Datasheet

−48 V Hot Swap Controller and Digital
Power Monitor with PMBus Interface
Data Sheet
ADM1075
Rev. B Document Feedback
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FEATURES
Constant power foldback for FET SOA protection
Precision (<1.0%) current and voltage measurement
Controls inrush and faults for negative supply voltages
Suitable for wide input range due to internal shunt regulator
25 mV/50 mV full-scale sense voltage
Fine tune current limit to allow use of standard sense resistor
Soft start inrush current limit profiling
1% accurate UVH and OV pins, 1.5% accurate UVL pin
PMBus/I
2
C interface for control, telemetry, and fault
recording
28-lead LFCSP and TSSOP
−40°C to 105°C junction temperature (T
J
) operating range
APPLICATIONS
Telecommunication and data communication equipment
Central office switching
−48 V distributed power systems
Negative power supply control
High availability servers
PRODUCT HIGHLIGHTS
1. Constant Power Foldback.
Maximum FET power set by a PLIM resistor divider. This
eases complexity when designing to maintain FET SOA.
2. Adjustable Current Limit.
The current limit is adjustable via the ISET pin allowing for
the use of a standard value sense resistor.
3. 12-Bit ADC.
Accurate voltage, current, and power measurements. Also
enables calculation of energy consumption over time.
4. PMBus/I
2
C Interface.
PMBus fast mode compliant interface used to read back
status and data registers and set warning and fault limits.
5. Fault Recording.
Latched status registers provide useful debugging infor-
mation to help trace faults in high reliability systems.
6. Built-In Soft Start.
Soft start capacitor controls inrush current profile with
di/dt control.
FUNCTIONAL BLOCK DIAGRAM
FAULT TIMER
FET POWER
FOLDBACK
CONTROL
DIGITAL
AND
PMBUS
12-BIT ADC
POWER
MULTIPLIER
POWER
ACCUMULATOR
GATE CONTROL
CURRENT LIMIT
DRAIN
RESTART
SHDN
LATCH
GPO1/ALERT1/CONV
GPO2/ALERT2
SDAO
SDAI
SCL
ADR
ADC_AUX
PWRGD
SPLYGD
UNDERVOLTAGE
AND
OVERVOLTAGE
DETECTOR
V
CC
AND
REFERENCE
GENERATOR
VIN
ADC_V
VCAP
UVL
UVH
SENSE+
GATE
PLIM
N-FET
R
SENSE
R
DROP
DC-TO-DC
CONVERTER
5V
12V
3.3V
2.8V
...etc.
GND
–48V RTN (0V)
–48V
VEE
SENSE–
ISET
TIMER
SS
VEE_G
VEE
OV
VEE
ADuM1250
SDA_ISO
SCL_ISO
C
LOAD
09312-001
Figure 1.

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