LTM4686/LTM4686-1
Ultrathin Dual 10A or Single 20A µModule Regulator
with Digital Power System Management
FEATURES
Dual, Fast, Analog Loops with Digital Interface for
Control and Monitoring
n
Wide Input Voltage Range: 4.5V to 17V Standalone,
2.375V to 17V with Aux 5V Bias (LTM4686-1)
n
Output Voltage Range: 0.5V to 3.6V
n
±0.5% Maximum DC Output Error Over Temperature
n
10A DC Typical, 12A Peak Output Current, per Channel
n
±5% Current Readback Accuracy at 10A Load
n
400kHz PMBus-Compliant I
2
C Serial Interface
n
Integrated 16-Bit
∆Σ
ADC
n
Supports Telemetry Polling Rates Up to 125Hz
n
Constant Frequency Current Mode Control
n
Parallel and Current Share Multiple Modules
n
All 7-Bit Slave Addresses Supported
n
Drop-In Pin-Compatible to Dual 9A LTM4675 and
Dual 13A LTM4676A and Dual 18A LTM4677
n
16mm
×
11.9mm
×
1.82mm LGA Package
Readable Data:
n
Input and Output Voltages, Currents, and Temperatures
n
Running Peak Values, Uptime, Faults and Warnings
n
Onboard EEPROM Fault Log Record with ECC
Writable Data and Configurable Parameters:
n
Output Voltage, Voltage Sequencing and Margining
n
Digital Soft-Start/Stop Ramp
n
OV/UV/OT, UVLO, Frequency and Phasing
n
DESCRIPTION
The
LTM
®
4686
is a dual 10A (12A Peak) or single 20A
(24A Peak) step-down µModule
®
(micromodule) DC/
DC regulator with 39ms turn-on time. It features
remote
configurability and telemetry-monitoring of power man-
agement parameters over PMBus—an
open standard
I
2
C-based digital interface protocol . The LTM4686 is
comprised of fast analog control loops, precision mixed-
signal circuitry, EEPROM, power MOSFETs, inductors and
supporting components. The LTM4686 product video is
available on the website. Click here .
The LTM4686’s 2-wire serial interface enables voltage
margining and sequencing, and telemetry readback of
currents, voltages, power, temperature, uptime and
peak
values.
Pin-strap resistors configure start-up settings. The
LTpowerPlay™
GUI, DC1613 USB-to-PMBus converter,
DC2086 programming adapter and
demo kits
are avail-
able. Applications running from 5V
IN
or supplying 5V
AUX
to SV
IN
should use LTM4686-1. Otherwise, use LTM4686:
MODULE PMBus COMMAND CODE
0x35, VIN_ON (SV
IN
UVLO-Rising)
0x36, VIN_OFF (SV
IN
UVLO-Falling)
0x58, VIN_UV_WARN_LIMIT
LTM4686
5.50V
5.25V
5.30V
LTM4686-1
4.25V
4.00V
4.09V
Pb-free and RoHS compliant, the LTM4686 is available in
a 16mm
×
11.9mm
×
1.82mm LGA package.
All registered trademarks and trademarks are the property of their respective owners. Protected
by U.S. Patents including 5408150, 5481178, 5705919, 5929620, 6144194, 6177787, 6580258,
7420359, 8163643. Licensed under U.S. Patent 7000125 and other related patents worldwide.
Click to view associated Video Design Idea.
APPLICATIONS
n
System Optimization in Prototype and Production
TYPICAL APPLICATION
V
IN
2.7V TO 5.5V
22µF
×2
V
IN0
V
IN1
SV
IN
V
OUT0
V
OSNS0
+
Dual 10A µModule Regulator with Digital
Interface for Control and Monitoring*
V
OUT0
,
ADJUSTABLE
UP TO 10A
LOAD
0
100µF
×4
Using PMBus and LTpowerPlay to Monitor Telemetry and Margin
V
OUT0
/V
OUT1
During Load Pattern Tests. 10Hz Polling Rate. 3.3V
IN
Output Voltage Readback, V
OUT
Margined 10% Low
1.1
1.9
V
OUT0
(V)
V
OUT1
(V)
4
I
IN0
(A)
2
0
Input Current Readback
6
I
IN1
(A)
3
0
12
1.0
0.9
0.8
0
3
6
TIME (s)
9
1.8
1.7
1.6
12
46861 TA01b
LTC3204B-5, 5V
OUT
DC/DC CHARGE-PUMP
ON/OFF CONTROL
FAULT INTERRUPTS,
POWER SEQUENCING
PWM CLOCK AND
TIME-BASE
SYNCHRONIZATION
REGISTER WRITE
PROTECTION
LTM4686-1
V
OSNS0–
INTV
CC
RUN
0
RUN
1
GPIO
0
GPIO
1
SYNC
SHARE_CLK
WP
V
OUT1
V
OSNS1
0
3
CHANNEL 0 TEMP (°C)
V
OUT1
,
ADJUSTABLE
UP TO 10A
LOAD
1
100µF
×4
6
TIME (s)
9
46861 TA01d
Output Current Readback, Varying Load Pattern
10
10
I
OUT1
(A)
I
OUT0
(A)
5
0
5
0
12
46861 TA01c
60
57
54
51
0
Power Stage Temperature Readback
CHANNEL 1 TEMP (°C)
60
57
54
SGND
SCL
SDA
ALERT
46861 TA01a
GND
*FOR COMPLETE CIRCUIT, SEE FIGURE 29
I
2
C/SMBus I/F WITH
PMBus COMMAND SET
TO/FROM IPMI OR OTHER
BOARD MANAGEMENT
CONTROLLER
0
3
6
TIME (s)
9
3
6
TIME (s)
9
51
12
46861 TA01e
Document Feedback
For more information
www.analog.com
1
Rev. A
LTM4686/LTM4686-1
TABLE OF CONTENTS
Features ..................................................... 1
Applications ................................................ 1
Typical Application ........................................ 1
Description.................................................. 1
Absolute Maximum Ratings .............................. 3
Order Information .......................................... 3
Pin Configuration .......................................... 3
Electrical Characteristics ................................. 4
Typical Performance Characteristics .................. 11
Pin Functions .............................................. 13
Simplified Block Diagram ............................... 18
Decoupling Requirements ............................... 18
Functional Diagram ...................................... 19
Test Circuits ............................................... 20
Operation................................................... 22
Power Module Introduction.........................................22
Power Module Configurability and
Readback Data ........................................................ 24
Time-Averaged and Peak Readback Data ....................26
Power Module Overview .............................................29
EEPROM .....................................................................33
Serial Interface............................................................34
Device Addressing ......................................................34
Fault Detection and Handling ......................................35
Responses to V
OUT
and I
OUT
Faults.............................36
Responses to Timing Faults ........................................ 37
Responses to SV
IN
OV Faults ...................................... 37
Responses to OT/UT Faults ......................................... 37
Responses to External Faults ..................................... 37
Fault Logging ..............................................................38
Bus Timeout Protection ..............................................38
PMBus Command Summary ............................ 39
PMBus Commands .................................................... 39
Applications Information ................................ 46
V
IN
to V
OUT
Step-Down Ratios .................................... 49
Input Capacitors.......................................................... 49
Output Capacitors ....................................................... 49
Light Load Current Operation...................................... 49
Switching Frequency and Phase .................................50
Minimum On-Time Considerations .............................. 52
Variable Delay Time, Soft-Start and Output Voltage
Ramping ................................................................. 52
Digital Servo Mode .....................................................53
Soft Off (Sequenced Off) ............................................54
Undervoltage Lockout .................................................54
Fault Detection and Handling ......................................55
Open-Drain Pins ..........................................................55
Phase-Locked Loop and Frequency Synchronization ..56
RCONFIG Pin-Straps (External Resistor
Configuration Pins) ................................................. 57
Voltage Selection ........................................................ 57
Connecting the USB to the I
2
C/SMBus/PMBus
Controller to the LTM4686 In System ..................... 57
LTpowerPlay: An Interactive GUI for Digital Power
System Management .............................................. 61
PMBus Communication and Command Processing ....62
Thermal Considerations and
Output Current Derating .........................................63
EMI Performance ........................................................ 70
Safety Considerations ................................................. 70
Layout Checklist/Example ........................................... 70
Typical Applications ...................................... 72
Appendix A ................................................. 78
Similarity Between PMBus, SMBus and I
2
C
2-Wire Interface ...................................................... 78
Appendix B ................................................. 79
PMBus Serial Digital Interface .................................... 79
Appendix C: PMBus Command Details ................ 83
Addressing and Write Protect .....................................83
General Configuration Registers .................................85
On/Off/Margin .............................................................86
PWM Config ...............................................................88
Voltage ........................................................................90
Current ........................................................................93
Temperature ................................................................96
Timing .........................................................................98
Fault Response ......................................................... 100
Fault Sharing ............................................................. 107
Scratchpad ................................................................ 109
Identification ............................................................. 109
Fault Warning and Status .......................................... 110
Telemetry .................................................................. 117
NVM (EEPROM) Memory Commands ....................... 121
Package Description ................................... 128
Package Photographs .................................. 129
Package Description ................................... 130
Revision History ........................................ 131
Typical Application ..................................... 132
Design Resources ...................................... 132
Related Parts ............................................ 132
Rev. A
2
For more information
www.analog.com
LTM4686/LTM4686-1
ABSOLUTE MAXIMUM RATINGS
(Note 1)
PIN CONFIGURATION
1
A
B
C
D
E
F
G
H
J
K
L
M
LGA PACKAGE
108-LEAD (16mm
×
11.9mm
×
1.82mm)
T
JMAX
= 125°C,
θ
JCtop
= 5.9°C/W,
θ
JCbottom
= 2°C/W,
θ
JB
= 2.7°C/W,
θ
JA
= 12.4°C/W
θ
VALUES DETERMINED PER JESD51-12
WEIGHT = 1.1 GRAMS
V
OUT1
V
IN1
GND
SGND
V
OUT0
V
IN0
2
3
TOP VIEW
4
5
6
7
8
9
Terminal Voltages:
V
INn
(Note 4), SV
IN
..................................... –0.3V to 20V
V
OUTn
........................................................... –0.3V to 6V
V
OSNS0+
, V
ORB0+
, V
OSNS1
, V
ORB1
, INTV
CC
.... –0.3V to 6V
RUN
n
, SDA, SCL,
ALERT
........................... –0.3V to 5.5V
F
SWPHCFG
, V
OUTnCFG
, V
TRIMnCFG
, ASEL .. –0.3V to 2.75V
V
DD33
,
GPIO
n
, SYNC, SHARE_CLK, WP,
COMP
na
, V
OSNS0 –
, V
ORB0 –
........................ –0.3V to 3.6V
SGND ........................................................ –0.3V to 0.3V
Temperatures
Internal Operating Temperature Range
(Notes 2, 3) ............................................ –40°C to 125°C
Storage Temperature Range .................. –55°C to 125°C
Peak Solder Reflow Package Body Temperature ... 260°C
ORDER INFORMATION
PART NUMBER
LTM4686EV#PBF
LTM4686IV#PBF
LTM4686EV-1#PBF
LTM4686IV-1#PBF
PAD OR BALL FINISH
Au (RoHS)
Au (RoHS)
Au (RoHS)
Au (RoHS)
PART MARKING*
DEVICE
LTM4686V
LTM4686V
LTM4686V-1
LTM4686V-1
FINISH CODE
e4
e4
e4
e4
PACKAGE
TYPE
LGA
LGA
LGA
LGA
MSL
RATING
4
4
4
4
TEMPERATURE RANGE
(See Note 2)
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
• Consult Marketing for parts specified with wider operating temperature
ranges. *Pad or ball finish code is per IPC/JEDEC J-STD-609.
•
Recommended LGA and BGA PCB Assembly and Manufacturing
Procedures
•
LGA and BGA Package and Tray Drawings
For more information
www.analog.com
3
Rev. A
LTM4686/LTM4686-1
The
l
denotes the specifications which apply over the specified internal
operating temperature range (Note 2). Specified as each individual output channel (Note 4). T
A
= 25°C, V
IN
= 12V, RUN
n
= 5V,
FREQUENCY_SWITCH = 500kHz, VOUT_COMMAND
n
= 1V and VOUT_UV_FAULT_RESPONSE
n
= TON_MAX_FAULT_RESPONSE
n
= 0x00
unless otherwise noted. All other command codes configured per factory-default EEPROM settings unless otherwise noted. Tested per
Circuit 1, unless otherwise noted.
SYMBOL
V
IN
V
OUTn
PARAMETER
Input DC Voltage
CONDITIONS
MIN
TYP
MAX UNITS
17
5.75
17
3.6
3.6
V
V
V
V
V
Test Circuit 1; 5.75V ≤ SV
IN
≤ 17V; INTV
CC
Open; VIN_OFF < VIN_ON = 5.5V
l
5.75
Test Circuit 2; 4.5V ≤ SV
IN
≤ 5.75V; INTV
CC
= SV
IN
; VIN_OFF < VIN_ON = 4.25V
l
4.5
Test Circuit 3; 4.5V ≤ SV
IN
≤ 5.75V; INTV
CC
= SV
IN
; VIN_OFF < VIN_ON = 4.25V
l
2.375
V
OUT0
Differentially Sensed on V
OSNS0+
/V
OSNS0–
Pin-Pair;
V
OUT1
Differentially Sensed on V
OSNS1
/SGND Pin-Pair;
Commanded by Serial Bus or with Resistors Present at Start-Up on
V
OUTnCFG
and/or V
TRIMnCFG
l
l
ELECTRICAL CHARACTERISTICS
Range of Output
Voltage Regulation
0.5
0.5
V
OUTn(DC)
Output Voltage, Total (Note 5
Variation with Line and V
OUTn
Low Range (MFR_PWM_MODE
n
[1] = 1
b
),
FREQUENCY_SWITCH = 425kHz )
Load
Digital Servo Engaged (MFR_PWM_MODE
n
[6] = 1
b
)
Digital Servo Disengaged (MFR_PWM_MODE
n
[6] = 0
b
)
Input Inrush Current at Test Circuit 1, V
OUTn
=1V, V
IN
= 12V; No Load Besides Capacitors;
Start-Up
TON_RISE
n
= 3ms
Input Supply Bias
Current
Input Supply Current
in Pulse-Skipping
Mode Operation
Input Supply Current
in Forced-Continuous
Mode Operation
Forced Continuous Mode, MFR_PWM_MODE
n
[0] = 1
b
RUN
n
= 5V, RUN
1-n
= 0V
Shutdown, RUN
0
= RUN
1
= 0V
Pulse-Skipping Mode, MFR_PWM_MODE
n
[0] = 0
b
,
I
OUTn
= 100mA
Forced Continuous Mode, MFR_PWM_MODE
n
[0] = 1
b
I
OUTn
= 100mA
I
OUTn
= 10A
Shutdown, RUN
n
= 0V
l
0.995
0.985
1.000
1.000
400
40
20
20
1.005
1.015
V
V
mA
mA
mA
mA
Input Specifications
I
INRUSH(VIN)
I
Q(SVIN)
I
S(VINn,PSM)
I
S(VINn,FCM)
40
1.06
50
mA
A
µA
I
S(VINn,SHUTDOWN)
Input Supply Current
in Shutdown
Output Specifications
I
OUTn
∆V
OUTn(LINE)
V
OUTn
Output Continuous
Current Range
Line Regulation
Accuracy
(Note 6)
Digital Servo Engaged (MFR_PWM_MODE
n
[6] = 1
b
)
Digital Servo Disengaged (MFR_PWM_MODE
n
[6] = 0
b
)
SV
IN
and V
INn
Electrically Shorted Together and INTV
CC
Open Circuit;
I
OUTn
= 0A, 5.75V ≤ V
IN
≤ 17V, V
OUT
Low Range
(MFR_PWM_MODE
n
[1] = 1
b
) FREQUENCY_SWITCH = 425kHz
(Referenced to 12V
IN
) (Note 5)
Digital Servo Engaged (MFR_PWM_MODE
n
[6] = 1
b
)
Digital Servo Disengaged (MFR_PWM_MODE
n
[6] = 0
b
)
0A ≤ I
OUTn
≤ 10A, V
OUT
Low Range, (MFR_PWM_MODE
n
[1] = 1
b
)
FREQUENCY_SWITCH = 425kHz (Note 5)
0
0.03
0.03
10
±0.2
A
%
%/V
l
∆V
OUTn(LOAD)
V
OUTn
V
OUTn(AC)
f
S
(Each
Channel)
∆V
OUTn(START)
t
START
Load Regulation
Accuracy
Output Voltage Ripple
l
0.03
0.2
10
0.5
%
%
mV
P-P
V
OUTn
Ripple Frequency FREQUENCY_SWITCH Set to 500kHz (0xFBE8)
Turn-On Overshoot
TON_RISE
n
= 2ms (Note 12)
l
475
500
8
525
kHz
mV
Turn-On Start-Up Time Time from V
IN
Toggling from 0V to 12V to Rising Edge of
GPIO
n
. TON_
DELAY
n
= 0ms, TON_RISE
n
= 2ms,
MFR_GPIO_PROPAGATE
n
= 0x0100,
MFR_GPIO_RESPONSE
n
= 0x0000
Turn-On Delay Time
Time from First Rising Edge of RUN
n
to Rising Edge of
GPIO
n
. TON_
DELAY
n
= 0ms, TON_RISE
n
= 3ms,
MFR_GPIO_PROPAGATE
n
= 0x0100,
MFR_GPIO_RESPONSE
n
= 0x0000.
V
IN
Having Been Established for at Least 39ms
l
34
39
ms
t
DELAY(0ms)
l
2.75
3.1
3.5
ms
4
Rev. A
For more information
www.analog.com
LTM4686/LTM4686-1
The
l
denotes the specifications which apply over the specified internal
operating temperature range (Note 2). Specified as each individual output channel (Note 4). T
A
= 25°C, V
IN
= 12V, RUN
n
= 5V,
FREQUENCY_SWITCH = 500kHz, VOUT_COMMAND
n
= 1V and VOUT_UV_FAULT_RESPONSE
n
= TON_MAX_FAULT_RESPONSE
n
= 0x00
unless otherwise noted. All other command codes configured per factory-default EEPROM settings unless otherwise noted. Tested per
Circuit 1, unless otherwise noted.
SYMBOL
∆V
OUTn(LS)
t
SETTLE
I
OUTn(OCL_PK)
I
OUTn(OCL_AVG)
Control Section
V
FBCM0
V
FBCM1
V
OUT-RNG0
Channel 0 Feedback
Input Common Mode
Range
Channel 1 Feedback
Input Common Mode
Range
Full-Scale Command
Voltage, Range 0
V
OSNS0–
Valid Input Range (Referred to SGND)
V
OSNS0+
Valid Input Range (Referred to SGND)
SGND Valid Input Range (Referred to GND)
V
OSNS1
Valid Input Range (Referred to SGND)
(Notes 7, 15)
V
OUTn
Commanded to 3.600V, MFR_PWM_MODE
n
[1] = 0
b
Resolution
LSB Step Size
(Notes 7, 15)
V
OUTn
Commanded to 2.750V, MFR_PWM_MODE
n
[1] = 1
b
Resolution
LSB Step Size
l
l
l
l
ELECTRICAL CHARACTERISTICS
PARAMETER
CONDITIONS
MIN
TYP
55
MAX UNITS
mV
Peak Output Voltage
Load: 0A to 5A and 5A to 0A at 5A/µs, Figure 61 Circuit,
Deviation for Dynamic V
OUTn
= 1V, V
IN
= 12V (Note 12)
Load Step
Settling Time for
Dynamic Load Step
Output Current Limit,
Peak
Output Current Limit,
Time Averaged
Load: 0A to 5A and 5A to 0A at 5A/µs, Figure 61 Circuit,
V
OUTn
= 1V, V
IN
= 12V (Note 12)
Cycle-by-Cycle Inductor Peak Current Limit Inception
Time-Averaged Output Inductor Current Limit Inception Threshold,
Commanded by IOUT_OC_FAULT_LIMIT
n
(Note 12)
35
18.8
µs
A
14.4A; See I
O-RB-ACC
Specification (Output Current
Readback Accuracy)
–0.1
0.3
4.1
0.3
4.1
V
V
V
V
–0.3
3.548
12
1.375
3.651
V
Bits
mV
V
Bits
mV
kΩ
kΩ
ns
Bits
V
OUT-RNG1
Full-Scale Command
Voltage, Range 1
2.711
12
0.6875
41
37
45
8
2.788
R
VSENSE0+
R
VSENSE1
t
ON(MIN)
N
OV/UV_COMP
V
OV-RNG
V
OU-STP
V
OSNS0+
Impedance to 0.05V ≤ V
VOSNS0+
– V
SGND
≤ 3.6V
SGND
V
OSNS1
Impedance to
SGND
Minimum On-Time
Resolution, Output
Voltage Supervisors
0.05V ≤ V
VOSNS1
– V
SGND
≤ 3.6V
(Note 8 )
(Note 15)
Analog OV/UV (Overvoltage/Undervoltage) Output Voltage Supervisor Comparators (VOUT_OV/UV_FAULT_LIMIT and VOUT_OV/UV_WARN_LIMIT Monitors)
Output OV Comparator (Note 15)
Threshold Detection
High Range Scale, MFR_PWM_MODE
n
[1] = 0
b
Range
Low Range Scale, MFR_PWM_MODE
n
[1] = 1
b
Output OV and UV
(Note 15)
Comparator Threshold
High Range Scale, MFR_PWM_MODE
n
[1] = 0
b
Programming LSB
Low Range Scale, MFR_PWM_MODE
n
[1] = 1
b
Step Size
Output OV Comparator (See Note 14)
Threshold Accuracy
2V ≤ V
VOSNS0+
– V
VOSNS0–
≤ 4V, MFR_PWM_MODE
0
[1] = 0
b
1V ≤ V
VOSNS0+
– V
VOSNS0–
≤ 2.7V, MFR_PWM_MODE
0
[1] = 1
b
0.5V ≤ V
VOSNS0+
– V
VOSNS0–
< 1V, MFR_PWM_MODE
0
[1] = 1
b
2V ≤ V
VSENSE1
– V
SGND
≤ 4V, MFR_PWM_MODE
1
[1] = 0
b
1.5V ≤ V
VSENSE1
– V
SGND
≤ 2.7V, MFR_PWM_MODE
1
[1] = 1
b
0.5V ≤ V
VSENSE1
– V
SGND
< 1.5V, MFR_PWM_MODE
1
[1] = 1
b
l
l
l
l
l
l
1
0.5
22
11
4.0
2.7
V
V
mV
mV
V
OV-ACC
±2
±2
±20
±2
±2
±30
%
%
mV
%
%
mV
For more information
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5
Rev. A
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