LINEAR TECHNOLOGY LTM4601, LTM4601-1 Technical data
FEATURES
LTM4601/LTM4601-1
12A DC/DC µModules
with PLL, Output Tracking
and Margining
U
DESCRIPTIO
■
Complete Switch Mode Power Supply
■
Wide Input Voltage Range: 4.5V to 20V
■
12A DC Typical, 14A Peak Output Current
■
0.6V to 5V Output Voltage
■
Output Voltage Tracking and Margining
■
Parallel Multiple µModules for Current Sharing
■
Differential Remote Sensing for Precision
Regulation (LTM4601 Only)
■
PLL Frequency Synchronization
■
±1.5% Regulation
■
Current Foldback Protection (Disabled at Start-Up)
■
Pb-Free (e4) RoHS Compliant Package with Gold
Finish Pads
■
Ultrafast Transient Response
■
Current Mode Control
■
Up to 95% Effi ciency at 5VIN, 3.3V
■
Programmable Soft-Start
■
Output Overvoltage Protection
■
Small Footprint, Low Profi le (15mm × 15mm ×
OUT
2.8mm) Surface Mount LGA Package
U
APPLICATIO S
■
Telecom and Networking Equipment
■
Servers
■
Industrial Equipment
■
Point of Load Regulation
The LTM®4601 is a complete 12A step-down switch mode
DC/DC power supply with onboard switching controller,
MOSFETs, inductor and all support components. The
TM
µModule
is housed in a small surface mount 15mm
×15mm × 2.8mm LGA package. Operating over an input
voltage range of 4.5 to 20V, the LTM4601 supports an
output voltage range of 0.6V to 5V as well as output voltage
tracking and margining. The high effi ciency design delivers
12A continuous current (14A peak). Only bulk input and
output capacitors are needed to complete the design.
The low profi le (2.8mm) and light weight (1.7g) package easily mounts in unused space on the back side of
PC boards for high density point of load regulation. The
µModule can be synchronized with an external clock for
reducing undesirable frequency harmonics and allows
®
PolyPhase
operation for high load currents.
A high switching frequency and adaptive on-time current
mode architecture deliver a very fast transient response
to line and load changes without sacrifi cing stability. An
onboard differential remote sense amplifi er can be used
to accurately regulate an output voltage independent of
load current. The onboard remote sense amplifi er is not
available in the LTM4601-1.
, LTC, LT and PolyPhase are registered trademarks of Linear Technology Corporation.
µModule is a trademark of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
Protected by U.S. Patents, including 5481178, 5847554, 6580258, 6304066, 6476589,
6774611, 6677210
TYPICAL APPLICATIO
1.5V/12A Power Supply with 4.5V to 20V Input
V
IN
4.5V TO 20V
ON/OFF
C
IN
R1
392k
5% MARGIN
PGOOD
RUN
COMP
INTV
DRV
MPGM
V
IN
CC
CC
TRACK/SSPLLIN
LTM4601
V
OUT_LCL
DIFFV
f
SETPGNDSGND
MARG0
MARG1
V
OSNS
V
OSNS
U
CLOCK SYNC
TRACK/SS CONTROL
V
OUT
V
FB
MARGIN
CONTROL
OUT
+
–
100pF
R
SET
40.2k
4601 TA01a
C
V
1.5V
12A
OUT
OUT
Effi ciency and Power Loss
vs Load Current
95
EFFICIENCY
90
85
80
75
70
EFFICIENCY (%)
65
60
55
50
0
5V
IN
12V
IN
12V
IN
POWER LOSS
24 681012 14
OUTPUT CURRENT (A)
4.0
3.5
3.0
POWER LOSS (W)
2.5
5V
IN
2.0
1.5
1.0
0.5
4601 TA01b
4601f
1
LTM4601/LTM4601-1
WW
W
U
ABSOLUTE AXI U RATI GS
(Note 1)
INTVCC, DRVCC, V
DIFFV
) .................................................... –0.3V to 6V
OUT
OUT_LCL
PLLIN, TRACK/SS, MPGM, MARG0, MARG1,
PGOOD, f
..............................–0.3V to INTVCC + 0.3V
SET
RUN ............................................................. –0.3V to 5V
, COMP ................................................ –0.3V to 2.7V
V
FB
............................................................. –0.3V to 20V
V
IN
V
OSNS
+
, V
–
.............................–0.3V to INTVCC – 1V
OSNS
Operating Temperature Range (Note 2) ... –40°C to 85°C
Junction Temperature ........................................... 125°C
Storage Temperature Range ...................–55°C to 125°C
, V
OUT
(V
OUT
≤ 3.3V with
UUW
PACKAGE/ORDER I FOR ATIO
TOP VIEW
RUN
COMP
PLLIN
INTVCCTRACK/SS
V
IN
PGND
V
OUT
118-LEAD (15mm ´ 15mm ´ 2.8mm)
T
JMAX
DERIVED FROM 95mm × 76mm PCB WITH 4 LAYERS
θ
JA
LGA PACKAGE
= 125°C, θJA = 15°C/W, θJC = 6°C/W,
WEIGHT = 1.7g
*LTM4601-1 ONLY
ORDER PART NUMBER LGA PART MARKING*
MPGM
f
SET
MARG0
MARG1
DRV
V
FB
PGOOD
SGND
V
OSNS
DIFFV
V
OUT_LCL
V
OSNS
CC
+
OUT
–
/NC2*
/NC3*
/NC1*
LTM4601EV#PBF
LTM4601IV#PBF
LTM4601EV-1#PBF
LTM4601IV-1#PBF
Consult LTC Marketing for parts specifi ed with wider operating temperature ranges.
*The temperature grade is identifi ed by a label on the shipping container.
The
ELECTRICAL CHARACTERISTICS
● denotes the specifi cations which apply over the –40°C to 85°C
LTM4601V
LTM4601V
LTM4601V-1
LTM4601V-1
temperature range, otherwise specifi cations are at TA = 25°C, VIN = 12V. Per typical application (front page) confi guration.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
IN(DC)
V
OUT(DC)
Input Specifi cations
V
IN(UVLO)
I
INRUSH(VIN)
I
Q(VIN,NOLOAD)
I
S(VIN)
Input DC Voltage
Output Voltage CIN = 10µF ×3, C
Undervoltage Lockout Threshold I
Input Inrush Current at Startup I
Input Supply Bias Current VIN = 12V, V
Input Supply Current VIN = 12V, V
V
= 5V, V
IN
V
IN
= 0A 3.2 4 V
OUT
= 0A. V
OUT
V
IN
V
IN
V
= 12V, V
IN
Continuous
V
= 5V, V
IN
V
= 5V, V
IN
Shutdown, RUN = 0, VIN = 12V
V
= 12V, V
IN
V
= 5V, V
IN
OUT
= 12V, V
OUT
= 5V
= 12V
OUT
OUT
= 1.5V, No Switching
OUT
= 1.5V, Switching Continuous
OUT
OUT
OUT
= 1.5V, I
OUT
= 200µF
OUT
= 1.5V, I
= 1.5V, I
OUT
= 1.5V
= 1.5V, No Switching
= 1.5V, Switching
= 1.5V, I
= 3.3V, I
OUT
OUT
OUT
= 0A
OUT
OUT
= 12A
= 12A
= 12A
= 0A
●
4.5 20 V
●
1.478
●
1.478
1.5
1.5
0.6
0.7
3.8
38
2.5
42
22
1.81
3.63
4.29
1.522
1.522
mA
mA
mA
mA
µA
4601f
V
V
A
A
A
A
A
2
LTM4601/LTM4601-1
The ● denotes the specifi cations which apply over the –40°C to 85°C
ELECTRICAL CHARACTERISTICS
temperature range, otherwise specifi cations are at T
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
INTV
CC
Output Specifi cations
I
OUTDC
ΔV
OUT(LINE)
V
ΔV
V
V
OUT(AC)
f
S
ΔV
t
START
ΔV
t
SETTLE
I
OUTPK
OUT(MIN)
OUT(0A-12A)
OUT(MIN)
OUT(START)
OUTLS
Remote Sense Amp (Note 3) (LTM4601 Only, Not Supported in the LTM4601-1)
+
, V
V
OSNS
OSNS
CM Range
DIFFV
V
A
Range Output Voltage Range VIN = 12V, DIFF OUT Load = 100k 0 INTV
OUT
OS
V
GBP Gain Bandwidth Product 3MHz
SR Slew Rate 2 V/µs
R
IN
CMRR Common Mode Rejection Mode 100 dB
Control Stage
V
FB
V
RUN
I
SS/TRACK
t
ON(MIN)
VIN = 12V, RUN > 2V No Load 4.7 5 5.3 V
Output Continuous Current Range
(See Output Current Derating Curves
for Different V
, V
and TA)
IN
OUT
Line Regulation Accuracy V
Load Regulation Accuracy V
Output Ripple Voltage I
Output Ripple Voltage Frequency I
Turn-On Overshoot,
TRACK/SS = 10nF
Turn-On Time, TRACK/SS = Open C
Peak Deviation for Dynamic Load Load: 0% to 50% to 0% of Full Load,
Settling Time for Dynamic Load Step Load: 0% to 50%, or 50% to 0% of Full Load
Output Current Limit C
–
Common Mode Input Voltage Range VIN = 12V, RUN > 2V 0 INTV
Input Offset Voltage Magnitude 1.25 mV
Differential Gain 1V/V
Input Resistance V
Error Amplifi er Input Voltage
Accuracy
RUN Pin On/Off Threshold 1 1.5 1.9 V
Soft-Start Charging Current V
Minimum On Time (Note 4) 50 100 ns
= 25°C, VIN = 12V. Per typical application (front page) confi guration.
A
= 12V, V
V
IN
= 1.5V, I
OUT
= 1.5V, 0A to 12A
OUT
V
IN
V
IN
= 0A, C
OUT
V
= 12V, V
IN
V
= 5V, V
IN
= 5A, VIN = 12V, V
OUT
C
= 200µF, V
OUT
V
= 12V
IN
V
= 5V
IN
= 200µF, V
OUT
= 1.5V 0 12 A
OUT
= 0A, VIN from 4.5V to 20V
OUT
= 12V, Remote Sense Amplifi er
= 12V (LTM4601-1)
= 2×, 100µF/X5R/Ceramic
OUT
= 1.5V
OUT
= 1.5V
OUT
= 1.5V 850 kHz
OUT
OUT
= 1.5V, I
OUT
= 0A
●
●
●
20
18
20
20
OUT
= 1.5V, I
OUT
= 1A
0.3 %
0.25
1
Resisitive Load
V
= 12V
IN
V
= 5V
IN
C
= 2 × 22µF/Ceramic, 470µF, 4V Sanyo
OUT
0.5
0.7
POSCAP
V
= 12V
IN
V
= 5V
IN
V
= 12V 25 µs
IN
= 200µF, Table 2
OUT
V
= 12V, V
IN
V
= 5V, V
IN
+
to GND 20 kΩ
OSNS
I
= 0A, V
OUT
SS/TRACK
= 1.5V
OUT
= 1.5V
OUT
OUT
= 1.5V
●
0.594 0.6 0.606 V
= 0V –1.0 –1.5 –2.0 µA
35
35
17
17
CC
mV
mV
– 1 V
CC
4601f
%
%
P-P
P-P
mV
mV
ms
ms
mV
mV
A
A
V
3
LTM4601/LTM4601-1
The ● denotes the specifi cations which apply over the –40°C to 85°C
ELECTRICAL CHARACTERISTICS
temperature range, otherwise specifi cations are at T
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
t
OFF(MIN)
R
PLLIN
I
DRVCC
R
FBHI
V
MPGM
, V
V
MARG0
MARG1
PGOOD Output
ΔV
FBH
ΔV
FBL
ΔV
FB(HYS)
Minimum Off Time (Note 4) 250 400 ns
PLLIN Input Resistance 50 kΩ
Current into DRVCC Pin V
Resistor Between V
Margin Reference Voltage 1.18 V
MARG0, MARG1 Voltage Thresholds 1.4 V
PGOOD Upper Threshold VFB Rising 7 10 13 %
PGOOD Lower Threshold VFB Falling –7 –10 –13 %
PGOOD Hysteresis VFB Returning 1.5 %
OUT
and V
FB
= 25°C, VIN = 12V. Per typical application (front page) confi guration.
A
OUT
DRV
= 1.5V, I
= 5V
CC
= 1A, Frequency = 850kHz,
OUT
18 25 mA
60.098 60.4 60.702 kΩ
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 LTM4601E/LTM4601E-1 are guaranteed to meet performance
specifi cations from 0°C to 85°C. Specifi cations over the –40°C to 85°C
operating temperature range are assured by design, characterization and
correlation with statistical process controls. The LTM4601I/LTM4601I-1
are guaranteed and tested over the –40°C to 85°C temperature range.
Note 3: Remote sense amplifi er recommended for ≤3.3V output.
Note 4: 100% tested at wafer level only.
4
4601f
w
UW
TYPICAL PERFOR A CE CHARACTERISTICS
LTM4601/LTM4601-1
(See Figure 18 for all curves)
Effi ciency vs Load Current
ith 5V
IN
100
95
90
85
80
75
EFFICIENCY (%)
70
65
60
0
0.6V
1.2V
1.5V
2.5V
3.3V
OUTPUT CURRENT (A)
1.2V Transient Response 1.5V Transient Response
V
OUT
50mV/DIV
I
OUT
5A/DIV
OUT
OUT
OUT
OUT
OUT
510
4601 G01
Effi ciency vs Load Current
with 12V
100
95
90
85
80
75
70
EFFICIENCY (%)
65
60
55
50
15
0
0.6V
OUT
1.2V
OUT
1.5V
OUT
2.5V
OUT
3.3V
OUT
5V
OUT
5
OUTPUT CURRENT (A)
10
15
4601 G02
Effi ciency vs Load Current
with 20V
100
95
90
85
80
75
EFFICIENCY (%)
70
65
60
0
IN
5
OUTPUT CURRENT (A)
1.2V
OUT
1.5V
OUT
2.5V
OUT
3.3V
OUT
5.0V
OUT
10 15
4601 G03
1.8V Transient Response
V
OUT
50mV/DIV
I
OUT
5A/DIV
V
OUT
50mV/DIV
I
OUT
5A/DIV
1.2V AT 6A/µs LOAD STEP
= 3 • 22µF 6.3V CERAMICS
C
OUT
470µF 4V SANYO POSCAP
C3 = 100pF
20µs/DIV
2.5V Transient Response 3.3V Transient Response
V
OUT
50mV/DIV
I
OUT
5A/DIV
2.5V AT 6A/µs LOAD STEP
C
OUT
470µF 4V SANYO POSCAP
C3 = 100pF
4601 G04
20µs/DIV
= 3 • 22µF 6.3V CERAMICS
1.5V AT 6A/µs LOAD STEP
C
= 3 • 22µF 6.3V CERAMICS
OUT
470µF 4V SANYO POSCAP
C3 = 100pF
4601 G07
20µs/DIV
V
OUT
50mV/DIV
I
OUT
5A/DIV
4601 G05
3.3V AT 6A/µs LOAD STEP
= 3 • 22µF 6.3V CERAMICS
C
OUT
470µF 4V SANYO POSCAP
C3 = 100pF
20µs/DIV
1.8V AT 6A/µs LOAD STEP
= 3 • 22µF 6.3V CERAMICS
C
OUT
470µF 4V SANYO POSCAP
C3 = 100pF
20µs/DIV
4601 G08
4601 G06
4601f
5
LTM4601/LTM4601-1
A
UW
TYPICAL PERFOR A CE CHARACTERISTICS
(See Figure 18 for all curves)
Start-Up, I
V
OUT
0.5V/DIV
I
IN
0.5A/DIV
= 12V
V
IN
V
OUT
C
OUT
3 × 22
SOFT-START = 10nF
VIN to V
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
OUTPUT VOLTAGE (V)
1.5
1.0
0.5
0
0
OUT
42
= 0A
OUT
5ms/DIV
= 1.5V
= 470µF
µF
Step-Down Ratio
12 14 18
86
10
INPUT VOLTAGE (V)
Start-Up, I
OUT
= 12A
(Resistive Load)
V
OUT
0.5V/DIV
I
IN
1A/DIV
4601 G09
= 12V
V
IN
= 1.5V
V
OUT
= 470µF
C
OUT
µF
3 × 22
SOFT-START = 10nF
3.3V OUTPUT WITH
130k FROM V
TO I
ON
5V OUTPUT WITH
100k RESISTOR
ADDED FROM f
TO GND
5V OUTPUT WITH
NO RESISTOR ADDED
FROM f
2.5V OUTPUT
1.8V OUTPUT
1.5V OUTPUT
1.2V OUTPUT
16
20
4601 G11
SET
OUT
SET
TO GND
TRACK/SS
0.5V/DIV
0.5V/DIV
V
1V/DIV
2ms/DIV
Track, I
V
FB
OUT
V
= 12V
IN
= 1.5V
V
OUT
= 470mF
C
OUT
m
3 ´ 22
SOFT-START = 10nF
= 12A
OUT
F
2ms/DIV
4601 G10
4601 G12
6
Short-Circuit Protection, I
V
OUT
0.5V/DIV
I
IN
1A/DIV
V
= 12V
IN
= 1.5V
V
OUT
= 470µF
C
OUT
µF
3 × 22
SOFT-START = 10nF
50µs/DIV
OUT
= 0
4601 G13
Short-Circuit Protection, I
V
OUT
0.5V/DIV
I
IN
1A/DIV
= 12V
V
IN
= 1.5V
V
OUT
= 470µF
C
OUT
µF
3 × 22
SOFT-START = 10nF
50µs/DIV
OUT
= 12A
4601 G14
4601f
PI FU CTIO S
LTM4601/LTM4601-1
UUU
(See Package Description for Pin Assignment)
VIN (Bank 1): Power Input Pins. Apply input voltage be-
tween these pins and PGND pins. Recommend placing
input decoupling capacitance directly between V
pins
IN
and PGND pins.
(Bank 3): Power Output Pins. Apply output load
V
OUT
between these pins and PGND pins. Recommend placing
output decoupling capacitance directly between these pins
and PGND pins. Review the fi gure below.
PGND (Bank 2): Power ground pins for both input and
output returns.
–
V
(Pin M12): (–) Input to the Remote Sense Amplifi er.
OSNS
This pin connects to the ground remote sense point. The
remote sense amplifi er is used for V
OUT
≤3.3V.
NC1 (Pin M12): No Connect On the LTM4601-1.
+
V
(Pin J12): (+) Input to the Remote Sense Amplifi er.
OSNS
This pin connects to the output remote sense point. The
remote sense amplifi er is used for V
OUT
≤3.3V.
NC2 (Pin J12): No Connect On the LTM4601-1.
DIFFV
fi er. This pin connects to the V
(Pin K12): Output of the Remote Sense Ampli-
OUT
OUT_LCL
pin.
NC3 (Pin K12): No Connect On the LTM4601-1.
DRVCC (Pin E12): This pin normally connects to INTVCC
for powering the internal MOSFET drivers. This pin can
be biased up to 6V from an external supply with about
50mA capability, or an external circuit shown in Figure 16.
This improves effi ciency at the higher input voltages by
reducing power dissipation in the module.
INTV
(Pin A7): This pin is for additional decoupling of
CC
the 5V internal regulator.
PLLIN (Pin A8): External Clock Synchronization Input to
the Phase Detector. This pin is internally terminated to
SGND with a 50k resistor. Apply a clock above 2V and
below INTV
. See Applications Information.
CC
TRACK/SS (Pin A9): Output Voltage Tracking and SoftStart Pin. When the module is confi gured as a master
output, then a soft-start capacitor is placed on this pin
to ground to control the master ramp rate. A soft-start
capacitor can be used for soft-start turn on as a stand
alone regulator. Slave operation is performed by putting
a resistor divider from the master output to the ground,
and connecting the center point of the divider to this pin.
See Applications Information.
MPGM (Pin A12): Programmable Margining Input. A resistor from this pin to ground sets a current that is equal
to 1.18V/R. This current multiplied by 10kΩ will equal a
value in millivolts that is a percentage of the 0.6V reference voltage. See Applications Information. To parallel
LTM4601s, each requires an individual MPGM resistor.
Do not tie MPGM pins together.
(Pin B12): Frequency Set Internally to 850kHz. An
f
SET
external resistor can be placed from this pin to ground
to increase frequency. This pin can be decoupled with a
1000pF capacitor. See Applications Information for frequency adjustment.
(Pin F12): The Negative Input of the Error Amplifi er.
V
FB
Internally, this pin is connected to V
OUT_LCL
pin with a
60.4k precision resistor. Different output voltages can be
programmed with an additional resistor between V
FB
and
SGND pins. See Applications Information.
BANK 1
PGND
BANK 2
V
OUT
BANK 3
V
IN
M
A
B
C
D
E
F
G
H
J
K
L
1234567
*LTM4601-1 ONLY
TOP VIEW
RUN
PLLIN
INTVCCTRACK/SS
8 9 10 11 12
COMP
MPGM
f
SET
MARG0
MARG1
DRV
V
FB
PGOOD
SGND
V
OSNS
DIFFV
V
OUT_LCL
V
OSNS
CC
+
/NC2*
/NC3*
OUT
–
/NC1*
4601f
7
LTM4601/LTM4601-1
UUU
PI FU CTIO S
(See Package Description for Pin Assignment)
MARG0 (Pin C12): This pin is the LSB logic input for the
margining function. Together with the MARG1 pin will
determine if margin high, margin low or no margin state
is applied. The pin has an internal pull-down resistor of
50k. See Applications Information.
MARG1 (Pin D12): This pin is the MSB logic input for the
margining function. Together with the MARG0 pin will
determine if margin high, margin low or no margin state
is applied. The pin has an internal pull-down resistor of
50k. See Applications Information.
SGND (Pin H12): Signal Ground. This pin connects to
PGND at output capacitor point.
COMP (Pin A11): Current Control Threshold and Error
Amplifi er Compensation Point. The current comparator
threshold increases with this control voltage. The voltage
ranges from 0V to 2.4V with 0.7V corresponding to zero
sense voltage (zero current).
W
SI PLIFIEDWBLOCK DIAGRA
PGOOD (Pin G12): Output Voltage Power Good Indicator.
Open-drain logic output that is pulled to ground when the
output voltage is not within ±10% of the regulation point,
after a 25µs power bad mask timer expires.
RUN (Pin A10): Run Control Pin. A voltage above 1.9V
will turn on the module, and when below 1.9V, will turn
off the module. A programmable UVLO function can be
accomplished with a resistor from V
to this pin that has
IN
a 5.1V zener to ground. Maximum pin voltage is 5V. Limit
current into the RUN pin to less than 1mA.
V
OUT_LCL
(Pin L12): V
to bypass the remote sense amplifi er, or DIFFV
connects directly to this pin
OUT
OUT
connects to this pin when remote sense amplifi er is used.
V
OUT_LCL
V
OUT
can be connected to V
is internally connected to V
on the LTM4601-1,
OUT
OUT_LCL
with 50Ω in the
LTM4601-1.
>2V = ON
<0.9V = OFF
MAX = 5V
R
SET
40.2k
C
SS
V
OUT_LCL
RUN
PGOOD
COMP
SGND
MARG1
MARG0
V
f
SET
MPGM
TRACK/SS
PLLIN
INTV
DRV
V
1M
(50Ω, LTM4601-1)
60.4k
INTERNAL
COMP
FB
39.2k
4.7µF
CC
CC
50k
OUT
5.1V
ZENER
POWER CONTROL
50k
50k
10k
INTV
V
IN
4.5V TO 20V
+
1.5µF
Q1
22µF
Q2
CC
10k
–
+
10k
10k
C
OUT
PGND
V
OSNS
V
OSNS
DIFFV
OUT
C
IN
V
OUT
1.5V
12A
+
–
+
NOT INCLUDED
IN THE LTM4601-1
–
= NC1
V
OSNS
+
= NC2
V
OSNS
= NC3
DIFFV
OUT
8
4601 F01
Figure 1. Simplifi ed LTM4601/LTM4601-1 Block Diagram
4601f
LTM4601/LTM4601-1
U
DECOUPLI G REQUIRE E TS
T
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
C
IN
C
OUT
External Input Capacitor Requirement
(V
= 4.5V to 20V, V
IN
External Output Capacitor Requirement
(V
= 4.5V to 20V, V
IN
OUT
OUT
= 1.5V)
= 1.5V)
WU
= 25°C, VIN = 12V. Use Figure 1 confi guration.
A
= 12A, 3× 10µF Ceramics 20 30 µF
I
OUT
= 12A 100 200 µF
I
OUT
U
OPERATIO
Power Module Description
The LTM4601 is a standalone nonisolated switching mode
DC/DC power supply. It can deliver up to 12A of DC output
current with some external input and output capacitors.
This module provides precisely regulated output voltage
programmable via one external resistor from 0.6V
5.0V
over a 4.5V to 20V wide input voltage. The typical
DC
DC
application schematic is shown in Figure 18.
The LTM4601 has an integrated constant on-time current
mode regulator, ultralow R
FETs with fast switch-
DS(ON)
ing speed and integrated Schottky diodes. The typical
switching frequency is 850kHz at full load. With current
mode control and internal feedback loop compensation,
the LTM4601 module has suffi cient stability margins and
good transient performance under a wide range of operating conditions and with a wide range of output capacitors,
even all ceramic output capacitors.
Current mode control provides cycle-by-cycle fast current
limit. Besides, foldback current limiting is provided in an
overcurrent condition while V
drops. Internal overvoltage
FB
and undervoltage comparators pull the open-drain PGOOD
output low if the output feedback voltage exits a ±10%
window around the regulation point. Furthermore, in an
overvoltage condition, internal top FET Q1 is turned off
and bottom FET Q2 is turned on and held on until the
overvoltage condition clears.
Pulling the RUN pin below 1V forces the controller into its
shutdown state, turning off both Q1 and Q2. At low load
current, the module works in continuous current mode by
to
default to achieve minimum output voltage ripple.
When DRV
pin is connected to INTVCC an integrated
CC
5V linear regulator powers the internal gate drivers. If a
5V external bias supply is applied on the DRV
CC
an effi ciency improvement will occur due to the reduced
power loss in the internal linear regulator. This is especially
true at the higher input voltage range.
The LTM4601 has a very accurate differential remote
sense amplifi er with very low offset. This provides for
very accurate remote sense voltage measurement. The
MPGM pin, MARG0 pin and MARG1 pin are used to support voltage margining, where the percentage of margin
is programmed by the MPGM pin, and the MARG0 and
MARG1 select margining.
The PLLIN pin provides frequency synchronization of the
device to an external clock. The TRACK/SS pin is used for
power supply tracking and soft-start programming.
pin, then
4601f
9
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