Analog Devices Inc. AD7853LARSZ

Overview

AD7853LARSZ from Analog Devices is a 12-bit, 100 kSPS pseudo-differential successive-approximation ADC optimized for low-power operation on single 3 V to 5.5 V supply. It features on-chip 2.5 V reference, system/self-calibration, and SPI/QSPI/μP-compatible serial interface in a 24-lead SSOP package - deployed in battery-powered medical instruments and portable data acquisition systems.

For engineers reviewing the AD7853LARSZ datasheet, AD7853LARSZ pinout, AD7853LARSZ application, or AD7853LARSZ equivalent, key selection considerations include its 4.5 mW typical power at 3 V, 100 kSPS throughput, ±1 LSB integral nonlinearity, flexible analog input ranges (0 to VREF or ±VREF/2), and support for automatic power-down after conversion.

Technical Context

The AD7853LARSZ implements a SAR architecture with integrated track-and-hold (500 ns acquisition time), internal 2.5 V reference, and calibration memory. Its dual-domain supply (AVDD/DVDD) isolates analog and digital sections, while the SM1/SM2/POLARITY pins configure five serial interface modes including self-clocking and external-clocking variants.

Calibration is supported via dedicated CAL pin and control register bits, enabling system offset, full-scale, and full self-calibration sequences. Power management includes three states: normal (4.5 mW @ 3 V), sleep (5 µA with clock off), and automatic post-conversion shutdown - all controlled without external logic.

Key Specifications

Pinout & Package

AD7853LARSZ is housed in a 24-lead SSOP (Shrink Small Outline Package), 0.150" body width, with 0.025" lead pitch and exposed pad not present. Pin 1 is marked by notch or dot; pin numbering follows standard counter-clockwise convention from top-left corner.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD7853ARSZ, AD7853LARSZ trades speed for 62% lower active power and integrated calibration; versus ADS7822U, it adds on-chip reference and system calibration at the cost of slightly larger footprint and fixed SSOP package.

Availability

AD7853LARSZ is available at Aetrix Electronics and suitable for battery-powered medical instruments, portable data loggers, and industrial field transmitters requiring stable component supply across long production lifecycles.

Supply support for AD7853LARSZ 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, headquartered in Wilmington, MA.

The AD7853LARSZ belongs to Analog Devices' precision SAR ADC product line, designed specifically for low-power, high-accuracy data acquisition in portable and embedded systems where calibration integrity and supply flexibility are critical.

FAQ

What is the maximum sampling rate of the AD7853LARSZ?

The AD7853LARSZ supports a maximum sampling rate of 100 kSPS, achieved with a 1.8 MHz master clock at 0°C to +70°C or 1 MHz master clock at –40°C to +85°C. This rate is fixed by the internal SAR timing architecture and cannot be increased beyond specification, even with faster clock inputs. The AD7853LARSZ datasheet confirms this limit under all valid operating conditions.

Does the AD7853LARSZ require an external reference voltage?

No, the AD7853LARSZ includes an internal 2.5 V reference with 20 ppm/°C tempco, making external reference optional. However, it supports external reference voltages from 1.2 V to AVDD applied to the REFIN/REFOUT pin. When using external reference, CREF1 and CREF2 capacitors remain mandatory for stability. The AD7853LARSZ functions fully with or without external reference.

How does the AMODE pin affect analog input configuration on the AD7853LARSZ?

The AMODE pin selects between two analog input ranges: Logic 0 configures unipolar 0 to VREF mode (straight binary coding); Logic 1 configures bipolar ±VREF/2 mode (two's complement coding). In bipolar mode, AIN(–) must be biased to +VREF/2, and AIN(+) must stay ≥0 V. This pin directly controls input scaling and output coding format in the AD7853LARSZ.

Can the AD7853LARSZ perform system-level calibration?

Yes, the AD7853LARSZ supports both self-calibration and system calibration via the CAL pin and control register. System calibration corrects for external gain and offset errors in the signal chain - requiring user-applied full-scale and zero-scale inputs. Calibration spans are ±0.05 × VREF for offset and ±0.025 × VREF for gain, as specified in the AD7853LARSZ datasheet.

What power-down modes are available on the AD7853LARSZ?

The AD7853LARSZ offers three power-down states: (1) Automatic post-conversion shutdown (25 µW typical), (2) Sleep mode with external clock off (5 µA max), and (3) Full power-down via control register (1 µA typical). All retain calibration data. Power state is controlled by SLEEP pin level and PMGT bits in the control register - no external circuitry needed for any AD7853LARSZ power mode.