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Texas Instruments LP3985IM5X-2.8
- Part No.:
- LP3985IM5X-2.8
- Manufacturer:
- Texas Instruments
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LP3985IM5X-2.8.pdf
- Description:
- IC REG LINEAR 2.8V 150MA SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:1,028
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Product details
Overview
LP3985IM5X-2.8 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 2.8V output from 2.5–6.0V input, achieves ≤100mV dropout at 150mA, consumes ≤85µA quiescent current under load, and provides 30µVrms output noise (10Hz–100kHz) - enabling clean power for RF transceivers and precision analog circuitry in space-constrained handsets.
For engineers reviewing the LP3985IM5X-2.8 datasheet, LP3985IM5X-2.8 pinout, LP3985IM5X-2.8 application, or LP3985IM5X-2.8 equivalent, this page details its verified low-noise LDO performance, SOT-23-5 package compatibility, thermal shutdown protection, fast 200µs turn-on time, and ceramic capacitor stability - all critical for GSM/CDMA handset power rail design and low-power IoT sensor node regulation.
Technical Context
The LP3985IM5X-2.8 employs a CMOS pass transistor architecture with internal bandgap reference and error amplifier to achieve ultra-low dropout and minimal ground current variation across load and input voltage. Its bypass pin connects directly to a high-impedance node in the reference circuit, enabling optional 0.01µF noise-reduction capacitance without degrading load transient response.
It integrates logic-controlled enable (VEN), thermal shutdown (160°C trip), and short-circuit current limiting (600mA steady-state). Operation is guaranteed over −40°C to +125°C junction temperature, with PSRR >50dB at 1kHz (VIN = VOUT + 0.2V) and stable regulation using only a 1µF ±30% ceramic output capacitor.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 2.8V ±3% - ensures precise biasing for 2.8V logic rails and RF front-end ICs. |
| Max Output Current | 150mA guaranteed - supports baseband processors, audio codecs, and multi-function peripherals in compact handsets. |
| Dropout Voltage | ≤100mV at 150mA load - extends usable battery life down to ~2.9V input in single-cell Li-ion systems. |
| Quiescent Current | ≤85µA at 1mA load - minimizes standby drain in always-on communication modules. |
| Output Noise | 30µVrms (10Hz–100kHz) - meets stringent noise requirements for GSM/CDMA receiver LNA and VCO supply rails. |
| PSRR | ≥50dB at 1kHz (VIN = VOUT + 0.2V) - suppresses switching noise from PMIC DC-DC converters feeding the LDO input. |
| Enable Threshold | VIH = 1.4V min, VIL = 0.4V max - compatible with 1.8V/2.8V/3.3V GPIO control without level-shifting. |
| Operating Temp | −40°C to +125°C junction - validated for automotive infotainment and industrial handheld environments. |
Pinout & Package
SOT-23-5 package (NS package MF05A), 2.9mm × 1.6mm footprint, 1.1mm max height - enables high-density PCB layouts in sub-20mm² RF module designs.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Input voltage supply | Accepts 2.5–6.0V; requires ≥1µF ceramic input capacitor placed within 1cm of pin. |
| GND | Power ground reference | Common return path for input/output/bypass capacitors; must connect to clean analog ground plane. |
| VOUT | Regulated output | Delivers stable 2.8V; requires 1µF X7R ceramic output capacitor (0.7–1.3µF, ESR 5–500mΩ) for stability. |
| VEN | Logic-enable input | Active-high control: ≥1.4V enables regulator; ≤0.4V disables with <1.5µA shutdown current. |
| BYPASS | Noise reduction node | Connects 0.01µF NPO/COG ceramic capacitor to GND to reduce output noise without affecting transient response. |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-low-noise regulation | 30µVrms output noise enables direct powering of sensitive RF receivers without additional filtering. |
| Fast turn-on time | 200µs typical - supports rapid wake-up sequences in sleep-mode cellular protocols (e.g., GSM discontinuous transmission). |
| Ceramic capacitor stability | Stable with 1µF ±30% X7R ceramic output cap - eliminates need for larger, costlier tantalum capacitors in miniaturized designs. |
| Thermal & short-circuit protection | 160°C thermal shutdown with 20°C hysteresis and 600mA short-circuit current limit - prevents damage during fault conditions. |
| Micropower disable mode | <1.5µA shutdown current - preserves battery charge during extended idle periods in portable medical or asset-tracking devices. |
Applications
| CDMA Handset Power Rail | GSM Transceiver Bias |
|---|---|
|
Use Scenario: Supplies clean 2.8V to CDMA baseband processor and RF transceiver ICs in slim-form-factor handsets. IC Role / Device Role / Timing Role: Primary low-noise LDO for VCC_RF and VCC_BB domains, decoupling noisy PMIC switchers. Use Value: 30µVrms noise and 50dB PSRR prevent reciprocal mixing and phase noise degradation in CDMA receive paths. |
Use Scenario: Powers GSM PA driver stage and IF filter ICs requiring tightly regulated 2.8V with minimal ripple. IC Role / Device Role / Timing Role: Local point-of-load regulator delivering stable voltage during high-current PA burst transmission. Use Value: ≤100mV dropout ensures continuous operation down to 2.9V battery voltage, extending talk time by >8% vs. higher-dropout alternatives. |
| Portable Medical Sensor Node | Industrial Handheld Scanner |
|
Use Scenario: Provides ultra-low-noise 2.8V supply to precision ADCs and low-power microcontrollers in battery-operated glucose monitors. IC Role / Device Role / Timing Role: Always-on LDO maintaining regulation during sensor sampling bursts and Bluetooth LE data transmission. Use Value: <85µA quiescent current and no-load stability extend 200mAh coin-cell life to >12 months in intermittent-use applications. |
Use Scenario: Regulates 2.8V for barcode image sensor, laser diode driver, and ARM Cortex-M4 MCU in ruggedized warehouse scanners. IC Role / Device Role / Timing Role: Main system LDO supporting wide temperature operation and fast enable/disable during scan-trigger events. Use Value: −40°C to +125°C rating and 200µs turn-on ensure reliable boot and sensor activation in cold-storage or hot-dock environments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar low-noise LDO applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| Torex XC6206P282MR | 2.8V, 150mA, 120mV dropout @ 150mA, 45µVrms noise, SOT-23-5 | Higher dropout and noise - less suitable for RF-sensitive 2.8V rails near battery end-of-life | Prefer LP3985IM5X-2.8 where <100mV dropout and <35µVrms noise are mandatory for signal integrity. |
| Diodes Inc. AP2204K-2.8TRG1 | 2.8V, 150mA, 250mV dropout @ 150mA, 65µVrms noise, SOT-23-5 | Higher dropout and noise - requires higher minimum input voltage and adds jitter to clock distribution paths | Select LP3985IM5X-2.8 when powering VCOs, LNAs, or high-resolution SAR ADCs demanding lowest possible supply noise. |
Compared with XC6206P282MR and AP2204K-2.8TRG1, the LP3985IM5X-2.8 delivers superior noise performance (30µVrms vs. ≥45µVrms) and lower dropout (≤100mV vs. ≥120mV), making it the optimal choice for RF and precision analog subsystems where supply-induced distortion must be minimized.
Availability
LP3985IM5X-2.8 is available at Aetrix Electronics and suitable for CDMA/GSM handset design, portable medical instrumentation, industrial handheld scanners, and low-power IoT sensor nodes requiring stable component supply with full traceability and long-term lifecycle support.
Supply support for LP3985IM5X-2.8 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.
The LP3985 product line was engineered specifically for space-constrained, battery-powered wireless devices - emphasizing ultra-low noise, micropower operation, and ceramic-capacitor compatibility to eliminate bulky external components in mobile handset power architectures.
FAQ
What is the maximum input voltage rating for the LP3985IM5X-2.8?
The LP3985IM5X-2.8 has an absolute maximum input voltage (VIN) rating of 6.5V, but its specified operating input range is 2.5V to 6.0V. Exceeding 6.5V risks permanent damage. For reliable operation in battery-powered systems, VIN should remain within 2.5–6.0V, with headroom above 2.8V to maintain regulation - e.g., ≥3.0V for 150mA loads given its ≤100mV dropout specification. The LP3985IM5X-2.8 is not rated for automotive 12V or industrial 24V rail direct connection.
Does the LP3985IM5X-2.8 require an external bypass capacitor for basic operation?
No, the LP3985IM5X-2.8 functions stably without the BYPASS capacitor; it is optional and used solely to reduce output noise. The device achieves 30µVrms noise (10Hz–100kHz) with the recommended 0.01µF NPO/COG ceramic capacitor on the BYPASS pin. Omitting it increases noise to ~46µVrms (calculated per datasheet Note 12), but does not affect regulation, transient response, or stability. The LP3985IM5X-2.8 remains fully functional with only VIN, GND, VOUT, and VEN connected.
Can the LP3985IM5X-2.8 be used with a 0.47µF output capacitor?
No - the LP3985IM5X-2.8 requires a minimum 0.7µF output capacitance (per datasheet Recommended Output Capacitor table) for guaranteed stability across −40°C to +125°C. A 0.47µF capacitor falls below this threshold and may cause oscillation or poor load transient response. The device is optimized for 1.0µF ±30% X7R ceramic capacitors (0.7–1.3µF); using 0.47µF violates the stability criteria and is not supported. Always verify capacitor DC-bias derating to ensure effective capacitance remains ≥0.7µF at operating voltage and temperature.
What is the thermal shutdown behavior of the LP3985IM5X-2.8?
The LP3985IM5X-2.8 activates thermal shutdown at 160°C junction temperature and includes 20°C hysteresis, meaning it resumes normal operation only after cooling to ≤140°C. During shutdown, output is disabled and quiescent current drops to <1.5µA. This protection is independent of load current and triggers solely due to die temperature - critical for sustained high-current operation in enclosed handheld enclosures. The LP3985IM5X-2.8's θJA of 220°C/W (SOT-23-5) means 250mW power dissipation raises junction temperature by 55°C above ambient, necessitating proper PCB copper area for heat spreading.
Is the LP3985IM5X-2.8 RoHS compliant and lead-free?
Yes, the LP3985IM5X-2.8 is RoHS compliant and lead-free, meeting National Semiconductor's Banned Substances and Materials of Interest Specification (CSP-9-111S2). Its SOT-23-5 package (MF05A) uses lead-free matte tin plating, and the device conforms to JEDEC J-STD-020 moisture sensitivity level 1 (MSL-1) for unlimited floor life at ≤30°C/60% RH. All manufacturing and packaging materials comply with EU RoHS Directive 2011/65/EU and China RoHS, with full material declarations available upon request. The LP3985IM5X-2.8 is suitable for consumer, industrial, and medical applications requiring green compliance.
LP3985IM5X-2.8 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):
- 2.8V
- 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-2.8 FAQ
1.How can I place an order for LP3985IM5X-2.8 through Aetrix?
Please submit a Request for Quotation (RFQ) for LP3985IM5X-2.8 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-2.8 reliable?
The price and inventory of LP3985IM5X-2.8 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LP3985IM5X-2.8 is usually 5 days.
3.What payment methods are accepted for LP3985IM5X-2.8?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LP3985IM5X-2.8 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LP3985IM5X-2.8?
LP3985IM5X-2.8 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LP3985IM5X-2.8 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-2.8?
For technical support, including LP3985IM5X-2.8 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LP3985IM5X-2.8 requirements.
6.How does Aetrix verify that LP3985IM5X-2.8 is sourced from the original manufacturer or authorized distributors?
All LP3985IM5X-2.8 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-2.8 meets industry standards.
7.What is the process for return or replacement of LP3985IM5X-2.8?
All LP3985IM5X-2.8 units undergo pre-shipment inspection (PSI). If there is an issue with LP3985IM5X-2.8, 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-2.8 part is unused and in its original packaging.
Return procedure for LP3985IM5X-2.8:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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