TLC27M4CPWR datasheet(30/47 Pages) TI

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Logic

(a) COMMON SUPPLY RAILS

(b) SEPARATE BYPASSED SUPPLY RAILS (preferred)

Logic

Power

Supply

Power

Supply

Output

REF

0.01 μF

VREF = VDD

R1 + R3

VO = (VREF – VI)

+ VREF

TLC27M4, TLC27M4A, TLC27M4B, TLC27M4Y, TLC27M9

SLOS093D – OCTOBER 1987 – REVISED OCTOBER 2012

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APPLICATION INFORMATION

Single-Supply Operation

While the TLC27M4 and TLC27M9 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 TLC27M4 and TLC27M9 permits the use of very large resistive values to

implement the voltage divider, thus minimizing power consumption.

The TLC27M4 and TLC27M9 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.

Figure 38. Inverting Amplifier With Voltage Reference

Figure 39. Common Versus Separate Supply Rails

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Product Folder Links: TLC27M4 TLC27M4A TLC27M4B TLC27M4Y TLC27M9

TLC27M4CPWR Datasheet(PDF) 30 Page - Texas Instruments