Monolithic Power Systems Inc. MP2158AGQH-Z

Overview

MP2158AGQH-Z from Monolithic Power Systems is a synchronous step-down DC-DC converter IC with integrated 120mΩ high-side and 90mΩ low-side MOSFETs, delivering up to 1A continuous output current from a 2.5V–6V input. It features constant-on-time (COT) control, 17μA quiescent current, 1.5MHz switching frequency, and 0.6V reference voltage with ±1.5% accuracy at 25°C - optimized for compact power rails in portable instrumentation and FPGA core supplies.

For engineers reviewing the MP2158AGQH-Z datasheet, MP2158AGQH-Z pinout, MP2158AGQH-Z application, or MP2158AGQH-Z equivalent, key selection criteria include its ultra-small QFN-8 (1.5mm×2mm) footprint, EN/PG signaling for sequencing, hiccup-mode short-circuit protection, and compatibility with low-ESR ceramic output capacitors without external compensation.

Technical Context

The MP2158AGQH-Z implements a constant-on-time control architecture with input-voltage feed-forward, enabling near-constant 1.5MHz switching across input (2.5V–6V) and output (0.6V–VIN) ranges while delivering fast transient response. Its internal PFET/NFET pair supports 100% duty-cycle operation in dropout, and the 60ns minimum off-time prevents sub-harmonic oscillation under light loads.

Power sequencing is enabled via active-high EN and open-drain PG with ±10% FB window detection and 50μs delay; thermal shutdown activates at 150°C with 30°C hysteresis. The device operates over –40°C to +125°C junction temperature and requires no external loop compensation due to COT stability with ceramic output capacitors.

Key Specifications

Pinout & Package

MP2158AGQH-Z is housed in an ultra-compact, thermally enhanced QFN-8 package (1.5mm × 2.0mm, 0.5mm pitch) with exposed thermal pad for efficient heat dissipation in high-density layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS62130ARGTR and RT7295BGJ5, MP2158AGQH-Z uniquely combines adjustable 0.6V output, integrated PG, ultra-small 1.5×2mm QFN-8, and COT control - making it optimal for space- and efficiency-critical portable power rails where sequencing and low-noise regulation are mandatory.

Availability

MP2158AGQH-Z is available at Aetrix Electronics and suitable for portable instrumentation, FPGA development platforms, wireless network cards, and low-voltage I/O system power requiring stable component supply across design-in, prototyping, and volume production phases.

Supply support for MP2158AGQH-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 MP2158A belongs to MPS's ultra-compact synchronous buck converter product line, engineered specifically for space-constrained, battery-sensitive applications demanding high efficiency, fast transient response, and minimal external component count.

FAQ

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

The MP2158AGQH-Z is stable with ≥10μF X5R/X7R ceramic output capacitors. Lower values may cause instability or excessive ripple; 22μF is recommended for 3.3V outputs or high-temperature operation to maintain phase margin above 45°.

Does MP2158AGQH-Z require external compensation components?

No. Its constant-on-time (COT) control architecture eliminates the need for external compensation networks. Stability is inherently achieved with low-ESR ceramic output capacitors, reducing BOM count and layout complexity.

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

PG remains low until FB reaches ±10% of 0.6V (i.e., 0.54V–0.66V); it then pulls high via internal 550kΩ resistor to VIN. During overcurrent or thermal shutdown, PG drops low within 50μs, providing precise system-level fault indication.

Can MP2158AGQH-Z operate with input voltage below 2.5V?

No. The absolute minimum operating input is 2.5V per datasheet specifications. Below this, UVLO disables the device. The under-voltage lockout rising threshold is 2.3V typical, with 260mV hysteresis - ensuring reliable turn-on only within rated range.

What is the maximum achievable output voltage accuracy over temperature?

Over –40°C to +85°C, feedback voltage accuracy degrades to ±2.5% (per datasheet Note 6). For precision applications, use 1% resistors in the FB divider and minimize thermal gradients across R1/R2 to hold total output error within ±3%.

Is the exposed thermal pad on the QFN-8 package electrically connected?

Yes - the exposed pad is internally connected to PGND. It must be soldered to a dedicated PGND copper pour with ≥4 thermal vias (0.3mm diameter) to ensure proper thermal performance and electrical grounding per JEDEC MO-220 guidelines.

How does light-load efficiency compare between CCM and DCM operation?

In discontinuous conduction mode (DCM), the MP2158AGQH-Z disables the low-side switch at zero inductor current, reducing switching losses. At 10mA load, DCM improves efficiency by ~8% versus forced CCM - critical for battery longevity in sleep-mode operation.