Analog Devices Inc. ADT7518ARQ-REEL

Overview

ADT7518ARQ-REEL from Analog Devices is a highly integrated mixed-signal IC combining a 10-bit temperature-to-digital converter, a 10-bit 4-channel ADC, and four buffered 8-bit voltage-output DACs in a single 16-lead QSOP package. It operates from 2.7 V to 5.5 V, delivers ±0.5°C internal temperature accuracy (0°C to +85°C), supports both SPI and I²C interfaces, and features simultaneous DAC output update via LDAC. It is used in smart battery chargers and process control systems requiring multi-function analog monitoring and programmable biasing.

For engineers reviewing the ADT7518ARQ-REEL datasheet, ADT7518ARQ-REEL pinout, ADT7518ARQ-REEL application, or ADT7518ARQ-REEL equivalent, key selection considerations include its dual-interface flexibility, guaranteed monotonic DAC performance, internal 2.25 V reference option, rail-to-rail output buffers, and thermal accuracy specification validity conditional on external DAC reference use.

Technical Context

The ADT7518ARQ-REEL integrates three independent data conversion subsystems: a bandgap-based internal temperature sensor digitized by a dedicated 10-bit ADC; four single-ended analog inputs (AIN1–AIN4) with DC bandwidth and 0 V to 2.25 V input range; and four 8-bit string DACs with double-buffered registers and software/hardware LDAC control. All subsystems share a unified serial interface controller supporting SPI/I²C/SMBus protocols with PEC support.

Its functional block includes an on-chip 2.25 V reference (80 ppm/°C TC), buffered VREF-IN input for DACs, open-drain INT output with configurable polarity, and power-on reset that forces DAC outputs to 0 V until first valid write. The device implements round-robin measurement sequencing across VDD, internal/external temperature, and AIN channels, with selectable averaging (16-sample) and fast/slow conversion modes.

Key Specifications

Pinout & Package

ADT7518ARQ-REEL is housed in a 16-lead QSOP (Quarter Size Outline Package) with 0.65 mm lead pitch, RoHS-compliant, moisture sensitivity level 3. Pin layout supports compact routing of analog outputs, digital interfaces, and dual-purpose analog/digital pins.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar mixed-signal monitoring and control applications.

Compared with ADT7518ARQ-REEL, ADT7519ARQ-REEL removes the internal-reference limitation for DAC-linked temperature accuracy, while LTC2635CGN-1#PBF offers higher DAC resolution but lacks integrated sensing - making ADT7518ARQ-REEL optimal for space-constrained, multi-function thermal-aware systems.

Availability

ADT7518ARQ-REEL is available at Aetrix Electronics and suitable for smart battery chargers, process control systems, and PCB thermal management applications requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for ADT7518ARQ-REEL 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 ADT7518ARQ-REEL belongs to Analog Devices' precision temperature and data acquisition product line, designed specifically for embedded systems needing consolidated thermal monitoring, analog input acquisition, and programmable analog output generation in minimal footprint.

FAQ

What is the operating temperature range of the ADT7518ARQ-REEL?

The ADT7518ARQ-REEL is specified for operation from –40°C to +120°C. Its internal temperature sensor achieves ±0.5°C typical accuracy over 0°C to +85°C when the internal reference is not used for the DAC, per the datasheet's thermal characteristics table. External transistor sensing (D+/D–) extends measurement capability beyond the die temperature.

Does the ADT7518ARQ-REEL support both SPI and I²C interfaces simultaneously?

No, the ADT7518ARQ-REEL supports SPI and I²C operation in mutually exclusive modes. Interface selection is determined by hardware configuration: CS must be tied high for I²C mode, while active-low CS enables SPI mode. The same physical pins (SCL/SCLK, SDA/DIN, DOUT/ADD) serve both protocols, but only one interface can be active at a time.

What is the purpose of the LDAC pin on the ADT7518ARQ-REEL?

The LDAC pin on the ADT7518ARQ-REEL is an active-low control input that transfers data from the DAC input registers to the DAC holding registers, enabling simultaneous update of all four DAC outputs. A minimum 20 ns pulse width is required. When enabled via Control Configuration 3 register bit C3, LDAC overrides software updates and ensures deterministic timing for synchronized analog output changes.

Can the ADT7518ARQ-REEL use its internal 2.25 V reference for both ADC and DAC functions?

The ADT7518ARQ-REEL's internal 2.25 V reference is used by default for the ADC channels. For DAC operation, it may be selected via configuration, but the datasheet explicitly states that the ±0.5°C internal temperature accuracy specification is only valid when the internal reference is *not* used for the DAC. Using the internal reference for DACs degrades thermal accuracy - hence the recommendation to use ADT7519ARQ-REEL for such configurations.

How does the ADT7518ARQ-REEL handle power-on initialization?

The ADT7518ARQ-REEL incorporates a power-on reset circuit that forces all four DAC outputs to 0 V at startup and holds them there until the first valid write to a DAC register occurs. This behavior ensures safe, known-state analog outputs during system boot, preventing unintended actuation of downstream circuitry before firmware takes control.