Datasheet

LTC2389-16
25
238916f
Figure 9a. LT6200 Buffering a Single-Ended Signal Source
applications inFormation
Single-Ended Unipolar and Bipolar Inputs
The LTC2389-16 accepts both single-ended unipolar
and single-ended bipolar input signals directly. For most
single-ended applications, it is recommended that the
LTC2389-16 be driven using the LT6200 ADC driver con-
figured as a unity-gain buffer, as shown in Figure 9a. The
LT6200 combines fast settling and good DC linearity with
a 0.95nV/
√Hz input-referred noise density, enabling it to
achieve the full ADC data sheet SNR and THD specifica-
tions in both pseudo-differential input modes, as shown
in the FFT plots in Figures 9b and 9c.
Figure 9c. 32k Point FFT f
SMPL
= 2.5Msps,
f
IN
= 2kHz, for Circuit Shown in Figure 9a;
Driven with Bipolar Inputs
Figure 9b. 32k Point FFT f
SMPL
= 2.5Msps,
f
IN
= 2kHz, for Circuit Shown in Figure 9a;
Driven with Unipolar Inputs
238916 F09a
IN
–
IN
+
1nF
10Ω
LOWPASS FILTER
LTC2389-16
LT6200
+
–
4.096V
0V
0V
4.096V
0V
2.048V
49.9Ω
49.9Ω
FREQUENCY (kHz)
0
AMPLITUDE (dBFS)
–60
–40
–20
–80
–100
500250 750 1000 1250
–160
–180
–120
0
–140
238916 F09b
SNR = 93.2dB
THD = –112dB
SINAD = 93.2dB
SFDR = 113dB
FREQUENCY (kHz)
0
AMPLITUDE (dBFS)
–60
–40
–20
–80
–100
500250 750 1000 1250
–160
–180
–120
0
–140
238916 F09c
SNR = 93.5dB
THD = –111dB
SINAD = 93.5dB
SFDR = 112dB