8 / 4 - C h a n n e l , 1 M s ps , 1 2 - B i t A D C w i t h S e q u e n c e r
D a ta S he e t
1 General Description
The AS1543/44 is a 12-bit high-speed, low-power, 8/4-
channel, successive-approximation ADC that operates
from a single 2.7 to 5.25V supply. The device features
high throughput rates (1Msps) and a low-noise, wide-
bandwidth track-and-hold amplifier that can handle input
frequencies in excess of 1 MHz.
The AS1543 features 8 single-ended or 4 fully differen-
tial analog inputs while the AS1544 offers 4 single-
ended or 2 fully differential analog inputs. Both include a
channel sequencer to allow a programmed selection of
channels to be converted sequentially. The conversion
time is determined by the SCLK frequency (also used as
the master clock to control the conversion).
The conversion process and data acquisition are con-
trolled using a chip select pin and a serial clock signal,
allowing the device to easily interface with microproces-
sors or DSPs. The input signal is sampled on the falling
edge of CSN and conversion is also initiated at this
point. There are no pipeline delays associated with the
device.
The AS1543/44 uses advanced design techniques to
achieve very low power dissipation at high throughput
rates. At maximum throughput rates, the AS1543/44
consumes just 2.8mA (@3.6V), and 3.5mA (@5.25V).
By using internal control register, single-ended or fully-
differential conversion mode with different input ranges
can be used with either straight binary or twos comple-
ment output coding.
The device is available in a TQFN(4x4)-20 pin package.
2 Key Features
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Single Supply Operation with V
DRIVE
Function:
2.7 to 5.25V
Fast Throughput Rate: 1 Msps
Sequencer & Channel Counter
Software-Configurable Analog Input Types:
- 8/4-Channel Single-Ended
- 4/2-Channel Fully-Differential
Software-Configurable Input Range
Low Power Consumption at Max Throughput Rates:
- 10.1mW @ 1Msps (3.6V Supply)
- 18.4mW @ 1Msps (5.25V Supply)
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Shutdown Mode Current: 0.5µA
Flexible Power/Serial Clock Speed Management
Wide Input Bandwidth: 71dB SNR @ 50 kHz Input
Frequency
No Pipeline Delays
High Speed SPI/QSPI/Microwire/DSP Interface
TQFN(4x4)-20 Package
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3 Applications
The devices are ideal for remote sensors, data-acquisi-
tion and data-logging devices, pen-digitizers, process
control, or any other space-limited A/D application with
low power-consumption requirements.
Figure 1. Typical Application
V
DD
REFIN
8
Multiplexer
V
IN0:7
Track/
Hold
12-Bit
ADC
DGND
AGND
Sequencer
GND
AS1543
Control
Logic
SCLK
DOUT
DIN
CSN
VDRIVE
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Revision 1.00
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AS1543/44
Data Sheet
1 General Description ................................................................................................................................ 1
2 Key Features .......................................................................................................................................... 1
Analog Input ......................................................................................................................................................... 13
Control Register ................................................................................................................................................... 14
Analog Input Configuration ............................................................................................................................
Transfer Functions ........................................................................................................................................
Two’s Complement Transfer Function ...........................................................................................................
Power Mode Selection ..................................................................................................................................
Serial Interface ..................................................................................................................................................... 20
Power Modes ....................................................................................................................................................... 22
Normal Mode (PM1 = 1, PM0 = 1) ................................................................................................................ 22
Auto Shutdown (PM1 = 0, PM0 = X) ............................................................................................................. 23
Power vs. Throughput Rate .................................................................................................................................. 23
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