Analog Devices Inc. ADT7518ARQZ

Overview

ADT7518ARQZ from Analog Devices is a highly integrated mixed-signal sensor interface IC combining a 10-bit temperature-to-digital converter, a 10-bit 4-channel ADC, and four 8-bit buffered 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 - enabling precise closed-loop thermal and analog control in compact embedded systems.

For engineers reviewing the ADT7518ARQZ datasheet, ADT7518ARQZ pinout, ADT7518ARQZ application, or ADT7518ARQZ equivalent, key selection considerations include its dual-interface flexibility (SPI/I²C), guaranteed monotonic 8-bit DACs with rail-to-rail output buffers, 10-bit multi-channel ADC with DC input bandwidth, internal 2.25 V reference option, and integrated thermal sensing for system-level monitoring and compensation.

Technical Context

The ADT7518ARQZ integrates three independent data conversion subsystems sharing a unified serial interface: a bandgap-based 10-bit temperature sensor with 0.25°C resolution, a 10-bit 4-channel ADC supporting 0 V–2.25 V or 0 V–VDD input ranges, and four 8-bit string DACs with double-buffered registers and software/hardware LDAC control. All analog outputs are buffered with rail-to-rail amplifiers and support simultaneous update.

Its dual-mode serial interface includes a 4-wire SPI-compatible protocol (CS/SCLK/SDA/DOUT) and a 2-wire SMBus/I²C mode (SCL/SDA), with ADD pin-selectable I²C addresses and PEC support. Power management includes a 1 µA power-down mode and power-on reset forcing DAC outputs to 0 V until first valid write.

Key Specifications

Pinout & Package

ADT7518ARQZ is housed in a 16-lead QSOP (Quarter Size Outline Package) with 0.65 mm lead pitch, optimized for space-constrained PCB layouts while maintaining thermal performance up to +120°C ambient.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar mixed-signal sensor interface applications.

Compared with ADT7518ARQZ, ADT7519ARQZ removes a critical accuracy dependency on reference configuration, while LTC2637CUD-12#PBF trades integrated functionality for higher DAC resolution - making ADT7518ARQZ optimal for cost-sensitive, space-constrained systems requiring balanced mixed-signal capability.

Availability

ADT7518ARQZ is available at Aetrix Electronics and suitable for smart battery chargers, personal computers, and domestic appliances requiring stable component supply with long-term industrial lifecycle support.

Supply support for ADT7518ARQZ 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, communications, automotive, and consumer markets since 1965.

The ADT7518ARQZ belongs to Analog Devices' precision sensor interface product line, designed specifically for embedded thermal management and multi-channel analog monitoring in resource-constrained systems.

FAQ

What communication interfaces does the ADT7518ARQZ support?

The ADT7518ARQZ supports both SPI (4-wire) and I²C (2-wire) serial interfaces, with SMBus packet error checking (PEC) compatibility. The interface mode is selected automatically based on signal timing: CS low activates SPI; SDA/SCL activity enables I²C. Pin 11 (ADD) configures the I²C address, and CS must be pulled high during I²C operation to avoid conflict. This dual-interface capability allows seamless integration with diverse host processors.

Does the ADT7518ARQZ require an external reference for accurate DAC operation?

No - the ADT7518ARQZ includes an internal 2.25 V reference with 80 ppm/°C temperature coefficient, usable for both ADC and DAC functions. However, datasheet Note 6 specifies that internal temperature sensor accuracy (±0.5°C) is only guaranteed when the internal reference is *not* used for the DAC. For designs requiring simultaneous high-accuracy temperature sensing and DAC operation, Analog Devices recommends ADT7519ARQZ instead.

How does the LDAC function work on the ADT7518ARQZ?

The LDAC pin (Pin 9) on the ADT7518ARQZ provides hardware-controlled simultaneous update of all four DAC outputs. A falling edge with minimum 20 ns width transfers data from input registers to DAC registers, ensuring synchronized analog transitions. Software LDAC is also supported via register writes. The LDAC function is enabled by default; bit C3 in Control Configuration 3 register disables it if needed. This feature is critical for applications requiring phase-aligned analog outputs, such as multi-channel bias generation.

What is the maximum sampling rate for the 4-channel ADC in the ADT7518ARQZ?

In Fast ADC mode with averaging disabled, the ADT7518ARQZ achieves a round-robin update rate of 400.84 µs per full 4-channel cycle (AIN1–AIN4) at 25°C when D+/D– pins are not selected. With averaging enabled (16 samples), the cycle time increases to 6.41 ms. Conversion time per individual channel is 44.5 µs (averaging off) or 712 µs (averaging on), enabling real-time monitoring of slowly varying analog signals like temperature or supply rails.

Can the ADT7518ARQZ measure external temperature using a transistor sensor?

Yes - the ADT7518ARQZ supports external temperature measurement using a standard NPN/PNP bipolar transistor (e.g., 2N3906) connected to Pins 7 (D+) and 8 (D–). The device applies a proportional current and measures the base-emitter voltage drop to compute temperature. External sensor accuracy is ±3°C (0°C to +85°C) at 3.3 V supply, with 10-bit resolution equivalent to 0.25°C. This capability extends thermal monitoring beyond the IC's die to heatsinks, motors, or ambient environments.