LTC3888-1
Dual Loop 8-Phase Step-Down DC/DC
Controller with Digital Power System Management
FEATURES
DESCRIPTION
2
The LTC®3888-1 is a PMBus-compliant dual loop DC/DC
synchronous step-down switching regulator controller
with eight expandable phases supporting a wide range of
master/slave configurations. The controller uses constant
frequency current mode architecture to provide excellent
transient response and output regulation. Each PWM
master is capable of producing output voltages from 0.3V
to 3.45V with multiple phase configurations using DrMOS
devices that provide an output current monitor.
n
PMBus/I C Compliant Serial Interface
n
Monitor Voltage, Current, Temperature and Faults
n
Digitally Program V , Margins, UV, OV, Current
OUT
Limit, Soft-Start/Stop and Sequencing
n
n
n
n
n
n
n
n
n
n
n
n
n
n
Expandable to >16 Phases
External Resistor Divider Programs Output Voltage
4.5V ≤ V ≤ 26.5V, 0.3V ≤ V
≤ 3.45V
IN
OUT
0.5ꢀ Output Voltage Accuracy
Programmable PWM Loop Compensation
Accurate PolyPhase® Current Sharing
Internal EEPROM with ECC and Fault Logging
DrMOS Output Current Monitor Interface
DrMOS Temperature/Fault Bus Interface
DrMOS Gate Drive Supply Monitor
Output voltage is set with an external voltage divider.
PMBus configuration and monitoring is supported by
LTpowerPlay™ software. Programmable loop compen-
sation and built-in load step emulation facilitate setting
bandwidth based on input voltage and output load capaci-
tance. PMBus commands allow read back of input volt-
age, output voltage and current, and operating status.
Operating parameters can be set via PMBus command or
stored in internal EEPROM for use at power up. Switching
frequency, phase configuration, output current limit and
device address can also be set using external program-
ming resistors.
Load Step Emulation
Internal or External PWM Clock from 250kHz to 1MHz
52-Pin (5mm × 8mm) QFN Package
AEC-Q100 Qualified for Automotive Applications
APPLICATIONS
n
High Current Distributed Power Systems
Servers, Network and Storage Equipment
All registered trademarks and trademarks are the property of their respective owners. Protected
by U.S. Patents, including 7420359, 8786265, 8786268 and 8823352. Licensed under U.S.
Patent 7000125 and other related patents worldwide.
n
SPI
V
SET BY PMBus
OPTIONAL
OUT
TYPICAL APPLICATION
ADJUST ANALOG V
CONTROL COMPENSATION
FB
OF V
OF V
ZERO
OUT
OUT
Dual 4-phase PSM Rails
ꢓ
ꢕꢓ ꢁꢖ ꢐꢗꢓ
ꢔꢍ
ꢘꢍꢖꢉꢔꢍꢑꢀꢙ
LTC3888
•
•
•
•
ꢐ.ꢐꢊꢋ
ꢗ.ꢧꢊꢋ
ꢆꢊꢋ
LTC3888-1
LTC3888-2
•
•
•
ꢓ
ꢔꢍ
ꢔꢍꢁꢓ
ꢂꢂ
ꢇꢖꢈꢛR ꢌꢁꢑꢎꢛ
ꢇꢖꢈꢛR ꢌꢁꢑꢎꢛ
ꢇꢈꢉ
ꢓ
ꢓ
ꢓ
ꢇꢈꢉ
ꢔꢉꢖꢍ
ꢇꢈꢉꢆ
ꢇꢈꢉ0
ꢌꢛꢍꢌꢛ0
ꢓ
ꢔꢍ
ꢖꢚꢁꢆ
ꢖꢚꢁ0
ꢔꢍ
0.ꢗꢓ ꢁꢖ
0.ꢗꢓ ꢁꢖ
ꢃ.ꢗꢕꢓ
ꢌꢈ
ꢔ
ꢔ
ꢔ
ꢔꢉꢖꢍ
ꢔRꢛꢋ
ꢌꢈ
ꢌꢛꢍꢌꢛꢆ
ꢃ.ꢗꢕꢓ
ꢑꢁ ꢆꢐ0ꢑ
Efficiency vs Load Current
(8-Phase Using LTC7051)
ꢀꢁꢂꢃꢄꢄꢄꢅꢆ
Rꢛꢋ
ꢎꢍꢏ
ꢔRꢛꢋ
ꢎꢍꢏ
ꢑꢁ ꢆꢐ0ꢑ
ꢁꢛꢉꢇ
ꢁꢌꢍꢌ0
ꢁꢛꢉꢇ
ꢁꢌꢍꢌꢆ
ꢀ00
ꢀꢁ
ꢀ0
ꢀꢁ
ꢀ0
ꢀꢁ
ꢡ
ꢢ
ꢡ
ꢓ
ꢓ
ꢓ
ꢓ
ꢀꢁꢂ ꢃ ꢄꢅꢀ
ꢌꢛꢍꢌꢛꢆ
ꢌꢛꢍꢌꢛꢆ
ꢌꢛꢍꢌꢛ0
ꢢ
ꢀꢁ ꢂ00ꢃꢄꢅ
ꢌꢛꢍꢌꢛ0
ꢏꢑꢖꢚꢁꢆ
ꢏꢑꢖꢚꢁ0
ꢓ
ꢋꢣ0
ꢓ
ꢋꢣꢆ
ꢌꢝꢍꢂ
ꢇꢎꢖꢖꢏ0
ꢇꢎꢖꢖꢏꢆ
FAULT0
FAULT1
Rꢚꢍ0
ꢇꢌꢉ
ꢌꢞꢑRꢛꢏ
ꢇꢔꢍꢌ
ꢌꢂꢀ
ꢌꢏꢑ
ꢇꢉꢣꢤꢥ
Rꢚꢍꢆ
ꢍꢖꢁꢛꢜ ꢌꢖꢉꢛ ꢏꢛꢁꢑꢔꢀꢌ ꢖꢉꢔꢁꢁꢛꢏ ꢋꢖR ꢂꢀꢑRꢔꢁꢝ
ꢖꢍꢀꢝ ꢁꢈꢖ ꢖꢋ ꢛꢔꢎꢞꢁ ꢂꢞꢑꢍꢍꢛꢀꢌ ꢌꢞꢖꢈꢍ
ꢌꢞꢑRꢛꢟꢂꢀꢠ ALERT
0.ꢀꢁ
0.ꢀꢁ
ꢀ.0ꢁ
ꢀ.ꢁꢂ
ꢔ
ꢔ
ꢔ
ꢁꢞRꢆ
ꢁꢞꢆ
ꢁꢞR0
ꢁꢞ0
ꢐꢐ00ꢦꢋ
ꢔ
ꢐꢐ00ꢦꢋ
ꢆ00ꢦꢋ
ꢆ00ꢦꢋ
ꢓ
ꢓ
ꢏꢏꢃꢃ
ꢏꢏꢐꢕ
ꢆꢊꢋ
ꢆꢊꢋ
ꢎꢍꢏ
ꢀ0
0
ꢀ0
ꢀꢁ0
ꢀꢁ0
ꢀꢁ0
ꢀ00
ꢃꢄꢄꢄꢆꢐ ꢁꢑ0ꢆꢒ
ꢀꢁꢂꢃ ꢄꢅRRꢆꢇꢈ ꢉꢂꢊ
ꢀꢁꢁꢁꢂꢃ ꢄ0ꢃ
Rev. 0
1
Document Feedback
For more information www.analog.com