LT6105_15 Datasheet, PDF (1/20 Pages) Linear Technology – Precision, Extended Input Range Current Sense Amplifier

LT6105
Precision, Extended Input
Range Current Sense Amplifier
FEATURES
n _{Very Wide, Over-the-Top}^®_{, Input Common Mode Range}
- Extends 44V Above V^– (Independent of V⁺)
- Extends –0.3V Below V^–
n _{Wide Power Supply Range: 2.85V to 36V}
n _{Input Offset Voltage: 300μV Maximum}
n _{Gain Accuracy: 1% Max}
n _{Gain Configurable with External Resistors}
n _{Operating Current: 150μA}
n _{Slew Rate: 2V/μs}
n _{Sense Input Current When Powered Down: 1nA}
n _{Full-Scale Output Current: 1mA Minimum}
n _{Operating Temperature Range –40°C to 125°C}
n _{Available in 2mm × 3mm DFN and 8-Lead MSOP}
Packages
APPLICATIONS
n _{High Side or Low Side Current Sensing}
n _{Current Monitoring on Positive or Negative Supply}
Voltages
n _{Battery Monitoring}
n _{Fuse/MOSFET Monitoring}
n _Automotive
n _{Power Management}
n _{Portable Test/Measurement Systems}
DESCRIPTION
The LT^®6105 is a micropower, precision current sense
amplifier with a very wide input common mode range.
The LT6105 monitors unidirectional current via the volt-
age across an external sense resistor. The input common
mode range extends from –0.3V to 44V, with respect to
the negative supply voltage (V^–). This allows the LT6105
to operate as a high side current sense monitor or a low
side current sense monitor. It also allows the LT6105 to
monitor current on a negative supply voltage, as well as
continuously monitor a battery from full charge to depletion.
The inputs of LT6105 can withstand differential voltages
up to ±44V, which makes it ideal for monitoring a fuse or
MOSFET switch.
Gain is configured with external resistors from 1V/V to
100V/V. The input common mode rejection and power
supply rejection are in excess of 100dB and the input offset
voltage is less than 300μV. A typical slew rate of 2V/μs
ensures fast response to unexpected current changes.
The LT6105 can operate from an independent power
supply of 2.85V to 36V and draws only 150μA. When
V⁺ is powered down, the sense pins are biased off. This
prevents loading of the monitored circuit, irrespective of
the sense voltage. The LT6105 is available in a 6-lead DFN
and 8-lead MSOP package.
, LT, LTC, LTM and Over-the-Top are registered trademarks of Linear Technology
Corporation. All other trademarks are the property of their respective owners.
TYPICAL APPLICATION
Gain of 50 Current Sense Amplifier
SOURCE
–0.3V TO 44V
V_S+
R_IN2
100Ω
0.02Ω
V_S–
R_IN1
100Ω
+IN ₊
–IN _–
V⁺
LT6105
V_OUT
V^–
V_OUT = 1V/A
R_OUT
4.99k
TO LOAD
2.85V TO 36V
6105 TA01
( ) ^VOUT ⁼
V_S⁺ − V_S^−
• ^ROUT ;
R_IN
A_V
=
R_OUT
R_IN
;
R_IN1 = R_IN2 = R_IN
Gain Error vs Input Voltage
4 _{V+ = 12V}
3
V_SENSE = 50mV
R_IN = 100Ω
2 ^{AV = 50V}
1
T_A = – 40°C
0
T_A = 25°C
–1
–2 ^{TA = 125°C TA = 85°C}
–3
–4
0
5 10 15 20 25 30 35 40 45
V_S+ INPUT VOLTAGE (V)
6105 TA01b
6105fa
1