AD7939 8-Channel, 1.5 MSPS, 10-Bit Parallel ADCs with a Sequencer

High throughput with low power consumption. Eight analog inputs with a channel sequencer. Accurate on-chip 2.5 V reference. Single-ended, pseudo differential, 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.

The AD7938/AD7939 are 12-bit and 10-bit, high speed, low power, successive approximation (SAR) analog-to-digital converters (ADCs). The parts operate from a single 2.7 V to 5.25 V power supply and feature throughput rates up to 1.5 MSPS. The parts contain a low noise, wide bandwidth, differential track-and-hold amplifier that can handle input frequencies up to 50 MHz.

The AD7938/AD7939 feature eight analog input channels with a channel sequencer that allows a preprogrammed selection of channels to be converted sequentially. These parts can operatewith either single-ended, fully differential, or pseudodifferential analog inputs.

The conversion process and data acquisition are controlled using standard control inputs that allow easy interfacing with microprocessors and DSPs. The input signal is sampled on the falling edge of CONVST and the conversion is also initiated at this point.

The AD7938/AD7939 have 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
  • High throughput with low power consumption.
  • Eight analog inputs with a channel sequencer.
  • Accurate on-chip 2.5 V reference.
  • Single-ended, pseudo differential, 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.
Features and Benefits
  • Throughput rate: 1.5 MSPS
  • Power consumption 
    6 mW maximum at 1.5 MSPS with 3 V supplies
    13.5 mW maximum at 1.5 MSPS with 5 V supplies
  • Software-configurable analog inputs
    8-channel single-ended inputs
    4-channel fully differential inputs
    4-channel pseudo differential inputs
    7-channel pseudo differential inputs
  • Specified for VDD of 2.7 V to 5.25 V
  • 8 analog input channels with a sequencer
  • Accurate on-chip 2.5 V reference ±0.2% maximum @ 25°C, 25 ppm/°C maximum
  • 70 dB SINAD at 50 kHz input frequency
  • No pipeline delays High speed parallel interface—word/byte modes
  • Full shutdown mode: 2 μA maximum
  • 32-lead LFCSP and TQFP packages
Analog to Digital Converters
Data Sheets
Documentnote
AD7938/AD7939: 8-Channel, 1.5 MSPS, 12-Bit and 10-Bit Data Sheet (Rev. C)PDF 738 kB
Order Information
Part NumberPackagePacking QtyTemp RangePrice 100-499Price 1000+RoHS
AD7939BCPZ Production32 ld LFCSP (5x5mm) w/3.1mm exposed padOTH 490-40 to 85C5.514.64Y
AD7939BCPZ-REEL7 Production32 ld LFCSP (5x5mm) w/3.1mm exposed padREEL 1500-40 to 85C04.64Y
AD7939BSUZ Production32 ld TQFP (7x7x1.0mm)OTH 250-40 to 85C5.514.64Y
AD7939BSUZ-REEL7 Production32 ld TQFP (7x7x1.0mm)REEL 500-40 to 85C04.64Y
Reference Materials
AD7938/AD7939: 8-Channel, 1.5 MSPS, 12-Bit and 10-Bit Data Sheet (Rev. C) ad7938
MS-2210:高速ADC的电源设计 ad9861