My Inquiry
My Account
Texas Instruments LM2705MFX-ADJ
- Part No.:
- LM2705MFX-ADJ
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LM2705MFX-ADJ.pdf
- Description:
- IC LED DRVR RGLTR 150MA SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:3,447
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LM2705MFX-ADJ from Texas Instruments is a micropower step-up DC-DC converter in a 5-pin SOT-23 package, delivering up to 20 V output with 150-mA peak switch current, 0.7-Ω internal NMOS switch, and 400-ns fixed off-time control. It operates from 2.2 V to 7 V input-ideal for single-cell Li-Ion battery-powered LCD bias and white-LED backlighting.
For engineers reviewing the LM2705MFX-ADJ datasheet, LM2705MFX-ADJ pinout, LM2705MFX-ADJ application, or LM2705MFX-ADJ equivalent, key selection criteria include adjustable 20-V output capability, ultra-low 0.01-µA shutdown current, input undervoltage lockout at 1.8 V, and compatibility with tiny surface-mount inductors (e.g., 33 µH) and ceramic capacitors in space-constrained portable designs.
Technical Context
The LM2705MFX-ADJ uses a constant off-time (COT) control architecture with a 400-ns fixed off-time and current-limited switching, enabling high light-load efficiency and stable operation across wide input (2.2–7 V) and temperature (–40°C to 125°C) ranges. Its feedback comparator trips at 1.237 V with ±8 mV hysteresis, and the internal 150-mA peak-current-limited NMOS switch features 0.7 Ω RDS(ON) at room temperature.
Shutdown is controlled via an active-low SHDN pin with 0.3 V low threshold and 1.1 V high threshold; in shutdown, quiescent current drops to 0.01 µA and output voltage decays to VIN minus diode drop. The device integrates undervoltage lockout (UVP) and requires external resistor divider (R1/R2) for output voltage setting per VOUT = 1.237 × (1 + R1/R2).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.2 V to 7 V - supports single Li-Ion (2.5–4.2 V) and multi-alkaline (2–4 cells) battery inputs without external regulation. |
| Output Voltage | Adjustable up to 20 V - set externally via FB pin resistor divider; enables LCD bias and multi-LED string drive from low-input sources. |
| Peak Switch Current Limit | 150 mA - defines maximum inductor energy transfer per cycle; constrains max load current and thermal design in boost topology. |
| Switch RDS(ON) | 0.7 Ω (typ.) - determines conduction loss and thermal rise under load; impacts efficiency at medium-to-high output currents. |
| Shutdown Current | 0.01 µA - enables ultra-low-power standby in battery-critical applications like handhelds and digital cameras. |
| Feedback Reference Voltage | 1.237 V ±31 mV - sets output accuracy and stability; used with external resistors to configure precise VOUT over temperature. |
| Switch Off-Time | 400 ns - fixes minimum energy transfer interval; enables use of small inductors (e.g., 33 µH) and reduces board area. |
Pinout & Package
LM2705MFX-ADJ is housed in a 5-pin SOT-23 (DBV) package measuring 2.90 mm × 1.60 mm, optimized for compact portable PCB layouts and reflow-compatible assembly.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - SW | Switch Drain Node | Connects to inductor and Schottky diode anode; high dv/dt node requiring minimal trace area to reduce EMI radiation. |
| 2 - GND | Power & Analog Ground | Must tie directly to ground plane; serves as return path for switch current and reference for FB/SHDN logic thresholds. |
| 3 - FB | Voltage Feedback Input | Senses output via resistor divider; trip point at 1.237 V enables precise output programming and regulates against load/line variation. |
| 4 - SHDN | Active-Low Enable Control | Drives <0.3 V to disable (0.01 µA IQ); drives >1.1 V to enable; open-drain compatible with microcontroller GPIO. |
| 5 - VIN | Input Power Supply | Accepts 2.2–7 V analog and power input; requires local 4.7-µF ceramic bypass capacitor placed adjacent to pin. |
Key Features
| Feature | Design Value |
|---|---|
| Micropower Operation | 235 µA typical operating IQ enables >100-hour runtime on coin-cell batteries in intermittent-use applications. |
| Fixed Off-Time Control | 400-ns off-time ensures predictable switching frequency scaling with load, simplifying EMI filtering and inductor selection. |
| Integrated 150-mA Switch | 0.7-Ω NMOS eliminates external MOSFET and gate driver, reducing BOM count and layout complexity in space-sensitive designs. |
| Input UVLO Protection | 1.8-V turn-on threshold prevents erratic startup and brownout operation during Li-Ion discharge below 2.5 V. |
| Small SOT-23 Package | 5-pin DBV footprint (2.9 × 1.6 mm) allows placement near battery connectors or display modules without sacrificing routing space. |
Applications
| LCD Bias Supply | White-LED Backlighting |
|---|---|
Use Scenario: Generating dual-polarity or high-voltage bias (e.g., +15 V / –10 V) for TFT-LCD panel gate drivers and source drivers. IC Role / Device Role / Timing Role: Primary boost regulator providing stable, low-noise high-voltage rail; FB pin regulates output within ±2% over temperature and load. Use Value: Enables single-cell Li-Ion operation without external charge pumps; 0.01-µA shutdown extends shelf life in always-on display modules. | Use Scenario: Driving 2–3串联 white LEDs (3.0–3.6 V each) from a 2.5–4.2 V Li-Ion battery in smartphones or PDAs. IC Role / Device Role / Timing Role: Constant-current LED driver via external current-sense resistor; SW pin switches at ~1 MHz (load-dependent) to maintain regulated LED current. Use Value: Delivers up to 8 mA at 12 V with >85% efficiency at 5 mA load; 400-ns off-time minimizes inductor size and audible noise. |
| Handheld Devices | Digital Cameras |
Use Scenario: Powering auxiliary rails (e.g., 5 V for USB interface, 12 V for flash memory programming) in barcode scanners or medical pens. IC Role / Device Role / Timing Role: Standby-capable boost converter activated on-demand by host MCU via SHDN pin; maintains fast wake-up (<100 µs). Use Value: 0.01-µA shutdown current preserves battery during weeks of idle time; 2.2-V start-up supports aging battery operation down to 2.3 V. | Use Scenario: Supplying 12 V for CCD/CMOS sensor bias and flash LED charging in compact point-and-shoot cameras. IC Role / Device Role / Timing Role: High-efficiency boost stage feeding charge pump or LDO; operates across full battery range (4.2 → 2.8 V) with <10% output droop. Use Value: 150-mA peak current limit safely handles flash LED surge loads; small SOT-23 footprint fits tight camera module layouts. |
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-current LED strings (>20 mA) or powering 3.3-V logic from Li-Ion; not optimal for ultra-low-IQ standby. | Select TPS61022DRVR when >15 mA output current or integrated soft-start is required; LM2705MFX-ADJ remains preferred for sub-10 mA, ultra-low-power roles. |
| MAX17222ETA+ | Lower 1.8-V min input, 1.2-µA shutdown IQ, but only 500-mA peak current and fixed 3.3/5.0 V outputs (non-adjustable). | Ideal for always-on sensors or wearables needing deeper battery savings; lacks adjustable 20-V capability for LCD/LED bias. | Choose MAX17222ETA+ for fixed-output, ultra-low-IQ applications; LM2705MFX-ADJ is necessary where programmable high-voltage output is mandatory. |
Compared with TPS61022DRVR and MAX17222ETA+, the LM2705MFX-ADJ uniquely balances 20-V adjustability, 150-mA capability, and 0.01-µA shutdown in a 2.9-mm footprint-making it irreplaceable for compact, high-voltage, battery-sensitive designs where neither higher current nor deeper sleep alone suffices.
Availability
LM2705MFX-ADJ is available at Aetrix Electronics and suitable for LCD bias supplies, white-LED backlighting, and handheld devices requiring stable component supply, long-term manufacturability, and RoHS-compliant packaging.
Supply support for LM2705MFX-ADJ 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 LM2705 product line delivers micropower, small-footprint DC-DC boost converters targeting battery-powered portable equipment where size, efficiency, and ultra-low shutdown current are critical system constraints.
FAQ
What is the recommended inductor value for LM2705MFX-ADJ in a 20-V output application?
The LM2705MFX-ADJ datasheet specifies a 68-µH inductor for 20-V output with Li-Ion input (2.5–4.2 V), balancing low ripple current and high light-load efficiency. For 12-V output, 33-µH is typical. Inductor saturation current must exceed peak switch current (150 mA), and DCR should be minimized to preserve efficiency. Coilcraft DT1608C and TDK SLF6020T series are validated choices per TI application notes.
How does the LM2705MFX-ADJ achieve adjustable output voltage?
The LM2705MFX-ADJ uses a resistor divider (R1/R2) connected between VOUT, FB, and GND to set output voltage per the equation VOUT = 1.237 V × (1 + R1/R2). For example, R1 = 510 kΩ and R2 = 33 kΩ yields ~20 V. The FB pin draws only 30 nA bias current, minimizing divider power loss and ensuring stable regulation across temperature.
What is the absolute maximum SW pin voltage rating for LM2705MFX-ADJ?
The absolute maximum SW pin voltage for LM2705MFX-ADJ is 21 V, as specified in the Absolute Maximum Ratings table. This allows safe operation with output voltages up to 20.5 V, accommodating diode forward drop and transient overshoot. Exceeding 21 V risks permanent damage to the internal NMOS switch and is strictly prohibited in design.
Can LM2705MFX-ADJ drive three white LEDs in series from a single Li-Ion cell?
Yes, the LM2705MFX-ADJ can drive up to three white LEDs in series from a single Li-Ion cell (2.5–4.2 V), delivering up to 8 mA at 12 V with >85% efficiency. TI's Figure 20 shows this configuration using a 33-µH inductor, 1-µF COUT, and appropriate feedback resistors. Peak switch current remains within the 150-mA limit, and the 400-ns off-time ensures stable operation even at low input voltages.
What is the thermal performance of LM2705MFX-ADJ in its SOT-23 package?
The LM2705MFX-ADJ in SOT-23 (DBV) package has a junction-to-ambient thermal resistance (RθJA) of 164.9°C/W. At 125°C max junction temperature and 25°C ambient, the maximum allowable power dissipation is 607 mW. In typical 8-mA/12-V operation, power loss is ~120 mW, resulting in ~20°C junction rise-well within safe limits with standard PCB copper pour.
LM2705MFX-ADJ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- SC-74A, SOT-753
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- 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
LM2705MFX-ADJ FAQ
1.How can I place an order for LM2705MFX-ADJ through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2705MFX-ADJ 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 LM2705MFX-ADJ reliable?
The price and inventory of LM2705MFX-ADJ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2705MFX-ADJ is usually 5 days.
3.What payment methods are accepted for LM2705MFX-ADJ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2705MFX-ADJ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2705MFX-ADJ?
LM2705MFX-ADJ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2705MFX-ADJ 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 LM2705MFX-ADJ?
For technical support, including LM2705MFX-ADJ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2705MFX-ADJ requirements.
6.How does Aetrix verify that LM2705MFX-ADJ is sourced from the original manufacturer or authorized distributors?
All LM2705MFX-ADJ 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 LM2705MFX-ADJ meets industry standards.
7.What is the process for return or replacement of LM2705MFX-ADJ?
All LM2705MFX-ADJ units undergo pre-shipment inspection (PSI). If there is an issue with LM2705MFX-ADJ, 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 LM2705MFX-ADJ part is unused and in its original packaging.
Return procedure for LM2705MFX-ADJ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM2705MFX-ADJ Tags
-
BCR402RE6327HTSA1
Infineon Technologies
-
BCR430UXTSA2
Infineon Technologies
-
BCR420UE6433HTMA1
Infineon Technologies
-
BCR420UE6327HTSA1
Infineon Technologies
-
BCR421UE6327HTSA1
Infineon Technologies
-
LYT1604D-TL
Power Integrations
-
HV9910CLG-G
Microchip Technology
-
CL2N8-G
Microchip Technology
-
BCR420UW6-7
Diodes Incorporated
-
BCR421UW6-7
Diodes Incorporated
-
BCR420UFD-7
Diodes Incorporated
-
BCR421UFD-7
Diodes Incorporated
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
