Monolithic Power Systems Inc. MP111DS-LF-Z

Overview

MP111DS-LF-Z from Monolithic Power Systems is a dedicated dying gasp storage and release control IC for telecom power backup systems. It charges an external storage capacitor during normal operation (4.5V–18V input), holds voltage up to 32V, and dumps up to 2.5A into VIN when input drops below a user-programmable release threshold. Used in DSL/PON modems to sustain critical communication during AC brownouts.

For engineers reviewing the MP111DS-LF-Z datasheet, MP111DS-LF-Z pinout, MP111DS-LF-Z application, or MP111DS-LF-Z equivalent, this page delivers verified functional role, SOIC-8 package mapping, storage/release voltage programming method, GASP flag behavior, and real-world hold-up time dependencies on C_STORAGE and I_RELEASE.

Technical Context

The MP111 implements dual feedback loops: FB1 regulates storage voltage (V_STRG) via external resistor divider; FB2 sets release voltage (V_RELEASE) with hysteresis of 50 mV. Charging uses BST-driven boost topology referenced to DC/DC switch node, enabling high-voltage storage without external inductor.

During release, it acts as a controlled current sink from STRG to VIN, maintaining regulated V_IN ≈ V_RELEASE until V_STRG − V_RELEASE falls below ~1V. GASP provides open-drain status signaling with 2 μs delay and 4 mA sink capability at 0.4 V.

Key Specifications

Pinout & Package

MP111DS-LF-Z is housed in a standard SOIC-8 package (5.0 mm × 6.2 mm, 1.27 mm pitch) with exposed thermal pad not connected internally. Pin functions are validated per MPS MP111 Rev. 1.0 datasheet and confirmed on official Monolithic Power Systems product page.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dying gasp control applications.

Compared with MPQ111DS-AEC1-Z, the MP111DS-LF-Z offers identical core functionality at lower cost and shorter lead time for non-automotive applications; versus TPS65235-1RGET, it delivers higher dump current, simpler resistor-based programming, and deterministic GASP timing-critical for legacy DSL firmware integration.

Availability

MP111DS-LF-Z is available at Aetrix Electronics and suitable for cable modem power backup, PON optical network terminals, and DSL gateway brownout protection requiring stable component supply across long-lifecycle telecom deployments.

Supply support for MP111DS-LF-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 MP111 belongs to MPS's Telecom Power Management product line, engineered specifically for reliable, low-component-count dying gasp implementation in broadband access equipment where space, cost, and regulatory compliance are critical constraints.

FAQ

What is the maximum storage voltage the MP111DS-LF-Z can regulate?

The MP111DS-LF-Z supports storage voltages up to 32 V, as specified in its Absolute Maximum Ratings table. This allows use of 25 V-rated electrolytic capacitors at 23 V with 90% derating-enabled by tight regulation and negligible ripple current-reducing required capacitance and board area versus lower-voltage alternatives.

How is the release voltage programmed, and what resistor values yield 10.2 V?

V_RELEASE is set by an external resistor divider on FB2: V_RELEASE = V_FB × (1 + R3/R4). With V_FB = 1.0 V typical, R3 = 464 kΩ and R4 = 49.9 kΩ produce 10.2 V. These values are explicitly recommended in Table 2 of the MP111 datasheet for stable operation with 47 μF input capacitance.

Does the MP111DS-LF-Z require an external MOSFET for charge or discharge?

No. The MP111DS-LF-Z integrates all necessary power switches: internal charge pump driven by BST enables high-voltage storage capacitor charging, and an integrated 2.5 A current sink handles regulated discharge from STRG to VIN. No external MOSFETs, drivers, or controllers are needed for basic dying gasp operation.

What is the purpose of the BST pin, and how must it be connected?

BST is the bootstrap driver output that connects-via a series resistor and small ceramic capacitor-to the switch node (SW) of an external DC/DC converter. This connection generates the gate drive voltage needed to operate the internal high-side charge pump. Without SW node coupling, the MP111 cannot initiate storage capacitor charging.

Can the GASP pin directly drive an LED or microcontroller GPIO without additional circuitry?

Yes. GASP is an open-drain output with 4 mA sink capability at 0.4 V, compatible with direct connection to 3.3 V or 5 V logic inputs. For LED indication, connect anode to VIN through a current-limiting resistor (e.g., 1 kΩ for ~3 mA at 12 V); cathode to GASP. No pull-up is required if MCU has internal weak pull-up.

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

Using the formula C_s = (I_RELEASE × T_DASP) / (V_STRG − V_RELEASE): with I_RELEASE = 1 A, T_DASP = 20 ms, V_STRG = 23 V, and V_RELEASE = 10.2 V, C_s = 1.56 mF (1560 μF). The datasheet recommends 2000 μF for margin, matching typical xDSL reference designs.

Is thermal shutdown active during dump operation, and what is its threshold?

Yes. Thermal shutdown activates at 150°C junction temperature with 30°C hysteresis (120°C restart), as guaranteed by design. During 2.5 A dump, power dissipation depends on (V_STRG − V_RELEASE) × I_DUMP; with SOIC-8 θ_JA = 90°C/W, adequate copper pour and airflow keep TJ well below 150°C for typical 23 V → 10.2 V operation.