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onsemi LP2951ACN
- Part No.:
- LP2951ACN
- Manufacturer:
- onsemi
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
LP2951ACN.pdf
- Description:
- IC REG LIN POS ADJ 100MA 8DIP
- Quantity:
- Payment:
- Shipping:
Inventory:2,117
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Product details
Overview
LP2951ACN from onsemi is a micropower low-dropout linear voltage regulator in an 8-pin PDIP package, delivering up to 100 mA output with ±0.5% initial output voltage accuracy at 25°C, 50 mV dropout at 100 µA load, and integrated error flag, shutdown control, and adjustable/programmable output (1.25 V to 29 V). It serves as a precision power supply for battery-powered microcontroller systems requiring stable 5.0 V or configurable rail generation.
For engineers reviewing the LP2951ACN datasheet, pinout, applications, or equivalent options, this page provides verified technical context, validated pin functions, confirmed design values for dropout, quiescent current, line/load regulation, and real-world application cards for embedded power management, battery monitoring, reset signaling, and programmable biasing.
Technical Context
The LP2951ACN integrates a precision 1.235 V bandgap reference, error amplifier with direct feedback access, open-collector error comparator with ~60 mV hysteresis, and logic-level shutdown input. Its architecture supports both fixed-output (5.0 V/3.3 V/3.0 V) and externally programmed configurations via resistive divider on Pin 7 (FB).
It employs internal current and thermal limiting, requires only a 1.0 µF output capacitor for stability in fixed-voltage mode, and maintains regulation down to 30 mV input–output differential at light loads - enabling operation in ultra-low headroom scenarios such as single-cell Li-ion or coin-cell powered devices.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | 5.0 V nominal, ±0.5% tolerance at 25°C; programmable from 1.25 V to 29 V using external resistors on FB pin |
| Dropout Voltage | 30 mV at 100 µA load; 350–450 mV at 100 mA - enables regulation from 5.35 V input for 5.0 V output under full load |
| Quiescent Current | 75 µA typical at no load; increases to 4.0–12 mA at 100 mA output - critical for multi-year battery life in always-on sensors |
| Line Regulation | 0.04% typical (max 0.10%) over Vin = VO+1.0 V to 30 V - ensures stable output across wide input transients |
| Load Regulation | 0.05% typical (max 0.10%) over 100 µA to 100 mA - maintains tight voltage control during dynamic MCU sleep/wake cycles |
| Error Flag Threshold | Triggers when output drops ~5% below nominal (e.g., <4.75 V for 5.0 V version); open-collector output sinks 400 µA |
| Shutdown Input | Logic-compatible: "On" when ≤0.7 V, "Off" when ≥2.0 V; draws ≤50 µA at 2.4 V - compatible with GPIOs of most MCUs |
Pinout & Package
LP2951ACN uses an 8-pin PDIP (Plastic Dual In-line Package), Case 626, with 0.3 inch body width and through-hole mounting. Thermal resistance θJA = 105°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Output) | Regulated voltage output | Delivers up to 100 mA; connects directly to load or external feedback network |
| 2 (Sense) | Output voltage sensing point | Used for remote sensing to compensate PCB trace IR drop; tied to Pin 1 for local regulation |
| 3 (Shutdown) | Active-low enable control | Pull ≤0.7 V to enable regulator; ≥2.0 V disables output and reduces IQ to ≤10 µA |
| 4 (Input) | Unregulated DC input supply | Accepts 4.0 V to 30 V; must be ≥VO + dropout to maintain regulation |
| 5 (Feedback) | Resistor divider node for adjustable output | Connects to external R1/R2; bias current ≤40 nA minimizes programming error |
| 6 (Error Output) | Open-collector fault indicator | Sinks 400 µA when output is out-of-regulation; requires external pull-up resistor (100 kΩ–1 MΩ) |
| 7 (VO Tap) | Internal 5.0 V reference tap | Provides fixed 5.0 V reference for setting output without external divider; used with Pin 6 for preset modes |
| 8 (GND) | Power and signal ground reference | Common return for input, output, feedback, and error circuits; must be low-impedance |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable output range | 1.25 V to 29 V via two-resistor feedback - supports custom rails without redesigning BOM |
| Integrated power-on reset | Error output doubles as µP reset signal with ~5% undervoltage detection - eliminates discrete supervisor IC |
| Ultra-low dropout | 30 mV at 100 µA enables use with single NiMH or LiFePO₄ cells - extends usable battery capacity |
| Stability with minimal capacitance | Stable with 1.0 µF ceramic or tantalum output cap - reduces board area vs. traditional LDOs needing >10 µF |
| Logic-level shutdown | Compatible with 1.8 V/3.3 V/5 V GPIOs - allows firmware-controlled power gating in portable devices |
Applications
| Microcontroller Power Supply | Battery Monitoring System |
|---|---|
Use Scenario: Providing clean, regulated 5.0 V to an ARM Cortex-M0+ MCU in a wireless sensor node powered by two AA alkaline cells. IC Role / Device Role / Timing Role: Primary LDO regulator supplying core logic voltage; error output feeds MCU's NMI pin for brown-out detection. Use Value: 0.5% output tolerance and 0.04% line regulation ensure ADC reference stability; 75 µA quiescent current extends battery life beyond 5 years in sleep mode. | Use Scenario: Monitoring voltage of a 12 V lead-acid backup battery in industrial gateway equipment, triggering disconnect before deep discharge. IC Role / Device Role / Timing Role: Adjustable regulator configured as 3.3 V reference; error flag signals battery sag via optocoupler to system controller. Use Value: Programmable threshold (via R1/R2) sets precise 11.8 V disconnect point; shutdown input enables controlled battery isolation during maintenance. |
| Programmable Bias Generator | Low-Power Reset Circuit |
Use Scenario: Generating a stable 2.500 V reference for a precision DAC in a portable medical instrument. IC Role / Device Role / Timing Role: Precision adjustable LDO operating at 1.25 V reference + resistor ratio; Sense pin used for Kelvin connection to load. Use Value: 0.5% initial accuracy and 0.05% load regulation ensure DAC full-scale error <±0.1%; 1.0 µF stability enables compact layout. | Use Scenario: Delivering power-on reset pulse to an FPGA during cold start from a 5.0 V supply derived from a switching converter. IC Role / Device Role / Timing Role: Fixed 5.0 V regulator with error output wired as active-low reset; pulled up to FPGA VCCO. Use Value: Error flag asserts within 10 µs of input ramp crossing 1.3 V, providing reliable POR before FPGA configuration begins. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar low-dropout regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LP2951CDR2G | Same architecture and pinout, but ±1.0% output tolerance at 25°C and SOIC-8 package | Lacks 0.5% precision; better suited for cost-sensitive industrial controls where tighter regulation isn't required | Select LP2951CDR2G if 1% tolerance is acceptable and surface-mount assembly is preferred |
| NCV2951ACDR2G | Automotive-grade variant with AEC-Q100 qualification, same ±0.5% tolerance and SOIC-8 package | Qualified for automotive ambient range (−40°C to +125°C) and PPAP-capable; higher screening cost | Choose NCV2951ACDR2G for automotive or harsh-environment applications requiring certified reliability |
Compared with LP2951CDR2G and NCV2951ACDR2G, the LP2951ACN offers identical electrical performance and functionality in a through-hole PDIP package - making it ideal for prototyping, legacy designs, and applications requiring manual assembly or high-reliability mechanical retention.
Availability
LP2951ACN is available at Aetrix Electronics and suitable for battery-powered instrumentation, industrial sensor nodes, medical wearables, and legacy control systems requiring stable component supply with long-term manufacturability.
Supply support for LP2951ACN 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
onsemi is a global semiconductor manufacturer focused on energy-efficient electronics, delivering silicon solutions for automotive, industrial, cloud, and IoT applications.
The LP2951 product line was designed for ultra-low-power, high-accuracy linear regulation in space-constrained and battery-dependent systems - emphasizing dropout minimization, quiescent current reduction, and integrated supervisory features.
FAQ
What is the maximum input voltage rating for the LP2951ACN?
The LP2951ACN has an absolute maximum input voltage rating of 30 VDC under continuous operation, with a peak transient rating of 32 VDC for durations under 300 ms. Exceeding these limits may cause permanent damage. For reliable operation, input should remain ≤30 V, and derating is recommended above 85°C ambient due to thermal constraints.
Can the LP2951ACN be used in adjustable-output mode, and what is the minimum output voltage?
Yes, the LP2951ACN supports adjustable output from 1.25 V to 29 V using external resistors on Pin 5 (Feedback) and Pin 6 (VO Tap). The minimum output is set by the internal 1.235 V reference; configuring below 1.25 V is not supported. Accuracy depends on resistor tolerance and feedback bias current (≤40 nA), with typical error <0.2% using 1% resistors.
How does the error output of the LP2951ACN function, and what external components are required?
The LP2951ACN error output (Pin 6) is an open-collector comparator that pulls low when output voltage drops ~5% below nominal (e.g., <4.75 V for 5.0 V mode). It requires an external pull-up resistor (100 kΩ–1 MΩ) to VOUT or another system rail. Pulling up to VOUT prevents invalid high state during power-down - a key design requirement per the datasheet.
What is the recommended output capacitor for stability with the LP2951ACN in fixed 5.0 V mode?
In fixed 5.0 V mode (Pin 1 → Pin 2, Pin 6 → Pin 7), the LP2951ACN is stable with a minimum 1.0 µF aluminum, tantalum, or multilayer ceramic capacitor between Pin 1 (Output) and Pin 8 (GND). Solid tantalum or X7R/X5R ceramics are preferred below −25°C. For adjustable configurations or loads >10 mA, ≥3.3 µF is recommended to maintain phase margin.
Does the LP2951ACN include thermal protection, and how does it behave under overload?
Yes, the LP2951ACN includes internal thermal shutdown and current limiting. When junction temperature exceeds ~150°C or output is shorted, it enters foldback current limiting (~220–300 mA) and reduces output to prevent damage. Recovery is automatic once temperature or load returns to safe levels - no latch-up or manual reset required.
LP2951ACN Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- 8-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Output Configuration:
- Positive
- Output Type:
- Adjustable (Fixed)
- Number of Regulators:
- 1
- Voltage - Input (Max):
- 30V
- Voltage - Output (Min/Fixed):
- 1.235V (5V)
- Voltage - Output (Max):
- 30V
- Voltage Dropout (Max):
- 0.45V @ 100mA
- Current - Output:
- 100mA
- Current - Quiescent (Iq):
- 120 µA
- Current - Supply (Max):
- 12 mA
- PSRR:
- -
- Control Features:
- -
- Protection Features:
- Over Current, Over Temperature
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 8-PDIP
LP2951ACN FAQ
1.How can I place an order for LP2951ACN through Aetrix?
Please submit a Request for Quotation (RFQ) for LP2951ACN 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 LP2951ACN reliable?
The price and inventory of LP2951ACN are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LP2951ACN is usually 5 days.
3.What payment methods are accepted for LP2951ACN?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LP2951ACN transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LP2951ACN?
LP2951ACN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LP2951ACN 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 LP2951ACN?
For technical support, including LP2951ACN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LP2951ACN requirements.
6.How does Aetrix verify that LP2951ACN is sourced from the original manufacturer or authorized distributors?
All LP2951ACN 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 LP2951ACN meets industry standards.
7.What is the process for return or replacement of LP2951ACN?
All LP2951ACN units undergo pre-shipment inspection (PSI). If there is an issue with LP2951ACN, 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 LP2951ACN part is unused and in its original packaging.
Return procedure for LP2951ACN:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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