Datasheet

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ADS820
12
SBAS037B
FIGURE 6. A Low Distortion DC-Coupled, Single-Ended to Differential Input Driver Circuit.
FIGURE 7. A Wideband DC-Coupled, Single-Ended to Differential Input Driver Circuit.
604Ω
301Ω
301Ω
301Ω
604Ω
49.9Ω
301Ω
604Ω
2.49kΩ
2.49kΩ
+2.25V
OPA842
OPA130
301Ω
0.1µF
OPA842
OPA842
+5V
–5V
+5V
(2)
+5V
–5V
+5V
+5V
+5V
–5V
BAS16
(1)
BAS16
(1)
301Ω
24.9Ω
Input Level
Shift Buffer
Optional
High Impedance
Input Amplifier
DC-Coupled
Input Signal
26 IN
22 CM
27 IN
ADS820
NOTES: (1) A Philips BAS16 diode or equivalent may be used.
(2) Supply bypassing not shown. (3) OPA620 or OPA650 may be
substituted. See “Driving the ADS820” section.
22pF
22pF
604Ω
0.1µF
0.1µF
(3)
(3)
(3)
50Ω
1kΩ
OTA
OPA860
OPA860
+1
+1
OPA130
1nF
OTA
+5V –5V
–5V
+5V
DC-Coupled
Input Signal
27 IN
22 CM
26 IN
ADS820
NOTE: Power supplies and bypassing not shown. The measured SNR performance with 12.5MHz input signal is 57dB with this driver circuit.
1kΩ
500Ω
500Ω
1kΩ
200Ω
243Ω
200Ω
3B
2
3
2
85
C
6
6
1
85
C
E
E
3
2
7
4
B
200Ω
C
1
15pF
22pF
22pF
0.1µF
2kΩ
V
OUT
–5V
243Ω