Rainbow Electronics MAX1299 - Manual (Page 11)

MAX1298/MAX1299
12-Bit Serial-Output Temperature Sensors
with 5-Channel ADC
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Detailed Description
The MAX1298/MAX1299 are low-power, serial-output,
multichannel ADCs with temperature-sensing capability
for thermostatic, process-control, and monitoring appli-
cations. An algorithmic switched-capacitor converter
with T/H circuitry for both positive and negative inputs
supports fully differential 12-bit conversions from an
internal temperature sensor, two external temperature
sensors, or voltage sources in a variety of channel con-
figurations. Microprocessor (µP) control is made easy
through a flexible 3-wire serial interface.
Figure 1 shows a simplified functional diagram of the
internal architecture for the MAX1298/MAX1299. In tem-
perature-sensing mode, the multiplexer (mux) steers
bias currents through internal or external diodes while
the ADC computes their temperature in relation to
changes in forward voltage. Channels not used for tem-
perature measurement can be configured to measure
other system voltages.
INPUT
REGISTER
DIODE
BIAS
CONTROL
CONTROL
LOGIC
INPUT
MUX
OUTPUT
REGISTER
CLOCK
12-BIT
ADC
SHIELD
OUTPUT
T/H
T/H IN+
IN- V
DD
GND
DOUT
CS
SCLK
DIN
AIN0
AIN1
AIN2
AIN3
AIN4
AIN5
V
DD
/4
SHO REF
REF
MAX1298
MAX1299
Figure 1. Functional Diagram