2.7 V to 5.25 V, Micropower, 2-Channel,
125 kSPS, 12-Bit ADC in 8-Lead MSOP
Data Sheet
AD7887
Rev. E Document Feedback
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FEATURES
Specified for V
DD
of 2.7 V to 5.25 V
Flexible power/throughput rate management
Shutdown mode: 1 μA max
One or two single-ended inputs
Serial interface: SPI®/QSPI™/MICROWIRE™/DSP compatible
8-lead narrow SOIC and MSOP packages
Qualified for automotive applications
APPLICATIONS
Battery-powered systems (personal digital assistants,
medical instruments, mobile communications)
Instrumentation and control systems
High speed modems
FUNCTIONAL BLOCK DIAGRAM
SAR + ADC
CONTROL LOGIC
GND
AIN0
SCLK
DOUT
DIN
V
DD
AD7887
CS
T/H
I/P
MUX
BUF
CHARGE
REDISTRIBUTION
DAC
COMP
IN1/
V
REF
AIN1/V
REF
SOFTWARE
CONTROL
LATCH
2.5V
REF
SPORT
6191-001
Figure 1.
GENERAL DESCRIPTION
The AD7887 is a high speed, low power, 12-bit analog-to-digital
converter (ADC) that operates from a single 2.7 V to 5.25 V
power supply. The AD7887 is capable of 125 kSPS throughput
rate. The input track-and-hold acquires a signal in 500 ns and
features a single-ended sampling scheme. The output coding for
the AD7887 is straight binary, and the part is capable of
converting full power signals of up to 2.5 MHz.
The AD7887 can be configured for either dual- or single-channel
operation via the on-chip control register. There is a default
single-channel mode that allows the AD7887 to be operated as a
read-only ADC. In single-channel operation, there is one
analog input (AIN0) and the AIN1/V
REF
pin assumes its V
REF
function. This V
REF
pin allows the user access to the part’s
internal 2.5 V reference, or the V
REF
pin can be overdriven by an
external reference to provide the reference voltage for the part.
This external reference voltage has a range of 2.5 V to V
DD
. The
analog input range on AIN0 is 0 to V
REF
.
In dual-channel operation, the AIN1/V
REF
pin assumes its AIN1
function, providing a second analog input channel. In this case,
the reference voltage for the part is provided via the V
DD
pin. As
a result, the input voltage range on both the AIN0 and AIN1
inputs is 0 to V
DD
.
CMOS construction ensures low power dissipation of typically
2 mW for normal operation and 3 μW in power-down mode.
The part is available in an 8-lead, 0.15-inch-wide narrow body
SOIC and an 8-lead MSOP package.
PRODUCT HIGHLIGHTS
1. Smallest 12-bit dual-/single-channel ADC; 8-lead MSOP
package.
2. Lowest power 12-bit dual-/single-channel ADC.
3. Flexible power management options, including automatic
power-down after conversion.
4. Read-only ADC capability.
5. Analog input range from 0 V to V
REF
.
6. Versatile serial input/output port (SPI/QSPI/MICROWIRE/
DSP compatible).
