4

Application Information

The HA-5320 has the uncommitted differential inputs of an

op amp, allowing the Sample and Hold function to be

combined with many conventional op amp circuits. See the

Intersil Application Note AN517 for a collection of circuit

ideas.

Layout

A printed circuit board with ground plane is recommended

for best performance. Bypass capacitors (0.01

µF to 0.1µF,

ceramic) should be provided from each power supply

terminal to the Supply Ground terminal on pin 13.

The ideal ground connections are pin 6 (SIG. Ground)

directly to the system Signal Ground, and pin 13 (Supply

Ground) directly to the system Supply Common.

Hold Capacitor

The HA-5320 includes a 100pF MOS hold capacitor,

sufficient for most high speed applications (the Electrical

Specifications section is based on this internal capacitor).

Additional capacitance may be added between pins 7 and

11. This external hold capacitance will reduce droop rate at

the expense of acquisition time, and provide other trade-offs

as shown in the Performance Curves.

from pin 8 to ground. Exact value and type are not critical.

resistance and low dielectric absorption, to minimize droop

errors. Polystyrene dielectric is a good choice for operating

Test Circuits and Waveforms

FIGURE 1. CHARGE TRANSFER AND DRIFT CURRENT

FIGURE 2. CHARGE TRANSFER TEST

FIGURE 3. DRIFT CURRENT TEST

FIGURE 4. HOLD MODE FEEDTHROUGH ATTENUATION

14

2

1

7

8

11

NC

NC

-INPUT

+INPUT

S/H CONTROL

CONTROL

INPUT

S/H

OUTPUT

HA-5320

S/H CONTROL

HOLD (+3.5V)

SAMPLE (0V)

NOTES:

S/H CONTROL

∆t

NOTES:

15. Observe the voltage “droop”,

16. Measure the slope of the output during hold,

HOLD (+3.5V)

SAMPLE (0V)

VIN

ANALOG

MUX OR

SWITCH

S/H CONTROL

+IN

-IN

OUT

7

1

2

14

V-

V+

S/H CONTROL

INPUT

95

100kHz

SINE WAVE

TO

SIGNAL

GND

TO

SUPPLY

COMMON

NC

13

11

6

NC

8

INT.

COMP.

REF

COM

SUPPLY

GND

HA-5320

NOTE:

Feedthrough in

where:

dB

20

V

OUT

V

IN

---------------

log

=

HA-5320

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