Datasheet

MAX9934
High-Precision, Low-Voltage, Current-Sense Amplifier
with Current Output and Chip Select for Multiplexing
EVALUATION KIT AVAILABLE
19-5011; Rev 3; 11/12
For pricing, delivery, and ordering information, please contact Maxim Direct
at 1-888-629-4642, or visit Maxim’s website at www.maximintegrated.com.
General Description
The MAX9934 high-precision, low-voltage, high-side
current-sense amplifier is ideal for both bidirectional
(charge/discharge) and unidirectional current measure-
ments in battery-powered portable and laptop devices.
Input offset voltage (V
OS
) is a low 10µV (max) at +25°C
across the -0.1V to 5.5V input common-mode voltage
range, and is independent of V
CC
. Its precision input
specification allows the use of very small sense volt-
ages (typically ±10mV full-scale) for minimally invasive
current sensing.
The output of the MAX9934 is a current proportional to
input V
SENSE
and is available in either 25µA/mV or
5µA/mV gain options (G
M
) with gain accuracy better
than 0.25% (max) at +25°C. A chip select (CS) allows
multiplexing of several MAX9934 current outputs to a
single microcontroller ADC channel (see the Typical
Operating Circuit ). CS is compatible with 1.8V and 3.3V
logic systems.
The MAX9934 is designed to operate from a 2.5V to
3.6V V
CC
supply, and draws just 120µA (typ) quiescent
current. When powered down (V
CC
= 0), RS+ and RS-
draw less than 0.1nA (typ) leakage current to reduce
battery load. The MAX9934 is robust and protected
from input faults of up to ±6V input differential voltage
between RS+ and RS-.
The MAX9934 is specified for operation over the -40°C
to +125°C temperature range and is available in an
8-pin µMAX
®
or a 6-bump UCSP™ (1mm x 1.5mm x
0.6mm), making it ideal for space-sensitive applications.
Applications
PDAs and Smartphones
MP3 Players
Sensor Instrumentation Amplifiers
Notebook PCs and Ultra-Mobile PCs
Portable Current Monitoring
Features
o Input Offset Voltage: 10µV (max)
o Gain Error Less than 0.25%
o -0.1V to +5.5V Input Common-Mode Voltage
Range
o Chip Select Allows Multiplexing Several MAX9934
Current Monitors to One ADC
o Current Output Allows R
OUT
Selection
for Gain Flexibility
o Single Supply Operation: 2.5V to 3.6V
o Two Gain Options: G
M
of 25µA/mV (MAX9934T)
and 5µA/mV (MAX9934F)
o Bidirectional or Unidirectional Operation
o Small, 6-Bump UCSP (1mm x 1.5mm x 0.6mm)
and 8-Pin µMAX Packages
Ordering Information
PART GAIN
PIN-
PACKAGE
TOP
MARK
MAX9934FART+T 5µA/mV 6 UCSP AAG
MAX9934FAUA+T 5µA/mV 8 µMAX —
MAX9934FAUA/V+T 5µA/mV 8 µMAX AAG
MAX9934TART+T 25µA/mV 6 UCSP AAF
MAX9934TAUA+T 25µA/mV 8 µMAX —
MAX9934TAUA/V+T 25µA/mV 8 µMAX AAF
Note: All devices are specified over the -40°C to +125°C
extended temperature range.
+ Denotes a lead(Pb)-free/RoHS-compliant package.
T = Tape and reel.
µMAX is a registered trademark and UCSP is a trademark of
Maxim Integrated Products, Inc.
I
LOAD
R
SENSE
RS-
RS+
-0.1V ≤ V
CM
≤ 5.5V
V
CC
= 3.3V
V
CC
CS
GND
MAX9934
OUT
R
OUT
10kΩ
V
OUT
TO ADC
FROM µC
CHIP SELECT
1000pF
0.1µF
Typical Operating Circuit