Digital Power Monitor with
PMBus Interface
Data Sheet
ADM1293/ADM1294
FEATURES
FUNCTIONAL BLOCK DIAGRAMS
SENSEP
SENSEN
Monitor current and two voltages
High accuracy current monitoring at low sense voltage
0.33% accurate at 20 mV sense voltage over temperature
Common-mode sense voltage from 0 V to 20 V (ADM1293)
Support high-side and low-side current sensing
Integrated shunt regulator for wide supply input (ADM1294)
Reports current, voltage, and power
ADM1293
VCC
INTERNAL
SUPPLY
LDO
VCAP
RANGE
SELECT
MUX
ADC
EN
VIN
VAUX
Power accumulation for energy metering
Bidirectional current sensing
GPO1/ALERT1/CONV
GPO2/ALERT2
ADDRESS
DECODER
PMBUS AND LOGIC
Digitally programmable overcurrent alert
Multifunctional pins with user configurable functions
ADC conversion enable input
ADR1 ADR2
GND SCL SDAI SDAO
Figure 1. ADM1293 Functional Block Diagram
Multisource alert output
User-controllable GPO
Peak detect registers for current, voltage, and power
PMBus fast mode compliant interface
VSHUNT
VCAP
ADM1294
LDO
ADR1
ADDRESS
DECODER
VEE
Separate SDA I/O for easy isolated communication
Two address pins for 16 unique I²C addresses
Available in 4 mm × 4 mm, 16-lead LFCSP and 14-lead TSSOP
Operation temperature range
ADM1293 TA = −40°C to +105°C
ADM1294 TJ = −40°C to +105°C
ADR2
IC POWER SUPPLY
GPO1/ALERT1/CONV
GPO2/ALERT2
RANGE
SELECT
MUX
VIN
PMBUS
AND
LOGIC
ADC
EN
SDAI
SDAO
SCL
VAUX
VEE
APPLICATIONS
SENSEN
SENSEP
Power monitoring/power budgeting
Central office equipment
Figure 2. ADM1294 Functional Block Diagram
Telecommunications and data communications equipment
PCs/servers
GENERAL DESCRIPTION
The ADM1293 and ADM1294 are high accuracy integrated digital
power monitors that offer digital current, voltage, and power
monitoring using an on-chip, 12-bit analog-to-digital converter
(ADC), communicated through a PMBus™ compliant I2C interface.
In conditions such as overcurrent, overvoltage, undervoltage,
and overpower, the ADM1293/ADM1294 devices can generate
an interrupt signal to the microprocessor through the
GPOx/
outputs. The threshold for these conditions is
ALERTx
digitally programmed via PMBus.
These devices acquire the current by measuring the voltage differ-
ence across the external sense resistor. This voltage is amplified
and digitized by an internal 12-bit ADC. The same ADC can also
sample the primary input voltage and an auxiliary input voltage.
The internal digital block can perform multiplication of the
current and primary input voltage for power calculation. The
ADM1293/ADM1294 also feature a power accumulator for
energy metering. An industry-standard PMBus interface allows a
master controller to read back these data from the device. The
master controller can then combine this information with a known
sense resistor value to calculate the current, voltage, power, and
energy consumption over time on the monitored rail.
The ADM1293 is designed for high-side supply monitoring
with a voltage monitoring range from 0 V to 20 V. The
ADM1294 is designed for low-side supply monitoring. Its
integrated shunt regulator allows it to be powered and to
monitor supply in wide voltage ranges.
The ADM1293/ADM1294 are available in 4 mm × 4 mm 16-lead
LFCSP and 14-lead TSSOP packages with a specified operating
ambient temperature range from −40°C to +105°C for the
ADM1293 and an operating junction temperature range from
−40°C to +105°C for the ADM1294.
Rev. B
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