Monolithic Power Systems Inc. MP5505GL-P

Overview

MP5505GL-P 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 slew rate (0.5–1.5 ms), 6V bus clamping, and 12V storage voltage capability. It delivers hold-up power during input outage for SSD/HDD systems using minimal external components in a 3mm×4mm QFN20 package.

For engineers reviewing the MP5505GL-P datasheet, MP5505GL-P pinout, MP5505GL-P application, or MP5505GL-P equivalent, key selection criteria include its programmable input current limit (up to 4.6A), dual feedback-controlled storage (FBS) and release (FBB) voltages, thermal shutdown (150°C), reverse-current protection, and EN/ENCH dual-enable sequencing for reliable hot-swap operation.

Technical Context

The MP5505GL-P implements a patented bidirectional Buck/Boost architecture: Boost mode charges the STRG capacitor to a user-set voltage (e.g., 12V) using a constant-on-time controller with ICH-adjustable peak current (500 mA typical); Buck mode releases stored energy to maintain VB at ≥4.2V during input failure, operating at fixed 500 kHz with 100% duty-cycle capability.

Its control logic integrates three critical timing functions: DVDT pin sets VB rise time via external capacitor (0.9 ms default), TPOR pin programs Power-On-Reset delay (0.4 ms default), and ILIM pin configures input current limit via resistor (4.6A @ 1.07 kΩ). All protections - thermal shutdown (150°C), VIN UVLO (2.5V rising), VB UVLO (1.8V rising), and reverse-current blocking - are hardware-asserted without firmware dependency.

Key Specifications

Pinout & Package

MP5505GL-P is housed in a thermally enhanced 20-pin QFN package (3mm × 4mm, 0.5mm pitch) with exposed thermal pad. The package supports 2.6W continuous power dissipation at +25°C ambient (θ_JA = 48°C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS43060 and LTC4420, MP5505GL-P uniquely integrates input current limiting, programmable dv/dt, bidirectional Buck/Boost, and dual feedback control in one QFN20 package - reducing BOM count by 7 components and PCB area by 45% versus discrete implementations.

Availability

MP5505GL-P is available at Aetrix Electronics and suitable for solid-state drive power hold-up, hard-disk drive crash protection, and industrial PLC backup power requiring stable component supply across extended production lifecycles.

Supply support for MP5505GL-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 energy management solutions.

The MP5505 product line targets compact, high-efficiency energy storage for storage-class memory and rotating media systems - designed to replace discrete hot-swap + capacitor + DC/DC solutions with a single-chip lossless architecture.

FAQ

What is the minimum storage capacitor value required for 20 ms hold-up at 4A with 5V input?

Using the formula C_S = (V_STORAGE² − V_RELEASE²) / (2 × I_RELEASE × V_RELEASE × τ_DASP) and assuming V_STORAGE = 12V, V_RELEASE = 4.2V, I_RELEASE = 4A, and τ_DASP = 20ms, the calculated minimum is 1500µF. Accounting for 10% efficiency loss, select ≥1650µF - typically implemented as two 1000µF POSCAPs in parallel.

Can MP5505GL-P operate with a 3.3V input supply?

Yes. The MP5505GL-P supports 2.7V–7V input range. At 3.3V input, configure storage voltage to ≥8V (e.g., 8V via R1=127kΩ/R2=14kΩ) and release voltage to ≥3.0V (e.g., 3.0V via R3=107kΩ/R4=40.2kΩ) to ensure sufficient headroom for Buck release operation and avoid UVLO triggering.

How does the ENCH pin sequencing prevent false release triggering?

When ENCH is asserted before VB stabilizes, high charge current can pull VB below the FBB threshold (0.79V), falsely triggering Buck release. By delaying ENCH until VB reaches ≥4.2V (confirmed by PGIN HIGH), the 23mV hysteresis between boost and release modes prevents oscillation - ensuring release occurs only during genuine input loss.

Is an external diode required on the VBO pin?

An external Schottky diode (e.g., 20V/5A) is strongly recommended between VBO and SW to prevent reverse current flow during Boost mode startup. Without it, inductor flyback can cause voltage spikes exceeding the 35V VSTRG absolute max rating, risking device damage - especially with large storage capacitors.

What is the thermal performance impact of the exposed paddle in QFN20 package?

The exposed thermal pad reduces θ_JA from 65°C/W (no pad) to 48°C/W (with 4-layer PCB per JESD51-7). Soldering the pad to a 200mm² copper pour lowers junction temperature by 22°C at 2.6W dissipation - critical for maintaining 125°C max operating junction temperature in enclosed industrial enclosures.

Does MP5505GL-P support dynamic adjustment of storage voltage during operation?

No. Storage voltage is set statically by the FBS resistor divider (R1/R2) and regulated to a fixed value (e.g., 12V). The feedback loop lacks digital interface or voltage-programming pins; changing V_STORAGE requires physical resistor replacement - intended for one-time system configuration, not runtime adaptation.

How does the internal 30mΩ disconnect switch improve system reliability?

The 30mΩ switch isolates STRG from VB during shutdown or fault conditions, preventing leakage discharge through the Buck/Boost inductor path. This extends hold-up time by >15% versus designs using only MOSFET body diodes, and eliminates parasitic discharge paths that degrade capacitor lifetime in long-term standby applications.