Analog Devices Inc. AD4684BCPZ-RL

Overview

AD4684BCPZ-RL from Analog Devices is a 16-bit, dual simultaneous sampling SAR ADC with 4 single-ended analog inputs, 1 MSPS throughput, 87.5 dB SNR (VREF = 3.3 V), ±1.5 LSB INL (typ), and integrated 2.5 V reference (10 ppm/°C max). It operates from −40°C to +125°C in motor control current sense and power quality monitoring systems.

For engineers reviewing the AD4684BCPZ-RL datasheet, AD4684BCPZ-RL pinout, AD4684BCPZ-RL application, or AD4684BCPZ-RL equivalent, key selection considerations include dual-channel simultaneity, oversampling capability (OSR up to 8), channel sequencer mode, 3 mm × 3 mm LFCSP package, and support for 1.8 V/2.5 V/3.3 V logic interfaces.

Technical Context

The AD4684BCPZ-RL integrates two independent SAR ADCs sharing a 4-channel multiplexer and on-chip sequencer, enabling true simultaneous sampling of two input pairs (AINA0/AINA1 and AINB0/AINB1) at up to 1 MSPS. Its acquisition time is 850 ns per channel in single-pair mode.

It features an integrated oversampling block supporting OSR modes (up to OSR = 8), resolution boost (18-bit effective), and configurable alert function triggered by threshold violation on either ADC output. The internal 2.5 V reference is buffered and accessible via REFIO, with external reference support up to 3.3 V.

Key Specifications

Pinout & Package

AD4684BCPZ-RL is housed in a 16-lead, 3 mm × 3 mm lead frame chip scale package (LFCSP) with exposed pad (EPAD) requiring connection to GND for thermal and electrical integrity.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-channel simultaneous sampling ADC applications.

Compared with AD4684BCPZ-RL, AD4685BCPZ-RL trades speed for lower power and cost in identical form factor, while AD7616BSTZ expands channel count at the expense of oversampling capability, smaller package, and higher layout complexity.

Availability

AD4684BCPZ-RL is available at Aetrix Electronics and suitable for motor control position feedback, power quality monitoring, and sonar signal acquisition requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for AD4684BCPZ-RL 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, automotive, communications, and healthcare markets since 1965.

The AD4684BCPZ-RL belongs to Analog Devices' precision SAR ADC product line, engineered for high-speed, low-latency, simultaneous sampling applications in harsh environments where accuracy, timing integrity, and thermal robustness are critical.

FAQ

What is the maximum sampling rate supported by the AD4684BCPZ-RL?

The AD4684BCPZ-RL supports a maximum throughput rate of 1 MSPS when operating in single-channel pair mode (e.g., AINA0/AINA1 only). In alternating-channel mode (sequencing across all four inputs), the rate drops to 500 kSPS. This is confirmed in Table 1 of the Rev. A datasheet under "THROUGHPUT" with test condition SEQ = 0 for AD4684. The device achieves this using a dual SAR architecture with shared control logic and optimized acquisition timing.

Does the AD4684BCPZ-RL require an external reference voltage?

No, the AD4684BCPZ-RL includes a buffered 2.5 V internal reference with 10 ppm/°C maximum temperature coefficient, accessible via the REFIO pin. An external reference (2.5 V to 3.3 V) is optional and enabled by setting the REFSEL bit in CONFIGURATION1 register. When using the internal reference, a 0.1 µF capacitor on REFIO is mandatory; for external reference, a 1 µF capacitor is required per datasheet Section "PIN CONFIGURATION AND FUNCTION DESCRIPTIONS".

How does the oversampling feature improve performance in the AD4684BCPZ-RL?

The AD4684BCPZ-RL's oversampling block supports OSR modes up to 8, increasing effective SNR by up to 5.5 dB (e.g., from 87.5 dB to 93 dB) and reducing effective noise floor without external hardware. It operates by averaging multiple conversions and can be configured via OSR_MODE and OSR bits in CONFIGURATION2 register. Oversampling also lowers required SCLK speed and relaxes anti-aliasing filter requirements, directly improving dynamic range in low-bandwidth applications like power quality analysis.

What is the purpose of the SDOB/ALERT pin on the AD4684BCPZ-RL?

The SDOB/ALERT pin on the AD4684BCPZ-RL serves dual roles: it outputs ADC B conversion results during normal SPI readback, or asserts a low-active hardware interrupt when a conversion result exceeds user-defined thresholds stored in ALERT_LOW_THRESHOLD and ALERT_HIGH_THRESHOLD registers. This alert function eliminates software polling, enabling real-time fault response in motor control or protection relays. The mode is controlled by the ALERT_EN bit in the Alert Register.

Can the AD4684BCPZ-RL interface with a 1.8 V microcontroller?

Yes, the AD4684BCPZ-RL supports 1.8 V logic interfaces via its dedicated VLOGIC supply pin (Pin 2), which accepts 1.65 V to 3.6 V. When VLOGIC = 1.8 V, digital inputs (CS, SDI, SCLK) recognize VIH ≥ 1.44 V and VIL ≤ 0.36 V, while digital outputs (SDOA, SDOB/ALERT) drive VOH ≥ 1.5 V and VOL ≤ 0.4 V-fully compatible with standard 1.8 V CMOS I/O. This is specified in Table 1 under "DIGITAL INPUTS" and "DIGITAL OUTPUTS" sections of the datasheet.