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Texas Instruments LM2705MF-ADJ/NOPB
- Part No.:
- LM2705MF-ADJ/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LM2705MF-ADJ/NOPB.pdf
- Description:
- IC LED DRVR RGLTR 150MA SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:2,661
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Product details
Overview
LM2705MF-ADJ/NOPB from Texas Instruments is a micropower step-up DC-DC converter in a 5-pin SOT-23 package, featuring 2.2–7 V input range, 150 mA peak switch current limit, 0.7 Ω internal NMOS switch, adjustable output up to 20 V, and 0.01 µA shutdown current. It serves as a compact, high-efficiency boost regulator for low-current bias and backlighting in portable Li-Ion-powered devices.
For engineers reviewing the LM2705MF-ADJ/NOPB datasheet, LM2705MF-ADJ/NOPB pinout, LM2705MF-ADJ/NOPB application, or LM2705MF-ADJ/NOPB equivalent, key selection criteria include input undervoltage lockout (1.8 V), feedback reference voltage (1.237 V), constant off-time control (400 ns), junction temperature range (–40°C to 125°C), and compatibility with small-footprint passive components (e.g., 33–68 µH inductors, 1–4.7 µF ceramics).
Technical Context
The LM2705MF-ADJ/NOPB employs a fixed-off-time, current-limited control architecture that enables high light-load efficiency and stable regulation across wide input and load variations. Its 21 V-rated internal switch supports output voltages up to 20.5 V while maintaining low quiescent current (235 µA typical enabled, 0.01 µA in shutdown).
Feedback is implemented via a precision 1.237 V reference with ±30 mV hysteresis; output voltage is set externally using resistor dividers (e.g., R1 = 510 kΩ, R2 = 33 kΩ for ~20 V). The 400 ns off-time enables use of miniature inductors and minimizes EMI-sensitive trace lengths.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.2 V to 7 V - supports single-cell Li-Ion (2.5–4.2 V) and multi-cell alkaline inputs without external LDO pre-regulation. |
| Output Voltage | Adjustable up to 20 V - set by external R1/R2 divider; enables LCD bias and white-LED string drive from low-voltage sources. |
| Peak Switch Current | 150 mA - limits inductor stress and thermal rise; sufficient for driving up to three white LEDs at ~20 mA each. |
| Internal Switch RDS(on) | 0.7 Ω (typ) - reduces conduction loss at light loads; contributes to >85% efficiency at 1–5 mA output. |
| Shutdown Current | 0.01 µA - extends battery life in standby mode; SHDN pin active-low with 0.3 V/1.1 V thresholds. |
| Feedback Reference | 1.237 V ±32 mV - provides accurate output regulation; hysteresis improves noise immunity in noisy portable environments. |
| Switch Off Time | 400 ns - enables use of low-profile, low-DCR inductors (e.g., 33 µH) and tight PCB layout with minimal EMI. |
Pinout & Package
SOT-23 (DBV) package, 2.90 mm × 1.60 mm body size, 5-pin surface-mount configuration with exposed pad not present. RoHS-compliant, Sn lead finish, MSL Level-1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - SW | Switch node | Drain of internal NMOS power switch; connects to inductor and Schottky diode anode; requires minimal trace area to reduce EMI radiation. |
| 2 - GND | Ground reference | Common return for analog and power paths; must tie directly to solid ground plane to ensure stable feedback and minimize noise coupling. |
| 3 - FB | Voltage feedback input | Senses output via resistive divider; trip point at 1.237 V; bias current ≤120 nA ensures minimal divider loading error. |
| 4 - SHDN | Enable/disable control | Active-low logic input; <0.3 V disables device (0.01 µA IQ); >1.1 V enables operation; internal pull-down ensures default-off behavior. |
| 5 - VIN | Power input | Supplies both control circuitry and switch driver; requires local 4.7 µF ceramic bypass capacitor placed adjacent to pin. |
Key Features
| Feature | Design Value |
|---|---|
| Micropower operation | 235 µA typical operating current and 0.01 µA shutdown current enable multi-week battery life in intermittent-use portable systems. |
| Integrated 0.7 Ω NMOS switch | Eliminates need for external MOSFET and gate driver; reduces BOM count and layout complexity in space-constrained designs. |
| Constant off-time control | 400 ns fixed off-time ensures predictable switching frequency scaling with load and input voltage - simplifies EMI filtering design. |
| Input UVLO | 1.8 V turn-on threshold prevents erratic startup during Li-Ion battery discharge below usable voltage, improving system reliability. |
| Small SOT-23 footprint | 5-pin DBV package occupies <5 mm² PCB area - ideal for wearables, medical sensors, and compact IoT endpoints. |
Applications
| LCD Bias Supply | White-LED Backlighting |
|---|---|
Use Scenario: Generating +15 V to –10 V bias rails for STN/TN LCD panels in handheld meters and industrial HMIs. IC Role / Device Role / Timing Role: Primary boost regulator providing regulated high-voltage rail; no timing-critical interface - operates autonomously based on feedback loop. Use Value: Enables single-cell Li-Ion operation without external charge pumps; 150 mA peak current supports multi-segment panel drive with <1% output drift over temperature. | Use Scenario: Driving 2–3串联 white LEDs (3.0–3.6 V each) from a 2.5–4.2 V Li-Ion source in feature phones and barcode scanners. IC Role / Device Role / Timing Role: Constant-current-capable boost controller; LED current set by external sense resistor; no PWM dimming interface required. Use Value: Delivers >82% efficiency at 8 mA output; 0.01 µA shutdown extends standby time; 400 ns off-time allows use of 33 µH inductor with <1 mm height. |
| USB-Powered Peripherals | Portable Medical Sensors |
Use Scenario: Providing 5 V or 12 V auxiliary supply from USB 5 V input for low-power ADCs, op-amps, or RF modules. IC Role / Device Role / Timing Role: Step-up converter with input undervoltage lockout; operates only when host USB port delivers stable 4.75–5.25 V. Use Value: Peak inductor current limited to 150 mA avoids USB port overcurrent trips; 0.7 Ω RDS(on) minimizes thermal rise under sustained 50 mA load. | Use Scenario: Powering low-noise analog front-ends (e.g., ECG amplifiers, pulse oximeter LEDs) from coin-cell or Li-Ion batteries. IC Role / Device Role / Timing Role: Isolated high-voltage bias generator; separates analog signal path from switching noise via careful layout and local decoupling. Use Value: 235 µA quiescent current preserves battery capacity during sleep cycles; FB pin bias <120 nA prevents divider-induced offset errors in precision sensing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar boost converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS61022DRVR | Higher 2-A switch current, 2.5-V min input, integrated soft-start; requires larger 2-mm × 2-mm WSON package. | Better suited for higher-output-current applications (e.g., >20 mA LED strings or 3.3-V logic rails); less optimal for ultra-low-IQ battery monitoring. | Select TPS61022DRVR when output current exceeds 10 mA and board space permits larger package; LM2705MF-ADJ/NOPB remains preferred for sub-5-mA bias supplies. |
| MAX77812EWA+T | Fixed 5-V output, 1.2-MHz switching, 3.5-µA shutdown current; no adjustable feedback - lacks external resistor flexibility. | Targeted at USB-C PD sink applications requiring fixed 5 V; unsuitable for variable-voltage LCD bias or LED configurations above 5 V. | Choose MAX77812EWA+T only for dedicated 5-V boost needs; LM2705MF-ADJ/NOPB offers broader voltage adaptability and lower cost for custom-rail designs. |
Compared with TPS61022DRVR and MAX77812EWA+T, the LM2705MF-ADJ/NOPB uniquely balances ultra-low shutdown current (0.01 µA), adjustable 20-V output, and minimal 5-pin SOT-23 footprint - making it the optimal choice for space- and energy-constrained portable biasing where precise voltage tuning and multi-year battery life are critical.
Availability
LM2705MF-ADJ/NOPB is available at Aetrix Electronics and suitable for LCD bias supplies, white-LED backlighting, and portable medical sensor power management requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.
Supply support for LM2705MF-ADJ/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 leader delivering analog, embedded processing, and connectivity solutions for industrial, automotive, and personal electronics markets.
The LM2705MF-ADJ/NOPB belongs to TI's micropower DC-DC converter product line, engineered specifically for ultra-low-quiescent-current, small-footprint boost regulation in battery-powered portable systems.
FAQ
What is the minimum input voltage required for stable operation of the LM2705MF-ADJ/NOPB?
The LM2705MF-ADJ/NOPB has a recommended minimum input voltage of 2.2 V and incorporates input undervoltage lockout (UVLO) that disables the device below approximately 1.8 V. Stable regulation begins once VIN exceeds 2.2 V across the full temperature range (–40°C to 125°C), as confirmed in the Recommended Operating Conditions table of the SNVS191F datasheet. Operation below 2.2 V may result in reduced output accuracy or dropout.
How is the output voltage adjusted on the LM2705MF-ADJ/NOPB?
The LM2705MF-ADJ/NOPB uses an external resistor divider on the FB pin to set output voltage according to the formula R1 = R2 × (VOUT / 1.237 V) – 1. For example, with R2 = 33 kΩ and R1 = 510 kΩ, VOUT ≈ 20 V. The FB pin reference is trimmed to 1.237 V ±32 mV over temperature, and bias current remains ≤120 nA to avoid significant divider error - ensuring accurate, stable adjustment across operating conditions.
Does the LM2705MF-ADJ/NOPB support true shutdown with near-zero current draw?
Yes, the LM2705MF-ADJ/NOPB achieves 0.01 µA typical shutdown current when the SHDN pin is driven below 0.3 V. This ultra-low state is verified across –40°C to 125°C and enables multi-year battery life in infrequently powered devices. During shutdown, the output floats to VIN minus one Schottky diode drop, and all internal circuitry - including bandgap reference and oscillator - is disabled.
What is the maximum achievable output current using the LM2705MF-ADJ/NOPB?
The LM2705MF-ADJ/NOPB delivers up to ~8 mA continuous output current at 20 V with high efficiency (>80%) when powered from a 3.6 V Li-Ion source, as demonstrated in Figure 17 and Figure 18 of the datasheet. Peak switch current is limited to 150 mA, but practical output depends on input voltage, inductor value, and thermal dissipation. At lower output voltages (e.g., 5 V), continuous current can reach ~20 mA with appropriate layout and component selection.
Can the LM2705MF-ADJ/NOPB be used in SEPIC topology applications?
Yes, the LM2705MF-ADJ/NOPB supports SEPIC configuration as documented in Figures 23 and 24 of the SNVS191F datasheet. Its constant off-time control and internal switch allow bidirectional energy transfer when paired with two coupled inductors and a coupling capacitor. Design equations for L1 and L2 are provided in Section 8.2.2.2, and TI validates operation up to 20 mA output in 3.3 V and 5 V SEPIC examples - extending utility beyond basic boost into buck-boost applications.
LM2705MF-ADJ/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- SC-74A, SOT-753
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- DC DC Regulator
- Topology:
- Step-Up (Boost)
- Internal Switch(s):
- Yes
- Number of Outputs:
- 1
- Voltage - Supply (Min):
- 2.2V
- Voltage - Supply (Max):
- 7V
- Voltage - Output:
- 20V
- Current - Output / Channel:
- 150mA
- Frequency:
- -
- Dimming:
- -
- Applications:
- Backlight
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-5
LM2705MF-ADJ/NOPB FAQ
1.How can I place an order for LM2705MF-ADJ/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2705MF-ADJ/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 LM2705MF-ADJ/NOPB reliable?
The price and inventory of LM2705MF-ADJ/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2705MF-ADJ/NOPB is usually 5 days.
3.What payment methods are accepted for LM2705MF-ADJ/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2705MF-ADJ/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2705MF-ADJ/NOPB?
LM2705MF-ADJ/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2705MF-ADJ/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 LM2705MF-ADJ/NOPB?
For technical support, including LM2705MF-ADJ/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2705MF-ADJ/NOPB requirements.
6.How does Aetrix verify that LM2705MF-ADJ/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2705MF-ADJ/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 LM2705MF-ADJ/NOPB meets industry standards.
7.What is the process for return or replacement of LM2705MF-ADJ/NOPB?
All LM2705MF-ADJ/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2705MF-ADJ/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 LM2705MF-ADJ/NOPB part is unused and in its original packaging.
Return procedure for LM2705MF-ADJ/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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