MAX9939 Maxim, MAX9939 Datasheet - Page 10

• Manufacturer Part Number: MAX9939
• Description: The MAX9939 is a general-purpose, differential-input programmable-gain amplifier (PGA) that is ideal for conditioning a variety of wide dynamic range signals such as those found in motor current-sense, medical instrumentation, and sonar data acquisit
• Manufacturer: Maxim

SPI Programmable-Gain Amplifier
with Input V
The output amplifier can be configured so that the
MAX9939 operates as a differential-input, differential-
output programmable gain amplifier. As shown in
Figure 4, use a 10kΩ resistor between OUTA and INB,
and between INB and OUTB. Such a differential-output
configuration is ideal for use in low-voltage applications
that can benefit from the 2X output voltage dynamic
range when compared to single-ended output format.
Table 4. Input Offset-Voltage Trim
10
Differential-Input, Differential-Output PGA
(V4 = 0 TRIMS POSITIVE, V4 = 1 TRIMS NEGATIVE)
______________________________________________________________________________________
V3:V0
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111
INPUT OFFSET VOLTAGE
OS
Trim and Output Op Amp
V
OS
10.6
11.7
12.7
13.7
14.7
15.7
16.7
17.6
1.3
2.5
3.8
4.9
6.1
7.3
8.4
0
(mV)
CMOS inputs on the output op amp makes it ideal for
use as an input transimpedance amplifier (TIA) in cer-
tain current-output sensor applications. In such a situ-
ation, keep in mind that the inverting input operates at
fixed voltage of V
feedback gain element, and use a feedback capacitor
in parallel with this resistor if necessary to aid amplifi-
er stability in the presence of high photodiode or
cable capacitance. The output of this TIA can be rout-
ed to INA+ or INA- for further processing and signal
amplification.
Bypass V
with a 1µF low-ESR capacitor placed as close as possi-
ble to the MAX9939.
Use of Output Operational Amplifier as TIA
CC
to GND with a 0.1µF capacitor in parallel
CC
/2. Use a high-value resistor as a
Power-Supply Bypassing