Monolithic Power Systems Inc. MP2158GQH-Z

Overview

MP2158GQH-Z from Monolithic Power Systems is a synchronous step-down DC/DC converter IC with integrated 118mΩ high-side and 88mΩ low-side MOSFETs, delivering 1A continuous output current from 2.5V–6V input 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 integrated power-good (PG) and enable (EN) functions-optimized for space-constrained portable instrumentation and FPGA core power.

For engineers reviewing the MP2158GQH-Z datasheet, MP2158GQH-Z pinout, MP2158GQH-Z application, or MP2158GQH-Z equivalent, key selection criteria include ultra-low IQ operation in battery-backed systems, COT-based stability with ceramic output capacitors, PG signaling for power sequencing, and thermal shutdown with hiccup-mode short-circuit protection.

Technical Context

The MP2158GQH-Z implements a Constant-On-Time control architecture with input-voltage feedforward, enabling near-constant 1.5MHz switching across its 2.5V–6V input range and maintaining stable regulation without external compensation. Its internal PFET/NFET power stage supports 100% duty-cycle operation in dropout and uses cycle-by-cycle current limiting with 2A threshold.

Power sequencing is enabled via dedicated EN and open-drain PG pins with ±10% output voltage window detection and 550kΩ internal pull-up. The device transitions between sleep mode (17μA IQ), DCM, and CCM based on load, using zero-current detection and proprietary light-load control to suppress ringing and maximize efficiency at sub-10mA loads.

Key Specifications

Pinout & Package

MP2158GQH-Z is housed in an ultra-small QFN-8 package measuring 2.0mm × 1.5mm with exposed thermal pad, optimized for high-density PCB layouts and thermal performance in thin-profile portable devices.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS62130ARGTR and ADP2370ACPZ-R7, MP2158GQH-Z uniquely combines adjustable 0.6V output, integrated PG/EN, 1.5MHz operation in 2.0×1.5mm, and 17μA IQ - making it optimal for compact, battery-sensitive, and sequenced power architectures.

Availability

MP2158GQH-Z is available at Aetrix Electronics and suitable for portable instrumentation, FPGA power delivery, wireless network cards, and battery-powered sensor nodes requiring stable component supply across extended production lifecycles.

Supply support for MP2158GQH-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 across Asia and North America and global manufacturing partnerships.

The MP2158 belongs to MPS's ultra-compact synchronous buck converter product line, engineered specifically for space- and power-constrained portable electronics where minimal footprint, low IQ, and seamless power sequencing are critical.

FAQ

What is the minimum recommended output capacitor value for stable operation?

A 10μF X5R/X7R ceramic capacitor is the minimum recommended value for most applications, placed close to the OUT and PGND pins. Lower values may cause instability under transient load steps due to insufficient phase margin in the COT control loop, especially when combined with inductors below 1μH.

Does MP2158GQH-Z require an external compensation network?

No. The Constant-On-Time control architecture eliminates the need for external compensation components. Stability is inherently achieved through input-voltage feedforward and internal ramp generation, allowing direct use with low-ESR ceramic output capacitors without loop tuning.

How does the PG pin behave during startup and fault conditions?

The PG pin remains low until the FB voltage settles within ±10% of 0.6V for ≥50μs. During overcurrent, thermal shutdown, or UVLO, PG pulls low immediately. After fault clearance, PG asserts high only after successful soft-start completion and sustained regulation - providing reliable power-good sequencing.

Can MP2158GQH-Z operate with input voltage below 2.5V?

No. The absolute minimum operating input is 2.5V per datasheet specifications. Below this, the internal UVLO circuit disables the device at ~2.3V rising threshold with 260mV hysteresis. Operation below 2.5V is not characterized and risks improper regulation or startup failure.

What is the thermal performance of the QFN-8 (2.0×1.5mm) package?

With a 4-layer JEDEC-standard PCB, the package exhibits θJA = 110°C/W and θJC = 55°C/W. At 1A load and 5V input, typical junction temperature rise is ~45°C above ambient - well within the 125°C max operating limit, provided the exposed thermal pad is soldered to ≥100mm² copper pour.

Is the 1.5MHz switching frequency adjustable?

No. The switching frequency is fixed at 1.5MHz nominal by the internal COT timing circuit and cannot be adjusted externally. Frequency variation is limited to ±20% over temperature and input voltage, ensuring predictable EMI profile and inductor sizing.

How does light-load efficiency compare between CCM, DCM, and sleep modes?

In sleep mode (≤1mA load), IQ drops to 17μA, achieving >85% efficiency at 100μA output. In DCM (1–10mA), efficiency rises to >90% via ZCD-controlled low-side turn-off. In CCM (>10mA), peak efficiency exceeds 94% at 500mA due to minimized conduction losses in both MOSFETs.