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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Special Purpose Regulators

Monolithic Power Systems Inc. MP161BGS-33-Z

Name: MP161BGS-33-Z
Brand: Monolithic Power Systems Inc.
SKU: MP161BGS-33-Z
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: MP161BGS-33-Z

Manufacturer:: Monolithic Power Systems Inc.

Category:: Special Purpose Regulators

Package:: 16-SOIC (0.154", 3.90mm Width)

Datasheet:: MP161BGS-33-Z.pdf

Description:: POWER SOLUTION WITH ULTRA-LOW ST

Quantity:: RFQ Add To RFQ list

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Product details

Overview

MP161BGS-33-Z from Monolithic Power Systems is a highly integrated power management IC combining a 700V switching regulator, a 3.3V low-dropout linear regulator, and two relay drivers in a single SOIC-16 package. It delivers 420mA typical peak current, 14Ω typical R_DS(ON), and ultra-low standby power via programmable STBY control-designed for relay-driven home/industrial automation systems requiring compact, self-contained power stages.

For engineers reviewing the MP161BGS-33-Z datasheet, MP161BGS-33-Z pinout, MP161BGS-33-Z application, or MP161BGS-33-Z equivalent, key selection considerations include its dual-rail output architecture (12V switching + 3.3V LDO), integrated freewheeling diodes for relay drive, standby-mode voltage reduction to 5.7V, and built-in protections including OLP, SCP, OTP, and VIN OVP.

Technical Context

The MP161BGS-33-Z implements constant-voltage regulation using internal loop compensation and an adjustable FB node or fixed 12V output referenced to VCC. Its 700V HV MOSFET operates with programmable peak-current limiting (420mA typ.) and frequency foldback to optimize light-load efficiency while suppressing audible noise via peak-current modulation.

The integrated 3.3V LDO accepts up to 30V input, features 3.3V ±2% output accuracy, 300mV dropout at 50mA, and independent over-temperature protection. Two 2Ω on-resistance relay drivers (OUTA/OUTB) support rail-to-rail logic inputs (INA/INB), include internal pull-downs and freewheeling diodes, and are powered directly from the switching regulator's output.

Key Specifications

Parameter	Value and Actual Design Meaning
Switching Regulator Output	Fixed 12V or adjustable via FB; regulated at 12.5V nominal during normal operation.
Peak Current Limit	420mA typical - sets maximum deliverable power before OLP triggers at 8192 consecutive min-off cycles.
HV MOSFET R_DS(ON)	14Ω typical at 25°C - determines conduction loss and thermal rise under full load.
LDO Output Voltage	3.3V ±2% - powers MCU peripherals or logic circuitry with stable low-noise supply.
Standby Output Voltage	5.7V typical - reduces switching regulator output to cut idle power consumption by >50%.
Relay Driver R_ON	2Ω typical - enables direct drive of standard 12V/24V relays without external FETs or flyback diodes.
Thermal Shutdown Threshold	150°C with 30°C hysteresis - ensures safe recovery after overtemperature events without latch-off.

Pinout & Package

MP161BGS-33-Z is housed in a 16-pin SOIC package with exposed pad (SOIC-16), optimized for thermal dissipation in high-voltage industrial environments. Pin assignments are validated per MPS MP161 Rev. 1.01 datasheet.

Pin/Terminal	Circuit Role	Design Meaning
1 INB	Logic input – Relay B	TTL/CMOS-compatible control signal; internal 450kΩ pull-down ensures default OFF state.
2 INA	Logic input – Relay A	Independent channel enable; supports simultaneous or staggered relay actuation.
3 STBY	Standby mode control	High = 5.7V regulated output; Low = 12.5V regulated output; hysteresis prevents chatter.
4, 14 GND	Power ground	Common reference for LDO, relay drivers, and logic; separate from SOURCE (HV return).
5 VO	LDO output	3.3V regulated supply; capable of driving 100mA load with <0.01%/mA load regulation.
8 DRAIN	HV MOSFET drain	700V-rated primary switch node; connects to rectified AC line or DC bus input.
9 VCC	Switching regulator supply	Internally regulated bias rail; also serves as feedback reference in fixed-output mode.
10 FB	Feedback input	Connect external resistor divider to set adjustable output; open = internal 12V regulation.
11 SOURCE	HV MOSFET source	High-side switch return path; referenced to DRAIN for HV current sensing.
13 VIN	LDO input	Accepts 3.9–29V; includes 28V OVP shutdown to protect downstream circuitry.
15 OUTA	Relay A output	Drives relay coil between OUTA and VIN; integrated freewheeling diode clamps inductive kick.
16 OUTB	Relay B output	Independent second channel; identical specs and protection to OUTA.

Key Features

Feature	Design Value
Integrated 700V HV MOSFET	Eliminates need for external high-voltage switch and gate driver in AC/DC auxiliary supplies.
Ultra-low standby power mode	Reduces VCC output from 12.5V to 5.7V, cutting no-load power by >55% in relay-idle states.
Dual-channel relay drivers	2Ω R_ON, 30V breakdown, integrated freewheeling diodes - removes 4 external components per channel.
Comprehensive protection suite	OTP, SCP, OLP, OVP, BOP, and UVLO - enables robust operation without external supervision circuitry.
Fixed 3.3V LDO with wide input range	Operates from 3.9V to 29V VIN; maintains regulation across brownout and surge conditions.

Applications

Smart Lighting Control

Industrial PLC I/O Module

Use Scenario: Controlling multiple AC-powered LED fixtures or ballasts via microcontroller-governed relay banks.

IC Role / Device Role / Timing Role: Single-chip power stage providing isolated 12V for relay coils and clean 3.3V for MCU and sensor interface.

Use Value: Reduces BOM count by integrating HV switching, LDO, and dual relay drivers - enabling sub-15mm² PCB footprint.

Use Scenario: Modular digital output card in programmable logic controllers handling 24VDC solenoid and valve actuation.

IC Role / Device Role / Timing Role: Powers local logic and drives two independent 24V relays with fast turn-on (<50ns) and controlled turn-off.

Use Value: Eliminates discrete HV FETs, flyback diodes, and LDO regulators - simplifying layout and improving reliability in harsh EMI environments.

Home Automation Hub

Energy Monitoring Gateway

Use Scenario: Centralized smart home controller managing HVAC, blinds, and security relays with local MCU processing.

IC Role / Device Role / Timing Role: Supplies 3.3V to ARM Cortex-M host and 12V to electromechanical relays; enters standby when all loads are de-energized.

Use Value: Achieves <30mW standby consumption via STBY-controlled output reduction - meeting Energy Star Level VI requirements.

Use Scenario: DIN-rail mounted gateway aggregating current/voltage sensor data and controlling utility-grade breakers.

IC Role / Device Role / Timing Role: Provides fault-tolerant 3.3V supply for isolation ICs and microcontroller, plus 12V for contactor drivers with OVP and OTP.

Use Value: Built-in VIN OVP (28V) and thermal shutdown prevent damage during grid transients or enclosure overheating.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MP161AGS-33-Z	Lower 240mA peak current limit and 17Ω R_DS(ON); same pinout and feature set.	Suitable for <1W relay loads; less thermal margin in continuous-duty industrial use.	Select when cost sensitivity outweighs power headroom; verify OLP trip point against worst-case load.
MP161BGS-5-Z	Identical architecture but 5V LDO output instead of 3.3V; shares same 420mA/14Ω HV stage.	Required where legacy 5V logic or sensors dominate; incompatible with 3.3V-only MCUs without level shifting.	Choose only if system-level voltage rails mandate 5V LDO; no electrical trade-offs in switching or relay performance.

Compared with MP161AGS-33-Z, MP161BGS-33-Z offers 75% higher peak current and lower conduction loss for demanding relay loads, while MP161BGS-5-Z preserves all power-stage advantages but shifts LDO compatibility to 5V ecosystems-making MP161BGS-33-Z optimal for new 3.3V MCU-based designs requiring robust relay drive.

Availability

MP161BGS-33-Z is available at Aetrix Electronics and suitable for home automation hubs, industrial PLC I/O modules, smart lighting controllers, and energy monitoring gateways requiring stable component supply across multi-year production cycles.

Supply support for MP161BGS-33-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 MP161 product line delivers fully integrated power solutions for relay-centric automation systems, combining HV switching, precision LDOs, and robust drivers to eliminate discrete power stage complexity in space-constrained industrial and smart-home applications.

FAQ

What is the maximum recommended load current for the 3.3V LDO output?

The MP161BGS-33-Z LDO is specified for up to 100mA continuous output with guaranteed line and load regulation. At 50mA, dropout is 300mV; derating is advised above 85°C ambient due to thermal limits. The LDO includes independent over-temperature protection that disables output above 150°C junction temperature.

Can the switching regulator output be adjusted to voltages other than 12V?

Yes - the FB pin supports external resistor divider configuration to set custom output voltages. With internal 450kΩ lower resistor and 4.1MΩ upper resistor, the default fixed output is ~12.5V. Replacing the upper resistor allows outputs from ~5V to ~24V, subject to VCC stability and minimum off-time constraints.

How does the STBY pin affect relay driver operation during standby mode?

STBY controls only the switching regulator output voltage (12.5V → 5.7V); it does not disable the LDO or relay drivers. VIN remains powered from the reduced VCC rail, so OUTA/OUTB retain full functionality - enabling active relay control even in low-power mode, provided total load stays within reduced VCC capability.

Is an external freewheeling diode required for the relay drivers?

No - each relay driver (OUTA/OUTB) integrates a freewheeling diode rated for continuous 30V reverse blocking and 100mA forward current. This eliminates external diodes and associated PCB area, while ensuring reliable coil-energy recirculation during turn-off.

What protections activate if the VIN supply exceeds 30V?

VIN overvoltage protection (VOVP) triggers at 28V typical, shutting down the switching regulator and discharging the external VIN capacitor via a 5mA internal sink. This prevents damage to the LDO and relay drivers, and remains active until VIN drops below the hysteresis threshold (~26.5V).

Does the MP161BGS-33-Z support synchronous rectification?

No - the MP161BGS-33-Z uses asynchronous rectification with an external diode in the switching regulator path. Its architecture relies on internal HV MOSFET + external flyback diode; no gate-drive signals or timing interfaces for synchronous FETs are provided.

What is the minimum off-time limitation and how does it impact OLP response?

The minimum off-time is 12.5μs typical for MP161BGS-33-Z. OLP triggers after 8192 consecutive cycles at this minimum off-time - corresponding to sustained overload lasting ~100ms at 80kHz switching. This delay prevents false trips during startup or transient surges while ensuring timely shutdown under persistent overloads.

MP161BGS-33-Z Specifications

Product attributes: Attribute value

Manufacturer:: Monolithic Power Systems Inc.

Series:: MP

Package/Case:: 16-SOIC (0.154", 3.90mm Width)

Packaging:: Tape & Reel (TR)

Product Status:: Active

Applications:: Converter, Industrial and Automotive Sensors

Voltage - Input:: 30V

Number of Outputs:: 2

Voltage - Output:: 3.3V

Operating Temperature:: -40°C ~ 125°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 16-SOIC

MP161BGS-33-Z FAQ

1.How can I place an order for MP161BGS-33-Z through Aetrix?

Please submit a Request for Quotation (RFQ) for MP161BGS-33-Z on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for MP161BGS-33-Z reliable?

The price and inventory of MP161BGS-33-Z are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MP161BGS-33-Z is usually 5 days.

3.What payment methods are accepted for MP161BGS-33-Z?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MP161BGS-33-Z transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for MP161BGS-33-Z?

MP161BGS-33-Z orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MP161BGS-33-Z order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for MP161BGS-33-Z?

For technical support, including MP161BGS-33-Z datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MP161BGS-33-Z requirements.

6.How does Aetrix verify that MP161BGS-33-Z is sourced from the original manufacturer or authorized distributors?

All MP161BGS-33-Z products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that MP161BGS-33-Z meets industry standards.

7.What is the process for return or replacement of MP161BGS-33-Z?

All MP161BGS-33-Z units undergo pre-shipment inspection (PSI). If there is an issue with MP161BGS-33-Z, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The MP161BGS-33-Z part is unused and in its original packaging.

Return procedure for MP161BGS-33-Z:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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