Analog Devices Inc. AD7829BRWZ-1

Overview

AD7829BRWZ-1 from Analog Devices is a high-speed, 8-channel, microprocessor-compatible 8-bit analog-to-digital converter with 2 MSPS throughput, 420 ns conversion time, on-chip 2.5 V reference, and flexible parallel interface. It operates from single 3 V ±10% or 5 V ±10% supply and supports data acquisition in DSP front ends and mobile communication subsampling systems.

For engineers reviewing the AD7829BRWZ-1 datasheet, AD7829BRWZ-1 pinout, AD7829BRWZ-1 application, or AD7829BRWZ-1 equivalent, key selection factors include its automatic power-down via CONVST, VMID-adjustable input span (0 V–2 V at 3 V, 0 V–2.5 V at 5 V), channel-to-channel isolation of −70 dB, and track-and-hold full-power bandwidth up to 10 MHz.

Technical Context

The AD7829BRWZ-1 implements a half-flash ADC architecture with two-stage conversion: a 4-bit coarse flash followed by a 4-bit fine flash, delivering full 8-bit resolution in ≤420 ns. Its track-and-hold amplifier acquires input signals within 200 ns and supports full-scale inputs up to 10 MHz.

Channel selection is performed externally via A2–A0 address lines without register writes; conversion is initiated by the falling edge of CONVST, which also samples logic level post-conversion to enable automatic power-down. The parallel interface uses CS/RD control with EOC pulse output for interrupt-driven or stand-alone operation.

Key Specifications

Pinout & Package

The AD7829BRWZ-1 is housed in a 28-lead wide-body SOIC (SOIC_W) package with standard 0.3-inch body width and 1.27 mm pitch.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 8-bit, multi-channel ADC applications.

Compared with AD7829BRWZ-1, the AD7829BRUZ-1 offers identical functionality in a smaller package but with reduced thermal performance, while the MAX1186EEE+ trades integrated features for lower cost and different timing constraints-neither is pin-compatible nor drop-in replaceable.

Availability

AD7829BRWZ-1 is available at Aetrix Electronics and suitable for disk drive servo control, mobile baseband subsampling, and industrial data acquisition requiring stable component supply and long-term production continuity.

Supply support for AD7829BRWZ-1 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Analog Devices is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, headquartered in Norwood, MA.

The AD7829 family was designed specifically for high-throughput, multi-channel data acquisition in resource-constrained embedded systems where speed, integration, and power efficiency are critical.

FAQ

What is the maximum input frequency the AD7829BRWZ-1 can accurately digitize?

The AD7829BRWZ-1 has a track-and-hold full-power bandwidth (FPBW) of 10 MHz, meaning it maintains specified SNR and distortion performance for full-scale sine wave inputs up to 10 MHz. This makes the AD7829BRWZ-1 suitable for subsampling applications where IF signals are directly digitized without prior analog downconversion. Performance degrades above this frequency due to aperture uncertainty and THD increase.

How does the AD7829BRWZ-1 handle power supply voltage detection?

The AD7829BRWZ-1 includes an internal VDD detector that automatically configures input span based on supply voltage: at VDD > 4.1 V, it selects 0 V–2.5 V range; at VDD < 3.8 V, it selects 0 V–2 V range. The detector includes glitch rejection for transients up to 60 ns. If VDD falls outside normal limits (e.g., brown-out), the AD7829BRWZ-1 may require two conversions to reinitialize correctly.

Can the AD7829BRWZ-1 operate in stand-alone mode without a microprocessor?

Yes-the AD7829BRWZ-1 supports stand-alone operation using its EOC pulse and parallel interface. When CS is permanently asserted low and RD is strobed manually (e.g., by a monostable or FPGA logic), the AD7829BRWZ-1 outputs converted data on DB0–DB7 after each EOC assertion. No external controller is needed for basic acquisition, making the AD7829BRWZ-1 ideal for simple trigger-and-capture systems.

What is the role of the VMID pin on the AD7829BRWZ-1, and how is it used in practice?

The VMID pin sets the center voltage of the AD7829BRWZ-1's analog input span. With no connection, VMID defaults to 1.25 V (5 V supply) or 1.0 V (3 V supply), yielding input ranges of AGND–2.5 V or AGND–2 V. Applying an external voltage (e.g., 2.5 V) shifts the range to VMID ±1.25 V (5 V) or VMID ±1.0 V (3 V), enabling bipolar signal capture or offset cancellation. The AD7829BRWZ-1's 6 kΩ VMID impedance requires buffering for driving external level-shift circuits.

Does the AD7829BRWZ-1 require external decoupling capacitors, and where should they be placed?

Yes-the AD7829BRWZ-1 requires local decoupling: a 0.1 µF ceramic capacitor between VDD and AGND/DGND (tied together at the device), and a 10 µF bulk capacitor near the supply entry. VREF IN/OUT should be decoupled with 0.1 µF to AGND if using the internal reference. VMID may also benefit from 0.1 µF decoupling when left unconnected. These reduce noise coupling into the analog path and ensure stable reference and track-and-hold operation.