ADCS7476/ADCS7477/ADCS7478
1MSPS, 12-/10-/8-Bit A/D Converters in 6-Lead SOT-23
General Description
The ADCS7476, ADCS7477, and ADCS7478 are low power,
monolithic CMOS 12-, 10- and 8-bit analog-to-digital con-
verters that operate at 1 MSPS. The ADCS7476/77/78 are
drop-in replacements for Analog Devices’ AD7476/77/78.
Each device is based on a successive approximation regis-
ter architecture with internal track-and-hold. The serial inter-
face is compatible with several standards, such as SPI™,
QSPI™, MICROWIRE™, and many common DSP serial in-
terfaces.
The ADCS7476/77/78 uses the supply voltage as a refer-
ence. This enables the devices to operate with a full-scale
input range of 0 to V
DD
. The conversion rate is determined
from the serial clock (SCLK) speed. These converters offer a
shutdown mode, which can be used to trade throughput for
power consumption. The ADCS7476/77/78 is operated with
a single supply that can range from +2.7V to +5.25V. Normal
power consumption during continuous conversion, using a
+3V or +5V supply, is 2 mW or 10 mW respectively. The
power down feature, which is enabled by a chip select (CS)
pin, reduces the power consumption to under 5 µW using a
+5V supply. All three converters are packaged in a 6-lead,
SOT-23 package that provides an extremely small footprint
for applications where space is a critical consideration.
These products are designed for operation over the
automotive/extended industrial temperature range of −40˚C
to +125˚C.
Features
n Variable power management
n Packaged in 6-lead, SOT-23
n Power supply used as reference
n Single +2.7V to +5.25V supply operation
n SPI™/QSPI™/MICROWIRE™/DSP compatible
Key Specifications
n Resolution with no Missing Codes 12/10/8 bits
n Conversion Rate 1 MSPS
n DNL +0.5, -0.3 LSB (typ)
n INL ± 0.4 LSB (typ)
n Power Consumption
3V Supply 2 mW (typ)
5V Supply 10 mW (typ)
Applications
n Automotive Navigation
n FA/ATM Equipment
n Portable Systems
n Medical Instruments
n Mobile Communications
n Instrumentation and Control Systems
Connection Diagram
20057701
MICROWIRE™ is a trademark of National Semiconductor Corporation.
TRI-STATE
®
is a trademark of National Semiconductor Corporation.
QSPI™ and SPI™ are trademarks of Motorola, Inc.
June 2003
ADCS7476/ADCS7477/ADCS7478
1MSPS,
12-/10-/8-Bit
A/D
Converters
in
6-Lead
SOT
-23
© 2003 National Semiconductor Corporation DS200577 www.national.com