LTC6910-1_15 Datasheet, PDF (1/24 Pages) Linear Technology – Digitally Controlled Programmable Gain Amplifiers in SOT-23

LTC6910-1
LTC6910-2/LTC6910-3
Digitally Controlled
Programmable
Gain Amplifiers in SOT-23
FEATURES
s _{3-Bit Digital Gain Control in Three Gain-Code}
Options
s _{Rail-to-Rail Input Range}
s _{Rail-to-Rail Output Swing}
s _{Single or Dual Supply: 2.7V to 10.5V Total}
s _{11MHz Gain Bandwidth Product}
s _{Input Noise Down to 8nV/√Hz}
s _{System Dynamic Range to 120dB}
s _{Input Offset Voltage: 1.5mV}
s _{8-Pin Low Profile (1mm) SOT-23}
(ThinSOT™) Package
U
APPLICATIO S
s _{Data Acquisition Systems}
s _{Dynamic Gain Changing}
s _{Automatic Ranging Circuits}
s _{Automatic Gain Control}
DESCRIPTIO
The LTC^®6910 family are low noise digitally program-
mable gain amplifiers (PGAs) that are easy to use and
occupy very little PC board space. The inverting gain is
adjustable using a 3-bit digital input to select gains of 0, 1,
2, 5, 10, 20, 50 and 100V/V in the LTC6910-1; 0, 1, 2, 4,
8, 16, 32 and 64V/V in the LTC6910-2; and 0, 1, 2, 3, 4, 5,6
and 7V/V in the LTC6910-3.
The LTC6910-Xs are inverting amplifiers with rail-to-rail
output. When operated with unity gain, they will also
process rail-to-rail input signals. A half-supply reference
generated internally at the AGND pin supports single
power supply applications. Operating from single or split
supplies from 2.7V to 10.5V, the LTC6910-X family is
offered in an 8-lead SOT-23 package.
, LTC and LT are registered trademarks of Linear Technology Corporation.
ThinSOT is a trademark of Linear Technology Corporation.
U.S. Patent Number 6121908.
TYPICAL APPLICATIO
Single Supply Programmable Amplifier
DIGITAL INPUTS GAIN IN VOLTS/VOLT
G2 G1 G0 6910-1 6910-2 6910-3
000 0
0
0
0 0 1 –1 –1 –1
0 1 0 –2 –2 –2
0 1 1 –5 –4 –3
1 0 0 –10 –8 –4
1 0 1 –20 –16 –5
1 1 0 –50 –32 –6
1 1 1 –100 –64 –7
V⁺
2.7V TO 10.5V
0.1µF
8
4
3
1
V_IN
LTC6910-X
V_OUT = GAIN • V_IN
2
5
6
AGND
7
1µF OR LARGER
G2 G1 G0
6910 TA01
PIN 2 (AGND) PROVIDES BUILT-IN HALF-SUPPLY
REFERENCE WITH INTERNAL RESISTANCE OF 5k.
AGND CAN ALSO BE DRIVEN BY A SYSTEM ANALOG
GROUND REFERENCE NEAR HALF SUPPLY
Frequency Response (LTC6910-1)
50
V_S = 10V, V_IN = 5mV_RMS
GAIN OF 100 (DIGITAL INPUT 111)
40
30 _{GAIN OF 50 (DIGITAL INPUT 110)}
GAIN OF 20 (DIGITAL INPUT 101)
20
GAIN OF 10 (DIGITAL INPUT 100)
10 ^{GAIN OF 5 (DIGITAL INPUT 011)}
GAIN OF 2 (DIGITAL INPUT 010)
0 _{GAIN OF 1 (DIGITAL INPUT 001)}
–10
100
1k 10k 100k 1M 10M
FREQUENCY (Hz)
6910 TA01b
6910123fa
1