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Texas Instruments LP3985IM5-2.7
- Part No.:
- LP3985IM5-2.7
- Manufacturer:
- Texas Instruments
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LP3985IM5-2.7.pdf
- Description:
- IC REG LINEAR 2.7V 150MA SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:1,024
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Product details
Overview
LP3985IM5-2.7 from National Semiconductor is a micropower, 150mA ultra-low-dropout CMOS voltage regulator optimized for battery-powered portable wireless systems. It delivers 2.7V output with ≤100mV dropout at 150mA load, 30µVrms output noise (10Hz–100kHz), and consumes <1.5µA in shutdown mode. It operates across −40°C to +125°C and is stable with a 1µF ±30% ceramic output capacitor.
For engineers reviewing the LP3985IM5-2.7 datasheet, LP3985IM5-2.7 pinout, LP3985IM5-2.7 application, or LP3985IM5-2.7 equivalent, key selection considerations include low-noise performance for RF/analog circuitry, fast 200µs turn-on time for power sequencing, thermal shutdown protection, and compatibility with miniature SOT-23-5 PCB layouts requiring minimal board area.
Technical Context
The LP3985IM5-2.7 uses a CMOS pass transistor architecture enabling ultra-low quiescent current and near-zero ground current increase in dropout. Its internal bandgap reference and bypass-capacitor-assisted startup circuit deliver fast, controlled power-on behavior without compromising noise performance.
It integrates logic-controlled enable (VEN), thermal shutdown (160°C trip), and short-circuit current limiting (600mA steady-state). PSRR exceeds 50dB at 1kHz under VIN = VOUT + 0.2V, maintaining high rejection down to low input voltages typical of discharging Li-ion cells.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 2.7V ±3% - ensures precise biasing for 2.7V-tolerant RF ICs and baseband processors. |
| Max Output Current | 150mA guaranteed - supports moderate-power RF front-end modules and sensor interfaces. |
| Dropout Voltage | ≤100mV @ 150mA - enables operation down to ~2.8V input, extending usable battery life in single-cell Li-ion systems. |
| Output Noise | 30µVrms (10Hz–100kHz) - minimizes phase noise injection into sensitive VCOs and ADC references. |
| Quiescent Current | 85µA typ. @ 1mA load - preserves battery runtime in always-on standby modes. |
| Shutdown Current | ≤1.5µA - essential for long-term storage or deep-sleep states in portable devices. |
| PSRR | 50dB @ 1kHz, VIN = VOUT + 0.2V - suppresses switching noise from PMICs or DC-DC converters feeding the LDO input. |
| Operating Temp | −40°C to +125°C junction - qualified for automotive infotainment and industrial handheld environments. |
Pinout & Package
LP3985IM5-2.7 is housed in a RoHS-compliant 5-pin SOT-23 package (NS package MF05A), footprint-compatible with industry-standard SOT-23-5 layouts and suitable for reflow assembly. Total package dimensions are 2.92mm × 1.6mm × 1.1mm (L × W × H).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Input voltage supply | Accepts 2.5V–6.0V; requires ≥1µF ceramic input capacitor placed within 1cm of pin for stability. |
| GND | Power ground reference | Common return path for input, output, and enable circuits; must connect to clean analog ground plane. |
| VOUT | Regulated output | Delivers stable 2.7V ±3%; requires 1µF X7R ceramic output capacitor (ESR 5–500mΩ) for guaranteed stability. |
| VEN | Logic-enable input | Active-high control: VIH ≥1.4V, VIL ≤0.4V; tie to VIN for always-on operation or drive from GPIO for dynamic power gating. |
| BYPASS | Noise-reduction node | Connects to 0.01µF NPO/COG ceramic capacitor to ground; reduces output noise without degrading load transient response. |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-low-noise regulation | 30µVrms output noise (10Hz–100kHz) enables clean power for RF transceivers and precision analog signal chains. |
| Fast 200µs turn-on time | Internal pre-charge circuit actively charges BYPASS capacitor, supporting rapid power-up in burst-mode communication systems. |
| Stable with 1µF ceramic output cap | Eliminates need for larger, costlier tantalum capacitors-reduces BOM count and PCB area in space-constrained designs. |
| Thermal shutdown & short-circuit protection | 160°C trip point with 20°C hysteresis and 600mA current limit prevent damage during overload or layout thermal bottlenecks. |
| Micropower shutdown mode | <1.5µA disable current allows multi-year shelf life in battery-backed memory or real-time clock applications. |
Applications
| CDMA Cellular Handsets | GSM Cellular Handsets |
|---|---|
Use Scenario: Powering RF transceiver ICs and baseband processors in compact dual-mode handsets. IC Role / Device Role / Timing Role: Low-noise 2.7V supply for VCO biasing and ADC reference rails. Use Value: 30µVrms noise prevents reciprocal mixing and maintains EVM compliance under 3GPP modulation schemes. |
Use Scenario: Supplying SIM interface, audio codec, and display driver in legacy GSM feature phones. IC Role / Device Role / Timing Role: Primary 2.7V LDO for digital I/O and low-voltage logic domains. Use Value: ≤100mV dropout extends talk time by >12 minutes per charge cycle compared to higher-dropout alternatives. |
| Wideband CDMA Handsets | Portable Information Appliances |
Use Scenario: Delivering clean 2.7V rail to high-speed data converters and GPS front-ends in WCDMA smartphones. IC Role / Device Role / Timing Role: Post-regulator for switched-capacitor DC-DC outputs to suppress ripple-induced jitter. Use Value: 50dB PSRR at 1kHz rejects noise from adjacent buck converter switching frequencies (e.g., 1.5MHz harmonics). |
Use Scenario: Powering flash memory controllers and touch-screen microcontrollers in e-readers and handheld scanners. IC Role / Device Role / Timing Role: Always-on 2.7V supply for RTC and SRAM keep-alive functions. Use Value: Stable no-load regulation and <1.5µA shutdown current enable >5-year battery retention without periodic recharge. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar low-noise LDO regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| Torex XC6206P272MR | 2.7V fixed, 150mA, 120mV dropout @ 150mA, 45µVrms noise, SOT-23-5 | Higher dropout and noise reduce suitability for RF-sensitive 2.7V rails | Acceptable where cost is primary constraint and PSRR/noise requirements are relaxed. |
| Diodes Inc. AP2204K-2.7TRG1 | 2.7V fixed, 150mA, 250mV dropout @ 150mA, 40µVrms noise, SOT-23-5 | Higher dropout limits usable input range; lacks BYPASS pin for noise optimization | Valid for non-RF digital loads where 2.5V minimum input suffices and noise is secondary. |
Compared with XC6206P272MR and AP2204K-2.7TRG1, LP3985IM5-2.7 provides superior noise performance (30µVrms vs. ≥40µVrms) and lower dropout (100mV vs. ≥120mV), making it the preferred choice for RF and precision analog subsystems where power integrity directly impacts signal fidelity.
Availability
LP3985IM5-2.7 is available at Aetrix Electronics and suitable for CDMA/GSM handset design, portable medical sensors, and industrial handheld terminals requiring stable component supply, full traceability, and long-lifecycle support.
Supply support for LP3985IM5-2.7 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
National Semiconductor was a U.S.-based analog semiconductor company acquired by Texas Instruments in 2011, known for high-performance power management, data conversion, and interface ICs.
The LP3985IM5-2.7 belongs to National's micropower LDO family designed specifically for space- and noise-constrained portable wireless applications, emphasizing ultra-low quiescent current, minimal PCB footprint, and RF-friendly regulation.
FAQ
What is the maximum input voltage rating for LP3985IM5-2.7?
The absolute maximum input voltage for LP3985IM5-2.7 is 6.5V, but the recommended operating range is 2.5V to 6.0V. Exceeding 6.5V risks permanent damage. For reliable operation with Li-ion batteries, VIN should remain ≤4.3V in normal use to avoid overstress during charging peaks.
Does LP3985IM5-2.7 require an external bypass capacitor to meet datasheet noise specifications?
Yes - the 30µVrms output noise specification for LP3985IM5-2.7 is measured with a 0.01µF NPO/COG ceramic capacitor connected between the BYPASS pin and ground. Omitting this capacitor increases output noise to approximately 230nV/√Hz spectral density, degrading performance in RF-sensitive applications.
Can LP3985IM5-2.7 operate without any load connected to VOUT?
Yes - LP3985IM5-2.7 is specified for no-load stability and remains in regulation with zero output current. This capability supports applications like CMOS RAM keep-alive circuits and real-time clocks where continuous low-current bias is required without risk of oscillation or dropout.
What is the thermal shutdown behavior of LP3985IM5-2.7?
LP3985IM5-2.7 activates thermal shutdown at 160°C junction temperature and includes 20°C hysteresis, meaning it resumes regulation only after cooling to ≤140°C. During shutdown, output is disabled and quiescent current drops to <1.5µA, protecting both the device and downstream circuitry from thermal runaway.
Is LP3985IM5-2.7 compatible with standard SOT-23-5 footprints?
Yes - LP3985IM5-2.7 uses the NS package MF05A, which conforms to JEDEC MO-178AB and is mechanically and solder-reflow compatible with standard SOT-23-5 land patterns. Pin 1 (VIN) is marked by a beveled corner on the package body, matching conventional SOT-23 orientation.
LP3985IM5-2.7 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- SC-74A, SOT-753
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Output Configuration:
- Positive
- Output Type:
- Fixed
- Number of Regulators:
- 1
- Voltage - Input (Max):
- 6V
- Voltage - Output (Min/Fixed):
- 2.7V
- Voltage - Output (Max):
- -
- Voltage Dropout (Max):
- 0.1V @ 150mA
- Current - Output:
- 150mA
- Current - Quiescent (Iq):
- 150 µA
- Current - Supply (Max):
- 250 µA
- PSRR:
- 50dB ~ 40dB (1kHz ~ 10kHz)
- Control Features:
- Enable
- Protection Features:
- Over Current, Over Temperature, Short Circuit
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-5
LP3985IM5-2.7 FAQ
1.How can I place an order for LP3985IM5-2.7 through Aetrix?
Please submit a Request for Quotation (RFQ) for LP3985IM5-2.7 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 LP3985IM5-2.7 reliable?
The price and inventory of LP3985IM5-2.7 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LP3985IM5-2.7 is usually 5 days.
3.What payment methods are accepted for LP3985IM5-2.7?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LP3985IM5-2.7 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LP3985IM5-2.7?
LP3985IM5-2.7 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LP3985IM5-2.7 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 LP3985IM5-2.7?
For technical support, including LP3985IM5-2.7 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LP3985IM5-2.7 requirements.
6.How does Aetrix verify that LP3985IM5-2.7 is sourced from the original manufacturer or authorized distributors?
All LP3985IM5-2.7 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 LP3985IM5-2.7 meets industry standards.
7.What is the process for return or replacement of LP3985IM5-2.7?
All LP3985IM5-2.7 units undergo pre-shipment inspection (PSI). If there is an issue with LP3985IM5-2.7, 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 LP3985IM5-2.7 part is unused and in its original packaging.
Return procedure for LP3985IM5-2.7:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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