Monolithic Power Systems Inc. MP3430HQ-P

Overview

MP3430HQ-P from Monolithic Power Systems is a monolithic 90V step-up converter with integrated high-side avalanche photodiode (APD) current monitoring, featuring 1.3MHz fixed-frequency current-mode control, 1:10 and 1:2 APD current mirror outputs, and programmable APD over-current protection via RLIM pin. It delivers precise APD biasing up to 90V in optical receivers for fiber-optic network equipment.

For engineers reviewing the MP3430HQ-P datasheet, MP3430HQ-P pinout, MP3430HQ-P application, or MP3430HQ-P equivalent, key selection criteria include APD current monitor accuracy (±5% tolerance), 50ns response speed for transient optical power events, 90V output capability with 2.7–5.5V input, and QFN16 thermal performance (θJA = 60°C/W).

Technical Context

The MP3430HQ-P implements a constant-frequency, current-mode boost architecture with internal compensation and soft-start, enabling fast transient response and cycle-by-cycle current limiting. Its PWM comparator compares a ramp-modulated switch current signal against a feedback-derived reference voltage to regulate output voltage across wide load and line variations.

It integrates a dedicated high-side APD current monitor with two mirrored outputs (MON1 at 1:10 ratio, MON2 at 1:2 ratio), both clamped to ≤3.5V and capable of sourcing up to 2.5mA. APD current limit is resistor-programmable via RLIM (0.36–4.3mA range), with independent over-current and thermal shutdown (160°C) protections.

Key Specifications

Pinout & Package

The MP3430HQ-P is housed in a thermally enhanced 3mm × 3mm QFN16 package with exposed thermal pad soldered to PCB ground plane. Pin 1 is marked by a dot or notch; pins 1 and 16 are internally connected PGND, and the exposed pad must be electrically and thermally tied to system ground.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar APD biasing and monitoring applications.

Compared with MAX3272EASA+ and TSM1082IR, the MP3430HQ-P uniquely integrates dual-ratio APD current monitoring, resistor-programmable over-current protection, and 90V capability in a single 3×3mm QFN, reducing total solution size by ≥40% and eliminating external sensing components required by alternatives.

Availability

MP3430HQ-P is available at Aetrix Electronics and suitable for fiber-optic receiver modules, optical line terminals, PIN diode biasing circuits, and LiDAR optical front-ends requiring stable component supply, long-lifecycle support, and RoHS-compliant packaging.

Supply support for MP3430HQ-P 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 over 20 years of expertise in DC/DC conversion, motor drivers, and optical power management.

The MP3430 product line targets high-voltage optical receiver subsystems, delivering integrated APD biasing and real-time current monitoring to replace multi-chip solutions in telecom, datacom, and sensing applications.

FAQ

What is the maximum APD voltage the MP3430HQ-P can safely bias?

The MP3430HQ-P supports up to 90V output voltage with absolute maximum rating of 100V on the APD pin. Operation at 90V is fully characterized across temperature and load; exceeding this requires derating per thermal limits and external protection circuitry.

How does the RLIM pin set APD over-current threshold?

The RLIM pin accepts a resistor to ground that programs the APD current limit between 0.36mA and 4.3mA. For example, a 27.2kΩ resistor sets a 2.5mA limit at 50V output; the relationship is linear and specified in the datasheet as I_RLIM = (V_RLIM × 122) – 48, where V_RLIM is determined by the resistor divider.

Can MON1 and MON2 be used simultaneously for differential monitoring?

Yes - MON1 (1:10) and MON2 (1:2) provide complementary current mirror outputs referenced to AGND. They can drive separate resistive loads to generate proportional voltages (e.g., 0.25V and 1.25V at 2.5mA APD current), enabling ratio-based diagnostics or redundant fault detection without additional amplifiers.

What is the purpose of the MONIN pin and how should it be decoupled?

MONIN supplies bias current to the internal APD monitor circuitry and must be filtered to reject switching noise. A low-pass RC filter (e.g., 10Ω series + 1µF ceramic to AGND) is recommended to suppress ripple from the SW node, ensuring accurate current mirroring and preventing gain error in MON1/MON2 outputs.

Does the MP3430HQ-P require external compensation components?

No - the MP3430HQ-P features internal compensation optimized for stable operation in discontinuous conduction mode (DCM) across its full input/output range. No external compensation network is needed, simplifying design and reducing board area versus controllers requiring external Type-II or Type-III compensation.

How does thermal shutdown interact with APD current limiting?

Thermal shutdown (160°C) and APD over-current protection operate independently: RLIM sets the APD current limit before thermal stress occurs, while thermal shutdown disables the entire IC if junction temperature exceeds safe limits. Both protections remain active simultaneously, with thermal shutdown taking precedence if both conditions occur.

Is the MP3430HQ-P pin-compatible with other MP3430 variants like MP3430GQ?

Yes - MP3430HQ-P and MP3430GQ share identical QFN16 (3mm×3mm) footprint, pinout, and electrical specifications. The HQ variant is recommended by MPS for new designs due to enhanced screening and reliability testing, but both are functionally and mechanically interchangeable.