Analog Devices Inc. ADP121-ACBZ25R7

Overview

ADP121-ACBZ25R7 from Analog Devices is a fixed-output 2.5 V, 150 mA CMOS low dropout linear regulator in a 4-ball 0.4 mm pitch WLCSP package. It operates from 2.3 V to 5.5 V input, delivers ±1% output accuracy, features 90 mV dropout at full load, and draws only 30 μA quiescent current-optimized for post-regulation in battery-powered digital audio devices.

For engineers reviewing the ADP121-ACBZ25R7 datasheet, ADP121-ACBZ25R7 pinout, ADP121-ACBZ25R7 application, or ADP121-ACBZ25R7 equivalent, key selection criteria include its ultra-low shutdown current (<1 μA), stability with 1 μF ceramic output capacitor, 70 dB PSRR at 10 kHz, 40 μV_rms output noise at 1.2 V, and logic-controlled enable functionality.

Technical Context

The ADP121-ACBZ25R7 integrates a PMOS pass transistor controlled by an error amplifier comparing a precision 0.8 V reference against resistive feedback. Its internal undervoltage lockout (UVLO) activates below 2.25 V input to ensure predictable power-up behavior.

Thermal shutdown triggers at 150°C with 15°C hysteresis, and current limiting engages at 225 mA (typical). The EN pin provides logic-level control with input thresholds referenced to VIN (VIH = 1.2 V, VIL = 0.4 V), and built-in soft-start limits inrush current with ~120 μs startup time to 90% of 2.5 V output.

Key Specifications

Pinout & Package

ADP121-ACBZ25R7 uses a halide-free 4-ball WLCSP (0.4 mm pitch) with bottom-side terminations. Package dimensions: 1.0 mm × 1.0 mm × 0.55 mm (max), suitable for space-constrained wearable and IoT PCBs.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-noise, low-quiescent-current LDO applications.

Compared with XC6219B251MR-G and RT9013-25GB, ADP121-ACBZ25R7 offers the smallest footprint (1.0 mm²), lowest dropout (90 mV), and best noise/PSRR trade-off for space- and noise-sensitive portable designs-though it lacks the higher current capability of the Richtek part or the ultra-low IQ of the Torex device.

Availability

ADP121-ACBZ25R7 is available at Aetrix Electronics and suitable for mobile audio power, digital camera core supply, wearable sensor hub, IoT edge node MCU supply, and post-DC/DC regulation requiring stable component supply across automotive-grade temperature ranges and long-lifecycle production programs.

Supply support for ADP121-ACBZ25R7 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 Norwood, MA, with design centers worldwide and ISO 9001-certified manufacturing.

The ADP121 product line delivers ultra-low-quiescent-current, low-noise LDOs optimized for battery-powered portable electronics-including smartphones, wearables, and imaging devices-where minimal footprint, high PSRR, and extended runtime are critical.

FAQ

What is the output voltage tolerance of the ADP121-ACBZ25R7 over temperature and load?

The ADP121-ACBZ25R7 guarantees ±2% output voltage accuracy for loads between 100 μA and 150 mA across the full input range (VOUT + 0.5 V to 5.5 V), and ±3% over the operating junction temperature range of −40°C to +125°C. At nominal 10 mA load and 25°C, the tolerance is tighter at ±1%, as specified in the Rev. G datasheet Table 1.

Does the ADP121-ACBZ25R7 require an external bypass capacitor on the EN pin?

No, the ADP121-ACBZ25R7 does not require an external capacitor on the EN pin. Its enable input includes internal hysteresis to prevent oscillation during threshold crossing, and the VIH/VIL thresholds scale with VIN. A clean, low-impedance GPIO signal is sufficient-no RC filter or decoupling capacitor is needed for reliable operation of the ADP121-ACBZ25R7.

Can the ADP121-ACBZ25R7 operate with a 0.7 μF output capacitor?

Yes-the ADP121-ACBZ25R7 is stable with a minimum 0.70 μF ceramic output capacitor (per Table 2), provided ESR remains ≤1 Ω. However, the datasheet recommends ≥1 μF for optimal transient response and margin across temperature/voltage bias. Using 0.7 μF may reduce load-step immunity but will maintain stability for the ADP121-ACBZ25R7 in most static conditions.

What is the maximum allowable input voltage for the ADP121-ACBZ25R7?

The absolute maximum input voltage for the ADP121-ACBZ25R7 is +6.5 V (per Table 3 Absolute Maximum Ratings), but the recommended operating range is 2.3 V to 5.5 V. Exceeding 5.5 V risks violating functional specifications and may accelerate parametric drift or reduce reliability-even if within absolute max limits-so system design should clamp or regulate VIN to ≤5.5 V for robust ADP121-ACBZ25R7 operation.

How does the ADP121-ACBZ25R7 behave during thermal shutdown?

When the ADP121-ACBZ25R7 junction temperature reaches 150°C (typical), thermal shutdown disables the output, reducing load current to zero. Recovery occurs only after the junction cools to ~135°C (15°C hysteresis). During sustained overload (e.g., VOUT-to-GND short), this causes oscillation between 225 mA current limit and zero output-protecting the die but requiring external thermal design to avoid repeated cycling. This behavior is intrinsic to the ADP121-ACBZ25R7's protection architecture.