4 physical pinout description, 5 reference voltage – Texas Instruments TLC3578EVM User Manual

Page 13

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Physical Pinout Description

2-3

Analog Interface

2.4

Physical Pinout Description

Samtec part numbers SSW-110-22-F-D-VS-K and TSM-110-01-T-DV-P
provide a convenient 10-pin dual row header/socket combination at P1. This
header/socket provides access to the analog input pins of the TLV2553/6.

Consult Samtec at

www.samtec.com

or 1−800−SAMTEC−9 for a variety of

mating connector options.

Table 2−1.

Analog Input Pinout Description

Pin Number

Header

Socket

Signal

Description

P1.2

J1.2

CH0

Channel 0 input, can be direct from P1/J1 connector or through Op-Amp

P1.4

J1.4

CH1

Channel 1 input, direct from P1/J1 connector

P1.6

J1.6

CH2

Channel 2 input, direct from P1/J1 connector

P1.8

J1.8

CH3

Channel 3 input, direct from P1/J1 connector

P1.10

J1.10

CH4

Channel 4 input, direct from P1/J1 connector

P1.12

J1.12

CH5

Channel 5 input, direct from P1/J1 connector

P1.14

J1.14

CH6

Channel 6 input, direct from P1/J1 connector

P1.16

J1.16

CH7

Channel 7 input, direct from P1/J1 connector

P1.18

J1.18

REF−

External Reference negative input

P1.20

J1.20

REF+

External Reference positive input

2.5

Reference Voltage

The accuracy of conversion from a SAR ADC depends directly upon the
accuracy of the reference voltage. It is very important, therefore, that the
reference be stable, accurate and low drift.

The ADC reference pin presents a dynamic capacitive load to the amplifier.
The voltage supplied to the ADC must be capable of driving this dynamic load
properly, ensuring that the reference remain stable regardless of load.

The bipolar and unipolar devices are specified to use a different voltage for the
reference pin.

Table 2−2.

ADC Reference Voltage

ADC

Reference Voltage

Bipolar input

TLC3578

3.3 V

TLC3574

3.3 V

TLC2578

3.3 V

TLC2574

3.3 V

Unipolar input

TLC3548

4.096 V

TLC3544

4.096 V

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