TLE2662

DUAL

µPOWER JFET-INPUT OPERATIONAL AMPLIFIER

WITH SWITCHED-CAPACITOR VOLTAGE CONVERTER

SLOS118B – DECEMBER 1992 – REVISED AUGUST 1994

24

POST OFFICE BOX 655303

APPLICATION INFORMATION

amplifier section

input characteristics

The TLE2662 is specified with a minimum and a maximum input voltage that if exceeded at either input, could

cause the device to malfunction.

Because of the extremely high input impedance and resulting low bias-current requirements, the TLE2662

operational amplifier section is well suited for low-level signal processing; however, leakage currents on printed-

circuit boards and sockets can easily exceed bias-current requirements and cause degradation in system

performance. It is a good practice to include guard rings around inputs (see Figure 47). These guards should

be driven from a low-impedance source at the same voltage level as the common-mode input.

The inputs of any unused amplifiers should be tied to ground to avoid possible oscillation.

+

+

+

–

–

–

VO

VO

VO

VI

VI

VI

Figure 47. Use of Guard Rings

switched-capacitor section

SCREF

REF

+

–

OSC

Q

Q

Drive

Drive

CAP +

VCC

Drive

Drive

GND

SCOUT

FB/SD

OSC

R

R

2.5 V

CAP –

COUT†

CIN†

† External capacitors

Figure 48. Functional Block Diagram for Switched-Capacitor Block Only