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Texas Instruments LP2957AIT/NOPB
- Part No.:
- LP2957AIT/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- TO-220-5 Formed Leads
- Datasheet:
-
LP2957AIT/NOPB.pdf
- Description:
- IC REG LINEAR 5V 250MA TO220-5
- Quantity:
- Payment:
- Shipping:
Inventory:376
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Product details
Overview
LP2957AIT/NOPB from Texas Instruments is a 5V fixed-output, low-dropout linear regulator with electronic shutdown, error flag output, and snap-on/snap-off programmability-designed for microprocessor power supply applications. It delivers 250 mA output current with 470 mV typical dropout at full load, 150 µA quiescent current at 1 mA load, and ±1.4% output accuracy over temperature (A-grade). Used in battery-powered embedded systems where clean, stable 5V rail generation and controlled power sequencing are critical.
For engineers reviewing the LP2957AIT/NOPB datasheet, LP2957AIT/NOPB pinout, LP2957AIT/NOPB application, or LP2957AIT/NOPB equivalent, key selection criteria include guaranteed 250 mA output, tight line/load regulation (0.04% typical), reverse-battery protection, thermal/current limiting, and integrated error flag signaling for system-level fault monitoring.
Technical Context
The LP2957AIT/NOPB integrates a precision 5V bandgap reference, PNP pass transistor, and internal error amplifier to achieve low dropout and high DC accuracy. Its shutdown input accepts logic-level control (turn-on threshold 1.14–1.32 V) with 10 nA bias current, enabling ultra-low-power state management.
It features an open-collector error flag comparator that asserts LOW when output falls >5% out of regulation-triggered by dropout, overcurrent, or thermal limit events-and includes built-in crowbar circuitry (50 mA typical pulldown) for rapid output discharge during shutdown or fault conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | 5.00 V ±1.4% over −40°C to +125°C (A-grade); enables direct replacement of legacy 5V logic rails without external feedback. |
| Dropout Voltage | 470 mV typical at 250 mA load; allows operation with only 5.47 V input for regulated 5 V output-critical for single-cell Li-ion or multi-cell NiCd systems. |
| Quiescent Current | 150 µA typical at 1 mA load; minimizes standby power loss in always-on microcontroller subsystems. |
| Line Regulation | 0.03% typical (VIN = 6 V to 30 V); ensures stable output despite wide input voltage swings from unregulated supplies. |
| Load Regulation | 0.04% typical (IL = 1 mA to 250 mA); maintains tight voltage control across dynamic processor load transients. |
| Error Flag Threshold | Triggers LOW when VO drops >250 mV below nominal (≈5%); provides deterministic fault detection for host MCU reset or watchdog intervention. |
| Shutdown Input Threshold | 1.14–1.32 V turn-on; compatible with standard CMOS/LVTTL logic levels without level-shifting. |
Pinout & Package
LP2957AIT/NOPB is housed in a 5-lead DDPAK/TO-263 surface-mount package (package code KTT0005B), featuring exposed thermal pad for enhanced heat dissipation. Thermal resistance θJA is 73°C/W with minimal PCB copper; reduces to 32°C/W with ≥1.6 in² copper area.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (IN) | Input Supply | Accepts 5.47 V to 30 V input; includes reverse-battery protection diode-no external polarity protection required. |
| 2 (GND) | Ground Reference | Common return for load, error flag pull-up, and shutdown bias; must be connected to system ground even when output is isolated. |
| 3 (OUT) | Regulated Output | 5 V output capable of sourcing 250 mA; requires ≥2.2 µF output capacitor (ESR ≤5 Ω) for stability. |
| 4 (SD) | Shutdown Control | Active-Low enable; <1.2 V disables regulator and activates output crowbar; 10 nA bias enables direct MCU GPIO drive. |
| 5 (ERR) | Error Flag Output | Open-collector comparator output; sinks 400 µA when VO is out-of-regulation; requires external pull-up to VO or another supply. |
Key Features
| Feature | Design Value |
|---|---|
| Snap-on/Snap-off Programmability | Enables clean power-up/power-down sequencing using three external resistors-eliminates intermediate voltage states that cause µP latch-up or undefined behavior. |
| Integrated Output Crowbar | 50 mA typical pulldown current rapidly discharges output capacitance during shutdown or fault-prevents back-feeding into powered-down circuitry. |
| Reverse Battery Protection | Internal diode blocks −20 V to GND on IN pin-protects downstream circuitry without adding external components in automotive or portable battery systems. |
| Tight Thermal Regulation | 0.05%/W typical; minimizes output drift during transient power dissipation-critical for thermally constrained embedded enclosures. |
| Low Noise Performance | 500 µV RMS (10 Hz–100 kHz) with 2.2 µF output cap; supports noise-sensitive analog peripherals (ADCs, sensors) sharing same 5V rail. |
Applications
| Portable Medical Instrumentation | Industrial PLC I/O Modules |
|---|---|
|
Use Scenario: Powering low-power microcontrollers and analog front-ends in handheld glucose meters and pulse oximeters operating from single Li-ion cells. IC Role / Device Role / Timing Role: Primary 5V LDO delivering stable rail to MCU core, ADC reference, and sensor interface-enabling accurate measurement under varying battery voltage. Use Value: 470 mV dropout allows >300 hours runtime from 3.7 V nominal cell; 150 µA quiescent current extends shelf life in standby mode. |
Use Scenario: Providing isolated 5V supply for digital input conditioning circuits in DIN-rail mounted programmable logic controllers. IC Role / Device Role / Timing Role: Regulator with error flag and shutdown used to monitor supply health and initiate safe I/O shutdown during brownout or overtemperature events. Use Value: Error flag signals MCU within 10 µs of output deviation; reverse-battery protection prevents damage during field wiring errors. |
| Automotive Body Control Units | Smart Energy Meters |
|
Use Scenario: Generating 5V rail for CAN transceiver and microcontroller in door module ECUs exposed to cold-crank (−20 V) and load-dump (30 V) conditions. IC Role / Device Role / Timing Role: Input-protected LDO with thermal/current limiting and crowbar-ensures fail-safe power removal during fault conditions per ISO 7637-2. Use Value: Withstands −20 V to +30 V input range; 125°C junction rating supports under-hood placement; error flag feeds diagnostic bus. |
Use Scenario: Powering metrology ASIC and real-time clock in utility-grade electricity meters requiring long-term calibration stability. IC Role / Device Role / Timing Role: Precision 5V reference source with 20 ppm/°C tempco and 0.04% load regulation-maintains ADC accuracy across temperature and load variations. Use Value: ±1.4% total output tolerance over −40°C to +125°C eliminates need for post-calibration trimming in production. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar low-dropout regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2957T-5.0/NOPB | Same pinout and electrical specs but TO-220 package (NDH0005D); higher θJA (60°C/W) limits power handling without heatsink. | Preferred for through-hole prototyping or lower-volume industrial assemblies where thermal mass of TO-220 aids reliability. | Select when board space permits larger footprint and heatsinking is impractical; verify thermal derating at 250 mA continuous load. |
| TPS76350DBVR | Lower quiescent current (85 µA typ), but only 150 mA output; no error flag or snap-on/snap-off; different pinout (SOT-23-5). | Suitable for ultra-low-power sensor nodes where 250 mA capability and fault signaling are unnecessary. | Choose only if load current ≤150 mA and system-level fault monitoring is handled externally; not drop-in compatible. |
Compared with LM2957T-5.0/NOPB, LP2957AIT/NOPB offers superior thermal performance in compact layouts; versus TPS76350DBVR, it trades higher IQ for robust 250 mA delivery, integrated diagnostics, and programmable sequencing-making it the sole choice for µP systems demanding both power and intelligence.
Availability
LP2957AIT/NOPB is available at Aetrix Electronics and suitable for portable medical instrumentation, industrial PLC I/O modules, automotive body control units, and smart energy meters requiring stable component supply with long lifecycle assurance.
Supply support for LP2957AIT/NOPB 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
Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and connectivity technologies-with decades of expertise in precision power management ICs.
The LP2957AIT/NOPB belongs to TI's legacy micropower LDO family, engineered specifically for microprocessor power integrity in battery-constrained and thermally demanding environments-prioritizing dropout, accuracy, and fault resilience over raw speed.
FAQ
What is the maximum input voltage rating for the LP2957AIT/NOPB?
The LP2957AIT/NOPB has an absolute maximum input supply voltage of +30 V and can withstand −20 V on the IN pin due to integrated reverse-battery protection. Operation beyond these limits risks permanent damage. For reliable long-term use, keep VIN within 5.47 V to 25 V to maintain regulation while respecting thermal limits at full 250 mA load.
Does the LP2957AIT/NOPB require an output capacitor, and what type is recommended?
Yes-the LP2957AIT/NOPB requires a minimum 2.2 µF output capacitor with ESR ≤5 Ω for stability; tantalum or aluminum electrolytic types are recommended. Film capacitors work but increase cost. At loads below 10 mA, capacitance may be reduced to 0.68 µF; below 1 mA, 0.22 µF suffices. Omitting the capacitor causes oscillation and unreliable regulation.
How does the error flag (ERR) pin function on the LP2957AIT/NOPB?
The ERR pin on the LP2957AIT/NOPB is an open-collector output that pulls LOW when the regulated output deviates >5% (≈250 mV) from 5 V-indicating dropout, overcurrent, or thermal shutdown. It sinks up to 400 µA and requires an external pull-up resistor (100 kΩ to 1 MΩ) to VO or another supply. Pulling up to VO avoids invalid HIGH states during power ramp-up.
Can the LP2957AIT/NOPB be used in snap-on/snap-off configuration, and what components are needed?
Yes-the LP2957AIT/NOPB supports snap-on/snap-off operation using three external resistors (R1, R2, R3) connected to the SD pin. This configures hysteresis between turn-on (VON) and turn-off (VOFF) thresholds, eliminating unstable mid-rail states during power transitions. Design Example #1 in the datasheet provides resistor calculation methods based on source impedance and required hysteresis voltage.
What thermal considerations apply when using the LP2957AIT/NOPB at 250 mA continuous load?
At 250 mA with 6 V input, LP2957AIT/NOPB dissipates ~250 mW. In the DDPAK/TO-263 package, θJA is 73°C/W with minimal copper; this yields ~18°C rise above ambient. With ≥1.6 in² PCB copper, θJA drops to 32°C/W, reducing rise to ~8°C. Always verify junction temperature stays ≤125°C using TJ = TA + (P × θJA)-especially in sealed enclosures or high-ambient environments.
LP2957AIT/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- TO-220-5 Formed Leads
- Packaging:
- Tube
- Product Status:
- Active
- Output Configuration:
- Positive
- Output Type:
- Fixed
- Number of Regulators:
- 1
- Voltage - Input (Max):
- 30V
- Voltage - Output (Min/Fixed):
- 5V
- Voltage - Output (Max):
- -
- Voltage Dropout (Max):
- 0.8V @ 250mA
- Current - Output:
- 250mA
- Current - Quiescent (Iq):
- 200 µA
- Current - Supply (Max):
- 33 mA
- PSRR:
- -
- Control Features:
- Enable
- Protection Features:
- Over Current, Over Temperature, Reverse Polarity
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-220-5
LP2957AIT/NOPB FAQ
1.How can I place an order for LP2957AIT/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LP2957AIT/NOPB 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 LP2957AIT/NOPB reliable?
The price and inventory of LP2957AIT/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LP2957AIT/NOPB is usually 5 days.
3.What payment methods are accepted for LP2957AIT/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LP2957AIT/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LP2957AIT/NOPB?
LP2957AIT/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LP2957AIT/NOPB 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 LP2957AIT/NOPB?
For technical support, including LP2957AIT/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LP2957AIT/NOPB requirements.
6.How does Aetrix verify that LP2957AIT/NOPB is sourced from the original manufacturer or authorized distributors?
All LP2957AIT/NOPB 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 LP2957AIT/NOPB meets industry standards.
7.What is the process for return or replacement of LP2957AIT/NOPB?
All LP2957AIT/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LP2957AIT/NOPB, 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 LP2957AIT/NOPB part is unused and in its original packaging.
Return procedure for LP2957AIT/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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