© 2002 Microchip Technology Inc.

DS21409B-page 5

TC3400

2.0

PIN DESCRIPTIONS

The descriptions of the pins are listed in Table 2-1.

TABLE 2-1:

PIN FUNCTION TABLE

Pin No.

(8-Pin SOIC)

(8-Pin PDIP)

Symbol

Description

1

IN+

Analog Input. This is the positive terminal of a true differential input consisting of IN+ and IN-.

2

IN-

Analog Input. This is the negative terminal of a true differential input consisting of IN+ and IN-.

Analog Input. The converter’s reference voltage is the differential between this pin and ground times

4

GND

Ground Terminal.

Analog Output. The internal reference connects to this pin. It may be scaled externally, if desired, and

external circuitry to this pin.

6

SDAT

Digital Output (push-pull). This is the microPort™ serial data output. SDAT is driven low while the

TC3400 is converting data, effectively providing a “busy” signal. After the conversion is complete,

every high to low transition on the SCLK pin puts a bit from the resulting data word on the SDAT pin

(from MSB to LSB).

7

SCLK

Digital Input. This is the microPort™ serial clock input. The TC3400 comes out of sleep mode and a

conversion cycle begins when this pin is driven low. After the conversion starts, each additional falling

conversion is complete, the data word can be shifted out on the SDAT pin by clocking the SCLK pin.

Power Supply Input.