MICROPROCESSOR

DSP

SCLK

CS

SDATA

GND

ADC081S051

LP2950

5V

1 PF

0.1 PF

0.1 PF

1 PF

000...001

000...010

0V

011...111

111...000

000...000

111...111

111...110

ANALOG INPUT

1 LSB

ADC081S051

www.ti.com

SNAS309E – APRIL 2005 – REVISED MARCH 2013

ADC081S051 TRANSFER FUNCTION

The output format of the ADC is straight binary. Code transitions occur midway between successive integer LSB

code transitions occur at steps of one LSB.

Figure 20. Ideal Transfer Characteristic

TYPICAL APPLICATION CIRCUIT

A typical application of the ADC is shown in Figure 21. Power is provided in this example by the LP2950 low-

dropout voltage regulator, available in a variety of fixed and adjustable output voltages. The power supply pin is

bypassed with a capacitor network located close to the ADC. Because the reference for the ADC is the supply

voltage, any noise on the supply will degrade device noise performance. To keep noise off the supply, use a

dedicated linear regulator for this device, or provide sufficient decoupling from other circuitry to keep noise off the

ADC supply pin. Because of the ADC's low power requirements, it is also possible to use a precision reference

as a power supply to maximize performance. The three-wire interface is shown connected to a microprocessor or

DSP.

Figure 21. Typical Application Circuit

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