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Texas Instruments LM2704MFX-ADJ
- Part No.:
- LM2704MFX-ADJ
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LM2704MFX-ADJ.pdf
- Description:
- IC LED DRVR RGLTR 550MA SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:1,339
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Product details
Overview
LM2704MFX-ADJ from Texas Instruments is a micropower step-up DC/DC converter with integrated 550mA NMOS switch (RDS(ON) = 0.7Ω), adjustable output voltage up to 20V, and 2.2V–7V input range. It operates in constant off-time mode with 400ns minimum off-time, enabling high efficiency in space-constrained white LED backlighting and LCD bias applications powered by single Li-Ion batteries.
For engineers reviewing the LM2704MFX-ADJ datasheet, LM2704MFX-ADJ pinout, LM2704MFX-ADJ application, or LM2704MFX-ADJ equivalent, key selection criteria include its 0.01µA shutdown current, input undervoltage lockout at 1.8V, feedback reference of 1.237V ±28mV, and thermal resistance of 220°C/W in SOT-23-5 package - critical for portable battery-powered designs requiring low quiescent current and stable high-voltage generation.
Technical Context
The LM2704MFX-ADJ employs a fixed off-time, current-mode control architecture where the internal NMOS switch turns off when inductor current reaches the 550mA peak limit, then remains off for a precise 400ns interval before restarting. This scheme minimizes operating current and enables use of small inductors and capacitors.
Output voltage is set externally via a resistive divider on the FB pin, referenced to a precision 1.237V bandgap. The SHDN pin provides active-low enable control with thresholds of 0.3V (disable) and 1.1V (enable), while input undervoltage lockout prevents operation below 1.8V to protect battery sources.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.2V to 7.0V - supports single-cell Li-Ion (2.7–4.2V) and alkaline/NiMH stacks without external regulation. |
| Output Voltage Range | Adjustable up to 20V - set by external resistor divider; enables driving 6–8 white LEDs in series from 3V input. |
| Switch Current Limit | 490–610mA typ. 550mA - defines maximum inductor peak current and power delivery capability. |
| Feedback Reference | 1.189V to 1.269V - tight 28mV tolerance ensures accurate output voltage setting across temperature. |
| Shutdown Current | 0.01µA max - preserves battery life during system sleep modes in handheld devices. |
| Off-Time | 400ns fixed - enables high-frequency switching (>1MHz with small inductors) and reduces output ripple. |
| RDS(ON) | 0.7Ω typ. - low conduction loss improves efficiency at light-to-moderate loads. |
Pinout & Package
LM2704MFX-ADJ is housed in a 5-pin SOT-23 package (DBV drawing, 2.9mm × 1.6mm × 1.45mm), optimized for low-profile portable PCBs with exposed pad not present.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - SW | Switch node | Drain of internal NMOS; connects to inductor and Schottky diode anode; requires minimal trace area to reduce EMI. |
| 2 - GND | Power and analog ground | Common return for all currents; must tie directly to ground plane to minimize noise coupling into FB. |
| 3 - FB | Feedback input | Senses output voltage via resistor divider; 30–120nA bias current flows into pin, affecting high-resistor-divider accuracy. |
| 4 - SHDN | Enable control | Active-low logic input; <0.3V disables device (0.01µA IQ); >1.1V enables operation (235–300µA IQ). |
| 5 - VIN | Input supply | Power input for analog and switch circuitry; requires local 4.7µF ceramic bypass capacitor placed adjacent to pin. |
Key Features
| Feature | Design Value |
|---|---|
| Micropower operation | 235–300µA quiescent current when enabled - extends runtime in always-on sensor or display bias circuits. |
| Adjustable output | Set from ~2.5V to 20V using two external resistors - eliminates need for multiple fixed-output variants. |
| Low-noise control | Fixed off-time architecture avoids subharmonic oscillation and simplifies EMI filtering vs. variable-frequency boosters. |
| Thermal protection | Junction temperature limit of 125°C with θJA = 220°C/W - allows safe operation in sealed handheld enclosures without forced air. |
| Battery-friendly UVLO | 1.8V input lockout threshold - prevents deep discharge of Li-Ion cells below safe voltage limits. |
Applications
| White LED Backlighting | LCD Bias Supply |
|---|---|
Use Scenario: Driving 6–8串联 white LEDs for smartphone or PDA display backlight from a single 3.7V Li-Ion cell. IC Role / Device Role / Timing Role: Step-up DC/DC controller generating regulated 18–20V output with current-mode feedback for consistent LED brightness. Use Value: 550mA peak switch current and 400ns off-time enable compact 2.2µH inductor and 10µF ceramic output cap, minimizing board area. | Use Scenario: Providing positive and negative bias voltages (e.g., +15V and –10V) for TFT-LCD source/gate drivers in portable instrumentation. IC Role / Device Role / Timing Role: Primary high-voltage boost stage; output feeds external inverting charge pump or linear regulator for negative rail. Use Value: Adjustable 20V output and 2.2V minimum input allow operation down to nearly-dead battery states, improving display uptime. |
| Handheld Medical Devices | Digital Camera Flash Support |
Use Scenario: Powering OLED status displays and analog front-end bias rails in portable glucose meters or pulse oximeters. IC Role / Device Role / Timing Role: Micropower voltage booster supplying stable 12V for op-amp references and sensor excitation from coin-cell or Li-Poly sources. Use Value: 0.01µA shutdown current and 1.8V UVLO preserve battery capacity over multi-month shelf life and intermittent use cycles. | Use Scenario: Charging a 100µF flash capacitor to 300V via cascaded boost stages in compact digital cameras. IC Role / Device Role / Timing Role: First-stage boost converter raising battery voltage to intermediate 12–15V, feeding subsequent flyback or charge-pump stages. Use Value: 21V-rated SW pin and 7V absolute max VIN support robust operation during transient load surges and input ripple. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-up DC/DC converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS61040DRVR | Higher 28V SW rating, 0.55Ω RDS(ON), 400kHz–3MHz adjustable frequency vs. fixed off-time | Supports higher output voltages and wider input ranges (1.8–6V); better suited for dynamic load regulation | Select when needing programmable frequency or >20V output; requires different compensation design |
| MAX682ESA+ | Fixed 5V output, 300mA switch, 1.5µA shutdown, SC70-5 package | Not adjustable; limited to low-voltage bias rails; smaller footprint but lower power capability | Select only for fixed 5V applications with ultra-low IQ priority and no voltage adjustment needed |
Compared with TPS61040DRVR and MAX682ESA+, the LM2704MFX-ADJ offers superior adjustability (up to 20V), tighter feedback tolerance (±28mV), and proven suitability for white LED strings from Li-Ion sources - making it optimal for cost-sensitive, space-constrained portable displays where fixed-frequency simplicity and micropower shutdown are critical.
Availability
LM2704MFX-ADJ is available at Aetrix Electronics and suitable for white LED backlighting, LCD bias supplies, and handheld medical devices requiring stable component supply, long-term manufacturability, and RoHS-compliant packaging.
Supply support for LM2704MFX-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 company delivering analog, embedded processing, and connectivity solutions for industrial, automotive, and personal electronics markets.
The LM2704MFX-ADJ belongs to TI's micropower DC/DC converter product line, designed specifically for battery-powered portable applications demanding high efficiency at light loads, small solution size, and reliable high-voltage generation from low-input sources.
FAQ
What is the maximum output voltage achievable with the LM2704MFX-ADJ?
The LM2704MFX-ADJ supports an adjustable output voltage up to 20V, determined by the external resistor divider on the FB pin and constrained by the 21V maximum SW pin voltage rating. Output stability and regulation are maintained across the full range when using appropriate inductor and output capacitor values per the datasheet design equations.
Does the LM2704MFX-ADJ require an external Schottky diode, and what specifications are critical?
Yes, the LM2704MFX-ADJ requires an external Schottky diode. Critical specifications include reverse breakdown voltage exceeding the output voltage (e.g., ≥25V for 20V output), average current rating greater than the peak inductor current (≤550mA), and low forward voltage (<0.4V) to maximize efficiency. TI recommends diodes such as the RB050M-30 or similar low-VF, fast-recovery types.
How does the LM2704MFX-ADJ handle input undervoltage conditions?
The LM2704MFX-ADJ incorporates an input undervoltage lockout (UVLO) circuit that disables switching when VIN falls below 1.8V (typical). This prevents erratic operation and excessive current draw from deeply discharged batteries. Once VIN rises above the 1.8V threshold, the device automatically resumes normal regulation without requiring a reset or external intervention.
What is the thermal performance of the LM2704MFX-ADJ in its SOT-23-5 package?
The LM2704MFX-ADJ has a junction-to-ambient thermal resistance (θJA) of 220°C/W in the standard SOT-23-5 (DBV) package. With a maximum junction temperature of 125°C and ambient temperature of 25°C, the maximum allowable power dissipation is approximately 455mW. Adequate copper pour on the GND pin and minimal trace length on SW are essential to maintain thermal safety in continuous operation.
Can the LM2704MFX-ADJ be used to drive multiple white LEDs in series, and how many are supported?
Yes, the LM2704MFX-ADJ is explicitly characterized for white LED backlighting and can drive up to 8 standard white LEDs (VF ≈ 3.2V each) from a single Li-Ion battery, requiring ~25.6V total - which exceeds its 20V limit. In practice, it reliably drives 6 LEDs (19.2V) with margin. For 8-LED strings, a higher-output converter like the TPS61040 is recommended.
LM2704MFX-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:
- 550mA (Switch)
- Frequency:
- -
- Dimming:
- -
- Applications:
- Backlight
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-5
LM2704MFX-ADJ FAQ
1.How can I place an order for LM2704MFX-ADJ through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2704MFX-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 LM2704MFX-ADJ reliable?
The price and inventory of LM2704MFX-ADJ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2704MFX-ADJ is usually 5 days.
3.What payment methods are accepted for LM2704MFX-ADJ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2704MFX-ADJ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2704MFX-ADJ?
LM2704MFX-ADJ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2704MFX-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 LM2704MFX-ADJ?
For technical support, including LM2704MFX-ADJ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2704MFX-ADJ requirements.
6.How does Aetrix verify that LM2704MFX-ADJ is sourced from the original manufacturer or authorized distributors?
All LM2704MFX-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 LM2704MFX-ADJ meets industry standards.
7.What is the process for return or replacement of LM2704MFX-ADJ?
All LM2704MFX-ADJ units undergo pre-shipment inspection (PSI). If there is an issue with LM2704MFX-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 LM2704MFX-ADJ part is unused and in its original packaging.
Return procedure for LM2704MFX-ADJ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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