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Microchip Technology MIC2951-3.3BM
- Part No.:
- MIC2951-3.3BM
- Manufacturer:
- Microchip Technology
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MIC2951-3.3BM.pdf
- Description:
- IC REG LIN POS ADJ 150MA 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,135
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Product details
Overview
MIC2951-3.3BM from Micrel is a 150mA, 3.3V fixed-output low-dropout linear voltage regulator in an 8-pin SOIC package, featuring 1% output voltage accuracy over –40°C to +125°C, 250mV dropout at 100mA load, and integrated reverse-battery (–20V) and load-dump (+60V) protection - deployed in automotive control modules requiring robust power conditioning under harsh electrical environments.
For engineers reviewing the MIC2951-3.3BM datasheet, MIC2951-3.3BM pinout, MIC2951-3.3BM application, or MIC2951-3.3BM equivalent, this page delivers verified specifications, validated pin functions, confirmed automotive-grade operating limits, error flag behavior, and real-world alternative selection guidance for battery-powered and high-reliability embedded systems.
Technical Context
The MIC2951-3.3BM integrates a precision 1.235V bandgap reference with ±1% initial tolerance and 50 ppm/°C temperature coefficient, enabling stable 3.3V regulation across industrial and automotive temperature ranges. Its error comparator monitors output voltage via feedback pin (FB), asserting open-collector /ERR when VOUT drops >5% below nominal - independent of load current.
It employs internal current and thermal limiting, supports logic-controlled shutdown (TTL-compatible SHDN input), and maintains stability with only 1.5µF output capacitance. The regulator operates from 2.0V to 30V input, tolerates transient inputs up to –20V (reverse battery) and +60V (≤100ms, ≤1% duty), and delivers <300µA quiescent current at light loads.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | 3.3V ±1% over –40°C to +125°C - ensures reliable 3.3V rail for microcontrollers and sensors in extended-temperature environments. |
| Max Output Current | 150mA continuous - sufficient for powering small MCUs, CAN transceivers, or sensor interfaces without external pass devices. |
| Dropout Voltage | 250mV at 100mA load - enables operation down to VIN = 3.55V while maintaining regulation, critical for battery discharge scenarios. |
| Quiescent Current | 100µA at 100µA load - minimizes standby power loss in always-on automotive modules and IoT edge nodes. |
| Input Transient Tolerance | –20V reverse battery & +60V load dump (≤100ms) - eliminates need for external TVS or polarity protection in 12V vehicle systems. |
| Error Flag Threshold | Active-low /ERR asserts when VOUT falls >5% below 3.3V (i.e., <3.135V) - provides early warning of brownout or failing input supply. |
| Shutdown Input | TTL-compatible SHDN: <0.7V = enable, >2.0V = shutdown - allows direct interfacing with 3.3V/5V logic without level-shifting. |
| Reference Voltage | 1.235V ±1.5% with 50 ppm/°C TC - supports accurate programmable outputs and stable voltage reference use in analog circuits. |
Pinout & Package
Package: 8-pin SOIC (M), body size 3.9mm × 4.9mm, 1.27mm pitch, standard lead finish. RoHS-compliant per Pb-Free variant MIC2951-3.3YM.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (OUT) | Regulated Output | 3.3V power rail output; requires ≥1.5µF ceramic/tantalum capacitor to ground for stability. |
| 2 (SNS) | Sense Input | Connects to OUT in fixed-voltage mode; senses regulated output to close feedback loop internally. |
| 3 (SHDN) | Shutdown Control | TTL-compatible enable input: low or open = active, high = shutdown (ISHDN ≤ 100µA at 30V). |
| 4 (GND) | Ground Reference | Power and signal ground return; must be low-impedance connection for noise-sensitive applications. |
| 5 (ERR) | Error Flag Output | Open-collector output; pulls low when VOUT drops >5%; requires external pull-up resistor (100kΩ–1MΩ). |
| 6 (TAP) | Internal Divider Tap | Provides 3.3V reference point for fixed-mode configuration; unused in adjustable setups. |
| 7 (FB) | Feedback Input | Monitors output via internal 1.235V reference; used with external resistors for programmable outputs. |
| 8 (IN) | Unregulated Input | Accepts 2.0V–30V DC input; withstands –20V reverse and +60V transient surges per spec. |
Key Features
| Feature | Design Value |
|---|---|
| Reverse-battery protection | Survives –20V applied to IN pin - eliminates need for series diode or external MOSFET in automotive battery connections. |
| Load-dump immunity | Withstands +60V transients ≤100ms at 1% duty cycle - meets ISO 7637-2 Pulse 5a requirements without external clamping. |
| Low-dropout performance | 250mV dropout at 100mA enables >92% efficiency at 3.3V out from 3.6V Li-ion or 5V buck-derived rails. |
| Integrated error flag | Open-collector /ERR provides system-level brownout detection and power-on reset signaling without external comparators. |
| Stability with minimal capacitance | Stable with 1.5µF output capacitor - reduces BOM cost and board space vs. regulators requiring ≥10µF ceramics. |
| Wide-input operation | Operates from 2.0V to 30V input - supports direct connection to 12V/24V vehicle batteries, SMPS post-regulation, and industrial supplies. |
Applications
| Automotive Body Control Module | Industrial Sensor Node |
|---|---|
Use Scenario: Powering 3.3V microcontroller, LIN transceiver, and temperature/humidity sensors in door module exposed to cold cranking and load dump events. IC Role / Device Role: Primary 3.3V LDO regulator with fault monitoring and reverse-polarity resilience. Use Value: Eliminates discrete protection circuitry; /ERR signal triggers MCU watchdog reset before brownout-induced data corruption. | Use Scenario: Battery-powered wireless sensor transmitting via LoRaWAN in remote pipeline monitoring, operating from –40°C to +85°C ambient. IC Role / Device Role: Low-quiescent-current 3.3V supply enabling multi-year battery life with periodic wake-up cycles. Use Value: 100µA IQ at light load extends CR123A battery life beyond 5 years; SOIC package supports automated assembly. |
| Avionics Cabin Monitoring Unit | Medical Portable Diagnostic Device |
Use Scenario: Regulating 3.3V rail for FPGA-based video processing and CAN bus interface in aircraft cabin environmental controllers. IC Role / Device Role: High-reliability LDO with transient immunity and tight line/load regulation (0.2% typical). Use Value: 0.04% line regulation prevents clock jitter in video timing circuits during 18–36V aircraft bus fluctuations. | Use Scenario: Powering ADC, op-amps, and Bluetooth LE SoC in handheld ECG device requiring low-noise, stable 3.3V supply. IC Role / Device Role: Precision voltage source with 50 ppm/°C TC and 100µVRMS noise (with 0.01µF FB bypass). Use Value: Enables <12-bit ENOB in 16-bit ADC measurements by minimizing supply-induced offset drift and noise coupling. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar low-dropout regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS76333DBVR | 300mV dropout at 150mA; no reverse-battery or load-dump protection; 3.3V ±2% accuracy; 85µA IQ. | Lacks automotive-grade transient immunity; suitable only for benign industrial or consumer environments. | Select if lowest quiescent current is critical and input transients are absent or externally managed. |
| NCP1117ST33T3G | 1.2V dropout at 800mA; no /ERR or SHDN; ±2% output accuracy; TO-220/SOT-223 packages only. | No fault reporting or enable control; higher dropout limits use in low-VIN battery apps; larger thermal footprint. | Choose for higher current needs where shutdown and error flag are unnecessary and board space permits DPAK. |
Compared with TPS76333DBVR and NCP1117ST33T3G, the MIC2951-3.3BM uniquely combines automotive-grade transient protection, integrated error flag, and 3.3V ±1% accuracy in an 8-pin SOIC - making it the only option among the three qualified for unguarded 12V vehicle battery interfaces with system-level fault awareness.
Availability
MIC2951-3.3BM is available at Aetrix Electronics and suitable for automotive electronics, industrial sensor nodes, avionics cabin units, and portable medical diagnostics requiring stable component supply across extended temperature and harsh electrical conditions.
Supply support for MIC2951-3.3BM 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, acquired by Microchip Technology in 2015. Its legacy LDO portfolio emphasizes ruggedness and integration for automotive and industrial markets.
The MIC2951 family was designed specifically for automotive power conditioning - delivering pin-compatible upgrades to LP2951 with enhanced dropout, lower quiescent current, and built-in reverse-battery/load-dump survival - targeting engine control units, body electronics, and infotainment subsystems.
FAQ
What is the maximum input voltage the MIC2951-3.3BM can handle continuously?
The MIC2951-3.3BM supports a continuous input voltage range of +2.0V to +30V. While it tolerates transient inputs up to –20V (reverse battery) and +60V (load dump), those extremes are limited to ≤100ms duration and ≤1% duty cycle per datasheet specification. For sustained operation, VIN must remain within 2.0V–30V to ensure reliability and avoid thermal overstress. The MIC2951-3.3BM's internal protection circuitry does not extend continuous rating beyond 30V.
Does the MIC2951-3.3BM require an external pull-up resistor on the ERR pin?
Yes, the MIC2951-3.3BM's ERR pin is an open-collector output and requires an external pull-up resistor to a valid logic-high voltage (e.g., VOUT or another supply). Typical values range from 100kΩ to 1MΩ - selected to balance response speed against leakage current in battery-critical applications. Without this resistor, the ERR signal cannot assert a valid high state, rendering fault detection nonfunctional. This requirement applies to every MIC2951-3.3BM implementation.
Can the MIC2951-3.3BM be used as a precision voltage reference?
Yes, the MIC2951-3.3BM can serve as a precision voltage reference due to its 1.235V internal bandgap reference with ±1.5% initial tolerance and 50 ppm/°C temperature coefficient. When configured in fixed 3.3V mode with SNS tied to OUT and FB tied to TAP, the reference node remains accessible and stable. Its low output impedance and tight regulation make it suitable for calibrating ADCs or biasing precision analog circuits - a documented secondary function confirmed in the MIC2951-3.3BM datasheet.
What is the minimum output capacitance required for stability with the MIC2951-3.3BM?
The MIC2951-3.3BM requires a minimum of 1.5µF output capacitance (tantalum or aluminum electrolytic) between OUT and GND for guaranteed stability across all load and temperature conditions. At loads below 10mA, capacitance may be reduced to 0.5µF; below 1mA, 0.15µF suffices. However, for full 150mA operation - especially near dropout - 1.5µF is mandatory. Using less risks oscillation and output ripple exceeding specification. This value is explicitly defined in the MIC2951-3.3BM datasheet Section "External Capacitors".
How does the shutdown function behave on the MIC2951-3.3BM?
The MIC2951-3.3BM's SHDN pin is TTL-compatible: a voltage ≤0.7V (or open circuit) enables regulation, while ≥2.0V disables output and reduces ground current to ≤20µA. During shutdown, the ERR pin remains high-impedance (floating), and the internal pass element is fully off - preventing backfeed from VOUT to VIN. This behavior is tested and specified across –40°C to +125°C and is consistent across all MIC2951-3.3BM units per the official datasheet.
MIC2951-3.3BM Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- 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 FAQ
1.How can I place an order for MIC2951-3.3BM through Aetrix?
Please submit a Request for Quotation (RFQ) for MIC2951-3.3BM 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 reliable?
The price and inventory of MIC2951-3.3BM 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 is usually 5 days.
3.What payment methods are accepted for MIC2951-3.3BM?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MIC2951-3.3BM transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MIC2951-3.3BM?
MIC2951-3.3BM orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MIC2951-3.3BM 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?
For technical support, including MIC2951-3.3BM datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MIC2951-3.3BM requirements.
6.How does Aetrix verify that MIC2951-3.3BM is sourced from the original manufacturer or authorized distributors?
All MIC2951-3.3BM 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 meets industry standards.
7.What is the process for return or replacement of MIC2951-3.3BM?
All MIC2951-3.3BM units undergo pre-shipment inspection (PSI). If there is an issue with MIC2951-3.3BM, 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 part is unused and in its original packaging.
Return procedure for MIC2951-3.3BM:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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