Monolithic Power Systems Inc. MP161BGS-5-P

Overview

MP161BGS-5-P from Monolithic Power Systems is an integrated power solution combining a 700V switching regulator, 5V low-dropout linear regulator, and two-channel relay drivers in a single SOIC-16 package. It delivers 12V/70mA and 5V/50mA outputs, features ultra-low standby power via STBY-controlled output voltage reduction to 5.7V, and includes built-in freewheeling diodes, OLP, SCP, OTP, and brown-out protection. It targets relay-driven MCU systems in home and industrial automation.

For engineers reviewing the MP161BGS-5-P datasheet, MP161BGS-5-P pinout, MP161BGS-5-P application, or MP161BGS-5-P equivalent, key selection criteria include its 420mA peak current limit, 14Ω HV MOSFET R_DS(ON), 2Ω relay driver on-resistance, fixed 5V LDO output, and SOIC-16 thermal performance (θ_JA = 80°C/W).

Technical Context

The MP161BGS-5-P implements constant-voltage regulation using internal loop compensation with FB feedback; its 700V HV MOSFET operates with programmable peak-current limiting (420mA typ.) and frequency foldback for light-load efficiency. Standby mode lowers V_CC regulation from 12.5V to 5.7V, reducing quiescent consumption while maintaining relay driver functionality.

Its dual relay drivers feature rail-to-rail 30V operation, integrated freewheeling diodes, and 50ns/100ns turn-on/turn-off delays; the 5V LDO accepts up to 30V input, delivers ±1% output accuracy, and includes independent over-temperature protection. All protections-OLP (8192-cycle delay), SCP (620mA threshold), OTP (150°C shutdown), and BOP-are latched and require V_CC discharge below 2.7V for recovery.

Key Specifications

Pinout & Package

MP161BGS-5-P is housed in a standard SOIC-16 package (8.0mm × 10.0mm, 1.27mm pitch) with exposed pad for thermal enhancement. Pin 1 is marked by a dot; pins 6, 7, and 12 are NC and must remain unconnected.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar integrated power management applications.

Compared with MP161AGS-5-P, MP161BGS-5-P provides 75% higher peak current and 18% lower R_DS(ON) for improved efficiency at medium loads, while MPQ161BG-AEC1 trades commercial cost optimization for automotive reliability - making MP161BGS-5-P the optimal balance of performance, integration, and value for industrial/home automation.

Availability

MP161BGS-5-P is available at Aetrix Electronics and suitable for home automation controllers, industrial PLC I/O modules, and smart appliance control boards requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MP161BGS-5-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 design centers across Asia and North America and global manufacturing partnerships.

The MP161 product line delivers highly integrated AC/DC power solutions targeting relay-based control systems in home and industrial automation, eliminating discrete power stages while maintaining robust protection and ultra-low standby consumption.

FAQ

What is the maximum continuous output power achievable with MP161BGS-5-P?

The MP161BGS-5-P supports up to 1.2W on the 12V switching regulator rail (12V × 100mA) and 0.5W on the 5V LDO rail (5V × 100mA) under TA = 25°C with proper PCB thermal design. Peak power is limited by OLP at 420mA peak current and minimum off-time; actual capability depends on inductor value, ambient temperature, and heatsinking.

Can MP161BGS-5-P drive relays rated for 24V DC coils?

Yes - the relay drivers support rail voltages up to 30V, so 24V DC relays can be driven directly by connecting the coil between OUTA/OUTB and VIN (which is supplied from the 12V switching regulator output). Ensure VIN remains ≥24V under load; use external boost if higher coil voltage is required.

How does the STBY pin affect the LDO output voltage?

The STBY pin has no effect on the 5V LDO output (VO); it only regulates the 12V switching regulator output (VCC). The LDO continues delivering 5V regardless of STBY state, enabling uninterrupted MCU operation while reducing relay coil power during standby.

Is an external feedback resistor divider required for fixed 12V output?

No - the MP161BGS-5-P uses an internal 450kΩ/4.1MΩ resistor divider between VCC and FB to set 12V output. Leave FB unconnected (open) for fixed operation; connect external resistors only when adjusting output voltage.

What happens during short-circuit protection (SCP) activation?

When SCP triggers (e.g., relay coil short), the HV MOSFET shuts off immediately, VCC discharges via ICCL (28μA), and the IC remains latched until VCC falls below 2.7V. Recovery occurs automatically once VCC recharges above VHVoff (4.65V), with soft-start reinitializing switching.

Does the MP161BGS-5-P support synchronous rectification?

No - the MP161BGS-5-P uses asynchronous rectification with an external diode in the flyback path. Its architecture relies on a single internal 700V MOSFET and does not provide gate drive signals for a synchronous rectifier FET.

What is the recommended input capacitor value for universal AC input (85–265VAC)?

For full-wave rectification feeding MP161BGS-5-P, use 1.5–2μF per watt of output power (e.g., 2.2μF for 1W output). A 4.7μF/400V electrolytic capacitor is typical for 12V/70mA + 5V/50mA combined output, ensuring sufficient hold-up during AC zero-crossings.