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Texas Instruments LM2681M6/NOPB
- Part No.:
- LM2681M6/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- SOT-23-6
- Datasheet:
-
LM2681M6/NOPB.pdf
- Description:
- IC REG CHARGE PUMP 2VIN SOT23-6
- Quantity:
- Payment:
- Shipping:
Inventory:3,119
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Product details
Overview
LM2681M6/NOPB from Texas Instruments is a CMOS switched-capacitor voltage converter operating as either a voltage doubler (2.5V–5.5V input → up to 11V output) or precision voltage splitter (1.8V–11V input → half-voltage output), delivering up to 20 mA with 15 Ω typical output impedance and 90% efficiency at full load - used in portable operational amplifier and interface power supplies.
For engineers reviewing the LM2681M6/NOPB datasheet, LM2681M6/NOPB pinout, LM2681M6/NOPB application, or LM2681M6/NOPB equivalent, key selection criteria include its fixed 160 kHz oscillator frequency, SOT-23-6 package compatibility, dual-mode operation (doubler/splitter), low 550 µA quiescent current, and requirement for external Schottky diode during start-up in doubler mode.
Technical Context
The LM2681M6/NOPB integrates four CMOS switches controlled by an internal 160 kHz oscillator to implement charge-pump voltage conversion. In doubler mode, it alternately charges and transfers energy via two external capacitors to generate 2×VIN; in splitter mode, it reconfigures the same switch network to divide VIN by two with no start-up diode required.
Its output resistance (15 Ω typ.) combines MOSFET RDS(on) (8–16 Ω sum), capacitor ESR contributions, and switching frequency effects. The device operates across −40°C to +85°C, supports 30 mA absolute max continuous output current, and requires external low-ESR capacitors (e.g., 3.3 µF tantalum or ceramic) for optimal ripple and efficiency performance.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Function Modes | Voltage doubler (2.5–5.5V input) or precision voltage splitter (1.8–11V input); mode selected by external pin configuration. |
| Oscillator Frequency | 160 kHz fixed; determines switching speed, output impedance, and ripple magnitude - higher frequency enables smaller capacitors. |
| Output Current | Up to 20 mA typical; limited by thermal dissipation and output resistance - derates above 85°C ambient. |
| Conversion Efficiency | 90% typical at 20 mA load; drops with higher ESR capacitors or lower input voltage due to fixed quiescent current (550 µA). |
| Output Impedance | 15 Ω typical at 20 mA; defines voltage drop under load (e.g., 300 mV drop at 20 mA) and impacts regulation capability. |
| Supply Current | 550 µA typical no-load; enables ultra-low-power operation in battery-powered systems such as PDAs and pagers. |
| Operating Temp | −40°C to +85°C junction range; validated for industrial portable equipment without derating in standard SOT-23 thermal profile. |
Pinout & Package
SOT-23-6 (DBV) package: 2.9 mm × 1.6 mm × 1.45 mm body, gull-wing leads, RoHS-compliant matte tin lead finish, MSL Level-1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (V+) | Positive supply input | Primary power rail for doubler mode; connects to input source - must be ≥2.5V for stable operation. |
| 2 (GND) | Ground reference | Common return path for supply, oscillator, and output circuits - requires low-impedance PCB connection. |
| 3 (CAP−) | Charge-pump capacitor negative terminal | Connects to negative side of flying capacitor C1 - critical node for charge transfer timing and EMI control. |
| 4 (GND) | Secondary ground terminal | Dedicated ground return for internal oscillator circuit - separate from Pin 2 in layout to minimize noise coupling. |
| 5 (OUT) | Output voltage node | Delivers doubled or halved voltage - connects to output capacitor C2 and load; requires Schottky diode only in doubler start-up. |
| 6 (CAP+) | Charge-pump capacitor positive terminal | Connects to positive side of flying capacitor C1 - forms charge-transfer loop with Pins 3 and 5 during switching cycles. |
Key Features
| Feature | Design Value |
|---|---|
| Dual-mode topology | Single IC supports both voltage doubling and precise halving via pin-strapping - eliminates need for separate converters in multi-rail designs. |
| Low quiescent current | 550 µA typical enables >100-hour battery life in 20 mA intermittent-load applications like handheld instruments. |
| Integrated CMOS switches | Four on-chip MOSFETs replace discrete switch arrays - reduces BOM count, layout area, and parasitic losses versus discrete charge pumps. |
| Fixed-frequency oscillator | 160 kHz operation ensures predictable EMI profile and simplifies filtering - avoids variable-frequency jitter issues in sensitive analog rails. |
| Robust thermal rating | 150°C max junction temperature with 210°C/W θJA allows 30 mA peak operation in compact SOT-23 without heatsinking. |
Applications
| Operational Amplifier Power Supply | Interface Power Supply |
|---|---|
Use Scenario: Generating ±5 V rails from a single 5 V supply for rail-to-rail op-amps in portable test equipment. IC Role / Device Role / Timing Role: Voltage doubler providing clean, low-noise positive boost rail - replaces inductor-based DC/DC for size-constrained layouts. Use Value: Eliminates magnetic components and reduces board area by 40% vs. inductive solutions while maintaining <10 mVpp ripple with 3.3 µF ceramic caps. |
Use Scenario: Powering RS-232 transceivers requiring ±12 V from a 3.3 V microcontroller system bus. IC Role / Device Role / Timing Role: Splitter generating regulated mid-rail reference for level-shifting logic - enables single-supply interface ICs to drive bipolar signaling lines. Use Value: Delivers stable 1.65 V reference with <0.5% drift over temperature - improves signal integrity in battery-operated communication modules. |
| Handheld Instrument Power | PDA Backlight Driver Support |
Use Scenario: Boosting 3.7 V Li-ion battery voltage to 7.4 V for analog front-end ADC biasing in field multimeters. IC Role / Device Role / Timing Role: Doubler supplying precision analog subsystem - operates continuously during measurement cycles with minimal load transient response delay. Use Value: Achieves 92% efficiency at 15 mA load, extending battery runtime by 18% compared to linear regulator alternatives. |
Use Scenario: Providing 3.3 V bias for white LED driver ICs in PDA displays using a 5 V system rail. IC Role / Device Role / Timing Role: Splitter generating intermediate voltage for gate control of external MOSFET LED switches - reduces gate drive loss in high-current backlight stages. Use Value: Enables 95% PWM dimming linearity by stabilizing gate threshold voltage - eliminates flicker in low-brightness display modes. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar switched-capacitor voltage converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX680ESA+ | ±5 V dual-output, 125 kHz oscillator, 100 mA max output, SO-8 package | Supports dual-polarity outputs without external inverter - better suited for op-amp dual-rail generation | Select MAX680ESA+ when bipolar ±VOUT is required; LM2681M6/NOPB preferred for single-rail boost/halve with minimal footprint. |
| TPS60403DBVR | 2.5–5.5 V input, 1.5 MHz switching, 60 mA output, SOT-23-6, integrated diodes | Eliminates external Schottky diode requirement and supports higher output current - ideal for space-constrained USB-powered devices | Choose TPS60403DBVR for higher current or diode-free design; LM2681M6/NOPB remains optimal for cost-sensitive, low-IQ portable systems. |
Compared with MAX680ESA+ and TPS60403DBVR, the LM2681M6/NOPB offers the lowest quiescent current (550 µA) and simplest external component count for single-output voltage scaling, making it ideal for long-life battery applications where 20 mA output suffices and board area is constrained to SOT-23-6.
Availability
LM2681M6/NOPB is available at Aetrix Electronics and suitable for cellular phones, handheld instruments, and portable interface power supplies requiring stable component supply, consistent parametric performance, and long-term industrial availability.
Supply support for LM2681M6/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 specializing in analog, embedded processing, and digital signal technologies - founded in 1930 and headquartered in Dallas, Texas.
The LM2681 belongs to TI's legacy precision power management portfolio, designed specifically for low-noise, capacitor-based voltage scaling in portable and battery-operated systems where inductors are impractical.
FAQ
What are the two primary operating modes of the LM2681M6/NOPB?
The LM2681M6/NOPB operates in voltage doubler mode (2.5–5.5 V input → up to 11 V output) or voltage splitter mode (1.8–11 V input → precisely half output). Mode selection depends on external pin connections: V+ and OUT are swapped between configurations. The LM2681M6/NOPB does not auto-detect mode - hardware wiring determines function.
Does the LM2681M6/NOPB require an external Schottky diode in all applications?
No - the LM2681M6/NOPB requires an external Schottky diode only during start-up in voltage doubler mode to ensure oscillator activation. In voltage splitter mode, no diode is needed because the internal oscillator receives power directly from the input applied across OUT and GND. The LM2681M6/NOPB datasheet recommends 1N5817 or MBR0520LT1 for doubler applications.
What is the maximum continuous output current specification for the LM2681M6/NOPB?
The LM2681M6/NOPB supports up to 20 mA typical continuous output current with 90% efficiency, and its Absolute Maximum Rating specifies 30 mA continuous output current into V+ or GND. Sustained 30 mA operation requires careful thermal management - junction temperature must remain ≤150°C, limiting practical use to short bursts or forced-air-cooled environments.
Can multiple LM2681M6/NOPB devices be paralleled to increase output current?
Yes - the LM2681M6/NOPB supports parallel operation to reduce effective output resistance and increase total current capacity. Each unit requires its own flying capacitor (C1), but a shared output capacitor (C2) suffices. The composite output resistance follows ROUT(total) = ROUT/N for N identical units, enabling scalable power delivery without redesigning the core charge-pump topology.
What capacitor types and values are recommended for optimal LM2681M6/NOPB performance?
TI recommends 3.3 µF low-ESR capacitors for both flying (C1) and output (C2) positions - specifically tantalum (AVX TPS, Sprague 593D) or ceramic (Murata, Taiyo Yuden) types. High-ESR electrolytics increase output impedance and ripple; the LM2681M6/NOPB's 15 Ω typical output resistance assumes ≤0.3 Ω ESR per capacitor. Ceramic capacitors also improve start-up reliability in splitter mode.
LM2681M6/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- SOT-23-6
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Ratiometric
- Output Configuration:
- Positive
- Topology:
- Charge Pump
- Output Type:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.5V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 2Vin, Vin/2
- Voltage - Output (Max):
- -
- Current - Output:
- 20mA
- Frequency - Switching:
- 80kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 85°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-6
LM2681M6/NOPB FAQ
1.How can I place an order for LM2681M6/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2681M6/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 LM2681M6/NOPB reliable?
The price and inventory of LM2681M6/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2681M6/NOPB is usually 5 days.
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LM2681M6/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2681M6/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 LM2681M6/NOPB?
For technical support, including LM2681M6/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2681M6/NOPB requirements.
6.How does Aetrix verify that LM2681M6/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2681M6/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 LM2681M6/NOPB meets industry standards.
7.What is the process for return or replacement of LM2681M6/NOPB?
All LM2681M6/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2681M6/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 LM2681M6/NOPB part is unused and in its original packaging.
Return procedure for LM2681M6/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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