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Texas Instruments LP2957ISX/NOPB
- Part No.:
- LP2957ISX/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- TO-263-6, D2PAK (5 Leads + Tab), TO-263BA
- Datasheet:
-
LP2957ISX/NOPB.pdf
- Description:
- IC REG LIN 5V 250MA DDPAK/TO263
- Quantity:
- Payment:
- Shipping:
Inventory:391
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Product details
Overview
LP2957ISX/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), enabling stable µP operation in battery-powered and space-constrained systems.
For engineers reviewing the LP2957ISX/NOPB datasheet, LP2957ISX/NOPB pinout, LP2957ISX/NOPB application, or LP2957ISX/NOPB equivalent, key selection considerations include its guaranteed 250 mA output, reverse-battery protection, integrated error comparator with open-collector output, programmable hysteresis for clean power sequencing, and thermal/current limiting for robust system-level reliability.
Technical Context
The LP2957ISX/NOPB integrates a precision 5V bandgap reference, PNP pass transistor with low saturation voltage, and dual comparators-one for shutdown control with 1.14–1.32 V turn-on threshold and 6 mV hysteresis, another for dropout detection with ±240 mV to ±380 mV thresholds referenced to output. Its ground pin current scales linearly with load (150 µA at 1 mA, up to 33 mA at 250 mA), reflecting true quiescent consumption.
It supports snap-on/snap-off operation via external resistor network (R1/R2/R3) to eliminate intermediate voltage states during power-up/down, critical for deterministic µP reset behavior. The error flag sinks 400 µA when output drops >5% out of regulation-triggered by low input, current limit, or thermal shutdown-and requires an external pull-up resistor tied to VOUT to avoid false logic-highs during brownout.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | 5.0 V ±1.4% over −40°C to +125°C (A-grade), ensuring reliable µP core voltage across industrial temperature range |
| Max Output Current | 250 mA guaranteed, supporting mid-power embedded controllers and peripheral ICs without derating |
| Dropout Voltage | 470 mV typical at 250 mA load, enabling regulation from 5.47 V input-critical for single-cell Li-ion or 6 V battery systems |
| Quiescent Current | 150 µA typical at 1 mA load, minimizing standby power loss in always-on IoT sensors and remote controls |
| Line/Load Regulation | 0.04% typical, maintaining tight output stability despite input ripple or dynamic load transients |
| Error Flag Threshold | Triggers at ~5% output deviation (≈250 mV drop), providing early fault indication before µP lockup or data corruption |
| Shutdown Input Threshold | 1.14–1.32 V with 6 mV hysteresis, compatible with standard CMOS/LVTTL logic and enabling clean power gating |
| Thermal Protection | Internally limited junction temperature (−40°C to +125°C), with automatic recovery after cooldown-no latch-up or manual reset required |
Pinout & Package
LP2957ISX/NOPB is packaged in the 5-lead DDPAK/TO-263 surface-mount package (Package Number 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 6–30 V DC input; reverse-battery protected up to −20 V when Shutdown pin is properly terminated |
| 2 (GND) | Ground Reference | Common return for load, error flag, and shutdown circuitry; must be connected to system ground to prevent damage |
| 3 (OUT) | Regulated Output | 5 V fixed output; requires ≥2.2 µF output capacitor (ESR ≤5 Ω) for stability; supports output isolation when IN is off |
| 4 (SD) | Shutdown Control | Active-low logic input; <1.2 V disables regulator and pulls output to ≈0 V via 50 mA internal pulldown |
| 5 (ERR) | Error Flag Output | Open-collector comparator output; sinks 400 µA when VOUT deviates >5%; requires external pull-up to VOUT |
Key Features
| Feature | Design Value |
|---|---|
| Snap-on/Snap-off Programmability | Enables clean, hysteresis-controlled power sequencing using three external resistors-eliminates ambiguous µP reset states during brown-in/brown-out |
| Reverse Battery Protection | Withstands −20 V input when Shutdown pin is pulled up to VIN, preventing damage in automotive or portable battery-reversal scenarios |
| Low Dropout at Full Load | 470 mV typical dropout at 250 mA allows use with 5.5 V nominal inputs (e.g., 4×AA alkaline), maximizing battery runtime |
| Integrated Error Detection | On-chip comparator asserts ERR pin within microseconds of output deviation-enables real-time system health monitoring without external circuitry |
| Tight Temperature Coefficient | 20 ppm/°C typical drift ensures <±10 mV output change over −40°C to +125°C-critical for precision analog subsystems |
| Current & Thermal Limiting | Self-protecting design limits peak output to ≈530 mA and shuts down above TJ = 125°C-no external foldback or thermal sensor needed |
Applications
| Battery-Powered Microcontroller Systems | Industrial Sensor Node Power |
|---|---|
Use Scenario: Powering ARM Cortex-M0+ or PIC18F MCU from 4×AA alkaline pack (6.4 V fresh, dropping to 4.8 V under load). IC Role / Device Role / Timing Role: Primary 5 V LDO supplying core logic, ADC reference, and I/O buffers-ensuring deterministic reset and clock stability. Use Value: 470 mV dropout enables regulation down to 5.27 V input, extending usable battery life by >15% versus higher-dropout alternatives. | Use Scenario: Regulating power for wireless temperature/humidity sensor with LoRaWAN radio and low-power sleep cycles. IC Role / Device Role / Timing Role: Always-on 5 V rail for RTC, wake-up controller, and RF front-end-maintaining timing integrity during deep-sleep transitions. Use Value: 150 µA quiescent current minimizes self-discharge, enabling >5-year battery life on CR123A cells. |
| Programmable Logic Power Supply | Automotive Body Control Module (BCM) |
Use Scenario: Providing clean 5 V to CPLD configuration memory and I/O banks in FPGA-based test equipment. IC Role / Device Role / Timing Role: Stable voltage reference for configuration bitstream loading and I/O voltage translation-preventing configuration errors during power ramp. Use Value: 0.04% line/load regulation and 20 ppm/°C TC ensure <±2 mV output variation across operating conditions-guaranteeing bitstream integrity. | Use Scenario: Powering LIN transceiver and microcontroller in door module, subject to load dump and reverse-battery events. IC Role / Device Role / Timing Role: Protected 5 V supply with reverse-polarity tolerance and fast error flag for ECU diagnostics. Use Value: −20 V reverse-battery rating and open-collector ERR output simplify compliance with ISO 7637-2 Pulse 1/2a-reducing need for external TVS diodes. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar low-dropout regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS76350QDBVRQ1 | Lower quiescent current (130 µA typ), but only 150 mA output; no snap-on/snap-off or reverse-battery protection | Suitable for lower-current automotive modules where sequencing control is handled externally | Select if system load <150 mA and external sequencing is acceptable; avoid if reverse-battery immunity or 250 mA is required |
| MCP1703T-5002E/MB | Higher dropout (600 mV @250 mA), no error flag or shutdown, but tighter initial accuracy (±0.4%) | Better for cost-sensitive consumer devices where fault reporting is not needed and input headroom is ample | Choose for high-volume, non-critical applications with >6 V input; skip if diagnostic capability or low-headroom operation is essential |
Compared with TPS76350QDBVRQ1 and MCP1703T-5002E/MB, LP2957ISX/NOPB uniquely combines 250 mA output, programmable snap-on/snap-off, reverse-battery protection, and integrated error flag-making it the only option among the three qualified for robust µP power sequencing in harsh environments.
Availability
LP2957ISX/NOPB is available at Aetrix Electronics and suitable for battery-powered microcontrollers, industrial sensor nodes, programmable logic supplies, and automotive body control modules requiring stable component supply and long-term production continuity.
Supply support for LP2957ISX/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 power management ICs for industrial, automotive, and computing markets.
The LP2957 product line was engineered specifically for microprocessor power integrity-delivering tightly regulated 5 V outputs with intelligent protection, sequencing, and diagnostic features in compact surface-mount packages.
FAQ
What is the maximum input voltage rating for LP2957ISX/NOPB?
The absolute maximum input supply voltage for LP2957ISX/NOPB is +30 V, and it can withstand −20 V with proper Shutdown pin termination. Operation beyond these limits risks permanent damage. For reliable long-term use, TI recommends keeping VIN ≤25 V in continuous operation and verifying power dissipation against thermal limits per the datasheet's θJA curves. LP2957ISX/NOPB's internal protection does not replace external overvoltage clamping in high-energy transient environments.
Does LP2957ISX/NOPB require an output capacitor, and what type is recommended?
Yes, LP2957ISX/NOPB requires a minimum 2.2 µF output capacitor with ESR ≤5 Ω for stability-tantalum or aluminum electrolytic capacitors are preferred. Film types work but increase cost. At loads <10 mA, capacitance may be reduced to 0.68 µF; below 1 mA, 0.22 µF suffices. LP2957ISX/NOPB becomes unstable and may oscillate without this capacitor, compromising µP operation. Solid tantalum is mandatory below −25°C due to electrolyte freezing in wet aluminum types.
How does the error flag (ERR pin) of LP2957ISX/NOPB behave during shutdown?
During active shutdown (SD pin <1.2 V), the ERR pin of LP2957ISX/NOPB goes high-impedance (open-collector) unless pulled up externally-TI recommends tying the pull-up resistor to VOUT to prevent false logic-highs when input voltage falls below 1.3 V. If pulled up to an external supply, ERR may float high during shutdown, generating invalid fault signals. LP2957ISX/NOPB's ERR pin asserts low only when output deviates >5% from regulation-not during intentional shutdown-so system firmware must distinguish between fault and commanded power-down.
Can LP2957ISX/NOPB be used without the shutdown function, and how should SD pin be connected?
Yes, LP2957ISX/NOPB can operate without shutdown by connecting the SD pin directly to VIN. This eliminates the need for a pull-up resistor and simplifies layout. However, doing so sacrifices reverse-battery protection because the SD pin's absolute maximum rating prohibits voltages <−0.3 V relative to GND. If reverse polarity immunity is required-as in automotive or field-replaceable battery packs-the SD pin must be pulled up to VIN via a 20–100 kΩ resistor. LP2957ISX/NOPB remains fully functional in either configuration.
What thermal management is required for LP2957ISX/NOPB at 250 mA output with 12 V input?
At 12 V input and 250 mA load, LP2957ISX/NOPB dissipates ≈1.75 W (P = (12−5)×0.25 + 12×0.033). With θJA = 73°C/W (DDPAK, minimal copper), junction temperature rise would exceed safe limits. TI recommends ≥1.6 in² PCB copper area (θJA = 32°C/W) or an external heatsink. Using Equation θHA = θJA − θJC − θCH, a 10°C/W heatsink with thermal interface yields TJ ≈ 85°C at 70°C ambient-within the −40°C to +125°C operating range. LP2957ISX/NOPB includes thermal shutdown but sustained operation near limit degrades long-term reliability.
LP2957ISX/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- TO-263-6, D2PAK (5 Leads + Tab), TO-263BA
- Packaging:
- Tape & Reel (TR)
- 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:
- Surface Mount
- Supplier Device Package:
- TO-263 (DDPAK-5)
LP2957ISX/NOPB FAQ
1.How can I place an order for LP2957ISX/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LP2957ISX/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 LP2957ISX/NOPB reliable?
The price and inventory of LP2957ISX/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LP2957ISX/NOPB is usually 5 days.
3.What payment methods are accepted for LP2957ISX/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LP2957ISX/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LP2957ISX/NOPB?
LP2957ISX/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LP2957ISX/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 LP2957ISX/NOPB?
For technical support, including LP2957ISX/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LP2957ISX/NOPB requirements.
6.How does Aetrix verify that LP2957ISX/NOPB is sourced from the original manufacturer or authorized distributors?
All LP2957ISX/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 LP2957ISX/NOPB meets industry standards.
7.What is the process for return or replacement of LP2957ISX/NOPB?
All LP2957ISX/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LP2957ISX/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 LP2957ISX/NOPB part is unused and in its original packaging.
Return procedure for LP2957ISX/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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