LTC6915_15 Datasheet, PDF (1/18 Pages) Linear Technology – Zero Drift, Precision Instrumentation Amplifier with Digitally Programmable Gain

LTC6915
Zero Drift, Precision
Instrumentation Amplifier with
Digitally Programmable Gain
Features
n _{14 Levels of Programmable Gain}
n _{125dB CMRR Independent of Gain}
n _{Gain Accuracy 0.1% (Typ)}
n _{Maximum Offset Voltage of 10µV}
n _{Maximum Offset Voltage Drift: 50nV/°C}
n _{Rail-to-Rail Input and Output}
n _{Parallel or Serial (SPI) Interface for Gain Setting}
n _{Supply Operation: 2.7V to ±5.5V}
n _{Typical Noise: 2.5µVP-P (0.01Hz to 10Hz)}
n _{16-Lead SSOP and 12-Lead DFN Packages}
Applications
n _{Thermocouple Amplifiers}
n _{Electronic Scales}
n _{Medical Instrumentation}
n _{Strain Gauge Amplifier}
n _{High Resolution Data Acquisition}
Description
The LTC^®6915 is a precision programmable gain instru-
mentation amplifier. The gain can be programmed to 0,
1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, or 4096
through a parallel or serial interface. The CMRR is typi-
cally 125dB with a single 5V supply with any programmed
gain. The offset is below 10µV with a temperature drift of
less than 50nV/°C.
The LTC6915 uses charge balanced sampled data tech-
niques to convert a differential input voltage into a single
ended signal that is in turn amplified by a zero-drift op-
erational amplifier.
The differential inputs operate from rail-to-rail and the
single-ended output swings from rail-to-rail. The LTC6915
can be used in single power supply applications as low as
2.7V, or with dual ±5V supplies. The LTC6915 is available
in a 16-lead SSOP package and a 12-lead DFN surface
mount package.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners
Typical Application
Differential Bridge Amplifier with Gain Programmed through the Serial Interface
3V
R < 10k
LTC6915 SSOP PACKAGE
3 IN⁺
_
2 IN
C_S
C_H
+
–
C_F
11 PARALLEL_SERIAL
OUT 15
SENSE 14
RESISTOR
ARRAY
REF 13
6 CS(D0)
µP
7 DIN(D1)
8 CLK(D2)
TO OTHER ^{9 DOUT(D3)}
DEVICES
MUX
4-BIT
LATCH
Q0 Q1 Q2 Q3 Q4 Q5 Q6 Q7
8-BIT
SHIFT-REGISTER
HOLD_THRU 5
V^{+ 16} 3V
0.1µF
SHDN ¹
DGND ¹⁰
V^{– 4}
6915 TA01
6915fb
1