Analog Devices Inc. AD7853LAR

Overview

AD7853LAR from Analog Devices is a 12-bit, pseudo-differential, serial-output sampling analog-to-digital converter optimized for low-power operation at up to 100 kSPS. It operates from a single 3 V to 5.5 V supply, features on-chip 2.5 V reference, self- and system-calibration, and supports unipolar (0 to VREF) or bipolar (±VREF/2) input ranges - ideal for battery-powered medical instruments and portable data acquisition.

For engineers reviewing the AD7853LAR datasheet, AD7853LAR pinout, AD7853LAR application, or AD7853LAR equivalent, key selection considerations include its 4.5 mW typical power dissipation at 3 V, 100 kSPS throughput, flexible SPI/QSPI/8051-compatible serial interface, and support for automatic power-down after conversion in embedded sensor interfaces.

Technical Context

The AD7853LAR uses a successive approximation register (SAR) architecture with integrated track-and-hold, calibrated DAC, and charge redistribution circuitry. Its conversion cycle begins on CONVST rising edge and completes in ≤10 µs (at 1 MHz CLKIN), with BUSY signaling active duration.

Calibration is managed via dedicated CAL input and internal control registers; self-calibration requires ~3.47 ms (system offset) to 31.25 ms (full self-cal), depending on master clock frequency. The device supports five serial interface modes selected by SM1/SM2 pins and polarity control via POLARITY pin.

Key Specifications

Pinout & Package

AD7853LAR is housed in a 24-lead SOIC (R-24) package with standard 0.3-inch width and 1.27 mm pitch. Pin functions are electrically validated per Analog Devices Rev. B datasheet and confirmed across all operating conditions.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 12-bit SAR ADC applications.

Compared with AD7853AR and ADS7822U, the AD7853LAR uniquely balances sub-7 mW active power, integrated 2.5 V reference, and factory-trimmed self-calibration - making it optimal for battery-operated test equipment and portable diagnostics where accuracy retention matters more than peak speed.

Availability

AD7853LAR is available at Aetrix Electronics and suitable for portable medical sensors, industrial data loggers, and pen-based computing systems requiring stable component supply and long-term lifecycle support.

Supply support for AD7853LAR 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.

The AD7853LAR belongs to Analog Devices' precision SAR ADC product line, designed specifically for low-power, high-accuracy data acquisition in portable and embedded instrumentation.

FAQ

What is the maximum sampling rate supported by the AD7853LAR?

The AD7853LAR supports a maximum throughput rate of 100 kSPS, achieved with a 1.8 MHz master clock (CLKIN) at 0°C to +70°C or 1 MHz CLKIN over –40°C to +85°C. Conversion time is ≤10 µs, and minimum acquisition time between conversions is 400 ns to ensure 12-bit settling. This rate is fixed for the L-version and cannot be increased beyond datasheet specifications.

Does the AD7853LAR require external reference components?

Yes, the AD7853LAR requires two external capacitors: a 0.1 µF multilayer ceramic capacitor (CREF1) and a 0.01 µF ceramic disc capacitor (CREF2), both connected between their respective pins and AGND. These stabilize the internal 2.5 V reference and DAC charge redistribution network. No external voltage reference IC is needed unless overriding the internal reference.

How does the AD7853LAR handle calibration without host processor intervention?

The AD7853LAR supports autonomous calibration via its CAL pin: connecting a 10 nF capacitor from CAL to DGND triggers full self-calibration on power-up. Alternatively, a logic-low pulse on CAL initiates immediate calibration. Calibration data is retained in sleep mode, and no host firmware interaction is required for basic read-only operation.

Can the AD7853LAR operate with a 3.3 V supply only?

Yes, the AD7853LAR is fully specified for AVDD and DVDD from 3.0 V to 5.5 V, including 3.3 V nominal operation. At 3.3 V, typical power dissipation is ~5.4 mW in normal mode and 3.6 µW in full power-down mode. All logic thresholds, reference behavior, and timing parameters remain valid per datasheet limits.

What serial interface protocols does the AD7853LAR support out-of-the-box?

The AD7853LAR supports five hardware-configurable serial modes via SM1/SM2/POLARITY pins, enabling native compatibility with SPI, QSPI, and 8051-style microcontrollers without bit-banging. It does not require software-driven clock generation - SCLK can be either host-provided (input) or device-generated (output), and SYNC adapts as chip-select or frame-sync based on mode selection.