AD8432 Analog Devices, AD8432 Datasheet - Page 24

• Manufacturer Part Number: AD8432
• Description: Dual-Channel Ultralow Noise Amplifier with Selectable Gain and Input Impedance
• Manufacturer: Analog Devices

Specifications of AD8432

• Vcc-vee: 4.5V to 5.5V
• Isy Per Amplifier: 12mA
• Packages: CSP
• -3db Bandwidth: 200MHz
• Slew Rate: 170V/µs
• Vos: 1mV
• Ib: n/a
• # Opamps Per Pkg: 2
• Input Noise (nv/rthz): 0.8nV/rtHz

AD8432
DIFFERENTIAL-TO-SINGLE-ENDED CONVERSION
Some applications require the low noise and high dynamic
range of the AD8432; however, they may also require a single-
ended output, rather than a differential output. The
or
differential-to-single-ended conversion of the AD8432 output,
as shown in Figure 72.
The AD8129 is a low noise, high gain (10 or greater) amplifier
intended for applications over very long cables, where signal
attenuation is significant. The AD8130 is stable at a gain of 1
and can be used for applications where lower gains are required.
The AD8129 and AD8130 have user-adjustable gain, set by the
ratio of two resistors, to help compensate for losses in the
transmission line.
AD8130
differential receiver amplifier can be used for the
IN1
R
15Ω
C
47
SH1
SH1
pF
0.1µF
0.1µF
Figure 72. AD8432 Differential-to-Single-Ended Conversion Using the AD8129/AD8130 with Unity Gain
ENB
INH1
IND1
INL1
G = 12 dB
0.1µF
VPS1
BIAS
VPS2
LNA1
GMH1
GOH1
GML1
GOL1
COMM
AD8129
0.1µF
OPH1
OPL1
Rev. B | Page 24 of 28
RESISTORS IF DRIVING
HIGH CAP LOAD
SERIES 20Ω
20Ω
20Ω
A transformer or balun can also be used to convert the differential
output of the AD8432 to a single-ended output. Transformers
have lower distortion; however, care must be taken to properly
match the impedance of the transformer. The test circuit for
distortion measurements in Figure 58 uses an ADTT1-1
transformer to perform differential-to-single-ended conversion.
TERMINATION IF NECESSARY
499Ω RESISTORS PROVIDE
BIAS CURRENT PATH AND
AC-COUPLING CAPS
0.1µF
0.1µF
(AD8432 HAS 2.5V
OUTPUT BIAS)
499Ω
499Ω
1
8
4
5
+
–
+
–
+V
–V
S
S
7
2
AD8130
6
V
OUT1