MAX9918 Maxim, MAX9918 Datasheet - Page 14

• Manufacturer Part Number: MAX9918
• Description: The MAX9918/MAX9919/MAX9920 are single-supply, high-accuracy current-sense amplifiers with a high input common-mode range that extends from -20V to +75V
• Manufacturer: Maxim

-20V to +75V Input Range, Precision
Uni-/Bidirectional, Current-Sense Amplifiers
The MAX9918/MAX9919/MAX9920 support both unidi-
rectional and bidirectional operation. The devices oper-
ate in unidirectional mode with V
output is then referenced to ground and the output volt-
age V
(V
Figure 1. Unidirectional Operation
Figure 2. Bidirectional Operation
14
SENSE
______________________________________________________________________________________
OUT
) from RS+ to RS- (Figure 1).
I
DISCHARGE
is proportional to the positive voltage drop
I
DISCHARGE
5V
5V
V
SHDN
CC
Uni-/Bidirectional Operation
SHDN
V
CC
RS+
RS+
MAX9919N
R
SENSE
GND
MAX9919N
R
SENSE
GND
RS-
RS-
REFIN
REFIN
I
OUT
CHARGE
REFIN
OUT
TO ADC
= V
2.5V
TO ADC
LOAD
GND
LOAD
. The
-20mV
CHARGE
CURRENT
V
OUT
The MAX9918/MAX9919 operate in bidirectional mode
by application of a low-source impedance reference
voltage in the 0V to V
to REFIN. For the MAX9920, the reference voltage range
is 0V to V
V
±V
0
2.7V
0.9V
3.6V
1.8V
OUT
SENSE
-10mV
10mV
relative to V
CC
voltage drop from RS+ to RS- (Figure 2).
V
OUT
- 2.4V (typically V
- V
20mV
REFIN
0
-1.8V
-0.9V
1.8V
0.9V
REFIN
CC
10mV
DISCHARGE
CURRENT
- 1.9V range, (typically V
20mV
is then proportional to the
G = 90V/V
G = 90V/V
CC
DISCHARGE
CURRENT
20mV
/2). The output voltage
30mV
V
SENSE
V
SENSE
CC
/2),