AD7450_15 Datasheet, PDF (1/22 Pages) Analog Devices – Differential Input, 1 MSPS 12-Bit ADC in
SOIC-8 and SO-8

a
Differential Input, 1 MSPS
12-Bit ADC in ␮SOIC-8 and SO-8
AD7450
FEATURES
Fast Throughput Rate: 1 MSPS
Specified for V_DD of 3 V and 5 V
Low Power at Max Throughput Rate:
3.75 mW Max at 833 kSPS with 3 V Supplies
9 mW Max at 1 MSPS with 5 V Supplies
Fully Differential Analog Input
Wide Input Bandwidth:
70 dB SINAD at 300 kHz Input Frequency
Flexible Power/Serial Clock Speed Management
No Pipeline Delays
High-Speed Serial Interface—SPI^TM/QSPI^TM
MICROWIRE^TM/DSP Compatible
Power-Down Mode: 1 ␮A Max
8-Lead ␮SOIC and SOIC Packages
APPLICATIONS
Transducer Interface
Battery-Powered Systems
Data Acquisition Systems
Portable Instrumentation
Motor Control
Communications
GENERAL DESCRIPTION
The AD7450 is a 12-bit, high-speed, low power, successive
approximation (SAR) analog-to-digital converter that features a
fully differential analog input. It operates from a single 3 V or 5 V
power supply and features throughput rates up to 833 kSPS or
1 MSPS, respectively.
This part contains a low noise, wide bandwidth, differential track-
and-hold amplifier (T/H) that can handle input frequencies in
excess of 1 MHz with the –3 dB point typically being 20 MHz.
The reference voltage for the AD7450 is applied externally to the
V_REF pin and can be varied from 100 mV to 3.5 V, depending
on the power supply and what suits the application. The value of
the reference voltage determines the common-mode voltage
range of the part. With this truly differential input structure and
variable reference input, the user can select a variety of input
ranges and bias points.
The conversion and data acquisition processes are controlled
using CS and the serial clock, allowing the device to interface
with microprocessors or DSPs. The input signals are sampled
on the falling edge of CS, and the conversion is also initiated at
this point.
The SAR architecture of this part ensures that there are no
pipeline delays.
FUNCTIONAL BLOCK DIAGRAM
V_DD
V_IN+
V_IN–
V_REF
T/H
12-BIT SUCCESSIVE
APPROXIMATION
ADC
AD7450
GND
CONTROL
LOGIC
SCLK
SDATA
CS
The AD7450 uses advanced design techniques to achieve low
power dissipation at high throughput rates.
PRODUCT HIGHLIGHTS
1. Operation with either 3 V or 5 V power supplies.
2. High throughput with low power consumption. With a 3 V
supply, the AD7450 offers 3.75 mW max power consumption
for 833 kSPS throughput.
3. Fully differential analog input.
4. Flexible power/serial clock speed management. The conversion
rate is determined by the serial clock, allowing the power
to be reduced as the conversion time is reduced through
the serial clock speed increase. This part also features a
shutdown mode to maximize power efficiency at lower
throughput rates.
5. Variable voltage reference input.
6. No pipeline delay.
7. Accurate control of the sampling instant via a CS input and
once-off conversion control.
8. ENOB > 8 bits typically with 100 mV reference.
SPI and QSPI are trademarks of Motorola, Inc.
MICROWIRE is a trademark of National Semiconductor Corporation.
Rev. A
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties that
may result from its use. No license is granted by implication or otherwise
under any patent or patent rights of Analog Devices.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: [phone]
www.analog.com
Fax: [phone]
© Analog Devices, Inc., 2002