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Texas Instruments LM2611AMF/NOPB
- Part No.:
- LM2611AMF/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LM2611AMF/NOPB.pdf
- Description:
- IC REG CUK ADJ 1.2A SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:1,091
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Product details
Overview
LM2611AMF/NOPB from Texas Instruments is a current-mode PWM Cuk converter IC with integrated DMOS switch, designed for high-efficiency positive-to-negative voltage conversion. 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 uses external inductors (L1/L2) and capacitors to achieve low input/output ripple. It is used in precision bias generation for MR heads and CCD sensors.
For engineers reviewing the LM2611AMF/NOPB datasheet, LM2611AMF/NOPB pinout, LM2611AMF/NOPB application, or LM2611AMF/NOPB equivalent, key selection criteria include its fixed 1.4-MHz Cuk topology, −1.23-V internal reference, shutdown threshold (1.5 V), thermal shutdown behavior (163°C trip), and SOT-23-5 package constraints for board space and thermal management.
Technical Context
The LM2611AMF/NOPB implements a current-mode control architecture with internal slope compensation, cycle-by-cycle peak current limiting, and type II/III internal compensation optimized for Cuk converters using matched 10–22 µH input/output inductors. Its feedback loop references a stable −1.23-V internal bandgap, and NFB pin bias current is −4.7 µA typical.
It operates in PWM mode under full load and transitions to pulse-skipping (hysteretic) mode at light loads to maintain regulation while reducing quiescent current to 0.024 µA in shutdown. Thermal shutdown activates at 163°C junction temperature and recovers at 155°C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switching frequency | 1.4 MHz typical; enables use of small, low-cost 10–22 µH inductors and ceramic capacitors. |
| Output voltage range | Adjustable down to −36×VIN(MAX); −5 V at 300 mA demonstrated with 5-V input. |
| RDS(ON) | 0.5 Ω typical (Grade A); reduces conduction loss and improves efficiency at 300 mA output. |
| Input voltage range | 2.7 V to 14 V; supports single-cell Li-ion, USB, and industrial 5–12 V rails. |
| Shutdown current | <1 µA typical; extends battery life in portable MR head or CCD bias applications. |
| Reference voltage | −1.23 V at NFB pin; sets output via resistor divider (e.g., 29.4 kΩ/10 kΩ for −5 V). |
| Thermal shutdown | 163°C trip / 155°C recovery; protects device during overload or poor PCB thermal design. |
Pinout & Package
LM2611AMF/NOPB is housed in a 5-pin SOT-23 (DBV) package, 1.60 mm × 2.90 mm body size, with exposed pad not electrically connected. Thermal resistance is RθJA = 163.5°C/W on standard 2-layer JEDEC board.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - SW | Drain of internal DMOS switch | Connects to node between L1 and CCUK; carries peak current up to 1.2 A; requires low-inductance layout. |
| 2 - GND | Analog and power ground | Common return for feedback, shutdown, and power paths; must be low-impedance and tied to power ground plane. |
| 3 - NFB | Negative feedback input | Accepts resistor divider from VOUT; −1.23 V reference enables precise output setting; bias current −4.7 µA affects divider accuracy. |
| 4 - SHDN | Active-high shutdown control | Logic-level input: ≥1.5 V enables operation; ≤0.5 V disables switch and reduces IQ to <1 µA. |
| 5 - VIN | Power input | Supplies internal circuitry and switch; requires local 0.1-µF ceramic bypass capacitor placed within 0.2 inches. |
Key Features
| Feature | Design Value |
|---|---|
| Cuk topology integration | Eliminates need for external controller and gate driver; enables low-noise, continuous input/output current waveforms. |
| Internal current limit | 1.2-A peak (Grade A) independent of duty cycle or temperature; simplifies overcurrent protection without sensing resistors. |
| Low-output ripple | 1-mVp-p typical; achieved via dual-inductor filtering and 1.4-MHz switching, critical for analog sensor bias stability. |
| Wide input compatibility | Operates from 2.7 V (single Li-ion) to 14 V (industrial rail); accommodates varying source conditions without external regulators. |
| Feed-forward compensation support | CFF capacitor across RFB1 adds zero-pole pair to improve transient response; recommended 330–1000 pF for −5 V designs. |
Applications
| MR Head Bias | Digital Camera CCD Bias |
|---|---|
|
Use Scenario: Providing stable negative bias voltage to magnetoresistive read elements in HDD preamplifiers. IC Role / Device Role / Timing Role: Inverting DC-DC converter generating precisely regulated −5 V from 5-V system rail. Use Value: Low 1-mVp-p ripple ensures signal integrity and minimizes noise coupling into sensitive analog front-end circuits. |
Use Scenario: Supplying negative bias to CCD image sensor vertical/horizontal shift registers. IC Role / Device Role / Timing Role: High-frequency Cuk regulator delivering −5 V at 300 mA with fast transient response. Use Value: Pulse-skipping mode maintains regulation at standby currents while minimizing dark current drift in low-light imaging. |
| LCD Panel Bias | GaAs FET Bias |
|
Use Scenario: Generating negative gate drive for active-matrix LCD source driver ICs requiring dual-rail supplies. IC Role / Device Role / Timing Role: Compact inverting converter mounted near display controller ICs on tight-space modules. Use Value: SOT-23-5 footprint and 1.4-MHz operation allow minimal external component count and PCB area usage. |
Use Scenario: Supplying gate bias to GaAs FETs in RF front-end modules for satellite communications receivers. IC Role / Device Role / Timing Role: Low-noise negative supply with thermal shutdown protecting expensive RF components. Use Value: 163°C thermal shutdown prevents irreversible damage during RF power surges or ambient temperature excursions. |
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/NOPB | Same silicon die, but in tape-and-reel packaging (no manual handling); identical electrical specs and pinout. | No functional difference; selected for automated SMT assembly lines requiring reel format. | Choose LM2611MFX/NOPB for volume production; LM2611AMF/NOPB is same device in cut-tape. |
| MAX764CSA+ | Fixed −5 V output (no feedback divider needed); 1.3-MHz switching; higher RDS(ON) (0.8 Ω); no pulse-skipping mode. | Better for fixed-output systems where simplicity outweighs adjustable voltage and light-load efficiency. | Select MAX764CSA+ when output voltage is fixed and board space allows larger thermal footprint. |
Compared with LM2611AMF/NOPB, LM2611MFX/NOPB offers identical performance in reel format for manufacturing scalability, while MAX764CSA+ trades adjustability and light-load efficiency for fixed-output simplicity and higher conduction loss-making it suitable only where output voltage is invariant and thermal margin is ample.
Availability
LM2611AMF/NOPB is available at Aetrix Electronics and suitable for MR head bias, CCD sensor bias, and LCD panel bias applications requiring stable component supply, consistent parametric performance, and long-term industrial availability.
Supply support for LM2611AMF/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 company specializing in analog, embedded processing, and power management technologies, with decades of leadership in precision power conversion ICs.
The LM2611AMF/NOPB belongs to TI's Cuk converter product line, engineered specifically for compact, low-noise negative-bias generation in data storage, imaging, and display systems where input/output current continuity and ripple suppression are critical.
FAQ
What is the maximum output current capability of the LM2611AMF/NOPB at −5 V with a 5-V input?
The LM2611AMF/NOPB delivers up to 300 mA at −5 V when supplied from a 5-V input, as confirmed in the datasheet's typical application circuit and Figure 23. This assumes proper layout, recommended 15 µH/47 µH inductors (L1/L2), and adequate thermal management per RθJA = 163.5°C/W. Exceeding this current risks thermal shutdown or reduced regulation accuracy.
How does the LM2611AMF/NOPB achieve low output ripple compared to buck-boost inverters?
The LM2611AMF/NOPB achieves 1-mVp-p output ripple by using a Cuk topology with separate input and output inductors, which enforce continuous current flow on both sides and minimize RMS current stress on COUT. Unlike buck-boost inverters, this topology avoids discontinuous current spikes and inherent diode reverse-recovery noise-directly enabled by the LM2611AMF/NOPB's integrated current-mode controller and 1.4-MHz fixed-frequency operation.
Can the LM2611AMF/NOPB be used with a 12-V input to generate −5 V, and what is the expected output current?
Yes, the LM2611AMF/NOPB supports 12-V input for −5-V output, with a maximum output current of approximately 375 mA per Figure 28 in the datasheet. This assumes L1 = L2 = 22 µH, proper CCUK/COUT selection, and thermal derating based on PCB copper area-since higher input voltage increases power dissipation in the 0.5-Ω RDS(ON) switch.
What is the function of the NFB pin on the LM2611AMF/NOPB, and how is it used to set output voltage?
The NFB pin on the LM2611AMF/NOPB is the negative feedback input referenced to an internal −1.23-V bandgap. To set VOUT = −5 V, a resistor divider (e.g., RFB1 = 29.4 kΩ, RFB2 = 10 kΩ) connects from VOUT to NFB and NFB to GND. The LM2611AMF/NOPB regulates so that the voltage at NFB equals −1.23 V, establishing the ratio that determines output magnitude.
Does the LM2611AMF/NOPB require external compensation components, and how is stability ensured?
No, the LM2611AMF/NOPB includes fully internal type II/III compensation optimized for Cuk converters with 10–22 µH inductors. Stability is ensured by adhering to TI's recommended L1/L2 values and optionally adding a feed-forward capacitor (CFF) across RFB1-e.g., 330 pF for 5-V-to−5-V designs-to add a zero-pole pair and improve phase margin during load transients.
LM2611AMF/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- SC-74A, SOT-753
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- 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
LM2611AMF/NOPB FAQ
1.How can I place an order for LM2611AMF/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2611AMF/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 LM2611AMF/NOPB reliable?
The price and inventory of LM2611AMF/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2611AMF/NOPB is usually 5 days.
3.What payment methods are accepted for LM2611AMF/NOPB?
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4.How is shipping managed for LM2611AMF/NOPB?
LM2611AMF/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2611AMF/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 LM2611AMF/NOPB?
For technical support, including LM2611AMF/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2611AMF/NOPB requirements.
6.How does Aetrix verify that LM2611AMF/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2611AMF/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 LM2611AMF/NOPB meets industry standards.
7.What is the process for return or replacement of LM2611AMF/NOPB?
All LM2611AMF/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2611AMF/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 LM2611AMF/NOPB part is unused and in its original packaging.
Return procedure for LM2611AMF/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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