(+2.4V to +5.5V)

GND

TRIP TEST

Microcontroller

LM57

ADC Input

Digital In

Digital Out

SENSE1

SENSE2

Analog

+2.4V to +5.5V

Input

Pin

LM57

Reset

Sample

GND

SAR Analog-to-Digital Converter

LM57-Q1

SNIS191A – JULY 2015 – REVISED JULY 2015

www.ti.com

8 Application and Implementation

NOTE

Information in the following applications sections is not part of the TI component

specification, and TI does not warrant its accuracy or completeness. TI’s customers are

responsible for determining suitability of components for their purposes. Customers should

validate and test their design implementation to confirm system functionality.

8.1 Application Information

The LM57-Q1 has several outputs allowing for varying system implementations.

8.1.1 ADC Input Considerations

(Analog to Digital Converter) input. Most CMOS ADCs found in microcontrollers and ASICs have a sampled data

comparator input structure. When the ADC charges the sampling cap, it requires instantaneous charge from the

output of the analog source such as the LM57-Q1 temperature sensor and many op amps. This requirement is

sampling capacitor and the sampling frequency. Because not all ADCs have identical input stages, the charge

requirements will vary. The general ADC application shown in Figure 20 is an example only.

Figure 20. Suggested Connection to a Sampling Analog-to-Digital Converter Input Stage

8.2 Typical Application

Figure 21. Typical Application Schematic with Microcontroller TRIP TEST Control

26

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