Detailed Description
The MAX9611/MAX9612 are high-side, current-sense
amplifiers with an integrated 12-bit ADC and an internal
selectable op amp/comparator. These devices are ideal
for a variety of industrial and automotive applications.
The MAX9611/MAX9612’s high-side, current-sense
amplifiers operate over a wide 0V to 60V input common-
mode voltage range. The programmable full-scale voltage
(440mV, 110mV, and 55mV) allows for a wide dynamic
range current measurement and application flexibility in
choosing sense resistor values.
The I2C bus is 1.8V and 3.3V logic compatible and
can interface with modern microcontrollers. An inter-
nal 12-bit, 500sps integrating analog-to-digital converter
(ADC) allows the user to read analog signals such as die
temperature, VOUT, VSET, VRSCM, and VSENSE.
At power-up, the selectable op-amp/comparator block
is configured in the op-amp mode. The op amp has an
effective 60V Class A-type output stage and can be used
to limit inrush currents and create a current source when
used in a closed-loop system. When the internal compara-
tor is selected, the MAX9611/MAX9612 can be configured
to have a latched and retry functionality, allowing a 60V
open-drain transistor output, ideal to operate high-side
relay-disconnect FETs. The MAX9611 has a noninverting
input-to-output configuration while the MAX9612 has an
inverting input-to-output configuration.
Current-Sense Amplier
The MAX9611/MAX9612 feature a precision current-
sense amplifier with a 0V to 60V input common-mode
voltage range. An internal negative charge pump elimi-
nates input stage crossover distortion, typical in most
rail-to-rail input current-sense amplifiers. Low input bias
currents and low input offset currents allow a wide selec-
tion of input filters to be designed without degrading the
accuracy of the current-sense amplifier.
The current-sense amplifier inputs feature both a
-0.3V/+65V common-mode absolute maximum rating
as well as a ±65V differential absolute maximum rating,
allowing a wide variety of fault conditions to be withstood
easily by the device without damage.
The current-sense amplifier has a gain of 2.5V/V and
connects directly to the output op-amp/comparator inputs.
The ADC path features a 1x, 4x, and 8x programmable
gain providing for 440mV, 110mV, and 55mV full-scale
sense voltage.
Analog-to-Digital Converter (ADC)
The MAX9611/MAX9612 feature an internal dual-slope
integrating 12-bit ADC that has a 2ms conversion time
and a 1.8V and 3.3V logic-compatible I2C bus. An inter-
nal mux allows the following on-chip variables to be read:
input sense voltage, input common-mode voltage, SET
voltage, OUT voltage, and die temperature.
Temperature Measurement
Die temperature can be read by the ADC over the entire
operating range (-40°C to +125°C) with 0.5°C resolution.
Die temperature can be used for application calibration
and thermal monitoring and is available in a 9-bit, two’s
complement format. Readings outside of normal operat-
ing temperature range (-40°C to +125°C) are inaccurate
and should be considered invalid. See Table 1 for binary
and hex values.
Table 1. Binary and Hex Digital Output Values for Temperature Measurements
TEMPERATURE (°C) DIGITAL OUTPUT
BINARY HEX
+122.4 0111 1111 1xxx xxxx 7F8x
+24 0001 1001 0xxx xxxx 190x
+0.48 0000 0000 1xxx xxxx 008x
0 0000 0000 0xxx xxxx 000x
-0.48 1111 1111 1xxx xxxx FF8x
-24 1110 0111 0xxx xxxx E70x
-40 1101 1001 1xxx xxxx D98x
MAX9611/MAX9612 High-Side, Current-Sense Ampliers with
12-Bit ADC and Op Amp/Comparator
www.maximintegrated.com Maxim Integrated
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