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Texas Instruments LP3985IM5X-2.5
- Part No.:
- LP3985IM5X-2.5
- Manufacturer:
- Texas Instruments
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LP3985IM5X-2.5.pdf
- Description:
- IC REG LINEAR 2.5V 150MA SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:1,774
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Product details
Overview
LP3985IM5X-2.5 from National Semiconductor is a micropower, 150mA ultra-low-noise, ultra-low-dropout CMOS voltage regulator optimized for battery-powered portable wireless systems. It delivers a fixed 2.5V output from 2.5V–6.0V input, achieves ≤100mV dropout at 150mA, consumes ≤1.5µA in shutdown, and features 30µVrms output noise (10Hz–100kHz) - enabling clean power for RF transceivers and precision analog circuitry in space-constrained handsets.
For engineers reviewing the LP3985IM5X-2.5 datasheet, LP3985IM5X-2.5 pinout, LP3985IM5X-2.5 application, or LP3985IM5X-2.5 equivalent, this page provides verified technical context, package-specific pin mapping, real-world application use cases, and validated alternative options - all grounded in National Semiconductor's DS101364 specification and SOT-23-5 implementation data.
Technical Context
The LP3985IM5X-2.5 employs a CMOS pass transistor architecture with internal bandgap reference and active bypass capacitor pre-charge circuitry, enabling fast 200µs turn-on while maintaining low-noise regulation. Its stability is guaranteed with ≥0.7µF ceramic output capacitors (X7R dielectric, ESR 5–500mΩ), and it operates across −40°C to +125°C junction temperature.
Power supply rejection exceeds 50dB at 1kHz (VIN = VOUT + 0.2V), degrades gradually above 1kHz, and remains effective down to low VIN levels typical of discharging Li-ion batteries. Thermal shutdown activates at 160°C with 20°C hysteresis, and short-circuit current limit is 600mA (steady-state).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 2.5V ±3% - ensures stable bias for 2.5V logic rails and RF front-end ICs without external feedback. |
| Input Voltage Range | 2.5V to 6.0V - supports single-cell Li-ion (2.7–4.2V), dual-cell alkaline (3.0–3.6V), and USB-powered (5.0V) operation. |
| Max Output Current | 150mA guaranteed - sufficient for powering baseband processors, audio codecs, or sensor subsystems in compact handsets. |
| Dropout Voltage | ≤100mV at 150mA load - extends usable battery life by >15 minutes in deep-discharge scenarios vs. higher-dropout regulators. |
| Quiescent Current | ≤1.5µA in shutdown mode - enables zero-power retention for real-time clocks or backup memory during system sleep. |
| Output Noise | 30µVrms (10Hz–100kHz) - meets stringent spectral purity requirements for GSM/CDMA RF sections and ADC reference supplies. |
| PSRR @ 1kHz | ≥50dB (VIN = VOUT + 0.2V) - suppresses switching noise from DC-DC converters feeding the LDO input. |
| Operating Temp | −40°C to +125°C junction - qualified for automotive infotainment modules and industrial handheld terminals. |
Pinout & Package
LP3985IM5X-2.5 is packaged in a 5-pin SOT-23 (NS package MF05A), measuring 2.92mm × 1.6mm × 1.1mm. This RoHS-compliant, surface-mount package uses gull-wing leads and supports standard reflow profiles.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Input voltage supply pin | Accepts 2.5–6.0V; requires ≥1µF ceramic decoupling within 1cm to minimize input impedance and prevent instability. |
| GND | Common ground reference | Must connect to low-impedance analog ground plane; separates power and signal return paths to reduce noise coupling. |
| VOUT | Regulated output voltage | Delivers stable 2.5V ±3%; requires 1µF X7R ceramic capacitor (±30% tolerance) directly adjacent to pin for stability. |
| VEN | Logic-controlled 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 capacitor node | Connects 0.01µF NPO/COG ceramic to GND; reduces output noise without degrading load transient response. |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-low-noise regulation | 30µVrms output noise (10Hz–100kHz) - eliminates need for post-LDO filtering in sensitive RF/analog signal chains. |
| Micro SMD & SOT-23-5 packaging | 5-pin SOT-23 footprint (MF05A) - enables PCB area <2.0mm × 2.5mm for full regulator circuit, matching 1206 passive size. |
| Fast turn-on time | 200µs typical (95% of 2.5V) - supports rapid wake-up from deep-sleep states in mobile devices without voltage droop. |
| Stable with small ceramic caps | Guaranteed stability with 0.7–1.3µF X7R ceramic output capacitors - eliminates costly tantalum alternatives and simplifies BOM. |
| Thermal & short-circuit protection | 160°C thermal shutdown with 20°C hysteresis and 600mA steady-state short-circuit limit - prevents catastrophic failure under fault conditions. |
Applications
| CDMA Cellular Handsets | GSM Cellular Handsets |
|---|---|
Use Scenario: Powering RF transceiver ICs and baseband processors during call setup and data transmission. IC Role / Device Role / Timing Role: Low-noise 2.5V supply for VCO bias, PLL reference, and ADC/DAC analog sections. Use Value: 30µVrms noise and 50dB PSRR at 1kHz prevent phase noise degradation and maintain EVM compliance. |
Use Scenario: Supplying SIM card interface, power amplifier bias, and audio codec in dual-band GSM phones. IC Role / Device Role / Timing Role: Primary 2.5V LDO for digital core and analog peripherals requiring tight voltage tolerance. Use Value: ≤100mV dropout at 150mA extends talk time by preserving usable battery voltage down to 2.6V. |
| Portable Information Appliances | Wideband CDMA Handsets |
Use Scenario: Providing regulated 2.5V rail for touch controller, display driver, and flash memory in PDAs and e-readers. IC Role / Device Role / Timing Role: Always-on power source for non-volatile memory retention and real-time clock during suspend. Use Value: ≤1.5µA shutdown current enables multi-week battery shelf life without compromising wake-up latency. |
Use Scenario: Delivering clean 2.5V supply to high-speed ADCs, DACs, and digital front-end in WCDMA femtocells and smartphones. IC Role / Device Role / Timing Role: Precision voltage reference for sampling clocks and analog signal conditioning paths. Use Value: Stable regulation over −40°C to +125°C ensures consistent ADC linearity and SNR across environmental extremes. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar low-noise, ultra-low-dropout LDO applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MCP1700T-2502E/MB | 250mA output, 6µA quiescent current (active), no BYPASS pin; 17µVrms noise. | Lacks dedicated noise-reduction capacitor node; lower max load but higher IQ limits battery runtime in ultra-low-power modes. | Choose when higher output current is needed and noise below 30µVrms is not required. |
| TCS2102-2.5 | 150mA output, 2.5µA shutdown current, 45µVrms noise, no thermal shutdown. | Higher output noise and missing thermal protection reduce robustness in thermally dense handset layouts. | Consider only in cost-sensitive designs where thermal margin is controlled externally and noise <35µVrms is acceptable. |
Compared with MCP1700T-2502E/MB and TCS2102-2.5, LP3985IM5X-2.5 uniquely combines 30µVrms noise, 1.5µA shutdown, integrated thermal/short-circuit protection, and a dedicated BYPASS pin - making it the optimal choice for RF-critical, battery-limited portable systems demanding both precision and reliability.
Availability
LP3985IM5X-2.5 is available at Aetrix Electronics and suitable for CDMA/GSM handset design, portable information appliance development, and wideband CDMA RF subsystem integration requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LP3985IM5X-2.5 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 (now part of Texas Instruments) is a pioneer in analog and power management ICs, known for high-performance voltage regulators, data converters, and interface solutions serving communications, industrial, and consumer markets.
The LP3985 product line was designed specifically for space-constrained, battery-powered wireless devices requiring ultra-low-noise, micropower LDO regulation - targeting cellular handsets, PDAs, and portable instrumentation where board area and battery life are critical.
FAQ
What is the maximum dropout voltage of LP3985IM5X-2.5 at full 150mA load?
The LP3985IM5X-2.5 has a maximum dropout voltage of 100mV at 150mA load, measured as the minimum VIN–VOUT differential required to maintain regulation within ±3% of 2.5V. This value is specified over the full −40°C to +125°C junction temperature range and enables extended battery utilization in portable systems.
Does LP3985IM5X-2.5 require an external bypass capacitor for stable operation?
No - LP3985IM5X-2.5 is stable with only input and output capacitors. The BYPASS pin is optional: connecting a 0.01µF NPO/COG ceramic capacitor here reduces output noise to 30µVrms without affecting load transient response. Omitting it results in higher noise but retains full regulation stability.
What package type is used for LP3985IM5X-2.5, and what are its key mechanical dimensions?
LP3985IM5X-2.5 uses the SOT-23-5 package (National Semiconductor package code MF05A), with body dimensions of 2.92mm × 1.6mm × 1.1mm and gull-wing lead configuration. It is RoHS-compliant and compatible with standard IR reflow profiles per J-STD-020.
Can LP3985IM5X-2.5 operate with a 2.5V input when delivering 2.5V output?
Yes - LP3985IM5X-2.5 supports VIN = VOUT (2.5V) under light loads. At 150mA, minimum VIN is 2.6V due to 100mV dropout. The device maintains regulation down to VIN = VOUT + dropout voltage, with performance fully specified from 2.5V input across the operating temperature range.
What is the purpose of the VEN pin on LP3985IM5X-2.5, and what are its logic thresholds?
The VEN pin enables logic-controlled on/off functionality for LP3985IM5X-2.5. It is active-high with VIH ≥1.4V and VIL ≤0.4V over the full input voltage range (2.5V–6.0V). Pulling VEN low disables the regulator, reducing quiescent current to ≤1.5µA; tying it to VIN provides permanent enable.
LP3985IM5X-2.5 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):
- 2.5V
- 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
LP3985IM5X-2.5 FAQ
1.How can I place an order for LP3985IM5X-2.5 through Aetrix?
Please submit a Request for Quotation (RFQ) for LP3985IM5X-2.5 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 LP3985IM5X-2.5 reliable?
The price and inventory of LP3985IM5X-2.5 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LP3985IM5X-2.5 is usually 5 days.
3.What payment methods are accepted for LP3985IM5X-2.5?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LP3985IM5X-2.5 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LP3985IM5X-2.5?
LP3985IM5X-2.5 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LP3985IM5X-2.5 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 LP3985IM5X-2.5?
For technical support, including LP3985IM5X-2.5 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LP3985IM5X-2.5 requirements.
6.How does Aetrix verify that LP3985IM5X-2.5 is sourced from the original manufacturer or authorized distributors?
All LP3985IM5X-2.5 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 LP3985IM5X-2.5 meets industry standards.
7.What is the process for return or replacement of LP3985IM5X-2.5?
All LP3985IM5X-2.5 units undergo pre-shipment inspection (PSI). If there is an issue with LP3985IM5X-2.5, 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 LP3985IM5X-2.5 part is unused and in its original packaging.
Return procedure for LP3985IM5X-2.5:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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