TLC27L4, TLC27L4A, TLC27L4B, TLC27L4Y, TLC27L9

LinCMOS

™ PRECISION QUAD OPERATIONAL AMPLIFIERS

SLOS053C – OCTOBER 1987 – REVISED AUGUST 1994

30

POST OFFICE BOX 655303

• DALLAS, TEXAS 75265

APPLICATION INFORMATION

single-supply operation

While the TLC27L4 and TLC27L9 perform well using dual power supplies (also called balanced or split

supplies), the design is optimized for single-supply operation. This design 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 3 V (C-suffix types), thus allowing operation with supply levels commonly

available for TTL and HCMOS; however, for maximum dynamic range, 16-V single-supply operation is

recommended.

Many single-supply applications require that a voltage be applied to one input to establish a reference level that

is above ground. A resistive voltage divider is usually sufficient to establish this reference level (see Figure 38).

The low input bias current of the TLC27L4 and TLC27L9 permits the use of very large resistive values to

implement the voltage divider, thus minimizing power consumption.

The TLC27L4 and TLC27L9 work 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 39); 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, high-frequency applications may require RC decoupling.

R4

VO

VDD

R2

R1

VI

VREF

R3

C

0.01

µF

VREF = VDD

R3

R1 + R3

VO = (VREF – VI )

R4

R2

+ VREF

Figure 38. Inverting Amplifier With Voltage Reference