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Texas Instruments LM2611AMFX
- Part No.:
- LM2611AMFX
- Manufacturer:
- Texas Instruments
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LM2611AMFX.pdf
- Description:
- IC REG CUK ADJ 1.2A SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:1,118
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Product details
Overview
LM2611AMFX from Texas Instruments is a current-mode PWM Cuk converter IC with integrated DMOS switch, designed for high-efficiency negative voltage generation. It delivers −5 V at 300 mA from a 5-V input, operates at 1.4 MHz switching frequency, features 0.5-Ω RDS(ON), and supports wide 2.7–14-V input range-used in LCD bias, CCD power supplies, and GaAs FET bias circuits.
For engineers reviewing the LM2611AMFX datasheet, LM2611AMFX pinout, LM2611AMFX application, or LM2611AMFX equivalent, this page provides verified technical context, exact pin functions, real-world design meaning of specifications, validated alternative parts, and supply-chain support for industrial embedded and portable electronics designs.
Technical Context
The LM2611AMFX implements a fixed-frequency (1.4 MHz) current-mode control architecture with internal slope compensation and cycle-by-cycle overcurrent protection. Its functional block includes an integrated 1.2-A/0.5-Ω DMOS switch, −1.23-V precision NFB reference, and hysteretic pulse-skipping mode for light-load efficiency.
It requires external Cuk topology components: two inductors (L1, L2), input/output capacitors, Cuk capacitor (CCUK), and feedback resistors (RFB1/RFB2). The NFB pin enables output voltage programming via resistor divider, while SHDN provides logic-level shutdown with <1 µA quiescent current.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switching frequency | 1.4 MHz typical - enables use of sub-22-µH inductors and <22-µF ceramic output capacitors, reducing board area and cost. |
| Output voltage range | −3.3 V to −10 V programmable - set by external RFB1/RFB2 divider referencing −1.23 V at NFB pin. |
| Max output current | 300 mA at −5 V / 5-V input - limited by 1.2-A switch current rating and thermal resistance (θJA = 163.5°C/W). |
| RDS(ON) | 0.5 Ω typical - reduces conduction loss and improves efficiency above 85% at mid-load in 5-V-to−5-V configuration. |
| Shutdown current | <1 µA - extends battery life in portable systems during standby; activated by grounding SHDN pin. |
| NFB reference voltage | −1.23 V ±25 mV - defines output regulation accuracy; sets VOUT = −1.23 × (1 + RFB1/RFB2) with ≤0.67 µA bias current. |
| Input voltage range | 2.7 V to 14 V - supports single-cell Li-ion, 3.3-V/5-V rails, and automotive 12-V systems with margin. |
Pinout & Package
LM2611AMFX is housed in a 5-pin SOT-23 package (1.60 mm × 2.90 mm body), optimized for thermal dissipation on standard PCBs with exposed pad not present.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - SW | Switch drain node | Connects to L1–CCUK junction; carries peak current up to 1.2 A; requires low-inductance layout to minimize ringing. |
| 2 - GND | Analog & power ground | Single-point return for feedback, shutdown, and power paths; must tie to low-impedance ground plane under IC. |
| 3 - NFB | Negative feedback input | Accepts resistor divider from VOUT; −1.23-V internal reference enables precise output programming with ≤0.67 µA bias. |
| 4 - SHDN | Logic-level shutdown control | High = enabled (VIN applied); low = disabled (<1 µA IQ); no pull-up required; compatible with GPIOs. |
| 5 - VIN | Power input | Supplies internal circuitry and switch; requires local 0.1-µF ceramic bypass within 0.2 inches to suppress HF noise. |
Key Features
| Feature | Design Value |
|---|---|
| Cuk topology integration | Eliminates need for external controller + MOSFET; reduces EMI vs buck-boost by minimizing input/output current ripple. |
| 1.4-MHz fixed-frequency PWM | Enables compact magnetics (e.g., SUMIDA CR32-150/CR32-470) and small ceramics (22 µF X5R), cutting solution size by >40% vs lower-frequency converters. |
| Internal current limit & thermal shutdown | 1.2-A switch current limit and 163°C thermal cutoff protect against overload and poor heatsinking without external sensing. |
| Low-RDS(ON) DMOS switch | 0.5 Ω typical RDS(ON) minimizes conduction loss, enabling >85% efficiency at 300 mA in 5-V-to−5-V operation. |
| Programmable negative output | VOUT set via two external resistors (e.g., 29.4 kΩ/10 kΩ for −5 V); NFB pin leakage ≤0.67 µA preserves accuracy. |
Applications
| MR Head Bias | Digital Camera CCD Bias |
|---|---|
Use Scenario: Precision negative bias for magnetoresistive read heads in HDD preamplifiers. IC Role / Device Role / Timing Role: Primary negative voltage regulator generating stable −5 V from 5-V system rail. Use Value: Low 1-mVp-p output ripple ensures signal integrity; 1.4-MHz operation avoids interference with servo timing bands. |
Use Scenario: High-stability analog bias for CCD image sensor vertical/horizontal drivers. IC Role / Device Role / Timing Role: Inverting DC-DC converter delivering −5 V at 300 mA with tight line/load regulation. Use Value: Better regulation than charge pumps enables consistent pixel charge transfer; low shutdown current extends camera standby time. |
| LCD Bias | GaAs FET Bias |
Use Scenario: Negative gate drive for TFT-LCD source driver ICs requiring −5 V to −10 V. IC Role / Device Role / Timing Role: Compact, low-noise inverter supplying regulated negative rail in space-constrained display modules. Use Value: Small 5-pin SOT-23 footprint fits tight bezel layouts; 2.7–14-V input supports diverse panel power architectures. |
Use Scenario: Gate bias for GaAs FET RF amplifiers in portable transceivers and test equipment. IC Role / Device Role / Timing Role: Efficient −5 V generator from 3.3-V or 5-V supply, supporting fast turn-on/turn-off sequencing. Use Value: 0.5-Ω RDS(ON) and current-mode control ensure stable bias under dynamic RF load conditions. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar inverting DC-DC converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2611MFX | Same pinout and electrical specs, but Grade B variant: 0.9-A switch current limit and 0.7-Ω RDS(ON). | Suitable for ≤200 mA loads at −5 V; lower efficiency at full load due to higher conduction loss. | Select LM2611MFX only if output current requirement is ≤200 mA and cost sensitivity outweighs efficiency needs. |
| MAX764CSA+ | Fixed −5 V output (no feedback resistors), 1.3-MHz switching, 0.35-Ω RDS(ON), but requires external diode and lacks Cuk topology. | Designed for simpler buck-boost implementations; no Cuk capacitor or dual-inductor optimization. | Choose MAX764CSA+ when board space allows larger magnetics and design priority is minimal BOM count over ripple performance. |
Compared with LM2611MFX and MAX764CSA+, the LM2611AMFX offers highest output current capability (300 mA), lowest RDS(ON) (0.5 Ω), and inherent Cuk advantages-lower input/output ripple and better EMI profile-making it optimal for noise-sensitive analog biasing.
Availability
LM2611AMFX is available at Aetrix Electronics and suitable for MR head bias, CCD imaging, LCD panel drivers, and GaAs FET bias applications requiring stable component supply, long-term lifecycle continuity, and traceable sourcing.
Supply support for LM2611AMFX 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 power management technologies, with decades of expertise in high-reliability power conversion ICs.
The LM2611AMFX belongs to TI's precision inverting DC-DC converter product line, engineered specifically for low-noise, high-efficiency negative voltage generation in portable and space-constrained analog systems.
FAQ
What is the maximum output current capability of the LM2611AMFX?
The LM2611AMFX delivers up to 300 mA at −5 V when supplied from a 5-V input, based on its 1.2-A switch current limit, 0.5-Ω RDS(ON), and thermal resistance of 163.5°C/W. At higher input voltages (e.g., 12 V), maximum output current decreases due to increased power dissipation; see Figure 23 in the LM2611AMFX datasheet for derating curves.
Can the LM2611AMFX generate output voltages other than −5 V?
Yes, the LM2611AMFX supports programmable negative outputs from −3.3 V to −10 V using an external resistor divider on the NFB pin, referenced to its internal −1.23-V precision bandgap. For example, −5 V is set with RFB1 = 29.4 kΩ and RFB2 = 10 kΩ; all resistors should be ≤50 kΩ to minimize NFB pin leakage error.
What is the role of the Cuk capacitor (CCUK) in the LM2611AMFX circuit?
The Cuk capacitor (CCUK) is essential to the Cuk topology used by the LM2611AMFX-it transfers energy between input and output inductors while enabling continuous input/output current waveforms. Typical values range from 1 pF to 2.2 pF depending on input voltage and inductor selection; incorrect CCUK sizing causes instability or excessive ripple.
Does the LM2611AMFX require external compensation components?
No, the LM2611AMFX features fully internal compensation optimized for 10–22-µH inductors. However, a feed-forward capacitor (CFF, e.g., 330 pF) may be added across RFB1 to improve transient response and phase margin-this is optional and application-dependent, not required for basic regulation.
How does shutdown functionality work on the LM2611AMFX?
The LM2611AMFX enters ultra-low-power shutdown mode (<1 µA IQ) when the SHDN pin is pulled to GND; it resumes normal operation when SHDN is raised to VIN level. No external pull-up is needed, and the pin accepts standard logic levels-making it directly controllable by microcontrollers or power sequencers.
LM2611AMFX Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- SC-74A, SOT-753
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Function:
- Step-Up/Step-Down
- Output Configuration:
- Negative
- Topology:
- Cuk
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.7V
- Voltage - Input (Max):
- 14V
- Voltage - Output (Min/Fixed):
- -1.23V
- Voltage - Output (Max):
- -32V
- Current - Output:
- 1.2A
- Frequency - Switching:
- 1.4MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-5
LM2611AMFX FAQ
1.How can I place an order for LM2611AMFX through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2611AMFX 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 LM2611AMFX reliable?
The price and inventory of LM2611AMFX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2611AMFX is usually 5 days.
3.What payment methods are accepted for LM2611AMFX?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2611AMFX transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2611AMFX?
LM2611AMFX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2611AMFX 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 LM2611AMFX?
For technical support, including LM2611AMFX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2611AMFX requirements.
6.How does Aetrix verify that LM2611AMFX is sourced from the original manufacturer or authorized distributors?
All LM2611AMFX 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 LM2611AMFX meets industry standards.
7.What is the process for return or replacement of LM2611AMFX?
All LM2611AMFX units undergo pre-shipment inspection (PSI). If there is an issue with LM2611AMFX, 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 LM2611AMFX part is unused and in its original packaging.
Return procedure for LM2611AMFX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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