Monolithic Power Systems Inc. MP2161AGJ-Z

Overview

MP2161AGJ-Z from Monolithic Power Systems is a synchronous step-down DC/DC converter IC with integrated 110mΩ high-side and 60mΩ low-side MOSFETs, delivering up to 2A continuous output current across a 2.5V–6V input range while regulating output down to 0.6V. It employs constant-on-time (COT) control for fast transient response, features 17μA quiescent current, 1.5MHz switching frequency, and power-good (PG) and enable (EN) pins for sequencing in portable power rails.

For engineers reviewing the MP2161AGJ-Z datasheet, MP2161AGJ-Z pinout, MP2161AGJ-Z application, or MP2161AGJ-Z equivalent, key selection criteria include its TSOT23-8 footprint compatibility, ±10% PG threshold accuracy, 1.5% VFB reference tolerance, hiccup-mode short-circuit protection, and support for ceramic output capacitors without external compensation.

Technical Context

The MP2161AGJ-Z implements a COT control architecture with input-voltage feedforward to maintain stable 1.5MHz switching across input and output variations; on-time is calculated as T_ON ≈ 0.667 μs × V_OUT/V_IN, with a fixed 60ns minimum off-time to prevent instability during transients.

It integrates dual power MOSFETs, a 0.6V precision feedback reference, internal soft-start (1.15ms typical), open-drain PG with 550kΩ pull-up, and cycle-by-cycle current limiting triggered at ~3.2A, entering hiccup mode under sustained overload or short-circuit conditions.

Key Specifications

Pinout & Package

MP2161AGJ-Z is housed in an 8-pin TSOT23 package (2.9mm × 1.6mm × 0.85mm), optimized for space-constrained portable designs and compatible with standard SMT reflow profiles.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar synchronous step-down converter applications.

Compared with TPS62865DLCR and RT7295BGJ8F, MP2161AGJ-Z uniquely combines ultra-low 17μA IQ, integrated PG with VIN-referenced pull-up, and pin-compatible TSOT23-8 layout - making it optimal for space- and battery-limited portable systems requiring seamless power sequencing.

Availability

MP2161AGJ-Z is available at Aetrix Electronics and suitable for wireless networking cards, portable medical instruments, and industrial handheld scanners requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MP2161AGJ-Z 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

Monolithic Power Systems (MPS) is a fabless semiconductor company specializing in high-performance analog and power ICs, with design centers in the US, China, and Taiwan, and global manufacturing partnerships.

The MP2161A belongs to MPS's high-efficiency, low-IQ synchronous buck converter product line, engineered specifically for battery-powered portable electronics where small size, light-load efficiency, and fast transient response are critical.

FAQ

What is the minimum recommended output capacitance for stable operation?

The MP2161AGJ-Z is stable with ≥10μF ceramic output capacitance (X5R/X7R). Lower values may cause instability due to insufficient phase margin; using two 4.7μF capacitors in parallel improves high-frequency ripple suppression and thermal derating.

Does MP2161AGJ-Z require external compensation components?

No external compensation is required. The COT control architecture and internal error amplifier are factory-tuned for stability with standard ceramic output capacitors and inductors between 0.68μH and 2.2μH, eliminating the need for type-II or type-III compensation networks.

How does the power-good (PG) pin behave during startup and fault conditions?

PG remains low until V_OUT reaches 90% of target (e.g., 1.08V for 1.2V output), then pulls high to VIN via its internal 550kΩ resistor. If V_FB drops outside ±10% of 0.6V due to overload or short circuit, PG immediately sinks to ground through an internal MOSFET with <400Ω R_DS(on).

Can MP2161AGJ-Z operate in 100% duty cycle mode, and under what conditions?

Yes - when V_IN ≤ V_OUT + 0.2V, the high-side switch remains continuously on, bypassing the inductor. This dropout mode maintains regulation down to V_IN = 2.5V for a 0.6V output, extending usable battery voltage range without requiring a separate LDO.

What is the maximum allowable junction temperature, and how is thermal protection implemented?

The absolute maximum junction temperature is 150°C, with thermal shutdown activated at that threshold and 30°C hysteresis. Protection is implemented via on-die thermal sensors that disable switching and hold the device in reset until die temperature falls below 120°C, preventing permanent damage during sustained overload.

Is the EN pin internally pulled down, and what logic levels define enable/disable states?

Yes - EN has an internal 1MΩ pulldown resistor to AGND. The device enables when EN voltage exceeds 1.2V (logic high) and disables when EN falls below 0.4V (logic low). Between 0.4V and 1.2V, behavior is undefined; external pull-up/pull-down is recommended for robust state control.