Analog Devices Inc. ADP1871ACPZ-1.0-R7

Overview

ADP1871ACPZ-1.0-R7 from Analog Devices is a synchronous buck controller implementing constant on-time and valley current-mode control for high-efficiency DC/DC conversion. It supports 3.25 V to 20 V input, delivers regulated output down to 0.6 V with ±1.0% reference accuracy, operates at 1.0 MHz switching frequency, integrates bootstrap diode and internal 5 V LDO bias regulator, and enables power-saving mode (PSM) for light-load efficiency in telecom POL supplies.

For engineers reviewing the ADP1871ACPZ-1.0-R7 datasheet, ADP1871ACPZ-1.0-R7 pinout, ADP1871ACPZ-1.0-R7 application, or ADP1871ACPZ-1.0-R7 equivalent, key selection criteria include PSM capability, 1.0 MHz operation with sub-100 ns minimum on-time, valley current sensing without external resistor, thermal shutdown at 155°C, and compatibility with all-N-channel MOSFET power stages.

Technical Context

The ADP1871ACPZ-1.0-R7 uses a pseudo-fixed-frequency constant on-time architecture combined with valley current-mode sensing to achieve fast transient response and stable regulation across wide duty-cycle ranges. Its valley current-limit detection occurs at the bottom of the switching cycle, enabling precise overcurrent protection and optimal low-duty-cycle performance.

It integrates an internal 5 V LDO (VREG) for gate driver biasing, a bootstrap rectifier between VREG and BST, and precision enable threshold (245–330 mV) with 37 mV hysteresis. The device starts into precharged loads and includes soft-start (3.0 ms), hiccup-mode short-circuit protection, and thermal overload shutdown.

Key Specifications

Pinout & Package

ADP1871ACPZ-1.0-R7 is housed in a 10-lead LFCSP package (3 mm × 3 mm × 0.8 mm) with exposed pad thermally connected to PGND.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar synchronous buck controller applications.

Compared with TPS54620RGYT and ISL85415IRZ-T7A, ADP1871ACPZ-1.0-R7 uniquely combines 1.0 MHz operation, valley current sensing without sense resistor, and PSM-making it optimal for high-density, thermally sensitive POL designs requiring both peak and light-load efficiency.

Availability

ADP1871ACPZ-1.0-R7 is available at Aetrix Electronics and suitable for telecom infrastructure, server VRMs, and consumer multimedia equipment requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.

Supply support for ADP1871ACPZ-1.0-R7 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.

The ADP1870/ADP1871 product line was designed specifically for high-efficiency, high-frequency synchronous buck control in intermediate bus and point-of-load applications demanding fast transient response and robust protection.

FAQ

What is the purpose of the COMP/EN pin on the ADP1871ACPZ-1.0-R7?

The COMP/EN pin on the ADP1871ACPZ-1.0-R7 serves dual functions: as the output of the internal error amplifier (COMP) for loop compensation, and as the precision enable input (EN). Pulling this pin below 245 mV disables the controller with 37 mV hysteresis, while releasing it initiates soft-start. This dual role simplifies system sequencing and eliminates need for external enable logic in ADP1871ACPZ-1.0-R7 designs.

Does the ADP1871ACPZ-1.0-R7 require an external current-sense resistor?

No, the ADP1871ACPZ-1.0-R7 does not require an external current-sense resistor. It implements valley current-mode sensing using the R_DS(on) of the low-side MOSFET, with gain programmable via a resistor from DRVL to PGND (e.g., 47 kΩ yields 3 V/V). This eliminates power loss and board area associated with discrete sense resistors in ADP1871ACPZ-1.0-R7 implementations.

What is the significance of the "-1.0" suffix in ADP1871ACPZ-1.0-R7?

The "-1.0" suffix in ADP1871ACPZ-1.0-R7 denotes the 1.0 MHz switching frequency option within the ADP1871 family. Analog Devices offers ADP1871 variants at 300 kHz, 600 kHz, and 1.0 MHz; the -1.0 version is optimized for high-frequency operation with minimum on-time of 60–85 ns, enabling compact designs for low-voltage, high-current POL applications using ADP1871ACPZ-1.0-R7.

How does the power saving mode (PSM) improve efficiency in the ADP1871ACPZ-1.0-R7?

The power saving mode (PSM) in the ADP1871ACPZ-1.0-R7 improves light-load efficiency by enabling pulse-skipping operation-disabling switching cycles when output regulation is maintained. This reduces switching losses and quiescent current, achieving up to 5–10% higher efficiency at loads below 200 mA compared to forced PWM mode, as verified in ADP1871ACPZ-1.0-R7 efficiency curves at 1.0 MHz.

What package type is used for the ADP1871ACPZ-1.0-R7, and why is thermal design critical?

The ADP1871ACPZ-1.0-R7 uses a 10-lead LFCSP package (3 mm × 3 mm) with exposed thermal pad. Its θ_JA is 40°C/W on a 4-layer board-significantly lower than MSOP alternatives-making thermal design critical for high-current applications. Proper soldering of the exposed pad to a thermal plane is mandatory to maintain junction temperature ≤125°C under 10 A load, as specified in ADP1871ACPZ-1.0-R7 thermal characteristics.