Multirange inputs, serial 16-bit adcs, Detailed description, Pin description (continued) – Rainbow Electronics MAX1303 User Manual

Page 13

MAX1302/MAX1303

8-/4-Channel, ±V

REF

Multirange Inputs,

Serial 16-Bit ADCs

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Detailed Description

The MAX1302/MAX1303 multirange, low-power, 16-bit
successive-approximation ADCs operate from a single
+5V supply and have a separate digital supply allowing
digital interface with 2.7V to 5.25V systems. These 16-bit
ADCs have internal track-and-hold (T/H) circuitry that
supports single-ended and fully differential inputs. For
single-ended conversions, the valid analog input voltage
range spans from -V

REF

below ground to +V

REF

above

ground. The maximum allowable differential input voltage
spans from -2 x V

REF

to +2 x V

REF

. Data can be convert-

ed in a variety of software-programmable channel and
data-acquisition configurations. Microprocessor (µP) con-

trol is made easy through an SPI-/QSPI-/MICROWIRE-
compatible serial interface.

The MAX1302 has eight single-ended analog input
channels or four differential channels (see the Block
Diagram at the end of the data sheet). The MAX1303 has
four single-ended analog input channels or two differential
channels. Each analog input channel is independently
software programmable for seven single-ended input
ranges (0 to +V

REF

/2, -V

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/2 to 0, 0 to +V

REF

, -V

REF

to 0,

±V

REF

/4, ±V

REF

/2, and ±V

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) and three differential input

ranges (±V

REF

/2, ±V

REF

, and ±2 x V

REF

). Additionally, all

analog input channels are fault tolerant to ±6V. A fault
condition on an idle channel does not affect the conver-
sion result of other channels.

Pin Description (continued)

PIN

MAX1300 MAX1301

NAME

FUNCTION

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.

DD2

Analog Supply Voltage 2. Connect AV

DD2

to a +4.75V to +5.25V power-supply voltage. Bypass

DD2

to AGND2 with a 0.1µF capacitor.

AGND2

Analog Ground 2. This ground carries approximately five times more current than AGND1.
DGND, DGNDO, AGND3, AGND2, and AGND1 must be connected together.

AGND1

Analog Ground 1. DGND, DGNDO, AGND3, AGND2, and AGND1 must be connected together.

4–20mA

PLC

ACCELERATION

PRESSURE

TEMPERATURE

WHEATESTONE

µF

0.1

µF

AGND2

DGNDO

AGND3

DGND

DD2

DD1

0.1

µF

0.1

µF

0.1

µF

5.0V

MAX1302

CHO

CH1

CH2

CH3

CH4

CH5

CH6

CH7

REF

AGND1

REFCAP

0.1

µF

3.3V

MC68HCXX

µC

DDO

SCLK

DIN

SSTRB

DOUT

SCK

I/O

MOSI

I/O

MISO

Figure 1. Typical Application Circuit