Datasheet AD7874 (Analog Devices)

a
LC2MOS 4-Channel, 12-Bit Simultaneous Sampling Data Acquisition System AD7874 FEATURES FUNCTIONAL BLOCK DIAGRAM Four On-Chip Track/Hold Amplifiers Simultaneous Sampling of 4 Channels INT CS RD CONVST V V DD DD Fast 12-Bit ADC with 8
m
s Conversion Time/Channel 29 kHz Sample Rate for All Four Channels INTERNAL On-Chip Reference CONTROL LOGIC CLK CLOCK V TRACK/
6
10 V Input Range IN1 HOLD 1
6
5 V Supplies V TRACK/ IN2 COMP APPLICATIONS HOLD 2 MUX SAR Sonar V TRACK/ IN3 Motor Controllers HOLD 3 DATA DB0 Adaptive Filters REGISTERS DB11 TRACK/ Digital Signal Processing VIN4 HOLD 4 REFERENCE BUFFER 12-BIT DAC REF IN AD7874 GENERAL DESCRIPTION 3V
The AD7874 is a four-channel simultaneous sampling, 12-bit
REF OUT REFERENCE
data acquisition system. The part contains a high speed 12-bit ADC, on-chip reference, on-chip clock and four track/hold am-
AGND DGND VSS
plifiers. This latter feature allows the four input channels to be sampled simultaneously, thus preserving the relative phase information of the four input channels, which is not possible if
PRODUCT HIGHLIGHTS
all four channels share a single track/hold amplifier. This makes 1. Simultaneous Sampling of Four Input Channels. the AD7874 ideal for applications such as phased-array sonar Four input channels, each with its own track/hold amplifier, and ac motor controllers where the relative phase information is allow simultaneous sampling of input signals. Track/hold ac- important. quisition time is 2 µs, and the conversion time per channel is 8 µs, allowing 29 kHz sample rate for all four channels. The aperture delay of the four track/hold amplifiers is small and specified with minimum and maximum limits. This allows sev- 2. Tight Aperture Delay Matching. eral AD7874s to sample multiple input channels simultaneously The aperture delay for each channel is small and the aperture without incurring phase errors between signals connected to delay matching between the four channels is less than 4 ns. several devices. A reference output/reference input facility also Additionally, the aperture delay specification has upper and allows several AD7874s to be driven from the same reference lower limits allowing multiple AD7874s to sample more than source. four channels. In addition to the traditional dc accuracy specifications such as 3. Fast Microprocessor Interface. linearity, full-scale and offset errors, the AD7874 is also fully The high speed digital interface of the AD7874 allows direct specified for dynamic performance parameters including distor- connection to all modern 16-bit microprocessors and digital tion and signal-to-noise ratio. signal processors. The AD7874 is fabricated in Analog Devices’ Linear Compat- ible CMOS (LC2MOS) process, a mixed technology process that combines precision bipolar circuits with low-power CMOS logic. The part is available in a 28-pin, 0.6" wide, plastic or her- metic dual-in-line package (DIP), in a 28-terminal leadless ce- ramic chip carrier (LCCC) and in a 28-pin SOIC. REV. C 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 which may result from its use. No license is granted by implication or
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
otherwise under any patent or patent rights of Analog Devices.
Tel: 617/329-4700 Fax: 617/326-8703