1
dc1833af
DEMO MANUAL DC1833A
DESCRIPTION
LTC6362
Fully Differential Amplifier
The LTC
®
6362 is a low power, low noise differential op amp
with rail-to-rail input and output swing that has been
optimized to drive low power SAR ADCs. The amplifier may
be configured to buffer a fully differential input signal or
convert a single-ended input signal to a differential output
signal. Demo circuit 1833A contains the LTC6362 amplifier
configured as a unity gain amplifier with 1kΩ feedback
and input resistors, where both inputs are AC-coupled by
a 1μF capacitor. The differential outputs of the DC1833A
can be configured with a first order RC network for driving
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.
PERFORMANCE SUMMARY
the differential inputs of an ADC. The LTC6362 differential
output can be DC-coupled or AC-coupled (AC-coupled is
the default configuration). Onboard jumpers configure
the DC1833A for dual or single power supply. In addition,
there are several optional surface mount pads that can be
used to change the LTC6362 configuration.
Design files for this circuit board are available at
http://www.linear.com/demo
This demo board is factory tested by measuring distortion with an 8V
P-P
, 2kHz
differential input, as given in Table 1. (T
A
= 25°C)
Table 1. LTC6362 Noise and Distortion
Differential Input, Referred Noise Voltage Density
3.9nV/√
Hz
Distortion, 8V
P-P
Differential Input, V
S
= 5V, F
IN
= 2kHz, R
LOAD
= 1000Ω
2nd Harmonic
3rd Harmonic
–128dBc
–114dBc
Figure 1. Typical Application for an LTC6362
2kHz Sine Wave,
V
IN
Diff 8V
P-P
16384 –Point FFT
V
+
0.1μF
0.1μF
–
–
+
+
R3, 1k
DC1833A F01a
C18
C
DIFF
V
IN
–
V
OUT
+
V
OUT
–
LTC6362
V
IN
+
V
OCM
R15
R14
R6, 1k
R5, 1k
R4, 1k
C19
C15
FREQUENCY (kHz)
0
–140
MAGNITUDE (dB)
–120
–80
–60
0
2
8
4
6
DC1833A FO1b
–100
–20
–40
–150
–130
–90
–70
–10
–110
–30
–50
10
12
14
18
20
16
V
+
= 5V
V
–
= 0V
HD2 = –128dBc
HD3 = –114dBc
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