ADC121S625
0.1 PF
10 PF
V
+
33:
V
+
560:
220 pF
560:
-
+
0.1 PF
10 PF
V
+
V
+
560:
560:
33:
560:
220 pF
560:
INPUT
10 PF
-
+
LMH6619
LMH6619
2 Ps/DIV
-4
-3
-2
-1
0
1
2
3
4
1 V/DIV
V
-
V
+
V
IN
V
OUT
LMH6619Q
SNOSC78A –JUNE 2012–REVISED NOVEMBER 2012
www.ti.com
low bias current.
• Common emitter push-push output stage. This architecture allows the output to reach within millivolts of either
supply rail.
• Consistent performance from any supply voltage
(2.7V - 11V)
with little variation with supply voltage for the most
important specifications (e.g. BW, SR, I
OUT
.)
• Significant power saving compared to competitive devices on the market with similar performance.
With 3V supplies and a common mode input voltage range that extends beyond either supply rail, the
LMH6619Q is well suited to many low voltage/low power applications. Even with 3V supplies, the −3 dB BW (at
A
V
= +1) is typically 120 MHz.
The LMH6619Q is designed to avoid output phase reversal. With input over-drive, the output is kept near the
supply rail (or as close to it as mandated by the closed loop gain setting and the input voltage). Figure 3 shows
the input and output voltage when the input voltage significantly exceeds the supply voltages.
Figure 3. Input and Output Shown with CMVR Exceeded
SINGLE TO DIFFERENTIAL ADC DRIVER
Figure 4 shows the LMH6619Q used to drive a differential ADC with a single-ended input. The ADC121S625 is a
fully differential 12-bit ADC. Table 1 shows the performance data of the LMH6619Q and the ADC121S625.
Figure 4. LMH6619Q Driving an ADC121S625
Table 1. Performance Data for the Single to Differential ADC Driver
Parameter Measured Value
Signal Frequency 10 kHz
Signal Amplitude 2.5V
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