MAX1403_02 Datasheet, PDF (11/36 Pages) Maxim Integrated Products – +3V, 18-Bit, Low-Power, Multichannel, Oversampling (Sigma-Delta) ADC

+3V, 18-Bit, Low-Power, Multichannel,
Oversampling (Sigma-Delta) ADC
Pin Description
PIN
NAME
FUNCTION
Clock Input. A crystal can be connected across CLKIN and CLKOUT. Alternatively, drive CLKIN with a
1
CLKIN
CMOS-compatible clock at a nominal frequency of 2.4576MHz or 1.024MHz, and leave CLKOUT uncon-
nected. Frequencies of 4.9152MHz and 2.048MHz may be used if the X2CLK control bit is set to 1.
Clock Output. When deriving the master clock from a crystal, connect the crystal between CLKIN and
2
CLKOUT CLKOUT. In this mode, the on-chip clock signal is not available at CLKOUT. Leave CLKOUT unconnected
when CLKIN is driven with an external clock.
Chip-Select Input. This active-low logic input is used to enable the digital interface. With CS hard-wired
3
CS
low, the MAX1403 operates in its 3-wire interface mode with SCLK, DIN, and DOUT used to interface to
the device. CS is used either to select the device in systems with more than one device on the serial bus,
or as a frame-synchronization signal for the MAX1403, when a continuous SCLK is used.
4
RESET
Active-Low Reset Input. Drive low to reset the control logic, interface logic, digital filter, and analog modu-
lator to power-on status. RESET must be high and CLKIN must be toggling in order to exit reset.
5
DS1
Digital Input for Auxiliary Data Input Bit 1. The status of this bit is reflected in the output data by bit D4.
Used to communicate the status of DS1 via the serial interface.
6
DS0
Digital Input for Auxiliary Data Input Bit 0. The status of this bit is reflected in the output data by bit D3.
Used to communicate the status of DS0 via the serial interface.
7
OUT2
Transducer Excitation Current Source 2
8
OUT1
Transducer Excitation Current Source 1
9
AGND
Analog Ground. Reference point for the analog circuitry. AGND connects to the IC substrate.
10
V+
Analog Positive Supply Voltage (+2.7V to +3.6V).
11
AIN1
Analog Input Channel 1. May be used as a pseudo-differential input with AIN6 as common, or as the posi-
tive input of the AIN1/AIN2 differential analog input pair (see On-Chip Registers section).
12
AIN2
Analog Input Channel 2. May be used as a pseudo-differential input with AIN6 as common, or as the neg-
ative input of the AIN1/AIN2 differential analog input pair (see On-Chip Registers section).
13
AIN3
Analog Input Channel 3. May be used as a pseudo-differential input with AIN6 as common, or as the posi-
tive input of the AIN3/AIN4 differential analog input pair (see On-Chip Registers section).
14
AIN4
Analog Input Channel 4. May be used as a pseudo-differential input with AIN6 as common, or as the neg-
ative input of the AIN3/AIN4 differential analog input pair (see On-Chip Registers section).
15
AIN5
Analog Input Channel 5. Used as a differential or pseudo-differential input with AIN6 (see On-Chip
Registers section).
16
AIN6
Analog Input 6. May be used as a common point for AIN1 through AIN5 in pseudo-differential mode, or as
the negative input of the AIN5/AIN6 differential analog input pair (see On-Chip Registers section).
Negative Gain Calibration Input. Used for system gain calibration. It forms the negative input of a fully
17
CALGAIN-
differential input pair with CALGAIN+. Normally these inputs are connected to reference voltages in the
system. When system gain calibration is not required and the auto-sequence mode is used, the
CALGAIN+/CALGAIN- input pair provides an additional fully differential input channel.
Positive Gain Calibration Input. Used for system gain calibration. It forms the positive input of a fully
18
CALGAIN+
differential input pair with CALGAIN-. Normally these inputs are connected to reference voltages in the
system. When system gain calibration is not required and the auto-sequence mode is used, the
CALGAIN+/CALGAIN- input pair provides an additional fully differential input channel.
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