Analog Devices Inc. AD876JST

Overview

AD876JST from Analog Devices is a 10-bit, 20 MSPS CMOS analog-to-digital converter (ADC) with on-chip sample-and-hold, differential nonlinearity of ±0.5 LSB, guaranteed no missing codes, and 160 mW power dissipation at +5 V AVDD/DVDD and +3.3 V DRVDD. It operates over 0°C to +70°C and targets high-speed imaging and video digitization systems requiring single-supply operation and low power.

For engineers reviewing the AD876JST datasheet, AD876JST pinout, AD876JST application, or AD876JST equivalent, key selection considerations include its 48-lead TQFP package, force-sense reference interface (REFTF/REFBF/REFTS/REFBS), three-state digital outputs, pipeline latency of 3.5 clock cycles, and compatibility with both +5 V and +3.3 V logic levels on DRVDD.

Technical Context

The AD876JST implements a multistage pipelined architecture with output error correction logic to achieve 10-bit accuracy at 20 MSPS while consuming only 160 mW. Its on-chip sample-and-hold amplifier supports full-scale 2 V_p-p input range with 5 pF input capacitance and 150 MHz full-power bandwidth.

It features separate analog (AVDD/AVSS), digital core (DVDD/DVSS), and I/O buffer (DRVDD/DRVSS) supply domains, enabling independent voltage scaling. Reference inputs use force-sense topology (REFTF/REFBF/REFTS/REFBS) to eliminate wiring resistance errors, supporting adjustable top/bottom reference voltages from 1.6 V to 4.5 V.

Key Specifications

Pinout & Package

The AD876JST is housed in a 48-lead thin quad flatpack (TQFP) package with 0.5 mm pitch, optimized for high-density PCB layouts and low-profile assemblies.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-speed ADC applications.

Compared with AD9203ARUZ and MAX1186ETL+, the AD876JST uniquely combines +5 V compatibility, force-sense reference architecture, and 28-/48-lead package options-making it the most suitable choice for legacy video digitization systems requiring drop-in upgrades and robust DC accuracy without redesigning reference or power delivery networks.

Availability

AD876JST is available at Aetrix Electronics and suitable for color scanner front-ends, digital copier image paths, and electronic still camera preview subsystems requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for AD876JST 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, serving industrial, communications, automotive, and consumer markets since 1965.

The AD876 series was designed specifically for high-speed, low-power digitization in imaging and video equipment-emphasizing single-supply operation, pin compatibility across resolutions, and integrated reference accuracy for CCD and CIS sensor interfaces.

FAQ

What is the operating temperature range specified for the AD876JST?

The AD876JST is specified for commercial temperature operation from 0°C to +70°C. This range is confirmed in the Ordering Guide section of the official Analog Devices datasheet Rev. B, where the "J" grade designation explicitly denotes the 0°C to +70°C range. The device's DC accuracy parameters-including INL, DNL, offset, and gain error-are guaranteed across this full interval under defined supply and reference conditions.

Does the AD876JST support both +5 V and +3.3 V logic levels on its digital I/O pins?

Yes, the AD876JST supports both +5 V and +3.3 V logic levels via its DRVDD supply pin. When DRVDD = +5 V, digital inputs accept VIH ≥ 4.0 V and VIL ≤ 1.0 V; when DRVDD = +3.3 V, VIH ≥ 2.4 V and VIL ≤ 0.6 V. Output drive levels (VOH/VOL) scale accordingly, ensuring interoperability with TTL, HC/HCT, and 3.3 V CMOS logic families without level shifters-this behavior is documented in the Digital Specifications table of the AD876 datasheet Rev. B.

What is the purpose of the REFTS and REFBS pins on the AD876JST?

The REFTS (Reference Top Sense) and REFBS (Reference Bottom Sense) pins on the AD876JST provide Kelvin connections to internal DAC tap points on the reference ladder. They enable force-sense reference configuration: external voltage sources connect to REFTF/REFBF, while REFTS/REFBS feed back to internal comparators-canceling voltage drops across the 5 Ω internal routing resistors. As stated in the datasheet, these pins must remain unconnected if force-sense is not used, because current flow in sense lines introduces unequal reference errors across pipeline stages.

How many clock cycles of latency does the AD876JST exhibit, and what does that mean for system timing?

The AD876JST exhibits a pipeline latency of 3.5 clock cycles, as specified in the Timing Specifications table. This means that the digital output corresponding to a given analog sample appears 3.5 CLK periods after the rising edge that initiated that sample's conversion. For example, at 20 MSPS (50 ns period), the delay is 175 ns-enabling predictable synchronization with downstream FPGAs or DSPs. This fixed latency is critical for real-time video line buffering and deterministic timing closure in imaging pipelines.

Can the AD876JST be used in battery-powered portable applications?

Yes, the AD876JST is explicitly designed for battery-powered portable applications. Its 160 mW active power at 20 MSPS and <50 mW standby power (activated via STBY pin) meet the thermal and energy constraints of electronic still cameras, camcorders, and handheld scanners. The datasheet highlights low-power suitability in Product Highlights and Applying the AD876 sections, noting compatibility with single +5 V supply and efficient power-down mode for idle intervals-confirmed by measured power vs. sample rate curves in Figure 8.