Test Circuits and Waveforms
HA-5340
1 -INPUT
2
+INPUT
8
OUTPUT
VO
S/H
CONTROL
INPUT
16 S/H CONTROL
HA-5340
12 NC
(CH = 135pF = INTERNAL)
FIGURE 1. HOLD STEP ERROR AND DROOP RATE
S/H CONTROL
VO
VP
NOTE:
6. Observe the “hold step” voltage VP.
HOLD (+4.0V)
SAMPLE (0V)
FIGURE 2. HOLD STEP ERROR
S/H CONTROL
HOLD (+4.0V)
SAMPLE (0V)
VO
∆VO
∆t
NOTES:
7. Observe the voltage “droop”, ∆VO/∆t.
8. Measure the slope of the output during hold, ∆VO/∆t.
9. Droop can be positive or negative - usually to one rail or the other
not to GND.
FIGURE 3. DROOP RATE TEST
V IN
20VP-P
200kHz
SINE WAVE
S/H CONTROL
INPUT
ANALOG
MUX OR
SWITCH
AIN
V+
V-
HA-5340
9
6
1 -IN
2 +IN
16 S/H
CONTROL
SUPPLY
GND
15
8
OUT
REF
COM
7
TO
SUPPLY
COMMON
TO
SIGNAL
GND
VOUT
NOTE:
10. Feedthrough in
dB = 20log -V----O----U----T- where:
VIN
VOUT = VP-P , Hold Mode,
VIN = VP-P
FIGURE 4. HOLD MODE FEEDTHROUGH ATTENUATION
5
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