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Preliminary Technical Data
FEATURES
Fast throughput rate: 1.5 MSPS Specified for VDD of 2.7 V to 5.25 V Low power 8 mW max at 1.5 MSPS with 3 V supplies 16 mW max at 1.5 MSPS with 5 V supplies 4 analog input channels with a sequencer Software configurable analog inputs 4-channel single-ended inputs 2-channel fully differential inputs 2-channel pseudo-differential inputs Accurate on-chip 2.5 V reference Wide input bandwidth 70 dB SNR at 50 kHz input frequency No pipeline delays High speed parallel interface—word/byte modes Full shutdown mode: 1 µA max 28 lead TSSOP package
4-Channel, 1.5 MSPS, 12-Bit and 10-Bit Parallel ADCs with a Sequencer AD7933/AD7934
FUNCTIONAL BLOCK DIAGRAM
VDD VREFIN/ VREFOUT VIN0 I/P MUX VIN3 T/H 12-/10-BIT SAR ADC AND CONTROL AGND
AD7933/AD7934
2.5V VREF CLKIN CONVST BUSY
SEQUENCER
PARALLEL INTERFACE/CONTROL REGISTER
VDRIVE
DB0 DB11
CS RD WR W/B
DGND
Figure 1.
GENERAL DESCRIPTION
The AD7933/AD7934 are 12-bit and 10-bit, high speed, low power, successive approximation (SAR) ADCs. The parts operate from a single 2.7 V to 5.25 V power supply and feature throughput rates to 1.5 MSPS. The parts contain a low noise, wide bandwidth, differential track-and-hold amplifier that can handle input frequencies up to 20 MHz. The AD7933/AD7934 feature 4 analog input channels with a channel sequencer to allow a consecutive sequence of channels to be converted on. These parts can accept either single-ended, fully differential, or pseudo-differential analog inputs. The conversion process and data acquisition are controlled using standard control inputs, which allows for easy interfacing to microprocessors and DSPs. The input signal is sampled on the falling edge of CONVST and the conversion is also initiated at this point. The AD7933/AD7934 has an accurate on-chip 2.5 V reference that can be used as the reference source for the analog-to-digital conversion. Alternatively, this pin can be overdriven to provide an external reference. These parts use advanced design techniques to achieve very low power dissipation at high throughput rates. They also feature flexible power management options. An on-chip control register allows the user to set up different operating conditions, including analog input range and configuration, output coding, power management, and channel sequencing.
PRODUCT HIGHLIGHTS
1. 2. 3. 4. High throughput with low power consumption. Four analog inputs with a channel sequencer. Accurate on-chip 2.5 V reference. Software configurable analog inputs. Single-ended, pseudodifferential, or fully differential analog inputs that are software selectable. Single-supply operation with VDRIVE function. The VDRIVE function allows the parallel interface to connect directly to 3 V, or 5 V processor systems independent of VDD. No pipeline delay. Accurate control of the sampling instant via a CONVST input and once off conversion control.
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Rev. PrG
Information furnished by Analog Devices is believed .