Monolithic Power Systems Inc. MP5505AGL-Z

Overview

MP5505AGL-Z from Monolithic Power Systems is a 2.7V–7V input, 4A lossless energy storage and management unit with integrated bidirectional buck/boost converter, programmable dv/dt bus start-up, and power-on-reset for SSD/HDD power-backup systems. It delivers up to 4.6A input current limit, 6V bus clamping, and supports 12V storage voltage with 4.2V release threshold in a QFN-20 (3mm × 4mm) package.

For engineers reviewing the MP5505AGL-Z datasheet, MP5505AGL-Z pinout, MP5505AGL-Z application, or MP5505AGL-Z equivalent, key selection criteria include programmable input-current limit via ILIM resistor, dual open-drain power-good indicators (PGIN/PGS), thermal shutdown at 150°C, and configurable storage/release voltages using external feedback dividers.

Technical Context

The MP5505AGL-Z implements a patented bi-directional energy transfer architecture: during normal operation, its boost converter charges the STRG capacitor to a user-set voltage (e.g., 12V) using pre-charge + regulated boost modes; upon input loss, it switches to fixed-frequency (500kHz) constant-on-time (COT) buck mode to discharge stored energy into the VB bus.

Its integrated hot-swap FET (50mΩ R_DS(ON)) provides input-current limiting with dv/dt-controlled soft-start via DVDT pin, reverse-current blocking, and EN/ENCH dual enable logic ensuring safe sequencing-ENCH must be asserted only after VB settles to avoid accidental release mode entry.

Key Specifications

Pinout & Package

MP5505AGL-Z is housed in a thermally enhanced QFN-20 (3mm × 4mm) package with exposed thermal pad (PGND-connected). Pin functions are validated per MPS datasheet Rev. 1.11, including dedicated control pins for dv/dt (DVDT), power-on-reset delay (TPOR), current limit (ILIM), and dual power-good outputs (PGIN/PGS).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar energy storage and management applications.

Compared with MP5504AGL-Z, MP5505AGL-Z adds TPOR programmability and 4.6A current capability for robust hot-swap; versus TPS43060RTER, it integrates bidirectional conversion and power-good signaling in one QFN-20 package, reducing BOM count by ≥7 components and layout area by >40%.

Availability

MP5505AGL-Z is available at Aetrix Electronics and suitable for solid-state drive power backup, hard-disk drive write-cache protection, and industrial PLC I/O module hold-up requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MP5505AGL-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 core expertise in DC/DC conversion, motor drivers, and energy management solutions.

The MP5505A product line targets compact, high-efficiency power-backup systems for storage devices, integrating lossless energy transfer, programmable sequencing, and robust protection features in minimal footprint.

FAQ

What is the minimum recommended storage capacitance for 20ms hold-up at 1A load?

For 1A release current, 12V storage, and 4.2V release threshold, the required capacitance is 1500μF per datasheet Equation (1). A 2200μF low-ESR POS capacitor is recommended to account for voltage derating and ensure ≥20ms margin under worst-case efficiency (90%).

Can EN and ENCH be tied together?

No-tying EN and ENCH together risks accidental release mode activation. ENCH must remain low until VB has fully settled (confirmed by PGIN high), otherwise the boost circuit may misinterpret bus voltage droop as input loss and trigger premature energy release.

What is the maximum allowable storage voltage?

The absolute maximum rating for STRG is 35V, but recommended operating range is VIN to 30V. For 5V input systems, 12V storage is optimal: it maximizes energy density (E = ½CV²) while staying within safe margin of the 30V limit and minimizing capacitor size.

Does MP5505AGL-Z support 3.3V input operation?

Yes-its 2.7V–7V input range fully supports 3.3V rails. At 3.3V, the input-current-limit FET R_DS(ON) rises to 68–83mΩ (vs. 50–65mΩ at 5V), so thermal design must account for higher conduction loss at full 4.6A load.

How is reverse-current protection implemented?

Reverse-current blocking is achieved via the integrated back-to-back hot-swap MOSFET pair. When input voltage falls below VB (or PGIN threshold), the upper FET turns off, preventing stored energy from flowing backward into the input source-no external diodes or controllers needed.

What happens if the DVDT capacitor is omitted?

Omitting the DVDT capacitor results in default soft-start time (~0.9ms from 0V to VIN). While functional, this may cause excessive inrush into large bus capacitors (e.g., >100μF), potentially tripping upstream current limits or causing voltage droop on shared rails.

Is a bootstrap capacitor required on BST pin?

Yes-a 100nF ceramic capacitor between BST and SW is mandatory. It supplies gate-drive voltage for the high-side switch during buck release mode; omission causes immediate failure of energy release functionality and potential latch-up.