Texas Instruments TLC3578EVM manual Physical Pinout Description, Reference Voltage

Physical Pinout Description

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		Signal	Description
Header	Socket
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

Analog Interface 2-3