect.
The VOUT1-5 linear regulators are easy to use and have
all the protection features expected in high performance
regulators. Included are short-circuit protection and safe
operating area protection, as well as thermal shutdown.
These linear regulators are especially well suited to applications needing multiple rails. Their architecture allows
their outputs to be adjusted down to zero volts. The output
voltage is set by a single resistor, handling modern low
voltage digital ICs as well as allowing easy parallel operation and simplified thermal management.
The RUN pin functions as a precision enable for the stepdown switching converter connected to VOUT0. If all VOUT1-3
LDO inputs including BIAS are tied to VOUT0, the RUN pin
will also implicitly enable or disable these LDOs as well,
unless some external power source is tied to VOUT0. Refer
to the Applications Information section Shorted Input Protection if VOUT0 is forced above VIN0. When the voltage at
the RUN pin is lower than 1.55V, switching is terminated.
Below the turn-on threshold, the RUN pin sinks 5.5μA. This
The linear regulators can be operated in two modes. One
mode has the BIAS123 and BIAS45 pins connected to the
linear regulator power input pins (VOUT0 and VIN45) which
gives a limitation of about 1.6V dropout. In the other mode,
the BIAS123 and BIAS45 pins can be tied to a voltage at
least 1.6V above their highest respective outputs. The linear
regulator power input (VOUT0 and VIN45) can then be set
to a lower voltage that meets the dropout requirement,
minimizing the power dissipation.
The switching frequency is determined by a resistor at
the RT pin. The LTM8001 may also be synchronized to an
external clock through the use of the SYNC pin. Please
see the Switching Frequency Synchronization section in
the Applications Information for further details.
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11
LTM8001
Applications Information
For most applications, the design process is straight
forward, summarized as follows:
1. Look at Table 1 and find the row that has the desired
input range and VOUT0 output voltage.
2. Apply the recommended CIN0, COUT0, RFB0 and RT values. Note that ceramic and electrolytic capacitors are
recommended. These are intended to work in concert
to optimize performance and solution size; apply both
capacitors.
3. Apply the set resistors for the VOUT1, VOUT2, VOUT3,
VOUT4 and VOUT5 regulators. To set the voltage of each
linear regulator, use the equation
RSETX =
VOUTX
10µA
where the value of RSET is in Ohms. Note that there is
no minimum positive output voltage for the regulator,
but a minimum load current is required to maintain
regulation regardless of output voltage, (please see
Electrical Characteristics table). For true zero voltage
output operation, this minimum load current must be
returned to a negative supply voltage. If paralleling the
linear regulators, set the output of each regulator to
the same voltage by tying the SETx pins together and
applying a single resistor. The value of the single set
resistor is given by the equation:
The maximum frequency (and attendant RT value) at
which the LTM8001 should be allowed to switch is given
in Table 1 in the fMAX column, while the recommended
frequency (and RT value) for optimal efficiency over the
given input condition is given in the fOPTIMAL column.
There are additional conditions that must be satisfied if
the synchronization function is used. Please refer to the
Switching Frequency Synchronization section for details.
Capacitor Selection Considerations
The CIN and COUT capacitor values in Table 1 are the
minimum recommended values for the associated operating conditions. Applying capacitor values below those
indicated in Table 1 is not recommended, and may result
in undesirable operation. Using larger values is generally
acceptable, and can yield improved dynamic response, if
necessary. Again, it is incumbent upon the user to verify
proper operation over the intended system’s line, load and
environmental conditions.
4. Apply the output capacitors for the VOUT1, VOUT2, VOUT3,
VOUT4 and VOUT5 regulators. A minimum output capacitor of 2.2μF with an ESR of 0.5Ω or less is recommended
to prevent oscillations.
Ceramic capacitors are small, robust and have very low ESR.
However, not all ceramic capacitors are suitable. X5R and
X7R types are stable over temperature, applied voltage and
give dependable service. Other types, including Y5V and
Z5U have very large temperature and voltage coefficients
of capacitance. In an application circuit they may have
only a small fraction of their nominal capacitance resulting in much higher output voltage ripple than expected.
Many of the output capacitances given in Table 1 specify
an electrolytic capacitor. Ceramic capacitors may also be
used in the application, but it may be necessary to use
more of them. Many high value ceramic capacitors have a
large voltage coefficient, so the actual capacitance of the
component at the desired operating voltage may be only
a fraction of the specified value. Also, the very low ESR of
ceramic capacitors may necessitate additional capacitors
for acceptable stability margin.
While these component combinations have been tested for
proper operation, it is incumbent upon the user to verify
proper operation over the intended system’s line, load and
environmental conditions. Bear in mind that the maximum
output current is limited by junction temperature, the relationship between the input and output voltage magnitude
and other factors. Please refer to the graphs in the Typical
Performance Characteristics section for guidance.
A final precaution regarding ceramic capacitors concerns
the maximum input voltage rating of the LTM8001. A
ceramic input capacitor combined with trace or cable
inductance forms a high Q (under damped) tank circuit.
If the LTM8001 circuit is plugged into a live supply, the
input voltage can ring to twice its nominal value, possibly exceeding the device’s rating. This situation is easily
avoided; see the Hot Plugging Safely section.
RSET =
VOUT
10µA •n
where n is the number of regulators paralleled.
12
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LTM8001
Applications Information
LTM8001 Table 1: Recommended Component Values and Configuration for VOUT0 (TA = 25°C)
VIN0
VOUT0
6V to 36V
1.2V
6V to 36V
1.5V
6V to 36V
CIN0
COUT0 (CERAMIC) COUT0 (ELECTROLYTIC)
10µF, 50V, 1210 100µF, 6.3V, 1210 470µF, 6.3V, 9mΩ, Chemi-Con,
APXF6R3ARA471MH80G
RFB0
fOPTIMAL RT(OPTIMAL)
fMAX
RT(MIN)
Open
200kHz
200k
250kHz
169k
10µF, 50V, 1210 100µF, 6.3V, 1210 470µF, 6.3V, 9mΩ, Chemi-Con,
APXF6R3ARA471MH80G
38.3k
300kHz
140k
350kHz
118k
1.8V
10µF, 50V, 1210 100µF, 6.3V, 1210 470µF, 6.3V, 9mΩ, Chemi-Con,
APXF6R3ARA471MH80G
19.6k
350kHz
118k
400kHz
102k
6V to 36V
2.5V
10µF, 50V, 1210 100µF, 6.3V, 1210 330µF, 4V, 27mΩ, OS-CON, 4SVPC330M
9.09k
450kHz
90.9k
525kHz
78.7k
6V to 36V
3.3V
7V to 36V
5V
10µF, 50V, 1210 100µF, 6.3V, 1210 330µF, 4V, 27mΩ, OS-CON, 4SVPC330M
5.62k
550kHz
75.0k
625kHz
64.9k
10µF, 50V, 1210 100µF, 6.3V, 1210 120µF, 16V, 27mΩ, OS-CON,
16SVPC120M
3.09k
600kHz
68.1k
700kHz
57.6k
10V to 36V
8V
10µF, 50V, 1210
100µF, 10V, 1210 120µF, 16V, 27mΩ, OS-CON,
16SVPC120M
1.74k
625kHz
64.9k
750kHz
53.6k
15V to 36V
12V
10µF, 50V, 1210
47µF, 16V, 1210
120µF, 16V, 27mΩ, OS-CON,
16SVPC120M
1.10k
650kHz
61.9k
800kHz
49.9k
22V to 36V
18V
10µF, 50V, 1210
22µF, 25V, 1210
47µF, 20V, 45mΩ, OS-CON, 20SVPS47M
715Ω
675kHz
59.0k
900kHz
44.2k
28V to 36V
24V
4.7µF, 50V, 1210
10µF, 50V, 1206
47µF, 35V, 30mΩ, OS-CON, 35SVPC47M
523Ω
700kHz
57.6k
1MHz
39.2k
9V to 15V
1.2V
10µF, 50V, 1210 100µF, 6.3V, 1210 470µF, 6.3V, 9mΩ, Chemi-Con,
APXF6R3ARA471MH80G
Open
200kHz
200k
525kHz
78.7k
9V to 15V
1.5V
10µF, 50V, 1210 100µF, 6.3V, 1210 470µF, 6.3V, 9mΩ, Chemi-Con,
APXF6R3ARA471MH80G
38.3k
300kHz
140k
650kHz
61.9k
9V to 15V
1.8V
10µF, 50V, 1210 100µF, 6.3V, 1210 470µF, 6.3V, 9mΩ, Chemi-Con,
APXF6R3ARA471MH80G
19.6k
350kHz
118k
800kHz
49.9k
9V to 15V
2.5V
10µF, 50V, 1210 100µF, 6.3V, 1210 330µF, 4V, 27mΩ, OS-CON, 4SVPC330M
9.09k
450kHz
90.9k
1MHz
39.2k
9V to 15V
3.3V
10µF, 50V, 1210 100µF, 6.3V, 1210 330µF, 4V, 27mΩ, OS-CON, 4SVPC330M
5.62k
550kHz
75.0k
1MHz
39.2k
9V to 15V
5V
10µF, 50V, 1210 100µF, 6.3V, 1210 120µF, 16V, 27mΩ, OS-CON,
16SVPC120M
3.09k
600kHz
68.1k
1MHz
39.2k
10V to 15V
8V
10µF, 50V, 1210
1.74k
625kHz
64.9k
1MHz
39.2k
100µF, 10V, 1210 120µF, 16V, 27mΩ, OS-CON,
16SVPC120M
18V to 36V 1.2V
10µF, 50V, 1210 100µF, 6.3V, 1210 470µF, 6.3V, 9mΩ, Chemi-Con,
APXF6R3ARA471MH80G
Open
200kHz
200k
250kHz
169k
18V to 36V 1.5V
10µF, 50V, 1210 100µF, 6.3V, 1210 470µF, 6.3V, 9mΩ, Chemi-Con,
APXF6R3ARA471MH80G
38.3k
300kHz
140k
350kHz
118k
18V to 36V 1.8V
10µF, 50V, 1210 100µF, 6.3V, 1210 470µF, 6.3V, 9mΩ, Chemi-Con,
APXF6R3ARA471MH80G
19.6k
350kHz
118k
400kHz
102k
18V to 36V 2.5V
10µF, 50V, 1210 100µF, 6.3V, 1210 330µF, 4V, 27mΩ, OS-CON, 4SVPC330M
9.09k
450kHz
90.9k
525kHz
78.7k
18V to 36V
3.3
10µF, 50V, 1210 100µF, 6.3V, 1210 330µF, 4V, 27mΩ, OS-CON, 4SVPC330M
5.62k
550kHz
75.0k
625kHz
64.9k
18V to 36V
5V
10µF, 50V, 1210 100µF, 6.3V, 1210 120µF, 16V, 27mΩ, OS-CON,
16SVPC120M
3.09k
600kHz
68.1k
700kHz
57.6k
18V to 36V
8V
10µF, 50V, 1210
100µF, 10V, 1210 120µF, 16V, 27mΩ, OS-CON,
16SVPC120M
1.74k
625kHz
64.9k
750kHz
53.6k
18V to 36V
12V
10µF, 50V, 1210
47µF, 16V, 1210
1.10k
650kHz
61.9k
800kHz
49.9k
120µF, 16V, 27mΩ, OS-CON,
16SVPC120M
Note: An input bulk capacitor is required.
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13
LTM8001
Applications Information
Programming Switching Frequency
Soft-Start
The LTM8001 has an operational switching frequency
range between 200kHz and 1MHz. This frequency is
programmed with an external resistor from the RT pin to
ground. Do not leave this pin open under any condition.
See Table 2 for resistor values and the corresponding
switching frequencies.
The soft-start function controls the slew rate of the power
supply output VOUT0 voltage during start-up. A controlled
output voltage ramp minimizes output voltage overshoot,
reduces inrush current from the VIN0 supply, and facilitates supply sequencing. A capacitor connected from the
SS pin to GND programs the slew rate. The capacitor is
charged from an internal 11μA current source to produce
a ramped output voltage.
Table 2. RT Resistor Values and Their Resultant Switching
Frequencies
SWITCHING FREQUENCY (MHz)
RT (kΩ)
1
39.2
0.75
53.6
0.5
82.5
0.3
140
0.2
200
Switching Frequency Trade-Offs
It is recommended that the user apply the optimal RT resistor value given in Table 1 for the input and output operating
condition. System level or other considerations, however,
may necessitate another operating frequency. While the
LTM8001 is flexible enough to accommodate a wide range
of operating frequencies, a haphazardly chosen one may
result in undesirable operation under certain operating or
fault conditions. A frequency that is too high can reduce
efficiency, generate excessive heat or even damage the
LTM8001 in some fault conditions. A frequency that is too
low can result in a final design that has too much output
ripple or too large of an output capacitor.
Maximum Output Current Adjust
The LTM8001 features an adjustable accurate current
limit. To adjust the load current limit, an analog voltage
is applied to the ILIM pin. Varying the voltage between
0V and 1.5V adjusts the maximum current between the
minimum and the maximum current, 5.6A typical. Above
1.5V, the control voltage has no effect on the regulated
inductor current. Graphs of the output current vs ILIM voltages are given in the Typical Performance Characteristics
section. The LTM8001 provides a 2V reference voltage for
conveniently applying resistive dividers to set the current
limit. The current limit can be set as shown in Figure 1
with the following equation:
IMAX = 7.47
R2
R1+R2
A convenient value of R1 may be 10k. In that case,
R2 =
10 •IMAX
kΩ
7.47 –IMAX
Switching Frequency Synchronization
The nominal switching frequency of the LTM8001 is
determined by the resistor from the RT pin to GND and
may be set from 200kHz to 1MHz. The internal oscillator
may also be synchronized to an external clock through
the SYNC pin. The external clock applied to the SYNC pin
must have a logic low below 0.8V and a logic high greater
than 1.2V. The input frequency must be 20% higher than
the frequency determined by the resistor at the RT pin.
The SYNC pin must be tied to GND if the synchronization to an external clock is not required. When SYNC is
grounded, the switching frequency is determined by the
resistor at the RT pin.
14
VREF
LTM8001
2V
R1
ILIM
R2
8001 F01
Figure 1. Setting the Output Current Limit, IMAX
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LTM8001
Applications Information
Load Current Derating Using the ILIM Pin
VOUT
In high current applications, derating the maximum
current based on operating temperature may prevent
damage to the load. In addition, many applications have
thermal limitations that will require the regulated current
to be reduced based on the load and/or board temperature. To achieve this, the LTM8001 uses the ILIM pin to
reduce the effective regulated current in the load. While
ILIM programs the regulated current in the load, it may
also be configured to reduce the regulated current. The
load/board temperature derating is programmed using a
resistor divider with a temperature dependant resistance,
as shown in Figure 2. When the board/load temperature
rises, the ILIM voltage will decrease.
RV
RV
VREF
R2
LTM8001
RNTC
RNTC
RX
RNTC
RNTC
RX
ILIM
8001 F02
R1
(OPTION A TO D)
A
B
C
D
Figure 2. Load Current Derating vs
Temperature Using an NTC Resistor
VOUT0 Output Overvoltage Protection
The LTM8001 switching regulator uses the FB0 pin to both
regulate the output voltage and to provide a high speed
overvoltage lockout to avoid high voltage output conditions. If the output voltage exceeds 125% of the regulated
voltage level (1.5V at the FB0 pin), the LTM8001 terminates
switching and shuts down switching for a brief period. The
output voltage at which output overvoltage protection engages must be greater than 1.5V and is set by the equation:

10k 
VOUT = 1.5V  1+
 RFB0 
where RFB0 is shown in Figure 3.
If the output overvoltage protection engages, the LTM8001
will stop switching. If this is due to some external power
source connected to VOUT0, this source will be free to pull
up VOUT0. If the VOUT0 voltage exceeds the VIN0 input, an
internal power diode will clamp the output to a diode drop
above the input.
VOUT
LTM8001
FB0
RFB0
8001 F03
Figure 3. Voltage Regulation and Overvoltage
Protection Feedback Connections
Thermal Shutdown
If the part is too hot, the LTM8001 engages its thermal
shutdown, terminates switching and discharges the softstart capacitor. When the part has cooled, the part automatically restarts. This thermal shutdown is set to engage at
temperatures above the 125°C absolute maximum internal
operating rating to ensure that it does not interfere with
functionality in the specified operating range. This means
that internal temperatures will exceed the 125°C absolute
maximum rating when the overtemperature protection is
active, possibly impairing the device’s reliability.
UVLO and Shutdown
The LTM8001 VOUT0 step-down regulator has an internal
UVLO that terminates switching, resets all logic, and discharges the soft-start capacitor for input voltages below
4.2V. The LTM8001 also has a precision RUN function
that enables switching when the voltage at the RUN pin
rises to 1.68V and shuts down the LTM8001 when the
RUN pin voltage falls to 1.55V. There is also an internal
current source that provides 5.5μA of pull-down current to
program additional UVLO hysteresis. For RUN rising, the
current source is sinking 5.5µA until RUN = 1.68V, after
which it turns off. For RUN falling, the current source is
off until the RUN = 1.55V, after which it sinks 5.5µA. The
following equations determine the voltage divider resistors for programming the falling UVLO voltage and rising
enable voltage (VENA) as configured in Figure 4.
R2 =
VENA – 1.084 UVLO
5.5µA
R1=
1.55 R2
UVLO– 1.55
For more information www.linear.com/LTM8001
8001fc
15
LTM8001
Applications Information
The RUN pin has an absolute maximum voltage of 6V.
To accommodate the largest range of applications, there
is an internal Zener diode that clamps this pin, so that it
can be pulled up to a voltage higher than 6V through a
resistor that limits the current to less than 100µA. For
applications where the supply range is greater than 4:1,
size R2 greater than 375k.
VIN
LTM8001
R2
R1
8001 F04
Figure 4. UVLO Configuration
Load Sharing
The VOUT0 step-down switching converter operates in
fixed frequency forced continuous mode, so it is able to
source and sink current. It is therefore not suitable for
load current sharing.
The linear regulators connected to VOUT1-VOUT5 are internally ballasted and may be paralleled. To do this, simply
tie the VOUTx and SETx terminals together. When the SET
pins of the regulators are tied together, the RSET resistor
is determined by the equation:
VOUT
n •10µA
where n is the number of linear regulator outputs tied
together.
All paralleled LDOs must be active in order for this equation to be true, as it is assumed that all paralleled LDOs
are contributing 10µA to a single voltage set resistor. If
any LDO is off or inactive, it will be unable to contribution
its share of the set current and the output voltage will be
lower than expected.
When paralleling LDOs, tie all of the VOUTx and all of the
SETx pins together. Examples are shown in the Typical
Applications section.
16
The LTM8001 contains a step-down switching regulator
that operates at a user-selectable frequency in forced
continuous mode. Step-down switching regulators that
operate in forced continuous mode are capable of both
sinking and sourcing current to maintain output voltage
regulation
When the LTM8001 is sinking current, it maintains its
output voltage regulation by power conversion, not power
dissipation. This means that the energy provided to the
LTM8001 is in turn delivered to its input power bus.
There must be something on this power bus to accept or
use the energy, or the LTM8001’s input voltage will rise.
Left unchecked, the energy can raise the input voltage
above the absolute maximum voltage rating and damage
the LTM8001.
VIN
RUN
RSET =
Input Precautions
In many cases, the system load on the LTM8001 input
bus will be sufficient to absorb the energy delivered by the
μModule regulator. The power required by other devices
will consume more than enough to make up for what
the LTM8001 delivers. In cases where the LTM8001 is
the largest or only power converter, this may not be true
and some means may need to be devised to prevent the
LTM8001’s input from rising too high. Figure 5a shows a
passive crowbar circuit that will dissipate energy during
momentary input overvoltage conditions. The breakdown
voltage of the zener diode is chosen in conjunction with
the resistor R to set the circuit’s trip point. The trip point
is typically set well above the maximum VIN voltage under
normal operating conditions. This circuit does not have a
precision threshold, and is subject to both part-to-part and
temperature variations, so it is not suitable for applications
where high accuracy is required or large voltage margins
are not available.
The circuit in Figure 5b also dissipates energy during momentary overvoltage conditions, but is more precise than
that in Figure 5a. It uses an inexpensive comparator and
the VREF output of the LTM8001 to establish a reference
voltage. The optional hysteresis resistor in the comparator
circuit avoids MOSFET chatter. Figure 5c shows a circuit
that latches on and crowbars the input in an overvoltage
8001fc
For more information www.linear.com/LTM8001
LTM8001
Applications Information
event. The SCR latches when the input voltage threshold
is exceeded, so this circuit should be used with a fuse, as
shown, or employ some other method to interrupt current
from the load.
As mentioned, the LTM8001 sinks current by energy
conversion and not dissipation. Thus, no matter what
protection circuit that is used, the amount of power that the
protection circuit must absorb depends upon the amount
of power at the input. For example, if the output voltage is
2.5V and can sink 5A, the input protection circuit should
be designed to absorb at least 7.5W. In Figures 5a and 5b,
let us say that the protection activation threshold is 30V.
Then the circuit must be designed to be able to dissipate
7.5W and accept 7.5W/30V = 250mA.
Figures 5a through 5c are crowbar circuits, which attempt
to prevent the input voltage from rising above some level
by clamping the input to GND through a power device. In
some cases, it is possible to simply turn off the LTM8001
when the input voltage exceeds some threshold. This
is possible when the voltage power source that drives
current into VOUT never exceeds VIN. An example of this
circuit is shown in Figure 5d. When the power source on
the output drives VIN above a predetermined threshold,
the comparator pulls down on the RUN pin and stops
switching in the LTM8001. When this happens, the input
capacitance needs to absorb the energy stored within the
LTM8001’s internal inductor, resulting in an additional
voltage rise. As shown in the Block Diagram, the internal
LOAD
CURRENT
VIN
ZENER
DIODE
Q
LOAD
CURRENT
VOUT0
VIN
LTM8001
GND
SCR
SOURCING
LOAD
ZENER
DIODE
VOUT0
LTM8001
FUSE
GND
SOURCING
LOAD
R
8001 F05a
8001 F05a
Figure 5a. The MOSFET Q Dissipates Momentary Energy to
GND. The Zener Diode and Resistor Are Chosen to Ensure That
the MOSFET Turns On Above the Maximum VIN Voltage Under
Normal Operation
Figure 5c. The SCR Latches On When the Activation Threshold is
Reached, So a Fuse or Some Other Method of Disconnecting the
Load Should be Used
LOAD
CURRENT
OPTIONAL
HYSTERESIS
RESISTOR
Q
+
–
VIN
LOAD
CURRENT
VOUT0
VREF GND
VOUT0
VIN
LTM8001
LTM8001
SOURCING
LOAD
RUN
10µF
8001 F05b
Figure 5b. The Comparator in This Circuit Activates the Q
MOSFET at a More Precise Voltage Than the One Shown in
Figure 5a. The Reference for the Comparator is Derived from
the VREF Pin of the LTM8001
–
+
GND
SOURCING
LOAD
EXTERNAL
REFERENCE
VOLTAGE
8001 F05d
Figure 5d. This Comparator Circuit Turns Off the LTM8001 if
the Input Rises Above a Predetermined Threshold. When the
LTM8001 Turns Off, the Energy Stored in the Internal Inductor
Will Raise VIN a Small Amount Above the Threshold.
8001fc
For more information www.linear.com/LTM8001
17
LTM8001
Applications Information
inductor value is 2.2uH. If the LTM8001 negative current
limit is set to 5A, for example, the energy that the input
capacitance must absorb is 1/2 LI2 = 27.5μJ. Suppose
the comparator circuit in Figure 5d is set to pull the RUN
pin down when VTRIP = 15V. The input voltage will rise
according to the capacitor energy equation:
1
C ( VIN2 – VTRIP 2 ) = 27.5µJ
2
If the total input capacitance is 10μF, the input voltage
will rise to:
(
1
27.5µJ = 10µF VIN2 – 15V 2
2
VIN = 15.2V
)
6. Use vias to connect the GND copper area to the board’s
internal ground planes. Liberally distribute these GND
vias to provide both a good ground connection and
thermal path to the internal planes of the printed circuit
board. Pay attention to the location and density of the
thermal vias in Figure 6. The LTM8001 can benefit from
the heat sinking afforded by vias that connect to internal
GND planes at these locations, due to their proximity
to internal power handling components. The optimum
number of thermal vias depends upon the printed
circuit board design. For example, a board might use
very small via holes. It should employ more thermal
vias than a board that uses larger holes.
COUT4
PCB Layout
Most of the headaches associated with PCB layout have
been alleviated or even eliminated by the high level of
integration of the LTM8001. The LTM8001 is nevertheless a switching power supply, and care must be taken to
minimize EMI and ensure proper operation. Even with the
high level of integration, you may fail to achieve specified
operation with a haphazard or poor layout. See Figure 6
for a suggested layout. Ensure that the grounding and heat
sinking are acceptable. A few rules to keep in mind are:
3. Place the ceramic COUT0 capacitor as close as possible
to the VOUT0 and GND connection of the LTM8001. The
electrolytic COUT0 capacitor may be farther from the
LTM8001. Place the remaining COUTx output capacitors
as close as possible to the VOUTx pins.
4. Place the CIN0 and COUT0 capacitors such that their
ground currents flow directly adjacent or underneath
the LTM8001.
5. Connect all of the GND connections to as large a copper
pour or plane area as possible on the top layer. Avoid
breaking the ground connection between the external
components and the LTM8001.
18
COUT2
GND
GND
VOUT4
VOUT5
COUT5
VOUT3
SET4
VOUT2
SET3 SET2
SET5
BIAS45
VOUT1
COUT1
SET1
VREF ILIM
BIAS123
GND
SYNC RT
VIN45
COMP
FBO
VOUT0
SS RUN
COUT0
1. Place the RSETx, RFB0 and RT resistors as close as possible to their respective pins.
2. Place the CIN0 capacitor as close as possible to the VIN0
and GND connection of the LTM8001.
COUT3
VIN0
GND
THERMAL VIAS
CIN0
8001 F06
Figure 6. Layout Showing Suggested External Components,
GND Plane and Thermal Vias
Hot Plugging Safely
The small size, robustness and low impedance of ceramic
capacitors make them an attractive option for the input
bypass capacitor of LTM8001. However, these capacitors
can cause problems if the LTM8001 is plugged into a live
input supply (see Application Note 88 for a complete discussion). The low loss ceramic capacitor combined with
stray inductance in series with the power source forms an
underdamped tank circuit, and the voltage at the VIN0 pin
of the LTM8001 can ring to more than twice the nominal
input voltage, possibly exceeding the LTM8001’s rating
8001fc
For more information www.linear.com/LTM8001
LTM8001
Applications Information
and damaging the part. If the input supply is poorly controlled or the user will be plugging the LTM8001 into an
energized supply, the input network should be designed
to prevent this overshoot. This can be accomplished by
installing a small resistor in series to VIN0, but the most
popular method of controlling input voltage overshoot is
to add an electrolytic bulk capacitor to the VIN0 net. This
capacitor’s relatively high equivalent series resistance
damps the circuit and eliminates the voltage overshoot.
The extra capacitor improves low frequency ripple filtering
and can slightly improve the performance of the circuit,
though it may be physically large.
Shorted Input Protection
Care needs to be taken in systems where the VOUT0 output will be held high when the input to the LTM8001 is
absent. If the VIN0 is allowed to float and the RUN pin is
held high (either by a logic signal or because it is tied to
VIN0), then the LTM8001’s internal circuitry will pull its
quiescent current through its internal power switch. This
is fine if your system can tolerate this state. If the RUN pin
is pulled low, the input current will drop to essentially zero.
However, if the VIN0 is grounded while the VOUT0 output is
held high, then parasitic diodes inside the LTM8001 can
pull large currents from the output through the VIN0 pin.
Figure 7 shows a circuit that will run only when the input
voltage is present and that protects against a shorted or
reversed input.
VIN
VIN
VOUT0
VOUT
RUN
LTM8001
RT
GND
Charging Applications
The LTM8001’s internal switching step-down regulator’s CVCC operation makes it well suited for battery or
supercapacitor charging applications. A schematic of the
LTM8001 charging a supercapacitor and then distributing power to various loads through the onboard LDOs is
shown in the Typical Applications section. In this application, the supercapacitor is charged through the step-down
switching regulator and not the LDOs. Each LDO is rated
for positive and differential voltages between its input
and output, but may experience a negative voltage during
start-up or turn-off transients if its output is connected to
a battery, supercapacitor or energized load. Avoid using
the LTM8001 in applications where the internal LDOs can
experience a negative voltage.
Thermal Considerations
The LTM8001 output current may need to be derated if it
is required to operate in a high ambient temperature. The
amount of current derating is dependent upon the input
voltage, output power and ambient temperature. The
temperature rise curves given in the Typical Performance
Characteristics section can be used as a guide. These curves
were generated by the LTM8001 mounted to a 59cm2
4-layer FR4 printed circuit board. Boards of other sizes
and layer count can exhibit different thermal behavior, so
it is incumbent upon the user to verify proper operation
over the intended system’s line, load and environmental
operating conditions.
For increased accuracy and fidelity to the actual application,
many designers use finite element analysis (FEA) to predict
thermal performance. To that end, the Pin Configuration
of this data sheet typically gives four thermal coefficients:
θJA: Thermal resistance from junction to ambient
8001 F07
Figure 7. The Input Diode Prevents a Shorted Input from
Discharging a Backup Battery Tied to the Output. It Also
Protects the Circuit from a Reversed Input. The LTM8001
Runs Only When the Input is Present
θJCbottom: Thermal resistance from junction to the bottom
of the product case
8001fc
For more information www.linear.com/LTM8001
19
LTM8001
Applications Information
θJCtop: Thermal resistance from junction to top of the
product case
θJB: Thermal resistance from junction to the printed
circuit board
While the meaning of each of these coefficients may seem
to be intuitive, JEDEC has defined each to avoid confusion
and inconsistency. These definitions are given in JESD
51-12, and are quoted or paraphrased below:
θJA is the natural convection junction-to-ambient air
thermal resistance measured in a one cubic foot sealed
enclosure. This environment is sometimes referred to as
“still air” although natural convection causes the air to
move. This value is determined with the part mounted to
a JESD 51-9 defined test board, which does not reflect an
actual application or viable operating condition.
θJCbottom is the junction-to-board thermal resistance with
all of the component power dissipation flowing through the
bottom of the package. In the typical µModule regulator,
the bulk of the heat flows out the bottom of the package,
but there is always heat flow out into the ambient environment. As a result, this thermal resistance value may
be useful for comparing packages but the test conditions
don’t generally match the user’s application.
θJCtop is determined with nearly all of the component power
dissipation flowing through the top of the package. As the
electrical connections of the typical µModule regulator are
on the bottom of the package, it is rare for an application
to operate such that most of the heat flows from the junction to the top of the part. As in the case of θJCbottom, this
value may be useful for comparing packages but the test
conditions don’t generally match the user’s application.
20
θJB is the junction-to-board thermal resistance where
almost all of the heat flows through the bottom of the
µModule regulator and into the board, and is really the
sum of the θJCbottom and the thermal resistance of the
bottom of the part through the solder joints and through a
portion of the board. The board temperature is measured
a specified distance from the package, using a two sided,
two layer board. This board is described in JESD 51-9.
Given these definitions, it should now be apparent that none
of these thermal coefficients reflects an actual physical
operating condition of a µModule regulator. Thus, none
of them can be individually used to accurately predict the
thermal performance of the product. Likewise, it would
be inappropriate to attempt to use any one coefficient to
correlate to the junction temperature vs load graphs given
in this product’s data sheet. The only appropriate way to
use the coefficients is when running a detailed thermal
analysis, such as FEA, which considers all of the thermal
resistances simultaneously.
A graphical representation of these thermal resistances
is Figure 8. The blue resistances are contained within the
µModule regulator, and the green are outside.
The die temperature of the LTM8001 must be lower than
the maximum rating of 125°C, so care should be taken in
the layout of the circuit to ensure good heat sinking of the
LTM8001. The bulk of the heat flow out of the LTM8001
is through the bottom of the module and the BGA pads
into the printed circuit board. Consequently a poor printed
circuit board design can cause excessive heating, resulting in impaired performance or reliability. Please refer to
the PCB Layout section for printed circuit board design
suggestions.
8001fc
For more information www.linear.com/LTM8001
LTM8001
Applications Information
JUNCTION-TO-AMBIENT RESISTANCE (JESD 51-9 DEFINED BOARD)
JUNCTION-TO-CASE (TOP)
RESISTANCE
JUNCTION
CASE (TOP)-TO-AMBIENT
RESISTANCE
JUNCTION-TO-BOARD RESISTANCE
JUNCTION-TO-CASE
CASE (BOTTOM)-TO-BOARD
(BOTTOM) RESISTANCE
RESISTANCE
At
BOARD-TO-AMBIENT
RESISTANCE
8001 F08
µMODULE DEVICE
Figure 8. Thermal Resistances Among μModule Device Printed Circuit Board and Ambient Environment
8001fc
For more information www.linear.com/LTM8001
21
LTM8001
Typical Applications
Five Output DC/DC µModule Regulator
BIAS45 BIAS123 VIN45
VIN
18V TO 36V
10µF
VIN0
510k
LDO 1
RUN
COMP
SS
VREF
ILIM
SYNC
LTM8001
12V1
300mA
VOUT1
SET1
12V2
300mA
VOUT2
STEP-DOWN LDO 2 SET2
SWITCHING
V
REGULATOR LDO 3 OUT3
SET3
LDO 4
GND
(13.5V)
VOUT0
+
12V4
300mA
VOUT4
SET4
953Ω
68.1k
120µF
12V3
300mA
VOUT5
FBO LDO 5 SET5
RT
47µF
2.2µF
2.2µF
2.2µF
2.2µF
2.2µF
1.21M
1.21M
1.21M
1.21M
1.21M
12V5
300mA
8001 TA02
600kHz
Dual Input, 2.5V 5A DC/DC µModule Converter Using a Single LTM8001
(External 3.3V Turns On Before or Simultaneously with 12V)
EXTERNAL
3.3V
VIN
12V
10µF
10µF
VIN45
VOUT0
VIN0
510k
LDO 1
RUN
BIAS123
BIAS45 LTM8001
COMP
SS
VREF
ILIM
SYNC
GND
VOUT1
SET1
LDO 4
VOUT4
SET4
VOUT5
FBO LDO 5 SET5
RT
6.65k
500kHz
3V
470µF
100µF
VOUT2
STEP-DOWN LDO 2 SET2
SWITCHING
V
REGULATOR LDO 3 OUT3
SET3
82.5k
22
+
22µF
10nF
2.5V
5A
49.9k
8001 TA03
8001fc
For more information www.linear.com/LTM8001
LTM8001
Typical Applications
Supercapacitor Charger and Two Output Regulator
VIN45
VIN
9V TO 15V
10µF
VOUT0
VIN0
200k
48.7k
RUN
BIAS123
BIAS45 LTM8001
COMP
SS
VREF
ILIM
SYNC
GND
LDO 1
3.3V
1A
VOUT1
SET1
VOUT2
STEP-DOWN LDO 2 SET2
SWITCHING
V
REGULATOR LDO 3 OUT3
SET3
LDO 4
68.1k
3.09k
2.5V
0.5A
VOUT4
SET4
VOUT5
FBO LDO 5 SET5
RT
47µF
5V
1.5F
5V SUPERCAP
PM-5ROV155-R
4.7µF
10µF
124k
110k
600kHz
8001 TA04
8001fc
For more information www.linear.com/LTM8001
23
LTM8001
Typical Applications
Use Two LTM8001s to Implement a 2.5VOUT 10A DC/DC µModule Converter
100µF
VIN45
VIN1
12V
10µF
×2
LDO 1
RUN
BIAS123
BIAS45 LTM8001
COMP
SS
VREF
ILIM
SYNC
GND
3V
470µF
VOUT0
VIN0
510k
+
2.5V
10A
VOUT1
SET1
VOUT2
STEP-DOWN LDO 2 SET2
SWITCHING
V
REGULATOR LDO 3 OUT3
SET3
LDO 4
VOUT4
SET4
VOUT5
FBO LDO 5 SET5
RT
82.5k
6.65k
22µF
500kHz
100µF
VIN45
LDO 1
470µF
VOUT1
SET1
VOUT2
STEP-DOWN LDO 2 SET2
SWITCHING
V
REGULATOR LDO 3 OUT3
SET3
LDO 4
VOUT4
SET4
VOUT5
FBO LDO 5 SET5
RT
82.5k
6.65k
500kHz
24
3V
VOUT0
VIN0
RUN
BIAS123
BIAS45 LTM8001
COMP
SS
VREF
ILIM
SYNC
GND
+
24.9k
8001 TA05
8001fc
For more information www.linear.com/LTM8001
0.635 ±0.025 Ø 121x
2.540
SUGGESTED PCB LAYOUT
TOP VIEW
1.270
PACKAGE TOP VIEW
0.3175
0.000
0.3175
4
1.270
PIN “A1”
CORNER
E
2.540
aaa Z
6.350
5.080
3.810
3.810
5.080
6.350
D
X
For more information www.linear.com/LTM8001
6.350
5.080
3.810
2.540
1.270
0.000
1.270
2.540
3.810
5.080
6.350
Y
aaa Z
// bbb Z
SYMBOL
A
A1
A2
b
b1
D
E
e
F
G
H1
H2
aaa
bbb
ccc
ddd
eee
H1
SUBSTRATE
A1
NOM
3.42
0.60
2.82
0.75
0.63
15.00
15.00
1.27
12.70
12.70
0.32
2.50
A
A2
MAX
3.62
0.70
2.92
0.90
0.66
NOTES
DETAIL B
PACKAGE SIDE VIEW
0.37
2.55
0.15
0.10
0.20
0.30
0.15
TOTAL NUMBER OF BALLS: 121
0.27
2.45
MIN
3.22
0.50
2.72
0.60
0.60
b1
DIMENSIONS
ddd M Z X Y
eee M Z
DETAIL A
Øb (121 PLACES)
DETAIL B
H2
MOLD
CAP
ccc Z
Z
(Reference LTC DWG# 05-08-1923 Rev A)
Z
BGA Package
121-Lead (15.00mm × 15.00mm × 3.42mm)
F
11
10
9
7
6
5
4
PACKAGE BOTTOM VIEW
8
G
3
2
1
DETAIL A
DETAILS OF PIN #1 IDENTIFIER ARE OPTIONAL,
BUT MUST BE LOCATED WITHIN THE ZONE INDICATED.
THE PIN #1 IDENTIFIER MAY BE EITHER A MOLD OR
MARKED FEATURE
BALL DESIGNATION PER JESD MS-028 AND JEP95
L
K
J
H
G
F
E
D
C
B
A
7
TRAY PIN 1
BEVEL
!
PACKAGE IN TRAY LOADING ORIENTATION
LTMXXXXXX
µModule
7
SEE NOTES
PIN 1
BGA 121 1112 REV A
PACKAGE ROW AND COLUMN LABELING MAY VARY
AMONG µModule PRODUCTS. REVIEW EACH PACKAGE
LAYOUT CAREFULLY
6. SOLDER BALL COMPOSITION CAN BE 96.5% Sn/3.0% Ag/0.5% Cu
OR Sn Pb EUTECTIC
5. PRIMARY DATUM -Z- IS SEATING PLANE
4
3
2. ALL DIMENSIONS ARE IN MILLIMETERS
NOTES:
1. DIMENSIONING AND TOLERANCING PER ASME Y14.5M-1994
e
COMPONENT
PIN “A1”
b
3
SEE NOTES
LTM8001
Package Description
Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings.
8001fc
25
LTM8001
Package Description
Table 3. LTM8001 Pinout (Sorted by Pin Number)
PIN
NAME
PIN
NAME
PIN
NAME
PIN
NAME
PIN
NAME
PIN
NAME
A1
GND
B1
GND
C1
GND
D1
GND
E1
GND
F1
GND
A2
GND
B2
GND
C2
GND
D2
GND
E2
GND
F2
GND
A3
VOUT0
B3
VOUT0
C3
VOUT0
D3
GND
E3
GND
F3
GND
A4
VOUT0
B4
VOUT0
C4
VOUT0
D4
GND
E4
GND
F4
GND
A5
VOUT0
B5
VOUT0
C5
VOUT0
D5
GND
E5
GND
F5
GND
A6
VIN45
B6
VIN45
C6
VIN45
D6
GND
E6
GND
F6
GND
A7
VIN45
B7
VIN45
C7
VIN45
D7
GND
E7
GND
F7
GND
A8
BIAS45
B8
BIAS123
C8
GND
D8
GND
E8
GND
F8
GND
A9
SET5
B9
GND
C9
GND
D9
GND
E9
GND
F9
GND
A10
VOUT5
B10
GND
C10
GND
D10
GND
E10
GND
F10
GND
A11
VOUT5
B11
VOUT4
C11
VOUT4
D11
SET4
E11
VOUT3
F11
VOUT3
PIN
NAME
PIN
NAME
PIN
NAME
PIN
NAME
PIN
NAME
G1
GND
H1
GND
J1
VIN0
K1
VIN0
L1
VIN0
G2
GND
H2
GND
J2
VIN0
K2
VIN0
L2
VIN0
G3
GND
H3
GND
J3
VIN0
K3
VIN0
L3
VIN0
G4
GND
H4
GND
J4
GND
K4
SS
L4
RUN
G5
GND
H5
GND
J5
GND
K5
GND
L5
FB0
G6
GND
H6
GND
J6
GND
K6
GND
L6
COMP
G7
GND
H7
GND
J7
GND
K7
SYNC
L7
RT
G8
GND
H8
GND
J8
GND
K8
VREF
L8
ILIM
G9
GND
H9
GND
J9
GND
K9
GND
L9
SET1
G10
GND
H10
GND
J10
GND
K10
GND
L10
VOUT1
G11
SET3
H11
SET2
J11
VOUT2
K11
VOUT2
L11
VOUT1
Package PHOTO
26
8001fc
For more information www.linear.com/LTM8001
LTM8001
Revision History
REV
DATE
DESCRIPTION
PAGE NUMBER
A
09/13
Update Features section
1
Update test conditions and limits
3, 4
Correct input power pin name
11
B
02/14
Add SnPb BGA package option
1, 2
C
08/14
Add MP-grade option
2, 3
8001fc
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection
of its circuits
as described
herein will not infringe on existing patent rights.
For more
information
www.linear.com/LTM8001
27
LTM8001
Typical Application
Three Output DC/DC µModule Converter
VIN45
VIN
9V TO 18V
10µF
VIN0
510k
10k
LDO 1
RUN
BIAS123
BIAS45 LTM8001
COMP
SS
VREF
ILIM
SYNC
GND
1.8V
1A
1V
2.2A
VOUT0
VOUT1
SET1
VOUT2
STEP-DOWN LDO 2 SET2
SWITCHING
V
REGULATOR LDO 3 OUT3
SET3
LDO 4
VOUT5
FBO LDO 5 SET5
RT
20.5k
118k
1.2V
1.3A
VOUT4
SET4
19.6k
4.7µF
10µF
60.4k
33.2k
470µF
+
100µF
8001 TA06
350kHz
Related Parts
PART NUMBER
DESCRIPTION
COMMENTS
LTM8026
36VIN, 5A Step-Down µModule Regulator with
Adjustable Current Limit
6V ≤ VIN ≤ 36V, 1.2V ≤ VOUT ≤ 24V, Adjustable Current Limit, Parallelable
Outputs, CLK Input, 11.25mm × 15mm × 2.82mm LGA
LTM8052
36VIN, ±5A Step-Down µModule Regulator with
Adjustable Current Limit
6V ≤ VIN ≤ 36V, 1.2V ≤ VOUT ≤ 24V, –5V ≤ IOUT ≤ 5A, Adjustable Current Limit,
CLK Input, 11.25mm × 15mm × 2.82mm LGA, Pin Compatible with LTM8026
LTM8061
32V, 2A Step-Down µModule Battery Charger with
Programmable Input Current Limit
Suitable for CC-CV Charging Single and Dual Cell Li-Ion or Li-Poly Batteries,
4.95V ≤ VIN ≤ 32V, C/10 or Adjustable Timer Charge Termination, NTC
Resistor Monitor Input, 9mm × 15mm × 4.32mm LGA
LTM8062A
32V, 2A Step-Down µModule Battery Charger with
Integrated Maximum Peak Power Tracking (MPPT) for
Solar applications
Suitable for CC-CV Charging Method Battery Chemistries (Li-Ion, Li-Poly,
Lead-Acid, LiFePO4), User Adjustable MPPT Servo Voltage, 4.95V ≤ VIN
≤ 32V, 3.3V ≤ VBATT ≤ 18.8V Adjustable, C/10 or Adjustable Timer Charge
Termination, NTC Resistor Monitor Input, 9mm × 15mm × 4.32mm LGA
LTM8033
36V, 3A EN55022 Class B Certified DC/DC Step-Down
µModule Regulator
3.6V ≤ VIN ≤ 36V, 0.8V ≤ VOUT ≤ 24V, Synchronizable, 11.25mm × 15mm ×
4.32mm LGA
LTM4613
36VIN, 8A EN55022 Class B Certified DC/DC StepDown µModule Regulator
5V ≤ VIN ≤ 36V, 3.3V ≤ VOUT ≤ 15V, PLL input, VOUT Tracking and Margining,
15mm × 15mm × 4.32mm LGA
LTM8048
1.5W, 725VDC Galvanically Isolated µModule Converter 3.1V ≤ VIN ≤ 32V, 2.5V ≤ VOUT ≤ 12V, 1mVP-P Output Ripple, Internal Isolated
Transformer, 9mm × 11.25mm × 4.92mm BGA
with LDO Post regulator
LTC2978
Octal Digital Power Supply Manager with EEPROM
I2C/PMBus Interface, Configuration EEPROM, Fault Logging, 16-Bit ADC with
±0.25% TUE, 3.3V to 15V Operation
LTC2974
Quad Digital Power Supply Manager with EEPROM
I2C/PMBus Interface, Configuration EEPROM, Fault Logging, per Channel
Voltage, Current and Temperature Measurements
LTC3880
Dual Output PolyPhase® Step-Down DC/DC Controller
with Digital Power System Management
I2C/PMBus Interface, Configuration EEPROM, Fault Logging, ±0.5% Output
Voltage Accuracy, MOSFET Gate Drivers
28
8001fc
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
For more information www.linear.com/LTM8001
(408) 432-1900 ● FAX: (408) 434-0507
●
www.linear.com/LTM8001
LT 0814 REV C • PRINTED IN USA
 LINEAR TECHNOLOGY CORPORATION 2013