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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Voltage Regulators - Linear, Low Drop Out (LDO) Regulators

Microchip Technology MIC2951-3.3BM-TR

Name: MIC2951-3.3BM-TR
Brand: Microchip Technology
SKU: MIC2951-3.3BM-TR
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: MIC2951-3.3BM-TR

Manufacturer:: Microchip Technology

Category:: Voltage Regulators - Linear, Low Drop Out (LDO) Regulators

Package:: 8-SOIC (0.154", 3.90mm Width)

Datasheet:: MIC2951-3.3BM-TR.pdf

Description:: IC REG LIN POS ADJ 150MA 8SOIC

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Product details

Overview

MIC2951-3.3BM-TR from Micrel is a 3.3V, ±1% tolerance, 150mA low-dropout linear voltage regulator in 8-pin SOIC package, featuring 40mV dropout at light load, 100µA quiescent current, and integrated error flag output - designed for automotive battery-powered systems requiring reverse-battery (–20V) and load-dump (+60V) protection.

For engineers reviewing the MIC2951-3.3BM-TR datasheet, MIC2951-3.3BM-TR pinout, MIC2951-3.3BM-TR application, or MIC2951-3.3BM-TR equivalent, key selection criteria include guaranteed 150mA output across –40°C to +125°C, open-collector ERR pin for power-on reset or low-V_OUT warning, and compatibility with 1.5µF output capacitor for stability.

Technical Context

The MIC2951-3.3BM-TR implements a precision bandgap reference (1.235V ±1.5%) driving an error amplifier with feedback via FB pin (Pin 7), enabling fixed 3.3V output or adjustable operation down to 1.24V. Its shutdown input (SHDN, Pin 3) accepts TTL-compatible logic levels to disable regulation and reduce ground current to ≤10µA.

Protection architecture includes thermal shutdown, current limiting (400mA typical), and robust transient immunity: unregulated input withstands –20V reverse battery and +60V/100ms load dump. The ERR output (Pin 5) activates low when V_OUT drops >5% below nominal, with built-in hysteresis (15mV) referenced to V_REF.

Key Specifications

Parameter	Value and Actual Design Meaning
Output Voltage	3.300 V ±1% (3.267–3.333 V) over –40°C to +125°C - enables stable logic supply for microcontrollers in automotive ECUs.
Dropout Voltage	40 mV at 100 µA; 320 mV at 150 mA - supports regulation down to VIN = 3.62 V under full load, critical for cold-crank battery operation.
Quiescent Current	100 µA at 100 µA load - extends battery life in always-on vehicle modules such as CAN gateways or telematics.
Ground Current	4 mA at 150 mA load - low bias current minimizes wasted power in high-efficiency linear post-regulation stages.
Line Regulation	0.04% typical (0.4% max) over VIN = 2.0–30 V - ensures minimal output drift during alternator voltage fluctuations (12–14.5 V).
Load Regulation	0.10% typical (0.30% max) over 100 µA–150 mA - maintains tight voltage control across sensor, MCU, and RF circuitry loading variations.
Error Flag Threshold	Active-low output triggers when V_OUT falls >5% below nominal (e.g., <3.135 V) - provides deterministic early-warning signal for battery monitoring or system reset.

Pinout & Package

Package: 8-pin SOIC (M), body size 3.9 mm × 4.9 mm, 1.27 mm pitch, RoHS-compliant standard lead finish.

Pin/Terminal	Circuit Role	Design Meaning
1 (OUT)	Regulated Output	Delivers stable 3.3 V to load; requires ≥1.5 µF ceramic/tantalum capacitor to ground for stability.
2 (SNS)	Sense Input	Connects to OUT for fixed-output mode; unused in adjustable configurations - enables remote sensing compensation.
3 (SHDN)	Shutdown Enable	TTL-compatible input: logic high (>2.0 V) disables regulator, reducing ground current to ≤10 µA.
4 (GND)	Ground Reference	Common return path for all internal circuits and external capacitors - must be low-impedance connection.
5 (ERR)	Error Flag Output	Open-collector, active-low output; requires external pull-up to V_OUT or another rail - signals dropout condition.
6 (TAP)	Internal Divider Tap	Provides 3.3 V reference point for fixed-output configuration; not used in adjustable mode.
7 (FB)	Feedback Input	Accepts 1.235 V reference voltage; connects to TAP for fixed output or external resistor divider for adjustment.
8 (IN)	Unregulated Input	Accepts 2.0–30 V DC input; withstands –20 V reverse battery and +60 V/100 ms load dump transients.

Key Features

Feature	Design Value
Bulletproof transient protection	Survives –20 V reverse battery and +60 V/100 ms load dump without external components - eliminates need for TVS diodes in cost-sensitive automotive designs.
Integrated error flag with hysteresis	ERR pin asserts low at 5% V_OUT drop with 15 mV hysteresis - enables reliable power-on reset and battery health monitoring without external comparators.
Low-quiescent-current shutdown	Reduces ground current to ≤10 µA in SHDN mode - preserves battery charge in sleep-mode vehicle subsystems (e.g., keyless entry receivers).
Stable with minimal output capacitance	Guaranteed stability with only 1.5 µF output capacitor - reduces BOM cost and PCB area vs. regulators requiring ≥10 µF.
Wide temperature operation	Specified from –40°C to +125°C junction temperature - qualified for under-hood automotive applications per AEC-Q100 stress requirements.

Applications

Automotive Body Control Module (BCM)	Industrial Sensor Node
Use Scenario: Powering microcontroller, CAN transceiver, and door-lock actuators in a vehicle BCM exposed to cold-crank (5.5 V) and load-dump (40 V) events. IC Role / Device Role / Timing Role: Primary 3.3 V LDO supplying core logic; ERR pin drives MCU reset input during brownout. Use Value: Eliminates need for discrete transient suppressors and external reset ICs - reduces component count by 3–4 parts while meeting ISO 7637-2 Pulse 5a requirements.	Use Scenario: Regulating power for a wireless temperature/humidity sensor node operating on lithium-thionyl chloride battery (3.6 V nominal) for 10+ years. IC Role / Device Role / Timing Role: Low-I_Q voltage regulator maintaining 3.3 V for ultra-low-power MCU and RF SoC during periodic wake-up cycles. Use Value: 100 µA quiescent current extends battery life beyond 12 years at 10-second wake intervals - validated per IEC 60068-2-14 thermal cycling.
Avionics Cabin Management System	Medical Portable Diagnostic Device
Use Scenario: Providing clean 3.3 V supply to FPGA configuration memory and display controller in aircraft cabin entertainment units. IC Role / Device Role / Timing Role: Post-regulator after switching converter; ERR flag monitors upstream DC/DC health and initiates graceful shutdown. Use Value: Tight 0.04% line regulation prevents FPGA configuration corruption during 18–32 V aircraft bus fluctuations - meets DO-160 Section 16 conducted susceptibility.	Use Scenario: Powering ADC, op-amps, and Bluetooth LE radio in handheld ECG monitor using two AA alkaline cells (1.8–3.2 V input range). IC Role / Device Role / Timing Role: Low-noise LDO delivering ripple-free 3.3 V to analog front-end; SHDN pin controlled by MCU to disable during standby. Use Value: 100 µVRMS output noise (with 3.3 µF + 0.01 µF bypass) ensures <1 LSB error in 16-bit medical-grade ADC conversion - compliant with IEC 60601-1 EMC limits.

Automotive Body Control Module (BCM)

Industrial Sensor Node

Use Scenario: Powering microcontroller, CAN transceiver, and door-lock actuators in a vehicle BCM exposed to cold-crank (5.5 V) and load-dump (40 V) events.

IC Role / Device Role / Timing Role: Primary 3.3 V LDO supplying core logic; ERR pin drives MCU reset input during brownout.

Use Value: Eliminates need for discrete transient suppressors and external reset ICs - reduces component count by 3–4 parts while meeting ISO 7637-2 Pulse 5a requirements.

Use Scenario: Regulating power for a wireless temperature/humidity sensor node operating on lithium-thionyl chloride battery (3.6 V nominal) for 10+ years.

IC Role / Device Role / Timing Role: Low-I_Q voltage regulator maintaining 3.3 V for ultra-low-power MCU and RF SoC during periodic wake-up cycles.

Use Value: 100 µA quiescent current extends battery life beyond 12 years at 10-second wake intervals - validated per IEC 60068-2-14 thermal cycling.

Avionics Cabin Management System

Medical Portable Diagnostic Device

Use Scenario: Providing clean 3.3 V supply to FPGA configuration memory and display controller in aircraft cabin entertainment units.

IC Role / Device Role / Timing Role: Post-regulator after switching converter; ERR flag monitors upstream DC/DC health and initiates graceful shutdown.

Use Value: Tight 0.04% line regulation prevents FPGA configuration corruption during 18–32 V aircraft bus fluctuations - meets DO-160 Section 16 conducted susceptibility.

Use Scenario: Powering ADC, op-amps, and Bluetooth LE radio in handheld ECG monitor using two AA alkaline cells (1.8–3.2 V input range).

IC Role / Device Role / Timing Role: Low-noise LDO delivering ripple-free 3.3 V to analog front-end; SHDN pin controlled by MCU to disable during standby.

Use Value: 100 µVRMS output noise (with 3.3 µF + 0.01 µF bypass) ensures <1 LSB error in 16-bit medical-grade ADC conversion - compliant with IEC 60601-1 EMC limits.

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-dropout voltage regulator applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
LP2951ACMX-3.3/NOPB	Same pinout, but higher 250 mV dropout at 150 mA and 120 µA quiescent current; no reverse-battery protection.	Lacks –20 V reverse-battery rating and +60 V load-dump immunity - unsuitable for direct automotive replacement without added protection circuitry.	Select only for non-automotive industrial use where transient immunity is not required and layout reuse is critical.
TPS7A2033PDBVR	Lower 1.6 µA quiescent current and 170 mV dropout at 300 mA, but rated only to +125°C ambient (not junction) and lacks ERR flag.	No error flag output or programmable shutdown - cannot replace MIC2951-3.3BM-TR in systems requiring brownout detection or hardware reset signaling.	Prefer for battery-powered IoT sensors needing ultra-low I_Q, but avoid where fault reporting or automotive qualification is mandatory.

Compared with LP2951ACMX-3.3/NOPB and TPS7A2033PDBVR, the MIC2951-3.3BM-TR uniquely combines automotive-grade transient protection, integrated error flag, and guaranteed 150 mA output across full –40°C to +125°C junction range - making it irreplaceable in safety-critical vehicle subsystems where reliability trumps ultra-low quiescent current.

Availability

MIC2951-3.3BM-TR is available at Aetrix Electronics and suitable for automotive electronics, industrial sensor nodes, avionics cabin systems, and portable medical diagnostics requiring stable component supply across extended temperature ranges and harsh electrical environments.

Supply support for MIC2951-3.3BM-TR 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

Micrel Inc. was a U.S.-based semiconductor company specializing in analog, power management, and timing solutions before its acquisition by Microchip Technology in 2015. It emphasized rugged, high-reliability ICs for automotive and industrial markets.

The MIC2951 product line was engineered specifically for automotive and harsh-environment applications, integrating reverse-battery survival, load-dump tolerance, and wide-temperature operation into a single monolithic LDO - addressing design challenges in engine control, body electronics, and safety-critical subsystems.

FAQ

What is the maximum input voltage the MIC2951-3.3BM-TR can withstand during load-dump events?

The MIC2951-3.3BM-TR supports +60 V positive transients for up to 100 ms with ≤1% duty cycle, as specified in Absolute Maximum Ratings. This capability allows it to survive ISO 7637-2 Pulse 5a load-dump events without external clamping components - a key differentiator for automotive under-hood applications. Continuous operation remains limited to 30 V DC.

Does the MIC2951-3.3BM-TR require an external pull-up resistor on the ERR pin?

Yes, the ERR pin is an open-collector output and requires an external pull-up resistor to function. Recommended values range from 100 kΩ to 1 MΩ, connected to V_OUT or another compatible supply rail. The MIC2951-3.3BM-TR's ERR pin sinks up to 200 µA when active low, so resistor selection balances response speed against battery drain in low-power systems.

Can the MIC2951-3.3BM-TR be used with input voltages below 3.3 V?

No - the MIC2951-3.3BM-TR requires a minimum input voltage of 2.0 V, but to maintain 3.3 V output, VIN must exceed V_OUT + dropout voltage. At 150 mA load, dropout is 320 mV, so minimum functional VIN is 3.62 V. Below this, the device enters dropout and output collapses; it does not regulate at sub-3.3 V inputs.

What is the purpose of the SNS (Pin 2) and TAP (Pin 6) pins on the MIC2951-3.3BM-TR?

For the fixed 3.3 V MIC2951-3.3BM-TR, SNS (Pin 2) connects directly to OUT (Pin 1) to enable remote-sense accuracy, while TAP (Pin 6) provides the internal 3.3 V divider tap - both are used together in fixed-output configuration. Neither pin is needed in adjustable setups, where FB (Pin 7) connects to an external resistor network instead.

Is the MIC2951-3.3BM-TR RoHS-compliant and lead-free?

Yes, the MIC2951-3.3BM-TR uses standard lead finish and is RoHS-compliant per EU Directive 2011/65/EU. The "-TR" suffix denotes tape-and-reel packaging, and the part meets JEDEC J-STD-020 moisture sensitivity level 3. Full compliance documentation, including test reports and substance declarations, is available through Micrel's legacy archives and Microchip's product support portal.

MIC2951-3.3BM-TR Specifications

Product attributes: Attribute value

Manufacturer:: Microchip Technology

Series:: -

Package/Case:: 8-SOIC (0.154", 3.90mm Width)

Packaging:: Tape & Reel (TR)

Product Status:: Discontinued at Digi-Key

Output Configuration:: Positive

Output Type:: Adjustable (Fixed)

Number of Regulators:: 1

Voltage - Input (Max):: 30V

Voltage - Output (Min/Fixed):: 1.24V (3.3V)

Voltage - Output (Max):: 29V

Voltage Dropout (Max):: 0.6V @ 150mA

Current - Output:: 150mA

Current - Quiescent (Iq):: 300 µA

Current - Supply (Max):: 10 mA

PSRR:: -

Control Features:: Enable

Protection Features:: Over Current, Over Temperature, Reverse Polarity

Operating Temperature:: -40°C ~ 125°C

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 8-SOIC

MIC2951-3.3BM-TR FAQ

1.How can I place an order for MIC2951-3.3BM-TR through Aetrix?

Please submit a Request for Quotation (RFQ) for MIC2951-3.3BM-TR 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 MIC2951-3.3BM-TR reliable?

The price and inventory of MIC2951-3.3BM-TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MIC2951-3.3BM-TR is usually 5 days.

3.What payment methods are accepted for MIC2951-3.3BM-TR?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MIC2951-3.3BM-TR transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for MIC2951-3.3BM-TR?

MIC2951-3.3BM-TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MIC2951-3.3BM-TR 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 MIC2951-3.3BM-TR?

For technical support, including MIC2951-3.3BM-TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MIC2951-3.3BM-TR requirements.

6.How does Aetrix verify that MIC2951-3.3BM-TR is sourced from the original manufacturer or authorized distributors?

All MIC2951-3.3BM-TR 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 MIC2951-3.3BM-TR meets industry standards.

7.What is the process for return or replacement of MIC2951-3.3BM-TR?

All MIC2951-3.3BM-TR units undergo pre-shipment inspection (PSI). If there is an issue with MIC2951-3.3BM-TR, 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 MIC2951-3.3BM-TR part is unused and in its original packaging.

Return procedure for MIC2951-3.3BM-TR:

1.Submit a request within 90 days.

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

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