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Texas Instruments LP3985IM5-285/NOPB
- Part No.:
- LP3985IM5-285/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LP3985IM5-285/NOPB.pdf
- Description:
- IC REG LIN 2.85V 150MA SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:3,902
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Product details
Overview
LP3985IM5-285/NOPB from Texas Instruments is a micropower, ultra-low-noise, 150mA CMOS low-dropout voltage regulator with 2.85V fixed output, 100mV max dropout at 150mA load, ≤1.5μA shutdown quiescent current, and 30μVrms output noise (10Hz–100kHz). It delivers stable power to RF front-ends and baseband ICs in space-constrained cellular handsets.
For engineers reviewing the LP3985IM5-285/NOPB datasheet, LP3985IM5-285/NOPB pinout, LP3985IM5-285/NOPB application, or LP3985IM5-285/NOPB equivalent, key selection criteria include its 200μs fast turn-on time, compatibility with 1µF ceramic output capacitors, thermal shutdown protection, and operation across −40°C to +125°C junction temperature.
Technical Context
The LP3985IM5-285/NOPB employs a CMOS pass transistor architecture enabling ultra-low dropout and minimal ground current increase in dropout-critical for battery runtime extension. Its internal bandgap reference (1.23V) feeds an error amplifier controlling the pass device, with fast turn-on achieved via a 70μA internal pre-charge current source on the BYPASS pin.
Stability is guaranteed with ≥0.7µF ceramic output capacitors (X7R dielectric, 5–500mΩ ESR); the optional 0.01µF bypass capacitor connects to a high-impedance node in the reference circuit to reduce output noise without degrading load transient response.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 2.85V ±2% tolerance ensures precise biasing of 2.8V–3.0V logic and RF ICs without external feedback. |
| Max Output Current | 150mA verified output supports GSM/CDMA transceiver modules, audio codecs, and sensor interfaces. |
| Dropout Voltage | ≤100mV at 150mA load enables regulation down to VIN = 2.95V-extending usable battery range in single-cell Li-ion systems. |
| Quiescent Current | ≤1.5μA in shutdown mode minimizes leakage current in always-on backup rails (e.g., RTC, SRAM keep-alive). |
| Output Noise | 30μVrms (10Hz–100kHz) supports noise-sensitive analog circuits like VCOs and ADC references. |
| PSRR | 50dB at 1kHz (VIN = VOUT + 0.2V) suppresses switching noise from DC/DC converters feeding the LDO input. |
| Turn-On Time | 200μs typical with 0.01µF BYPASS capacitor enables rapid power sequencing in wake-up events. |
| Operating Temp | −40°C to +125°C junction range qualifies for automotive infotainment and industrial handheld applications. |
Pinout & Package
LP3985IM5-285/NOPB uses the SOT-23-5 (DBV) package: 2.92mm × 1.6mm footprint, 1.0mm height, gull-wing leads, RoHS-compliant CuSn finish, MSL Level-1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Input voltage supply | Accepts 2.5V–6.0V; requires ≥1µF ceramic input capacitor within 1cm of pin for stability. |
| GND | Power ground reference | Common return path for input/output/bypass; must connect to clean analog ground plane. |
| VOUT | Regulated output | Delivers 2.85V ±2%; stable with 0.7–1.3µF X7R ceramic capacitor (ESR 5–500mΩ). |
| VEN | Logic-controlled enable | Active-high input; VIH = 1.4V min, VIL = 0.4V max; tie to VIN for always-on operation. |
| BYPASS | Noise reduction node | Connects 0.01µF NPO/COG ceramic capacitor to GND; reduces output noise without slowing transient response. |
Key Features
| Feature | Design Value |
|---|---|
| Micropower shutdown | ≤1.5μA quiescent current preserves battery life in standby modes of portable devices. |
| Ultra-low-noise regulation | 30μVrms output noise (10Hz–100kHz) meets stringent requirements for RF synthesizers and precision analog signal chains. |
| Fast, controlled startup | 200μs turn-on time with active BYPASS pre-charge enables deterministic power sequencing in multi-rail systems. |
| Robust protection | Integrated thermal shutdown (160°C trigger) and short-circuit current limit (600mA steady-state) prevent damage under fault conditions. |
| Minimal board area | SOT-23-5 package allows full regulator circuit (including 1µF COUT) in <2.5mm² PCB area-ideal for compact mobile designs. |
Applications
| CDMA Cellular Handset Power Rail | GSM Transceiver Bias Supply |
|---|---|
Use Scenario: Powers CDMA baseband processor I/O and RF front-end ICs requiring clean, stable 2.85V from a shared Li-ion battery rail. IC Role / Device Role / Timing Role: Primary low-noise LDO delivering regulated 2.85V with fast transient response to handle burst-mode transmission current spikes. Use Value: 30μVrms noise and 50dB PSRR at 1kHz prevent AM-to-PM distortion in power amplifiers and maintain EVM compliance. |
Use Scenario: Supplies GSM PA driver stage and frequency synthesizer where voltage ripple directly impacts spectral mask performance. IC Role / Device Role / Timing Role: Low-dropout regulator providing 2.85V with ≤100mV dropout to maximize battery utilization during high-current TX bursts. Use Value: 150mA output capability and 200μs turn-on support rapid TX/RX state transitions without brownout or delay penalties. |
| Portable Information Appliance Core Logic | Wireless Sensor Node MCU Supply |
Use Scenario: Powers ARM Cortex-M core and peripherals in handheld PDAs where board space and battery life are critical constraints. IC Role / Device Role / Timing Role: Micropower LDO supplying 2.85V to digital logic; enabled only during active processing cycles via VEN control. Use Value: ≤1.5μA shutdown current extends shelf life and operational runtime; SOT-23-5 footprint saves >50% area vs. larger LDO packages. |
Use Scenario: Provides regulated 2.85V to ultra-low-power microcontrollers (e.g., MSP430, nRF52) in battery-operated IoT sensors. IC Role / Device Role / Timing Role: Always-on LDO maintaining MCU VDD during deep-sleep states; stable with no-load condition per spec. Use Value: No-load stability and −40°C to +125°C operation ensure reliable boot and sensor data acquisition across environmental extremes. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar low-noise, micropower LDO applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPL720F285DRVR | 200mA output, 25μVrms noise, 1.2V–5.5V input, but requires minimum 2.2µF output capacitor for stability. | Better noise performance but larger output cap increases board area; not drop-in for 1µF-ceramic designs. | Select if lower noise is prioritized and layout allows ≥2.2µF COUT; verify thermal derating at 150mA in SOT-563 package. |
| MCP1700T-285I/TT | 250mA output, 35μVrms noise, 2.7V–13.2V input, 6μA quiescent current in shutdown (vs. 1.5μA). | Higher IQ reduces battery life in long-duration sleep modes; wider input range suits multi-cell battery systems. | Prefer for cost-sensitive industrial sensors where 6μA shutdown is acceptable and input may exceed 6V. |
Compared with LP3985IM5-285/NOPB, TPL720F285DRVR offers lower noise but demands larger output capacitance, while MCP1700T-285I/TT provides higher current and input voltage range at the expense of 4× higher shutdown current-making LP3985IM5-285/NOPB optimal for space- and battery-limited 2.5–6.0V portable designs.
Availability
LP3985IM5-285/NOPB is available at Aetrix Electronics and suitable for CDMA/GSM handset power management, portable information appliance core logic, and wireless sensor node MCU supply requiring stable component supply, RoHS compliance, and long-term lifecycle support.
Supply support for LP3985IM5-285/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 industrial applications.
The LP3985 product line was designed specifically for battery-powered wireless devices demanding ultra-low noise, micropower shutdown, and minimal PCB footprint-targeting cellular handsets, PDAs, and compact IoT endpoints.
FAQ
What is the maximum input voltage rating for LP3985IM5-285/NOPB?
The absolute maximum input voltage for LP3985IM5-285/NOPB is 6.5V, but the recommended operating range is 2.5V to 6.0V per the datasheet. Exceeding 6.0V risks violating the specified operating conditions and may impact long-term reliability, especially at elevated temperatures. The device's 100mV dropout at 150mA is guaranteed only within the 2.5–6.0V input window.
Does LP3985IM5-285/NOPB require an external bypass capacitor to meet its 30μVrms noise specification?
Yes, the 30μVrms output noise (10Hz–100kHz) for LP3985IM5-285/NOPB is measured with a 0.01µF ceramic capacitor connected between the BYPASS pin and GND. Without this capacitor, typical output noise rises to 230nV/√Hz broadband density, resulting in higher integrated noise. The BYPASS capacitor must be NPO/COG or film type to minimize leakage-induced output voltage error.
Can LP3985IM5-285/NOPB operate stably with no load connected to VOUT?
Yes, LP3985IM5-285/NOPB remains stable and in regulation with zero load current-a feature explicitly validated in the datasheet under "NO-LOAD STABILITY." This makes it suitable for applications like SRAM keep-alive rails or real-time clock backup supplies where continuous regulation is required even during system sleep states.
What is the thermal shutdown threshold and hysteresis for LP3985IM5-285/NOPB?
LP3985IM5-285/NOPB activates thermal shutdown at a junction temperature of 160°C, with 20°C hysteresis-meaning the device resumes normal operation only after the junction cools to approximately 140°C. This behavior is consistent across both SOT-23-5 and DSBGA packages and protects against sustained overloads or poor PCB thermal design.
Is the SOT-23-5 package of LP3985IM5-285/NOPB RoHS-compliant and lead-free?
Yes, LP3985IM5-285/NOPB carries the "/NOPB" suffix indicating RoHS-compliant, lead-free construction with CuSn (copper-tin) lead finish. It meets JEDEC MSL Level-1 (260°C peak reflow), has no halogen or antimony restrictions, and is qualified for surface-mount assembly per TI's SMT guidelines in AN-1112.
LP3985IM5-285/NOPB 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):
- 2.85V
- 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
LP3985IM5-285/NOPB FAQ
1.How can I place an order for LP3985IM5-285/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LP3985IM5-285/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 LP3985IM5-285/NOPB reliable?
The price and inventory of LP3985IM5-285/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LP3985IM5-285/NOPB is usually 5 days.
3.What payment methods are accepted for LP3985IM5-285/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LP3985IM5-285/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LP3985IM5-285/NOPB?
LP3985IM5-285/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LP3985IM5-285/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 LP3985IM5-285/NOPB?
For technical support, including LP3985IM5-285/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LP3985IM5-285/NOPB requirements.
6.How does Aetrix verify that LP3985IM5-285/NOPB is sourced from the original manufacturer or authorized distributors?
All LP3985IM5-285/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 LP3985IM5-285/NOPB meets industry standards.
7.What is the process for return or replacement of LP3985IM5-285/NOPB?
All LP3985IM5-285/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LP3985IM5-285/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 LP3985IM5-285/NOPB part is unused and in its original packaging.
Return procedure for LP3985IM5-285/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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