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Texas Instruments LP3985IM5X-2.8/NOPB
- Part No.:
- LP3985IM5X-2.8/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LP3985IM5X-2.8/NOPB.pdf
- Description:
- IC REG LINEAR 2.8V 150MA SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:2,634
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Product details
Overview
LP3985IM5X-2.8/NOPB from Texas Instruments is a fixed-output, ultra-low-dropout CMOS LDO voltage regulator delivering 150 mA at 2.8 V with ≤100 mV dropout at full load, 30 µVRMS output noise (10 Hz–100 kHz), and 50 dB PSRR at 1 kHz - designed for RF power amplifiers and baseband ICs in space-constrained cellular handsets.
For engineers reviewing the LP3985IM5X-2.8/NOPB datasheet, LP3985IM5X-2.8/NOPB pinout, LP3985IM5X-2.8/NOPB application, or LP3985IM5X-2.8/NOPB equivalent, key selection criteria include verified 2.8-V output tolerance (±3%), shutdown current ≤1.5 µA, DSBGA-5 package footprint (1.502 mm × 1.045 mm), and compatibility with 1-µF ceramic output capacitors.
Technical Context
The LP3985IM5X-2.8/NOPB uses a PMOS pass transistor architecture enabling ultra-low dropout and minimal ground current increase in dropout. Its internal 1.23-V bandgap reference and fast-turnon circuit actively pre-charge the BYPASS pin capacitor to achieve 200 µs startup time.
It integrates thermal shutdown (160°C trip, 20°C hysteresis) and short-circuit current limiting (600 mA steady-state). Stability is guaranteed with 1-µF ±30% ceramic or high-quality tantalum output capacitors - no ESR requirements - and operation is supported across −40°C to 125°C junction temperature.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 2.8 V ±3% over −40°C to 125°C; enables direct replacement of 2.8-V rail in GSM/CDMA baseband circuits. |
| Max Dropout Voltage | 100 mV at 150 mA load; allows operation down to VIN = 2.9 V, extending battery runtime in single-cell Li-ion systems. |
| Output Noise | 30 µVRMS (10 Hz–100 kHz); low enough for sensitive RFIC and ADC power domains without additional filtering. |
| PSRR | 50 dB at 1 kHz (VIN = VOUT + 0.2 V); suppresses switching noise from upstream DC-DC converters feeding cellular transceivers. |
| Quiescent Current | 140 µA typical at 150 mA load; increases only marginally in dropout, preserving battery life during deep discharge. |
| Shutdown Current | ≤1.5 µA when EN < 0.4 V; supports ultra-low-power sleep modes in portable information appliances. |
| Enable Threshold | VIH = 1.4 V, VIL = 0.4 V; compatible with 1.8-V and 3.3-V logic interfaces without level-shifting. |
Pinout & Package
LP3985IM5X-2.8/NOPB is packaged in a 5-pin DSBGA (YZR) with 1.502 mm × 1.045 mm body size and 0.5-mm pitch - optimized for minimal PCB area in mobile phone mainboards.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BYPASS (A3) | Noise reduction node | Accepts 0.01-µF capacitor to reduce output noise without degrading load transient response; internally pre-charged for fast turn-on. |
| IN (C3) | Input supply connection | Accepts 2.5–6 V input; requires ≥1-µF ceramic decoupling within 1 cm of pin to suppress high-frequency ripple. |
| EN (A1) | Logic-controlled enable | Active-high digital control: drives high (>1.4 V) to enable, low (<0.4 V) to enter 1.5-µA shutdown state. |
| GND (B2) | Power ground reference | Common return path for IN, OUT, EN, and BYPASS; must connect to clean analog ground plane to maintain PSRR and noise performance. |
| OUT (C1) | Regulated output | Delivers stable 2.8 V to load; requires ≥1-µF ceramic capacitor (X7R, 0603 or larger) placed within 1 cm for stability. |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-low-noise regulation | 30 µVRMS output noise with 0.01-µF BYPASS capacitor - meets stringent spectral purity requirements for RF power amplifier bias rails. |
| DSBGA-5 footprint | 1.502 mm × 1.045 mm package - reduces total circuit area to <2 mm × 2.5 mm, enabling placement directly under cellular baseband ICs. |
| Zero-load stability | Maintains regulation with no external load - supports CMOS RAM keep-alive and always-on real-time clock circuits without minimum load resistors. |
| Fast enable response | 200 µs turn-on time from EN high to 95% VOUT - enables rapid power sequencing in multi-rail handset architectures. |
| Robust protection | Integrated thermal shutdown (160°C) and short-circuit current limit (600 mA) - prevents damage during board-level fault conditions. |
Applications
| CDMA Cellular Handset RF Power Amplifier | GSM Baseband Processor Core Supply |
|---|---|
Use Scenario: Powers final-stage RF power amplifier in CDMA handsets requiring ultra-low noise and tight voltage regulation under pulsed load conditions. IC Role / Device Role / Timing Role: Low-noise LDO providing clean 2.8-V bias to PA driver stage; replaces bulkier solutions with higher PSRR degradation at RF frequencies. Use Value: 30 µVRMS noise and 50 dB PSRR at 1 kHz prevent AM-to-PM distortion and adjacent channel leakage ratio (ACLR) degradation in transmit paths. |
Use Scenario: Supplies core logic voltage to GSM baseband processor during active call mode with dynamic current draw up to 150 mA. IC Role / Device Role / Timing Role: Primary 2.8-V LDO delivering regulated power to ARM9-based baseband IC; enabled synchronously with system wake-up signal. Use Value: 100-mV dropout ensures sustained 2.8-V output down to 2.9-V battery voltage, maximizing usable capacity from single-cell Li-ion packs. |
| Portable Information Appliance LCD Bias Rail | Wideband CDMA Transceiver Analog Front-End |
Use Scenario: Generates stable 2.8-V bias for TFT-LCD source driver ICs in handheld PDAs and e-readers with intermittent display usage. IC Role / Device Role / Timing Role: Always-on LDO powering LCD interface circuitry; leverages zero-load stability to eliminate standby current waste. Use Value: ≤1.5 µA shutdown current extends battery life during display-off periods; 2.8-V output matches standard LCD gate driver requirements. |
Use Scenario: Supplies low-noise 2.8-V power to analog front-end (AFE) components including IF filters, mixers, and ADC drivers in WCDMA femtocells. IC Role / Device Role / Timing Role: Precision LDO isolating AFE from noisy digital supply domains; BYPASS pin used to suppress broadband switching artifacts. Use Value: 0.01-µF bypass capacitor reduces integrated noise to <30 µVRMS, preventing SNR degradation in 64-QAM receiver chains. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LDO voltage regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPL720F285PDBVR | 2.85-V output, 200-mA rating, SOT-23-5 package; 25 µVRMS noise but requires 2.2-µF output capacitor. | Higher output voltage shifts bias point for newer RFICs; larger output cap increases PCB area by 3× vs. LP3985IM5X-2.8/NOPB's 1-µF requirement. | Select when 2.85-V compliance is mandatory and board space permits larger capacitor footprint. |
| MCP1702T-2802E/MB | 2.8-V output, 250-mA rating, SOT-23-3 package; 65 µVRMS noise, no BYPASS pin, 170 µA quiescent current. | Lacks noise-reduction capability and enable control; suitable only for non-RF digital loads where PSRR >40 dB is sufficient. | Choose for cost-sensitive digital subsystems where ultra-low noise is not required and 3-pin simplicity is prioritized. |
Compared with TPL720F285PDBVR and MCP1702T-2802E/MB, LP3985IM5X-2.8/NOPB uniquely combines 2.8-V precision, DSBGA-5 miniaturization, 30 µVRMS noise via BYPASS, and 1.5-µA shutdown - making it the only option qualified for RF-sensitive 2.8-V rails in space-constrained cellular designs.
Availability
LP3985IM5X-2.8/NOPB is available at Aetrix Electronics and suitable for CDMA handset RF power amplifiers, GSM baseband processors, portable information appliance LCD bias rails, and wideband CDMA transceiver analog front-ends requiring stable component supply across production lifecycles.
Supply support for LP3985IM5X-2.8/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 company specializing in analog, embedded processing, and connectivity technologies for industrial, automotive, and communications markets.
The LP3985 family was developed specifically for battery-powered wireless devices demanding ultra-low noise, ultra-low dropout, and minimal PCB area - targeting cellular handsets, portable medical sensors, and IoT edge nodes.
FAQ
What is the maximum input voltage for LP3985IM5X-2.8/NOPB?
The absolute maximum input voltage for LP3985IM5X-2.8/NOPB is 6.5 V, but the recommended operating range is 2.5 V to 6 V. Operation above 6 V risks permanent damage, while input below 2.9 V (2.8 V + 100 mV dropout) may cause dropout and unregulated output. The device is commonly used with single-cell Li-ion sources (3.0–4.2 V).
Does LP3985IM5X-2.8/NOPB require an external bypass capacitor to function?
No, LP3985IM5X-2.8/NOPB operates stably without the BYPASS capacitor. However, connecting a 0.01-µF capacitor to the BYPASS pin reduces output noise from 30 µVRMS to lower levels and enables the internal 70-µA pre-charge circuit for 200-µs turn-on time. Omitting it increases noise but does not affect regulation or stability.
Can LP3985IM5X-2.8/NOPB be used with ceramic output capacitors smaller than 1 µF?
No - the datasheet specifies stability with ≥1-µF ±30% ceramic or high-quality tantalum output capacitors. Using smaller values (e.g., 0.47 µF) risks oscillation and poor transient response. X7R dielectric in 0603 or larger case sizes is recommended to maintain capacitance under DC bias and temperature variation.
What is the thermal shutdown behavior of LP3985IM5X-2.8/NOPB?
LP3985IM5X-2.8/NOPB activates thermal shutdown at 160°C junction temperature and remains latched off until junction temperature falls by 20°C (hysteresis). During shutdown, output is disabled and quiescent current drops to ≤1.5 µA. Recovery is automatic once temperature falls below 140°C - no external reset is needed.
Is LP3985IM5X-2.8/NOPB pin-compatible with other LP3985 variants?
Yes - all LP3985 variants (including LP3985IM5X-2.5/NOPB, LP3985IM5X-3.3/NOPB) share identical DSBGA-5 pinout and package dimensions. Only the output voltage differs; no PCB layout change is required when substituting between fixed-voltage versions in the same package.
LP3985IM5X-2.8/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- SC-74A, SOT-753
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- 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/NOPB FAQ
1.How can I place an order for LP3985IM5X-2.8/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LP3985IM5X-2.8/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 LP3985IM5X-2.8/NOPB reliable?
The price and inventory of LP3985IM5X-2.8/NOPB 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/NOPB is usually 5 days.
3.What payment methods are accepted for LP3985IM5X-2.8/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LP3985IM5X-2.8/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LP3985IM5X-2.8/NOPB?
LP3985IM5X-2.8/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LP3985IM5X-2.8/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 LP3985IM5X-2.8/NOPB?
For technical support, including LP3985IM5X-2.8/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LP3985IM5X-2.8/NOPB requirements.
6.How does Aetrix verify that LP3985IM5X-2.8/NOPB is sourced from the original manufacturer or authorized distributors?
All LP3985IM5X-2.8/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 LP3985IM5X-2.8/NOPB meets industry standards.
7.What is the process for return or replacement of LP3985IM5X-2.8/NOPB?
All LP3985IM5X-2.8/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LP3985IM5X-2.8/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 LP3985IM5X-2.8/NOPB part is unused and in its original packaging.
Return procedure for LP3985IM5X-2.8/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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