Analog Devices Inc. AD7643BCPZRL

Overview

AD7643BCPZRL from Analog Devices is an 18-bit, 1.25 MSPS charge redistribution SAR analog-to-digital converter with fully differential input, internal 2.048 V reference (±8 ppm/°C drift), no pipeline delay, and dual parallel/serial interface supporting 2.5 V/3.3 V/5 V logic. It delivers 93.5 dB SINAD at 20 kHz and operates from a single 2.5 V supply - used in high-dynamic-range medical instrumentation and spectrum analysis systems.

For engineers reviewing the AD7643BCPZRL datasheet, AD7643BCPZRL pinout, AD7643BCPZRL application, or AD7643BCPZRL equivalent, key selection considerations include true differential input range (±VREF), guaranteed no missing codes over 18 bits, power-down mode (2 μW), temperature sensor output (278 mV @ 25°C), and hardware-calibrated AC performance including SNR and THD.

Technical Context

The AD7643BCPZRL implements a charge redistribution SAR architecture with integrated conversion clock, error correction circuitry, and factory calibration for both DC (gain/offset/INL) and AC (SNR/SINAD/THD) parameters. Its fully differential front-end supports ±2.048 V input range with 58 dB CMRR at 100 kHz and 50 MHz −3 dB bandwidth.

It features dual digital interface modes: configurable 18-/16-/8-bit parallel bus or SPI/QSPI/MICROWIRE/DSP-compatible serial interface with master/slave clocking options, selectable via MODE[1:0] pins and EXT/INT control. Internal reference buffer (REFBUFIN) enables external reference scaling to 2.048 V with 1 nA input current.

Key Specifications

Pinout & Package

AD7643BCPZRL is packaged in a Pb-free 48-lead LFCSP (7 mm × 7 mm, 0.85 mm height) with exposed pad for thermal enhancement. Pin functions are validated per Analog Devices Rev. A datasheet Figures 4 and 5 and Table 6.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD7643BCPZRL, AD7641BCPZRL offers double the throughput at the expense of higher power and no advantage in linearity or noise floor, while AD7622BCPZRL trades 2 bits of resolution and integrated features for raw speed - making AD7643BCPZRL optimal for 18-bit, 1.25 MSPS applications demanding self-contained precision.

Availability

AD7643BCPZRL is available at Aetrix Electronics and suitable for medical instrumentation, high-speed data acquisition, and spectrum analysis requiring stable component supply, long-term lifecycle support, and guaranteed Pb-free compliance.

Supply support for AD7643BCPZRL 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 leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, headquartered in Norwood, MA, with design and manufacturing expertise spanning precision converters, amplifiers, and RF solutions.

The AD7643BCPZRL belongs to Analog Devices' PulSAR® family of precision SAR ADCs, engineered for applications demanding high resolution, high speed, and low power in instrumentation, medical, and industrial systems - with emphasis on ease of use via integrated references and calibration.

FAQ

What is the maximum supported external reference voltage for AD7643BCPZRL?

The AD7643BCPZRL accepts an external reference voltage from 1.8 V to AVDD + 0.1 V (i.e., up to 2.6 V), as specified in the Rev. A datasheet Table 2. When using external reference, PDREF must be high and PDBUF may be set low to enable internal buffer scaling - allowing 1.2 V applied to REFBUFIN to produce 2.048 V on REF. This configuration maintains compatibility with the internal reference's output level and noise performance.

Does AD7643BCPZRL support simultaneous sampling with other ADCs?

No, AD7643BCPZRL does not support hardware-triggered simultaneous sampling across multiple devices. It features a single CNVST input for initiating conversion and lacks dedicated synchronization pins (e.g., SYNC_IN or daisy-chain capability beyond SDIN/SDOUT). While multiple AD7643BCPZRL units can be driven from a common CNVST source, inter-device aperture jitter mismatch (5 ps rms per unit) limits true simultaneity to <10 ps skew - insufficient for sub-picosecond coherent sampling. For synchronized multi-channel acquisition, consider AD7654 or AD7634 families instead.

How is the temperature sensor output of AD7643BCPZRL calibrated and what accuracy can be expected?

The AD7643BCPZRL's TEMP pin outputs 278 mV at 25°C with a nominal sensitivity of 1 mV/°C, as characterized in production and verified per Rev. A datasheet specifications. No user calibration is required; absolute accuracy is ±1°C over −40°C to +85°C after accounting for PCB thermal gradients. The output impedance is 4.7 kΩ, so low-capacitance ADC input or op-amp buffering is recommended for precise digitization - especially when sharing AGND/DGND planes with noisy digital circuits.

Can AD7643BCPZRL operate with OVDD = 3.3 V while AVDD/DVDD = 2.5 V?

Yes, AD7643BCPZRL supports OVDD = 2.3 V to 3.6 V independently of AVDD and DVDD (both 2.37 V to 2.63 V), enabling direct interfacing with 3.3 V microcontrollers or FPGAs without level shifters. Digital outputs (D[17:0], BUSY, RD, CS) are OVDD-referenced and tolerate VIH up to 5.25 V, while VOL remains ≤0.4 V at ISINK = 500 μA. This rail-to-rail I/O flexibility simplifies mixed-voltage system design and avoids additional translation components in the data path.

What is the significance of the "BCPZRL" suffix in AD7643BCPZRL?

The "BCPZRL" suffix denotes a specific packaging and ordering variant of the AD7643: "B" indicates commercial temperature grade (−40°C to +85°C), "CP" specifies the 48-lead LFCSP package (7 mm × 7 mm), "Z" confirms Pb-free (RoHS-compliant) finish, and "RL" indicates tape-and-reel packaging (1,000 units per reel). This exact variant is documented in the AD7643 Rev. A Ordering Guide (Page 28) and matches the mechanical drawings in Figure 4 - distinct from the LQFP option (AD7643BSTZRL).