Linear Technology LTM4636, Analog Devices LTM4636-1 User Manual
LTM4636
4.70V TO
VIN ≤ 5.5V, TIE VIN, INTVCC AND PV
40A
PINS NOT USED IN THIS CIRCUIT:
CLKOUT, GMON, PGOOD, PHMODE, PWM,
SW, TEST1, TEST2, TEST3, TEST4, TMON
OUTPUT CURRENT (A)
EFFICIENCY (%)
100
4636 TA01b
40
40A DC/DC µModule
Regulator
FeaTures
n
Stacked Inductor Acts as Heat Sink
n
Wide Input Voltage Range: 4.7V to 15V
n
0.6V to 3.3V Output Voltage Range
n
±1.3% Total DC Output Voltage Error Over Line,
Load and Temperature (–40°C to 125°C)
n
Differential Remote Sense Amplifier for Precision
Regulation
n
Current Mode Control/Fast Transient Response
n
Frequency Synchronization
n
Parallel Current Sharing (Up to 240A)
n
Internal or External Compensation
n
88% Efficiency (12VIN, 1V
n
Overcurrent Foldback Protection
n
16mm × 16mm × 7.07mm BGA Package
OUT
) at 40A
applicaTions
n
Telecom Servers and Networking Equipment
n
Industrial Equipment and Medical Systems
DescripTion
The LTM®4636 is a 40A step-down µModule (power
module) switching regulator with a stacked inductor as a
heat sink for quicker heat dissipation and cooler operation
in a small package. The exposed inductor permits direct
contact with airflow from any direction. The LTM4636
can deliver 40W (12V
IN
, 1V
40°C rise over the ambient temperature. Full-power 40W
is delivered, up to 83°C ambient and half-power 20W is
supported at 110°C ambient.
The LTM4636 operates at 92%, 90% and 88% efficiency,
delivering 15A, 30A and 40A, respectively, to a 1V load
). The µModule regulator is scalable such that four
(12V
IN
µModules in current sharing mode deliver 160W with only
40°C rise and 88% efficiency (12V
The LTM4636 is offered in a 16mm × 16mm × 7.07mm
BGA package.
L, LT, LT C , LT M , PolyPhase, Burst Mode, µModule, Linear Technology, LTpowerCAD 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 5481178,
5847554, 6580258, 6304066, 6476589, 6774611, 6677210, 8163643.
, 40A, 200LFM) with only
OUT
IN
, 1V
, 400LFM).
OUT
Typical applicaTion
> 5.5V, THEN OPERATE AS SHOWN
V
IN
15V
+
100µF
25V
1V, 40A DC/DC µModule Regulator
TOGETHER, TIE RUNP TO GND.
PV
22µF
16V
×5
34.8k
OPTIONAL TEMP MONITOR
CC
15k
0.1µF
INTV
CC
CC
RUNC
RUNP
HIZREG
FREQ
TRACK/SS
MODE/PLLIN
SNSP1
SNSP2
COMPA
COMPB
TEMP
PV
CC
INTV
CC
V
INTV
IN
+
PV
CC
CC
LTM4636
V
OUT
+
V
OUTS1
–
V
OUTS1
V
TEMP–SGND
For more information www.linear.com/LTM4636
FB
PGND
7.5k
22µF
1V
+
470µF
6.3V
×3
4636 TA01a
V
OUT
1V,
100µF
6.3V
×4
95
90
85
80
75
70
0
12VIN , 1V
OUT
vs Output Current
20 30
15 25
5 10
Efficiency
35
4636f
1
LTM4636
TOP VIEW
×
SNSP2
TEST4 (FLOAT PIN)
absoluTe MaxiMuM raTings
(Note 1)
VIN, SW, HZBREG, RUNP ........................... –0.3V to 16V
V
.......................................................... –0.3V to 3.5V
OUT
PGOOD, RUNC, TMON, PV
FREQ, TRACK/SS, TEST1, TEST2, V
, MODE/PLLIN, PHMODE,
CC
OUTS1
–
, V
OUTS1
+
,
SNSP1, SNSP2, TEST3, TEST4 .....–0.3V to INTVCC (5V)
VFB, COMPA, COMPB (Note 7) .................. –0.3V to 2.7V
PVCC Additional Output Current ................ 0mA to 50mA
Note: PWM, CLKOUT, and GMON are outputs only.
pin conFiguraTion
+
TEST2
HIZREG
SNSP1
TRACK/SS
RUNC
PGOOD
SGND
CLKOUT
MODE/PLLIN
T
θ
–
V
OUTS1
1
2 3 4 5 6 7 8 9 10 11 12
A
B
C
D
E
F
G
TEST3
H
J
K
GND
L
M
= 125°C, θJA = 7.5°C/W, θ
JMAX
= DERIVED FROM 95mm × 76mm PCB WITH 6 LAYERS, WEIGHT = 3.95g
JA
θ VALUES DETERMINED PER JESD51-12
COMPB
V
OUTS1
COMPA
V
FB
INTV
FREQ
TEST1
144-LEAD (16mm
BGA PACKAGE
JCbottom
V
OUT
GND
CC
GND
PWM
V
IN
16mm × 7.07mm)
= 3°C/W, θ
TMON
NC
JCtop
GND
= 15°C/W, θ
TEMP+, TEMP– .......................................... –0.3V to 0.8V
INTVCC Peak Output Current (Note 6) ....................20mA
Internal Operating Temperature Range
(Note 2) .................................................. –40°C to 125°C
Storage Temperature Range .................. –55°C to 125°C
Reflow (Peak Body) Temperature ..........................250°C
PHASMD
RUNP
PV
CC
–
TEMP
+
TEMP
GMON
SW
= 12°C/W
JBA
Note: θJA = (θ
orDer inForMaTion
PART NUMBER PAD OR BALL FINISH
LTM4636EY#PBF
LTM4636IY#PBF –40°C to 125°C
• Device temperature grade is indicated by a label on the shipping
container.
• Pad or ball finish code is per IPC/JEDEC J-STD-609.
• Terminal Finish Part Marking: www.linear.com/leadfree
• This product is not recommended for second side reflow. For more
JCbottom
+ θ
)||θ
; θ
JBA
JCtop
is Board to Ambient
JBA
http://www.linear.com/product/LTM4636#orderinfo
PART MARKING*
SAC305 (RoHS) LTM4636 BGA
• Recommended BGA PCB Assembly and Manufacturing Procedures:
www.linear.com/BGA-assy
• BGA Package and Tray Drawings: www.linear.com/packaging
• This product is moisture sensitive. For more information, go to:
www.linear.com/BGA-assy
PACKAGE
TYPE
MSL
RATING
TEMPERATURE RANGE
(SEE NOTE 2)DEVICE FINISH CODE
–40°C to 125°C
information, go to www.linear.com/BGA-assy
2
For more information www.linear.com/LTM4636
4636f
LTM4636
elecTrical characTerisTics
The l denotes the specifications which apply over the specified internal
operating temperature range (Note 2), otherwise specifications are at TA = 25°C. VIN = 12V, per the Typical Application in Figure 20.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
IN
V
OUT
V
OUT(DC)
Input DC Voltage VIN ≤ 5.5V, Tie VIN, INTVCC and PVCC Together, Tie RUNP
to GND
V
Range
OUT
DC Output Voltage, Total
Variation with Line and Load
C
= 22µF × 5
IN
= 100µF × 4 Ceramic, 470µF POSCAP × 3
C
OUT
= 40.2k, MODE_PLLIN = GND
R
FB
= 4.75V to 15V, I
V
IN
= 0A to 40A (Note 4)
OUT
Input Specifications
V
RUNC
V
RUNCHYS
V
RUNP
RUNC Pin On Threshold V
RUNC Pin On Hysteresis 150 mV
RUNP Pin On Threshold RUNP Pin Rising
Rising 1.1 1.22 1.35 V
RUNC
RUNP HYS RUNP Pin Hysteresis 60 mV
HIZREG HIZREG Input Threshold V
HIZREG HYS HIZREG Hysteresis V
I
Q(VIN)
I
S(VIN)
Input Supply Bias Current VIN = 12V, V
Input Supply Current VIN = 5V, V
= 12V, RUNC = 5V, RUNP = VIN, V
IN
= 12V, RUNC = 5V, RUNP = VIN, V
IN
= 1.5V, Burst Mode Operation, I
= 12V, V
V
IN
= 12V, V
V
IN
Shutdown, RUN = 0, V
= 12V, V
V
IN
OUT
= 1.5V, Pulse-Skipping Mode, I
OUT
= 1.5V, Switching Continuous, I
OUT
OUT
OUT
= 1.5V, I
IN
= 1.5V, I
= 12V
= 40A
OUT
OUT
= 40A
= 1.5V 2.3 V
OUT
= 1.5V 0.8 V
OUT
= 0.1A
OUT
= 0.1A
OUT
= 0.1A
OUT
Output Specifications
I
OUT(DC)
∆V
OUT
V
∆V
OUT
V
V
OUT(AC)
∆V
OUT(START)
t
START
∆V
OUTLS
t
SETTLE
I
OUTPK
(Line)
OUT
(Load)
OUT
Output Continuous Current
Range
Line Regulation Accuracy V
Load Regulation Accuracy V
Output Ripple Voltage
Turn-On Overshoot
Turn-On Time
Peak Deviation for Dynamic
Load
Settling Time for Dynamic
Load Step
Output Current Limit VIN = 12V, V
VIN = 12V, V
= 1.5V, VIN from 4.75V to 15V
OUT
= 0A
I
OUT
= 1.5V, I
OUT
I
= 0A, C
OUT
= 12V, V
V
IN
C
= 100µF × 4 Ceramic, 470µF × 3 POSCAP,
OUT
= 1.5V, I
V
OUT
C
= 100µF × 3 Ceramic, 470µF × 3 POSCAP,
OUT
No Load, TRACK/SS = 0.001µF, V
= 1.5V (Note 4) 0 40 A
OUT
= 0A to 40A, VIN = 12V (Note 4)
OUT
= 100µF × 3 Ceramic, 470µF × 3 POSCAP,
OUT
= 1.5V
OUT
= 0A, VIN = 12V, TRACK/SS = 0.1µF
OUT
= 12V
IN
Load: 0% to 50% to 0% of Full Load
= 100µF × 4 Ceramic, 470µF × 3 POSCAP,
C
OUT
= 12V, V
V
IN
= 1.5V, CFF = 22pF
OUT
Load: 0% to 50% to 0% of Full Load, VIN = 5V,
= 100µF × 4 Ceramic, 470µF × 3 POSCAP,
C
OUT
= 12V, V
V
IN
= 5V, V
V
IN
= 1.5V, CFF = 22pF
OUT
= 1.5V
OUT
= 1.5V
OUT
Control Section
V
FB
I
FB
V
OVL
I
TRACK/SS
t
ON(MIN)
R
FBHI
Voltage at VFB Pin I
Current at VFB Pin (Note 6) –30 –100 nA
Feedback Overvoltage
Lockout
Track Pin Soft-Start Pull-Up
Current
Minimum On-Time (Note 3) 100 ns
Resistor Between V
Pins
and V
FB
OUTS1
= 0A, V
OUT
Measure at V
OUT
OUTS1
= 1.5V
TRACK/SS = 0V, Default 750µs Turn on with TRACK/SS
Tied to INTV
CC
l
4.7 15 V
l
0.6 3.3 V
l
1.4805 1.5 1.5195 V
l
0.7 0.8 0.9 V
16
23
105
30
14.7
5.66
l
l
0.02 0.06 %/V
0.2 0.35 %
15 mV
5 mV
50 ms
45 mV
25 µs
54
54
l
0.594 0.600 0.606 V
l
5 7.5 10 %
1.1 1.35 1.6 µA
4.99 kΩ
mA
mA
mA
µA
P-P
4636f
A
A
A
A
For more information www.linear.com/LTM4636
3
LTM4636
elecTrical characTerisTics
The l denotes the specifications which apply over the specified internal
operating temperature range (Note 2), otherwise specifications are at TA = 25°C. VIN = 12V, per the typical application in Figure 20.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Remote Sense Amplifier
A
V(VFB)
Path Gain Bandwidth Product (Note 5) 4 MHz
GBP V
FB
General Control or Monitor Pins
I
TMON
I
TMON(SLOPE)
V
PGOOD
V
PGL
t
PGOOD
I
PGOOD(OFF)
V
PG1(HYST)
Linear Regulator
INTV
CC
V
INTVCC
Load Reg INTVCC Load Regulation ICC = 0mA to 10mA 0.5 %
V
INTVCC
UVLO HYS Controller UVLO Hysteresis (Note 6) 0.5 V
PV
CC(UVLO)
PV
CC(HYS)
PV
CC
Oscillator and Phase-Locked Loop
f
OSC
I
FREQ
R
MODE/PLLIN
V
MODE/PLLIN
V
CLKOUT
PWM-CLKOUT PWM to Clockout Phase Delay
PWM/PWMEN Outputs
PWM PWM Output High Voltage
VFB Differential Gain (Note 6) 1 V/V
Temperature Monitor Current, TJ = 25°C Into 25kΩ
Temperature Monitor Current, T
Temperature Monitor Current Slope, R
= 150°C Into 25kΩ
J
= 25kΩ 0.144 µA/°C
TMON
PGOOD Trip Level VFB With Respect to Set Output
V
Ramping Negative
FB
V
Ramping Positive
FB
PGOOD Voltage Low I
V
High-to-Low Delay 65 µs
PGOOD
PGOOD Leakage Current V
= 2mA 0.2 0.4 V
PGOOD
= 5V –2 2 µA
PGOOD
PGOOD Trip Level
38 40.3 5844 µA
µA
–7.5
7.5
2.5 %
Hysteresis
Internal VCC Voltage Source 6V < VIN < 15V 5.3 5.5 5.7 V
Drivers and Power
PVCC Rising 3.5 3.8 4.1 V
MOSFETs UVLO
PVCC UVLO Hysteresis 0.45 V
Power Stage Bias 12V Input, PVCC Load = 50mm 5.0 V
Oscillator Frequency
V
= 0V
PHSMD
FREQ Pin Output Current V
MODE_PLLIN Input
= 30.1kΩ
R
FREQ
R
= 47.5kΩ
FREQ
R
= 54.9kΩ
FREQ
R
= 75.0kΩ
FREQ
Maximum Frequency
Minimum Frequency
= 0.8V 19 20 21 µA
FREQ
l
l
210
540
625
945
1.2
250
600
750
1.05
290
660
825
1.155
0.2
250 kΩ
kHz
kHz
kHz
MHz
MHz
MHz
Resistance
PLLIN Input Threshold V
Low Output Voltage
High Output Voltage
PWM Output Low Voltage
MODE/PLLIN
V
MODE/PLLIN
Verified Levels
Measurements on CLKOUT
V
PHSMD
V
PHSMD
V
PHSMD
V
PHSMD
V
PHSMD
I
LOAD
I
LOAD
Rising
Falling
2
1.2
0.2
5.2
= 0V
= 1/4 INTVCC
= Float
= 3/4 INTVCC
= INTV
CC
90
90
120
60
180
Deg
Deg
Deg
Deg
Deg
= 500µA 5.0 V
= –500µA 0.5 V
%
%
V
V
V
V
4
4636f
For more information www.linear.com/LTM4636
LTM4636
4636 G01
4636 G02
50mV/DIV
4636 G06
elecTrical characTerisTics
The l denotes the specifications which apply over the specified internal
operating temperature range (Note 2), otherwise specifications are at TA = 25°C. VIN = 12V, per the typical application in Figure 20.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Temperature Diode
Diode V
F
Diode Forward Voltage I = 100µA, TEMP+ to TEMP
TC Temperature Coefficient
–
l
0.598 V
–2.0 mV/°C
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 LTM4636 is tested under pulsed load conditions such that
T
≈ TA. The LTM4636E is guaranteed to meet performance specifications
J
over the 0°C to 125°C internal operating temperature range. 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 LTM4636I is guaranteed to meet specifications over the
full –40°C to 125°C internal operating temperature range. Note that the
maximum ambient temperature consistent with these specifications is
determined by specific operating conditions in conjunction with board
layout, the rated package thermal resistance and other environmental
factors.
Note 3: The minimum on-time condition is specified for a peak-to-peak
inductor ripple current of ~40% of I
Information section)
Note 4: See output current derating
Note 5: Guaranteed by design.
Note 6: 100% tested at wafer level.
Typical perForMance characTerisTics
Efficiency vs Load Current
with 5V
100
95
90
85
EFFICIENCY (%)
80
75
70
0
IN
OUTPUT CURRENT (A)
3.3V
, 500kHz
OUT
, 500kHz
2.5V
OUT
, 450kHz
1.8V
OUT
, 425kHz
1.5V
OUT
, 300kHz
1.2V
OUT
, 300kHz
1V
OUT
2515 35
4020105 30
Efficiency vs Load Current with
8V
IN
100
95
90
85
3.3V
EFFICIENCY (%)
80
75
70
0
OUTPUT CURRENT (A)
OUT
2.5V
OUT
1.8V
OUT
1.5V
OUT
1.2V
OUT
1V
OUT
2515 35
, 700kHz
, 600kHz
, 500kHz
, 450kHz
, 400kHz
, 350kHz
Load. (See the Applications
MAX
, V
curves for different V
and TA.
IN
OUT
Efficiency vs Load Current with
12V
IN
100
95
90
85
3.3V
, 750kHz
EFFICIENCY (%)
80
75
4020105 30
70
0
OUTPUT CURRENT (A)
OUT
, 650kHz
2.5V
OUT
, 600kHz
1.8V
OUT
, 550kHz
1.5V
OUT
, 400kHz
1.2V
OUT
, 350kHz
1V
OUT
2515 35
4020105 30
4636 G03
Burst Mode Efficiency
vs Load Current
100
Burst Mode OPERATION
12V
V
IN
90
1.5V
V
OUT
80
70
EFFICIENCY (%)
60
50
40
0
OUTPUT CURRENT (A)
32 4
4636 G04
51
1V Transient Response 1.2V Transient Response
50mV/DIV
50µs/DIV
10A/DIV
18A/µs
STEP
12V TO 1V TRANSIENT RESPONSE
= 4 × 100µF CERAMIC, 3 × 470µF 2.5V
C
OUT
POSCAP 5mΩ
= 22pF, SW FREQ = 400kHz
C
FF
For more information www.linear.com/LTM4636
4636 G05
50µs/DIV
10A/DIV
18A/µs
STEP
12V TO 1.2V TRANSIENT RESPONSE
= 4 × 100µF CERAMIC, 3 × 470µF 2.5V
C
OUT
POSCAP 5mΩ
= 22pF, SW FREQ = 400kHz
C
FF
= 100pF
C
COMP
4636f
5
LTM4636
0.5V/DIV
4636 G11
0.5V/DIV
4636 G12
100µs/DIV
200mA/DIV
4636 G13
OUT
0.5V/DIV
4636 G14
100µs/DIV
200mA/DIV
4636 G15
COMP
50mV/DIV
4636 G07
COMP
100µs/DIV
4636 G08
COMP
100mV/DIV
4636 G09
COMP
100mV/DIV
4636 G10
Typical perForMance characTerisTics
1.5V Transient Response
50µs/DIV
10A/DIV
18A/µs
STEP
12V TO 1.5V TRANSIENT RESPONSE
= 4 × 100µF CERAMIC, 3 × 470µF 2.5V
C
OUT
POSCAP 5mΩ
= 22pF, SW FREQ = 425kHz
C
FF
= 100pF
C
3.3V Transient Response
100µs/DIV
10A/DIV
18A/µs
STEP
12V TO 3.3V TRANSIENT RESPONSE
= 6 × 100µF CERAMIC, 2 × 470µF 4V
C
OUT
POSCAP 5mΩ
= 22pF, SW FREQ = 750kHz
C
FF
= 100pF
C
50mV/DIV
10A/DIV
18A/µs
STEP
V
OUT
5V/DIV
1.8V Transient Response
12V TO 1.8V TRANSIENT RESPONSE
= 6 × 100µF CERAMIC, 2 × 470µF 4V
C
OUT
POSCAP 5mΩ
= 22pF, SW FREQ = 500kHz
C
FF
= 100pF
C
Start-Up with Soft-Start No-Load
V
IN
20ms/DIV
RUN PIN CAPACITOR = 0.1µF
TRACK/SS CAPACITOR = 0.1µF
= 4 × 100µF CERAMIC AND 3 × 470µF
C
OUT
POSCAP
100µs/DIV
10A/DIV
18A/µs
STEP
5V/DIV
2.5V Transient Response
12V TO 2.5V TRANSIENT RESPONSE
= 6 × 100µF CERAMIC, 2 × 470µF 4V
C
OUT
POSCAP 5mΩ
= 22pF, SW FREQ = 650kHz
C
FF
= 100pF
C
Start-Up with Soft-Start Full Load
V
OUT
V
IN
20ms/DIV
RUN PIN CAPACITOR = 0.1µF
TRACK/SS CAPACITOR = 0.1µF
= 4 × 100µF CERAMIC AND 3 × 470µF
C
OUT
POSCAP
6
40A Load Short-Circuit
V
OUT
0.5V/DIV
L
IN
Start-Up with 0.5V Output Pre-Bias
V
OUT
V
IN
5V/DIV
RUN PIN CAPACITOR = 0.1µF
TRACK/SS CAPACITOR = 0.1µF
= 4 × 100µF CERAMIC AND 3 × 470µF
C
For more information www.linear.com/LTM4636
20ms/DIV
No-Load Short-Circuit
V
OUT
0.5V/DIV
L
IN
4636f
pin FuncTions
LTM4636
PACKAGE ROW AND COLUMN LABELING MAY VARY
AMONG µModule PRODUCTS. REVIEW EACH PACKAGE
LAYOUT CAREFULLY.
V
(A1-A12, B1-B12, C1-C12, D1-D2, D11-D12): Power
OUT
Output Pins. Apply output load between these pins and GND
pins. Recommend placing output decoupling capacitance
between these pins and GND pins. Review Table 4.
MODE_PLLIN (H3): Forced Continuous Mode, Burst Mode
Operation, or
Pulse-Skipping Mode Selection Pin and
External Synchronization Input to Phase Detector Pin.
Connect this
pin to INTV
to enable pulse-skipping mode
CC
of operation. Connect to ground to enable forced continuous
mode of operation. Floating this pin will enable Burst Mode
operation. A clock on this pin will enable synchronization
with forced continuous operation. See the Applications
Information section.
–
V
(D3): VOUT Sense Ground for the Remote Sense
OUTS1
Amplifier. This pin connects to the ground remote sense
point. Connect to ground when not used. See the Applica
-
tions Information section.
+
V
(D4): This pin should connect to V
OUTS1
connected to V
through a 4.99k resistor. This pin is
FB
OUT
and is
used to connect to a remote sense point of the load for
accurate voltage sensing. Either connect to remote sense
point or directly to V
. See the Applications Information
OUT
section for details.
COMPB (D5): Internal
compensation network provided that
coincides with proper stability utilizing the values in Table
5. Just connect this pin to COMPA for internal compensa
tion. In parallel operation with other LTM4636 devices,
connect COMPA and COMPB pins together for internal
compensation, then connect all COMPA pins together.
GND (D6-D10, E6-E10, E12, F7, F8, F10-F12, G1-G2, G6
G10, H1, H10-H12, J1-J3, J8-J12, K1-K3, K9-K10, K12,
L1-L3, L9-L10, L12, M1-M3, M9-M12): Ground Pins for
Both Input and Output Returns.
PGOOD (E1): Output Voltage Power Good Indicator. Opendrain logic output is pulled to ground when the output
voltage exceeds a ±7.5% regulation window.
RUNC (E2): Run Control Pin. A voltage above 1.35V will
turn on the control section of the module. A 10k resistor
to ground is internal to the module for setting the RUN
pin threshold with a resistor to 5V, and allowing a pullup resistor to PV
for enabling the device. See Figure 1
CC
Block Diagram.
TRACK/SS (E3): Output Voltage Tracking Pin and Soft-Start
Inputs. The pin has a 1.25µA pull-up current source. A
capacitor from this pin to ground
In tracking, the regulator output can be tracked to a
rate.
will set a soft-start ramp
different voltage. The different voltage is applied to a voltage
divider then to the slave output’s track pin. This voltage
divider is equal to the slave output’s feedback divider for
coincidental tracking. Default soft-start of 750µs with
TRACK/SS pin connected to INTV
tions Information
section. In PolyPhase® applications tie
pin. See the Applica-
CC
the TRACK/SS pins together.
(E4): The Negative Input of the Error Amplifier. Inter-
V
FB
nally, this pin
is connected to V
with a 4.99k precision
OUTS1
resistor. Different output voltages can be programmed
with an additional resistor between V
PolyPhase operation, tying the V
FB
and V
FB
OUTS1
pins together allows for
parallel operation. See the Applications Information section.
COMPA (E5): Current Control Threshold and Error Amplifier
Compensation Point. The current comparator threshold
increases with this control voltage. Tie all COMPA pins
together for parallel operation. This pin allows external
compensation. See the Applications Information section.
SNSP2 (F1): Current Sense Signal Path. Connect this pin
to SNSP1 (F2).
SNSP1 (F2): Current Sense Signal Path. Connect this pin
to SNSP2 (F
1). Both pins are used to calibrate current
sense matching and current limit at final test.
HIZREG
(F3): When this pin is pulled low the power stage
is disabled into high impedance. Tie this pin to V
for normal operation.
TV
CC
IN
–
. In
or in
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4636f
7
LTM4636
pin FuncTions
SGND (F4, G4): Signal Ground Pin. Return ground path for
all analog and low power circuitry. Tie a single connection
to the output capacitor GND in the application. See layout
guidelines in Figure 18.
INTV
Circuitry in the LTM4636. INTV
when RUNC is activated high. Tie to V
≤ 5.5V, minimum V
(F6): Internal 5.5V LDO for Driving the Control
CC
is controlled and enabled
CC
, when 4.7V ≤ VIN
IN
= 4.2V.
IN
FREQ (G5): A resistor can be applied from this pin to
ground to set the operating frequency. This pin sources
20µA. See the Applications Information section.
PHASMD (G7): This pin can be voltage programmed to
change the phase relationship of the CLKOUT pin with
reference to the internal clock or an input synchronized
clock. The INTV
(5.5V) output can be voltage divided
CC
down to the PHASMD pin to set the particular phase. The
Electrical Characteristics show the different settings to
select a particular phase. See the Applications Informa
-
tion section.
RUNP (
can be connected to V
PV
RUNC. A 15k resistor
G8): This pin enables the PV
, or tie to ground when connecting
IN
to VIN ≤ 5.5V. RUNP needs to sequence up before
CC
from PVCC to RUNC with a 0.1µF
supply. This pin
CC
capacitor will provide enough delay. In parallel operation
with multiple LTM4636s, the resistor can be reduced in
value by N times and the 0.1µF can be increased N times.
See Applications Information section. RUNP can be used to
set the minimum UVLO with a voltage divider. See Figure 1.
NC (G9): No Connection.
(F9): 5V Power Output and Power for Internal Power
PV
CC
MOSFET Drivers. The regulator can power 50mA of external
sourcing for additional use. Place a 22µF ceramic filter
capacitor on this pin to ground. When V
< 5.5V, tie VIN
IN
and PV
GND. If V
together along with INTVCC. Then tie RUNP to
CC
> 5.5V then operate PVCC regulator as normal.
IN
See the Typical Application examples.
+
TEMP
(G12): Temperature Monitor. An internal diode
connected NPN transistor. See the Applications Information section.
–
TEMP
(G11): Low Side of the Internal Temperature
Monitor.
CLKOUT (G3): Clock out signal that can be phase selected
to the main internal clock or synchronized clock using
the PHASMD pin. CLKOUT can be used for multiphase
applications. See the Applications Information section.
TEST1 (H4), TEST2 (F5), TEST3 (H2), TEST4 (E
11), GMON
(H9):These are test pins used in the final production test
of the part. Leave floating.
(H5-H6, J4-J7, K4-K8, L4-L8, M4-M8): Power Input
V
IN
Pins. Apply input voltage between these pins and GND
pins. Recommend placing input decoupling capacitance
directly between V
and GND pins.
IN
PWM (H7): PWM output that drives the power stage.
Primarily used for test, but can be monitored in debug
or testing.
TMON (H8): Temperature Monitor Pin. Internal temperature
monitor, varies from 1V at 25°C to 1.44V at 150°C, disables
power stage at 150°C. If this feature is not desired, then
tie the TMON pin to GND.
SW (L11, K11): These are pin connections to the internal
switch node for test evaluation and monitoring. An R-C
snubber can be placed from the switch pins to GND to
eliminate any high frequency ringing. See the Applications
Information section.
8
4636f
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block DiagraM
15k = (PV
V
UVLO
4636 F01
0.85V
IN
EXAMPLE
– 0.85V) (15K)
IN
(V
R1 =
CC
PV
15k
22µF
R1
RUNP
,
IN
CC
AND PV
CC
≤ 5.5V, TIE TO V
IN
INTV
VIN4.70V TO 15V
V
TOGETHER,TIE RUNP
IN
C
+
IN
V
> 5.5V
IN
OPERATE AS SHOWN
TO GND. V
2.2Ω, 0805
LTM4636
2200pF
1.5V AT 40A
OUT
V
OUT
C
+
GND
OUT
V
SW
2.2Ω
SNSP2
–
TEMP
+
TEMP
–
TEMP
GMON
TMON
–
+
PWM
OUTS1
OUTS1
V
V
TEST4
> 0.85V = ON
IN
V
5V
CC
PV
INTERNAL 5V REGULATOR
1µF
1µF
M1
TDRV
PWM LOGIC CONTOL,
POWER MOSFET DRIVERS,
POWER MOSFET
0.18µH
CONTROL
OPTIMIZED
DEAD TIME
PWM INPUT
PWM
CURRENT
DIFF
FB
V
POWER CONTROL
–
NETWORK
DCR SENSE
M2
BDRV
150C DISABLE
DISABLE
SENSE
AMP
SNS
SNSP2
TEMP MONITOR
CURRENT
+
–
–
–
+
SGND
CONNECT
TO SNSP1
IMON
40µA AT 25°C
60µA AT 150°C
SNSP1
SNS
SNSP1 AND SNSP2
CONNECTED AT PCB
24.9k
0.1µF
470pFQ1
1%
4.99k 0.5%
Figure 1. Simplified LTM4636 Block Diagram
TEST1
TEST2
INTV
CC
TEST3
PV
10k
CC
10k
PGOOD
RUNC
0.1µF
15k
≥ 5V
PV
> 1.35V = ON
UVLO EXAMPLE
– 1.35V)(10k)/1.35V
DISABLES AT ~ 3.75V
CC
10pF
1%
COMP
INTERNAL
FREQ
FREQ
R
TRACK/SS
40k
SOFT-START
PHMODE
HIZREG
CLKOUT
SGND
COMPB
COMPA
CC
INTV
CC
MODE_PLLIN
INTVCC 5.5V
4.7µF
SNSP1
FB
V
R6
3.32k
4636f
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9
LTM4636
Decoupling requireMenTs
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
C
IN
C
OUT
External Input Capacitor Requirement
(V
= 4.70V to 16V, V
IN
External Output Capacitor Requirement
(V
= 4.70V to 16V, V
IN
OUT
OUT
= 1.5V)
= 1.5V)
I
OUT
(See Table 4)
I
OUT
TA = 25°C. Use Figure 1 configuration.
= 40A, 6 × 22µF Ceramic X7R Capacitors
= 40A (See Table 4) 1000 µF
100 µF
operaTion
Power Module Description
The LTM4636 is a high efficiency regulator that can provide
a 40A output with few external input and output capacitors.
This module provides precisely regulated output voltages
programmable via external resistors from 0.6V DC to 3.3V
DC over a 4.70V to 15V input range. The Typical Applica
tion schematic is shown in Figure 20.
The LTM4636 has an integrated constant-frequency current mode
protection
regulator, power MOSFETs, 0.18µH inductor,
circuitry, 5V regulator and other supporting
discrete components. The switching frequency range is
from 250kHz to 770kHz, and the typical operating frequency
is 400kHz. For switching noise-sensitive applications, it
can be externally synchronized from 250kHz to 800kHz,
subject to minimum on-time limitations and limiting the
inductor ripple current to less than 40% of maximum
output current.
A single resistor is used to program the frequency. See
the Applications Information section.
With current mode control
compensation,
ity margins
range
of output capacitors, even with all ceramic output
the LTM4636 module has sufficient stabil-
and good transient performance with a wide
and internal feedback loop
capacitors. An option has been provided for external loop
®
compensation. LTpowerCAD
can be used to optimize
the external compensation option. See the Applications
Information section.
Current mode control provides cycle-by-cycle fast current
limit in an overcurrent condition. An internal overvoltage
monitor feedback pin referred will attempt to protect the
output voltage in the event of an overvoltage >10%. The
top MOSFET is turned off and the bottom MOSFET is
turned on until the output is cleared.
Pulling the RUNC pin below 1.1V forces the regulator con
troller into
programming
a shutdown state. The TRACK/SS pin is used for
the output voltage ramp and voltage tracking
during start-up. See the Applications Information section.
The LTM4636 is internally compensated to be stable over
all operating conditions. Table 5 provides a guideline for
input and output capacitances for several operating condi
tions. LTpowerCAD is available for transient and stability
analysis. This tool can be used to optimize the regulators
loop response.
A remote sense amplifier is provided for accurately sensing
output voltages at the load point.
Multiphase operation can be easily employed with the
internal clock source or a synchronization clock applied
to the MODE/PLLIN input using an external clock source,
and connecting the CLKOUT pins. See the Applications
Information section. Review Figure 4.
High efficiency at light loads can be accomplished with
selectable Burst Mode operation using the MODE_PLLIN
pin. These light load features will accommodate battery
operation. Efficiency graphs
eration
A
in the Typical Performance Characteristics section.
+
TEMP
and TEMP– pins are provided to allow the internal
are provided for light load op-
device temperature to be monitored using an onboard
diode connected NPN transistor.
-
-
10
4636f
For more information www.linear.com/LTM4636
applicaTions inForMaTion
4.99k+ R
FB
4.99k /N
0.6V
V
I
LTM4636
The typical LTM4636 application circuit is shown in
Figure 20. External component selection
is primarily
determined by the maximum load current and output
voltage. Refer to Table 5 for specific external capacitor
requirements for particular applications.
to V
V
IN
There are restrictions in the V
Step-Down Ratios
OUT
IN
to V
step-down ratio that
OUT
can be achieved for a given input voltage. The maximum
duty cycle is 94% typical at 500kHz operation. The V
minimum dropout is a function of load current and
V
OUT
IN
to
operation at very low input voltage and high duty cycle
applications. At very low duty cycles the minimum 100ns
on-time must be maintained. See the Frequency Adjust
-
ment section and temperature derating curves.
Output V
oltage Programming
The PWM controller has an internal 0.6V ±1% reference
voltage. As shown in the Block Diagram, a 4.99k internal
+
feedback resistor connects the V
gether. When
and V
OUTS1
the remote sensing is used, then V
–
are connected to the remote V
points. If no remote sense the V
OUTS1
OUTS1
and VFB pins to-
OUTS1
and GND
OUT
+
connects to V
+
OUT
The output voltage will default to 0.6V with no feedback
resistor. Adding
a resistor R
from VFB to ground pro-
FB
grams the output voltage:
V
= 0.6V •
OUT
Table 1. VFB Resistor Table vs Various Output Voltages
V
(V) 0.6 1.0 1.2 1.5 1.8 2.5 3.3
OUT
(k) Open 7.5 4.99 3.32 2.49 1.58 1.1
R
FB
FB
R
For parallel operation of N LTM4636s, the following
equation can be used to solve for R
FB
:
Or use V
on one channel and connect all feedback
OUTS1
pins together utilizing a single feedback resistor.
Tie the VFB pins together for each parallel output. The COMP
pins must be tied together also. See Typical Application
section examples.
Input Capacitors
The LTM4636 module should be connected to a low ACimpedance DC source. Additional input capacitors are
needed for the RMS input ripple current rating. The I
equation which follows can be used to calculate the input
capacitor requirement. Typically 22µF X7R ceramics are a
good choice with RMS ripple current ratings of ~4A each.
A 47µF to 100µF surface mount aluminum electrolytic bulk
capacitor can be used for more input bulk capacitance.
This bulk input capacitor is only needed if the input source
impedance is compromised by long inductive leads, traces
or not enough source capacitance. If low impedance power
planes are used, then this bulk capacitor is not needed.
For a buck converter, the switching duty cycle can be
estimated as:
.
D=
OUT
V
IN
Without considering the inductor ripple current, for each
output the RMS current of the input capacitor can be
estimated as:
I
CIN(RMS)
OUT(MAX )
=
η%
• D•(1–D)
where η% is the estimated efficiency of the power module. The bulk capacitor can be a switcher-rated aluminum
electrolytic capacitor or a Polymer capacitor.
CIN(RMS)
RFB=
V
OUT
–1
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