TC3402 Datasheet, PDF (5/16 Pages) Microchip Technology – +1.8 Low Power, Quad Input, 16-Bit Sigma-Delta A/D Converter

TC3402
2.0 PIN DESCRIPTIONS
The descriptions of the pins are listed in Table 2-1.
TABLE 2-1: PIN FUNCTION TABLE
Pin No.
(16-Pin PDIP) Symbol
(16-Pin QSOP)
Description
1
IN1+ Analog Input. This is the positive terminal of a true differential input consisting of IN1+ and IN1-.
V_IN1 = (IN1+ – IN-). See Section 1.0, Electrical Characteristics.
2
IN1- Analog Input. This is the negative terminal of a true differential input consisting of IN1+ and IN1-.
V_IN1 = (IN+ – IN-) IN1- can swing to, but not below, ground. See Section 1.0, Electrical Characteristics.
3
IN2+ Analog Input. This is the positive terminal of a true differential input consisting of IN2+ and IN2-.
V_IN2 = (IN2+ – IN-). (See Section 1.0, Electrical Characteristics.)
4
IN2- Analog Input. This is the negative terminal of a true differential input consisting of IN2+ and N2-.
V_IN2 = (IN+ – IN-) IN2- can swing to, but not below, ground. See Section 1.0, Electrical Characteristics.
5
IN3+ Analog Input. This is the positive terminal of a true differential input consisting of IN3+ and IN3-.
V_IN3 = (IN3+ – IN-). See Section 1.0, Electrical Characteristics.
6
IN3- Analog Input. This is the negative terminal of a true differential input consisting of IN3+ and IN3-.
V_IN3 = (IN+ – IN-) IN1- can swing to, but not below, ground. See Section 1.0, Electrical Characteristics.
7
REF_IN Analog Input. The converter’s reference voltage is the differential between this pin and ground times
two. It may be tied directly to REF_OUT or scaled using a resistor divider. Any user supplied reference
voltage less than 1.25V may be used in place of REF_OUT.
8
GND Ground Terminal.
9
REF_OUT Analog Output. The internal reference connects to this pin. It may be scaled externally and tied to the
REF_IN input to provide the converter’s reference voltage. Care must be taken in connecting external
circuitry to this pin.
10
SDAT Digital Output (push-pull). This is the microPort™ serial data output. SDAT is driven low while the
TC3402 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).
11
IN4- Analog Input. This is the negative terminal of a true differential input consisting of IN4+ and IN4-.
V_IN4 = (IN+ – IN-) IN4- can swing to, but not below, ground. See Section 1.0, Electrical Characteristics.
12
IN4+ Analog Input. This is the positive terminal of a true differential input consisting of IN4+ and IN4-.
V_IN4 = (IN4+ – IN-). See Section 1.0, Electrical Characteristics.
13
A1 Digital Input. Controls analog multiplexer in conjunction with A0 to select one of the four Input
channels. This address is latched at the falling edge of the SCLK, which starts an A/D conversion.
A1, A0 = 00 = Input 1; 01 = Input 2; 10 = Input 3; 11 = Input 4.
14
A0 Digital Input. Controls analog multiplexer in conjunction with A1 to selec one of four Input
channels. This address is latched at the falling edge of the SCLK, which starts an A/D conversion.
A1, A0 = 00 = Input 1; 01 = Input 2; 10 = Input 3; 11 = Input 4.
15
SCLK Digital Input. This is the microPort™ serial clock input. The TC3402 comes out of Sleep mode and a
conversion cycle begins when this pin is driven low. After the conversion starts, each additional falling
edge (up to six) detected on SCLK for t₄ seconds reduces the A/D resolution by one bit. When the
conversion is complete, the data word can be shifted out on the SDAT pin by clocking the SCLK pin.
16
V_DD Power Supply Input.
© 2002 Microchip Technology Inc.
DS21411B-page 5