8-Channel, 1 MSPS, 12-Bit SAR ADC
with Temperature Sensor
AD7298
Rev. B
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FEATURES
12-bit SAR ADC
8 single-ended inputs
Channel sequencer functionality
Fast throughput of 1 MSPS
Analog input range: 0 V to 2.5 V
12-bit temperature-to-digital converter
Temperature sensor accuracy of ±1°C
Temperature range: −40°C to +125°C
Specified for V
DD
: 2.8 V to 3.6 V
Logic voltage V
DRIVE
: 1.65 V to 3.6 V
Power-down current: <10 μA
Internal 2.5 V reference
Internal power-on reset
High speed serial interface SPI
20-lead LFCSP
GENERAL DESCRIPTION
The AD7298 is a 12-bit, high speed, low power, 8-channel,
successive approximation ADC with an internal temperature
sensor. The part operates from a single 3.3 V power supply and
features throughput rates up to 1 MSPS. The device contains a
low noise, wide bandwidth track-and-hold amplifier that can
handle input frequencies in excess of 30 MHz.
The AD7298 offers a programmable sequencer, which enables
the selection of a preprogrammable sequence of channels for
conversion. The device has an on-chip, 2.5 V reference that can
be disabled to allow the use of an external reference.
The AD7298 includes a high accuracy band gap temperature
sensor, which is monitored and digitized by the 12-bit ADC to
give a resolution of 0.25°C. The device offers a 4-wire serial
interface compatible with SPI and DSP interface standards.
The AD7298 uses advanced design techniques to achieve very
low power dissipation at high throughput rates. The part also
offers flexible power/throughput rate management options.
The part is offered in a 20-lead LFCSP package.
FUNCTIONAL BLOCK DIAGRAM
TEMP
SENSOR
12-BIT
SUCCESSIVE
APPROXIMATION
ADC
INPUT
MUX
T/H
DD
GND
PD/RST
SCLK
DOUT
DIN
CS
V
DRIVE
V
IN7
V
IN0
CONTROL
LOGIC
SEQUENCER
REF
BUFREF
AD7298
08754-001
T
SENSE
_BUSY
Figure 1.
PRODUCT HIGHLIGHTS
1. Ideally Suited to Monitoring System Variables in a Variety
of Systems. This includes telecommunications, and process
and industrial control.
2. High Throughput Rate of 1 MSPS with Low Power
Consumption.
3. Eight Single-Ended Inputs with a Channel Sequencer.
A consecutive sequence of channels can be selected on
which the ADC cycles and converts.
4. Integrated Temperature Sensor with 0.25°C Resolution.
