Analog Devices Inc. AD7829BNZ

Overview

AD7829BNZ from Analog Devices is an 8-bit, 2 MSPS, 8-channel parallel-output analog-to-digital converter with on-chip 2.5 V reference, 420 ns conversion time, and single-supply operation at 3 V ±10% or 5 V ±10%. It integrates track-and-hold, half-flash ADC architecture, and automatic power-down triggered by CONVST logic level at end-of-conversion - used in high-speed data acquisition front ends for DSP systems and mobile communications subsampling.

For engineers reviewing the AD7829BNZ datasheet, AD7829BNZ pinout, AD7829BNZ application, or AD7829BNZ equivalent, key selection considerations include its 8-channel single-ended input support, VMID-adjustable input span (0 V to 2.5 V p-p at 5 V, 0 V to 2 V p-p at 3 V), channel address decoding via A0–A2, EOC-driven interrupt capability, and industrial temperature range (−40°C to +85°C).

Technical Context

The AD7829BNZ implements a two-stage half-flash ADC architecture: a 4-bit flash stage provides MSBs, followed by a second flash stage for LSBs - achieving full 8-bit resolution in ≤420 ns. Its track-and-hold acquires input within 200 ns and supports full-power bandwidth up to 10 MHz, enabling accurate digitization of high-frequency signals in subsampling applications.

Channel selection is performed externally via A0–A2 address inputs synchronized with RD; no internal register write is required. Power management combines automatic power-down (sampled at EOC high) and optional external PD control (not present on AD7829), while the parallel interface uses CS/RD-gated 8-bit data bus (DB0–DB7) with EOC pulse for microprocessor/DSP handshaking.

Key Specifications

Pinout & Package

The AD7829BNZ is supplied in a 28-lead, 0.6" wide plastic dual in-line package (PDIP) with 0.1" lead pitch and standard through-hole mounting. Thermal resistance θ_JA = 105°C/W; maximum power dissipation = 450 mW.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD7825BNZ and MAX1186BCPP+, the AD7829BNZ uniquely delivers 8-channel parallel interfacing with VMID-adjustable input span and dual 3 V/5 V supply support - making it the only option for legacy MPU-based, high-channel-count, mixed-voltage data acquisition where deterministic timing and minimal software overhead are critical.

Availability

AD7829BNZ is available at Aetrix Electronics and suitable for data acquisition systems, disk drive read channels, and mobile communication subsampling applications requiring stable component supply, long-term industrial lifecycle support, and traceable sourcing from authorized channels.

Supply support for AD7829BNZ 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, Inc. is a global semiconductor leader specializing in high-performance analog, mixed-signal, and digital signal processing technologies for precision instrumentation, communications, and industrial applications.

The AD7822/AD7825/AD7829 family was designed specifically for high-speed, low-latency, microprocessor-compatible data acquisition - emphasizing fast conversion, flexible input scaling, and seamless integration into real-time DSP and embedded control systems.

FAQ

What is the maximum sampling rate supported by the AD7829BNZ?

The AD7829BNZ supports a maximum throughput of 2 MSPS, corresponding to a maximum conversion time of 420 ns. This rate is achievable across the full industrial temperature range (−40°C to +85°C) and both supply conditions (3 V ±10% and 5 V ±10%). The device maintains specified dynamic performance - including 48 dB SNR and ±0.75 LSB INL - only when operated within this limit and with proper layout and decoupling per the datasheet recommendations. Exceeding 2 MSPS violates timing specifications and degrades accuracy.

Does the AD7829BNZ require an external reference voltage?

No, the AD7829BNZ does not require an external reference voltage because it integrates a 2.5 V ±2% on-chip reference with 50 ppm/°C temperature coefficient. The VREF IN/OUT pin can be left unconnected for internal reference use, or decoupled to AGND with a 0.1 µF capacitor. An external 2.5 V reference may be applied to this pin if higher accuracy or lower drift is needed - but doing so disables the internal reference. The AD7829BNZ reference error remains within ±50 mV over temperature and supply variations, making it suitable for many cost-sensitive applications without external components.

How is channel selection implemented on the AD7829BNZ?

Channel selection on the AD7829BNZ is performed externally using three digital address inputs: A0, A1, and A2. These pins accept static logic levels (TTL/CMOS compatible) to select one of eight analog inputs (VIN1–VIN8) in binary format (A2 A1 A0). Selection occurs synchronously with the falling edge of the RD signal - no internal register writes or serial commands are required. This architecture eliminates firmware overhead and allows direct connection to FPGA GPIO or microcontroller port pins, making the AD7829BNZ ideal for systems requiring rapid, deterministic channel switching without processor intervention.

What power-saving features does the AD7829BNZ offer?

The AD7829BNZ offers two complementary power-saving mechanisms: automatic power-down and manual power-down. Automatic power-down is triggered when the CONVST pin is sampled low at the rising edge of the EOC signal - reducing supply current from 12 mA (typical) to 5 µA (max). Manual power-down is not available on the AD7829BNZ (unlike AD7822/AD7825), as it lacks a dedicated PD pin. In normal operation, power dissipation is 36 mW max at 3 V and 60 mW max at 5 V. The automatic mode is especially effective in burst-mode acquisition, where idle time between conversions significantly lowers average power consumption.

Is the AD7829BNZ pin-compatible with other members of the AD782x family?

No, the AD7829BNZ is not pin-compatible with AD7822BNZ or AD7825BNZ. It uses a 28-lead PDIP package with unique pin assignments - including A2, VIN5–VIN8, and absence of PD pin - whereas AD7822BNZ uses 20-lead PDIP and AD7825BNZ uses 24-lead PDIP. Pin functions such as CONVST, EOC, RD, CS, and DB0–DB7 are consistent across the family, but physical layout, channel count, and address/control pin presence differ. Migration requires PCB redesign; however, register mapping, timing behavior, and interface protocol remain functionally aligned, easing firmware adaptation.