Datasheet

MAX1303
4-Channel, ±V
REF
Multirange Inputs,
Serial 16-Bit ADC
12 ______________________________________________________________________________________
Pin Description
PIN NAME FUNCTION
1 AGND1 Analog Ground 1. DGND, DGNDO, AGND3, AGND2, and AGND1 must be connected together.
2 AVDD1
Analog Supply Voltage 1. Connect AVDD1 to a +4.75V to +5.25V power-supply voltage. Bypass AVDD1 to
AGND1 with a 0.1µF capacitor.
3 CH0 Analog Input Channel 0
4 CH1 Analog Input Channel 1
5 CH2 Analog Input Channel 2
6 CH3 Analog Input Channel 3
7 CS
Active-Low Chip-Select Input. When CS is low, data is clocked into the device from DIN on the rising edge
of SCLK. With CS low, data is clocked out of DOUT on the falling edge of SCLK. When CS is high, activity
on SCLK and DIN is ignored and DOUT is high impedance.
8DIN
Serial Data Input. When CS is low, data is clocked in on the rising edge of SCLK. When CS is high,
transitions on DIN are ignored.
9 SSTRB
Serial-Strobe Output. When using the internal clock, SSTRB rising edge transitions indicate that data is
ready to be read from the device. When operating in external clock mode, SSTRB is always low. SSTRB
does not tri-state, regardless of the state of CS, and therefore requires
a dedicated I/O line.
10 SCLK
Serial Clock Input. When CS is low, transitions on SCLK clock data into DIN and out of DOUT. When CS is
high, transitions on SCLK are ignored.
11 DOUT
Serial Data Output. When CS is low, data is clocked out of DOUT with each falling SCLK transition. When
CS is high, DOUT is high impedance.
12 DGNDO Digital I/O Ground. DGND, DGNDO, AGND3, AGND2, and AGND1 must be connected together.
13 DGND Digital Ground. DGND, DGNDO, AGND3, AGND2, and AGND1 must be connected together.
14 DVDDO
Digital I/O Supply Voltage Input. Connect DVDDO to a +2.7V to +5.25V power-supply voltage. Bypass
DVDDO to DGNDO with a 0.1µF capacitor.
15 DVDD
Digital-Supply Voltage Input. Connect DVDD to a +4.75V to +5.25V power-supply voltage. Bypass DVDD
to DGND with a 0.1µF capacitor.
16 REFCAP
Bandgap-Voltage Bypass Node. For external reference operation, connect REFCAP to AVDD. For internal
reference operation, bypass REFCAP with a 0.01µF capacitor to AGND1 (V
REFCAP
≈ 4.096V).
17 REF
Reference-Buffer Output/ADC Reference Input. For external reference operation, apply an external
reference voltage from 3.800V to 4.136V to REF. For internal reference operation, bypassing REF with a
1µF capacitor to AGND1 sets V
REF
= 4.096V ±1%.
18 AGND3
Analog Signal Ground 3. AGND3 is the ADC negative reference potential. Connect AGND3 to AGND1.
DGND, DGNDO, AGND3, AGND2, and AGND1 must be connected together.
19 AVDD2
Analog Supply Voltage 2. Connect AVDD2 to a +4.75V to +5.25V power-supply voltage. Bypass AVDD2 to
AGND2 with a 0.1µF capacitor.
20 AGND2
Analog Ground 2. This ground carries approximately five times more current than AGND1. DGND,
DGNDO, AGND3, AGND2, and AGND1 must be connected together.