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Texas Instruments LP3985ITLX-2.8/NOPB
- Part No.:
- LP3985ITLX-2.8/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 5-WFBGA, DSBGA
- Datasheet:
-
LP3985ITLX-2.8/NOPB.pdf
- Description:
- IC REG LINEAR 2.8V 150MA 5DSBGA
- Quantity:
- Payment:
- Shipping:
Inventory:3,000
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Product details
Overview
LP3985ITLX-2.8/NOPB from Texas Instruments is a fixed-output, micropower, ultra-low-dropout CMOS 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 - optimized for RF power amplifier biasing in cellular handsets.
For engineers reviewing the LP3985ITLX-2.8/NOPB datasheet, LP3985ITLX-2.8/NOPB pinout, LP3985ITLX-2.8/NOPB application, or LP3985ITLX-2.8/NOPB equivalent, key selection criteria include DSBGA package footprint (1.502 mm × 1.045 mm), enable-controlled shutdown (<1.5 µA quiescent current), bypass-capacitor–enabled low-noise operation, and compatibility with 1-µF ceramic output capacitors.
Technical Context
The LP3985ITLX-2.8/NOPB employs a PMOS pass transistor architecture enabling ultra-low dropout (60 mV typical at 150 mA) and minimal ground current increase in dropout - critical for battery runtime extension. Its internal bandgap reference (1.23 V nominal) and fast-turnon circuit actively pre-charge the BYPASS pin capacitor to achieve 200 µs startup time.
Power supply rejection exceeds 50 dB below 1 kHz and remains >40 dB up to 10 kHz, while thermal shutdown (160°C) and short-circuit current limiting (600 mA steady-state) provide robust protection in compact portable systems operating from −40°C to 125°C junction temperature.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 2.8 V ±3% - ensures stable bias for RF PA stages without external feedback components. |
| Max Dropout Voltage | 100 mV at 150 mA - enables regulation down to VIN = 2.9 V, extending usable battery range in single-cell Li-ion systems. |
| Output Noise | 30 µVRMS (10 Hz–100 kHz) - meets stringent spectral purity requirements for GSM/CDMA/WCDMA transceiver LDO applications. |
| PSRR | 50 dB at 1 kHz - suppresses switching noise from upstream DC-DC converters feeding the RF section. |
| Quiescent Current | 140 µA typical at 150 mA load; ≤1.5 µA in shutdown - minimizes standby power loss in always-on mobile subsystems. |
| Enable Threshold | VIH = 1.4 V, VIL = 0.4 V - compatible with standard 1.8-V/2.8-V/3.3-V logic interfaces without level-shifting. |
| Operating Temp | −40°C to +125°C junction - qualified for automotive infotainment and industrial handheld environments. |
Pinout & Package
LP3985ITLX-2.8/NOPB uses the 5-pin DSBGA (YZR) package with body size 1.502 mm × 1.045 mm - the smallest PCB footprint in its class, enabling <2 mm × 2.5 mm total circuit area.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BYPASS (A3) | Noise reduction node | Accepts 0.01 µF capacitor to reduce output noise without degrading transient response; internally pre-charged for fast turn-on. |
| EN (A1) | Digital enable input | Active-high logic control: drives high (>1.4 V) to enable regulator; pulls low (<0.4 V) to enter sub-1.5 µA shutdown mode. |
| GND (B2) | Power ground reference | Common return path for IN, OUT, EN, and BYPASS; must be connected to clean analog ground plane for noise integrity. |
| IN (C3) | Input power supply | Accepts 2.5 V to 6 V input; requires ≥1 µF ceramic capacitor placed within 1 cm of pin for stability and EMI suppression. |
| OUT (C1) | Regulated output | Delivers 2.8 V ±3% at up to 150 mA; stable with 1 µF ±30% X7R ceramic capacitor; low ESR (5–500 mΩ) required. |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-low-noise regulation | 30 µVRMS output noise with 0.01 µF BYPASS capacitor - enables clean RF PA biasing without additional filtering. |
| DSBGA space optimization | 1.502 mm × 1.045 mm footprint - reduces PCB area by >70% vs. SOT-23-5, critical for ultra-thin mobile designs. |
| Fast, controlled startup | 200 µs turn-on time with active BYPASS pre-charge - synchronizes cleanly with baseband processor power sequencing. |
| Low-dropout operation | 60 mV typical dropout at 150 mA - sustains regulation through deep battery discharge (down to ~2.86 V on 3.7 V Li-ion). |
| Robust protection suite | Thermal shutdown (160°C) + hysteresis (20°C) + 600 mA short-circuit limit - prevents damage during RF PA fault conditions. |
Applications
| CDMA RF Power Amplifier Bias | GSM Transmitter Chain Supply |
|---|---|
Use Scenario: Powers final-stage RF power amplifier in CDMA handset where spectral purity directly impacts adjacent channel leakage ratio (ACLR). IC Role / Device Role / Timing Role: Low-noise, fast-response LDO supplying clean 2.8 V bias to GaAs FET PA under dynamic envelope tracking. Use Value: 30 µVRMS noise and 50 dB PSRR prevent AM-to-PM distortion and maintain ACLR compliance across 800/1900 MHz bands. | Use Scenario: Supplies voltage to GSM PA driver and output stage during TDMA burst transmission with high peak current demands. IC Role / Device Role / Timing Role: Enables/disables PA supply via EN pin synchronized to GSM timeslot timing (4.615 ms frame period). Use Value: 200 µs turn-on time ensures full PA bias is established before transmit ramp-up begins, eliminating burst clipping. |
| WCDMA Front-End Module | Portable GPS Receiver LNA |
Use Scenario: Provides regulated 2.8 V to WCDMA front-end module containing PA, switch, and duplexer - sensitive to supply ripple-induced desensitization. IC Role / Device Role / Timing Role: Primary LDO for integrated FEM; BYPASS pin used to suppress broadband noise coupling into antenna path. Use Value: 100 mV max dropout preserves headroom during 3GPP-defined peak current pulses (up to 150 mA), preventing gain compression. | Use Scenario: Powers low-noise amplifier in battery-operated GPS receiver where phase noise degradation directly impacts C/N₀ and time-to-first-fix. IC Role / Device Role / Timing Role: Ultra-low-noise 2.8 V source for LNA bias; operates continuously during satellite acquisition and tracking. Use Value: 30 µVRMS noise floor avoids raising LNA input-referred noise, maintaining sensitivity better than −160 dBm/Hz. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar low-noise LDO applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPL720F2815PDBVR | 2.8 V fixed, 200 mA output, 75 mV dropout (typ), 25 µVRMS noise, SOT-23-5 package | Larger footprint (2.9 mm × 1.6 mm); higher output current but no BYPASS pin for noise tuning | Select when higher current headroom is needed and board space permits SOT-23; not suitable for DSBGA-constrained layouts. |
| MCP1804T-2802I/OT | 2.8 V fixed, 150 mA, 350 mV dropout (max), 40 µVRMS noise, SOT-23-5 package | Higher dropout limits usable input range; no enable pin; higher noise degrades RF performance | Acceptable only for non-RF applications like MCU core supply where noise and dropout are less critical. |
Compared with LP3985ITLX-2.8/NOPB, TPL720F2815PDBVR offers higher current but lacks the BYPASS-controlled noise optimization essential for RF biasing, while MCP1804T-2802I/OT's higher dropout and noise make it unsuitable for battery-powered RF front ends requiring tight voltage headroom and spectral purity.
Availability
LP3985ITLX-2.8/NOPB is available at Aetrix Electronics and suitable for CDMA/WCDMA handset design, portable GPS receivers, and industrial handheld terminals requiring stable component supply with guaranteed long-term manufacturability.
Supply support for LP3985ITLX-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 and embedded processing technologies, with leadership in power management ICs for portable and wireless systems.
The LP3985 product line delivers micropower, ultra-low-noise, ultra-low-dropout regulation specifically for battery-powered RF subsystems in cellular handsets and portable communications equipment.
FAQ
What is the minimum input voltage required for LP3985ITLX-2.8/NOPB to regulate at full 150 mA load?
The LP3985ITLX-2.8/NOPB requires VIN ≥ VOUT + dropout voltage. With a maximum dropout of 100 mV at 150 mA, the minimum functional input is 2.9 V. Below this, output voltage drops below 2.8 V specification. The datasheet specifies 2.5 V as absolute minimum VIN, but regulation at full load is only guaranteed above 2.9 V.
Can LP3985ITLX-2.8/NOPB operate without the optional BYPASS capacitor?
Yes, LP3985ITLX-2.8/NOPB functions normally without the BYPASS capacitor. However, output noise increases from 30 µVRMS to approximately 230 nV/√Hz broadband density. The BYPASS pin is optional - omitting it simplifies layout but sacrifices noise performance critical for RF PA biasing.
Is LP3985ITLX-2.8/NOPB stable with a 1-µF X5R ceramic capacitor?
Yes, LP3985ITLX-2.8/NOPB is stable with 1-µF X5R ceramic capacitors meeting ESR requirements (5–500 mΩ). However, X5R exhibits greater capacitance loss over temperature (−55°C to +85°C) versus X7R. For extended temperature operation (−40°C to +125°C), X7R is preferred to maintain ≥0.7 µF effective capacitance.
What happens to LP3985ITLX-2.8/NOPB when the EN pin is left floating?
The EN pin has no internal pull-up or pull-down. If left floating, LP3985ITLX-2.8/NOPB behavior is undefined and may oscillate or remain partially enabled due to noise coupling. TI explicitly recommends tying EN to VIN if enable functionality is unused - this guarantees reliable turn-on and avoids erratic operation.
Does LP3985ITLX-2.8/NOPB support reverse current blocking?
No, LP3985ITLX-2.8/NOPB does not include reverse current blocking. When VIN < VOUT, reverse current can flow from OUT to IN through the PMOS pass device body diode. For applications requiring reverse polarity protection or back-powering prevention, an external Schottky diode in series with the IN pin is required.
LP3985ITLX-2.8/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 5-WFBGA, DSBGA
- 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:
- 5-DSBGA (1.41x1.08)
LP3985ITLX-2.8/NOPB FAQ
1.How can I place an order for LP3985ITLX-2.8/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LP3985ITLX-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 LP3985ITLX-2.8/NOPB reliable?
The price and inventory of LP3985ITLX-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 LP3985ITLX-2.8/NOPB is usually 5 days.
3.What payment methods are accepted for LP3985ITLX-2.8/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LP3985ITLX-2.8/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LP3985ITLX-2.8/NOPB?
LP3985ITLX-2.8/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LP3985ITLX-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 LP3985ITLX-2.8/NOPB?
For technical support, including LP3985ITLX-2.8/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LP3985ITLX-2.8/NOPB requirements.
6.How does Aetrix verify that LP3985ITLX-2.8/NOPB is sourced from the original manufacturer or authorized distributors?
All LP3985ITLX-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 LP3985ITLX-2.8/NOPB meets industry standards.
7.What is the process for return or replacement of LP3985ITLX-2.8/NOPB?
All LP3985ITLX-2.8/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LP3985ITLX-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 LP3985ITLX-2.8/NOPB part is unused and in its original packaging.
Return procedure for LP3985ITLX-2.8/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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