–

+

TLE2426

V

V

DD *

V

I

2

R1

)

V

DD

2

VO

VI

R1

R2

VDD

Figure 31. Inverting Amplifier With Voltage

Reference

TLC2810Z, TLC2810Y

LinCMOS

™ PRECISION

DUAL OPERATIONAL AMPLIFIERS

SLOS120A – AUGUST 1993 – REVISED AUGUST 1994

19

POST OFFICE BOX 655303

APPLICATION INFORMATION

single-supply operation

While

the

TLC2810Z

performs

well

using

dual-power supplies (also called balanced or split

supplies), the design is optimized for single-

supply operation. This includes an input common-

mode voltage range that encompasses ground as

well as an output voltage range that pulls down to

ground. The supply voltage range extends down

to 4 V, thus allowing operation with supply levels

commonly available for TTL and CMOS.

Many single-supply applications require that a

voltage be applied to one input to establish a

reference level that is above ground. This virtual

ground can be generated using two large

resistors, but a preferred technique is to use a

virtual ground generator such as the TLE2426 (see Figure 31). The TLE2426 supplies an accurate voltage equal

The TLC2810Z works well in conjunction with digital logic. However, when powering both linear devices and

digital logic from the same power supply, the following precautions are recommended:

1.

Power the linear devices from separate bypassed supply lines (see Figure 32). Otherwise, the linear

device supply rails can fluctuate due to voltage drops caused by high switching currents in the digital logic.

2.

Use proper bypass techniques to reduce the probability of noise-induced errors. Single capacitive

decoupling is often adequate. However, RC decoupling may be necessary in high-frequency applications.

–

+

Logic

Logic

Logic

Power

Supply

–

+

Logic

Logic

Logic

Power

Supply

(a) COMMON SUPPLY RAILS

(b) SEPARATE BYPASSED SUPPLY RAILS (preferred)

Output

Output

Figure 32. Common Versus Separate Supply Rails