Monolithic Power Systems Inc. MP2308GD-Z

Overview

MP2308GD-Z from Monolithic Power Systems is a synchronous step-down DC-DC converter IC with integrated 60 mΩ high-side and 30 mΩ low-side MOSFETs, delivering up to 4A continuous output current across a 4.75V–18V input range, supporting 300 kHz–2 MHz programmable switching frequency, and operating in current-mode control for fast transient response - used in DSL/cable modems and set-top boxes for compact, efficient 3.3V/5V rail generation.

For engineers reviewing the MP2308GD-Z datasheet, MP2308GD-Z pinout, MP2308GD-Z application, or MP2308GD-Z equivalent, key selection criteria include verified thermal shutdown (150°C), feedback voltage accuracy (800–830 mV), EN logic thresholds (1.12 V low / 1.50 V high), soft-start programmability (8 µA current source), and QFN2x3 package thermal resistance (θJA = 70°C/W).

Technical Context

The MP2308GD-Z implements fixed-frequency peak-current-mode control with internal error amplifier, 0.815 V reference, and hiccup-mode overcurrent protection triggered when FB falls below 70% of reference while current limit is exceeded. Its oscillator uses external R_FREQ to set frequency between 300 kHz and 2 MHz.

It integrates a 5 V internal VCC regulator powered from VIN, bootstrap circuitry for high-side gate drive (BST-SW capacitor required), and dual-mode light-load operation (CCM/DCM/PSM) selectable via AAM pin voltage. Thermal shutdown activates at 150°C with 30°C hysteresis, and UVLO triggers at 4.25 V rising threshold.

Key Specifications

Pinout & Package

MP2308GD-Z is housed in a thermally enhanced 2 mm × 3 mm, 14-pin QFN package with exposed thermal pad (connected to GND). The package supports high-power density layout with low θ_JA (70°C/W) on standard 4-layer PCBs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP2307DN-LF-Z and RT7297BZSP, MP2308GD-Z uniquely combines 4 A capability, programmable frequency, hiccup OCP, and AAM-selectable light-load modes - making it optimal for broadband and industrial applications demanding both performance headroom and operational adaptability.

Availability

MP2308GD-Z is available at Aetrix Electronics and suitable for DSL modems, cable modems, and set-top boxes requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MP2308GD-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 MP2308 belongs to MPS's high-density synchronous buck converter product line, engineered for compact, efficient point-of-load regulation in broadband communications and consumer electronics where thermal performance and minimal external components are critical.

FAQ

What is the minimum recommended input voltage for reliable startup?

The MP2308GD-Z has an input UVLO rising threshold of 4.25 V. Reliable startup requires VIN ≥ 4.25 V; operation below this level disables the IC until voltage rises above the hysteresis threshold of 3.38 V. Input capacitors must maintain voltage above 4.25 V during load transients to prevent unintended shutdown.

How is the output voltage set, and what tolerance does the FB pin introduce?

Output voltage is set using a resistor divider from VOUT to GND, with the FB pin connected to the midpoint. The internal reference is 815 mV (typical), with min/max of 800–830 mV across temperature and process. This ±1.8% reference tolerance directly contributes to VOUT accuracy, independent of resistor tolerance.

Can the MP2308GD-Z operate without an external bootstrap diode?

Yes - the MP2308GD-Z uses internal charge-pump circuitry to bootstrap the high-side driver via the BST–SW capacitor. An external diode (e.g., IN4148) is optional and only recommended for high-duty-cycle applications (VIN/VOUT > 1.5) to improve efficiency by ~1–2% and reduce BST capacitor stress.

What thermal derating applies at 85°C ambient temperature?

With θJA = 70°C/W, the maximum allowable power dissipation at T_A = 85°C is PD_MAX = (150°C − 85°C)/70°C/W ≈ 0.93 W. At 4 A output and 12 V input, typical losses are ~0.6 W - confirming full 4 A operation is viable with adequate PCB copper area and airflow.

Is the EN pin 5 V tolerant, and what is the safe pull-up resistor range?

The EN pin includes an internal 6.7 V Zener clamp. For 12 V VIN, a pull-up resistor ≥53 kΩ limits EN current to <100 µA. Direct connection to >6 V sources risks Zener damage; use resistor isolation or clamp diodes if interfacing with higher-voltage logic.

Does the MP2308GD-Z support pre-biased output startup?

Yes - when the output is pre-biased, the IC disables switching until the soft-start capacitor voltage exceeds the sensed FB voltage. This prevents reverse current flow through the low-side MOSFET and ensures controlled, non-destructive startup into pre-charged loads.

What is the purpose of the AAM pin, and how does it affect light-load efficiency?

The AAM pin selects light-load operation mode: grounded → forced CCM; tied to VCC → DCM/PSM with ~240 mA peak inductor current (at 12 V/3.3 V). Higher AAM voltage increases peak current, improving efficiency but increasing output ripple - enabling design trade-offs per application needs.