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Texas Instruments LM2611AMFX/NOPB
- Part No.:
- LM2611AMFX/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LM2611AMFX/NOPB.pdf
- Description:
- IC REG CUK ADJ 1.2A SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:1,286
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Product details
Overview
LM2611AMFX/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, features 1.4-MHz fixed switching frequency, 0.5-Ω typical RDS(ON), and −1.23-V internal reference for precise output regulation in compact space-constrained bias supplies.
For engineers reviewing the LM2611AMFX/NOPB datasheet, LM2611AMFX/NOPB pinout, LM2611AMFX/NOPB application, or LM2611AMFX/NOPB equivalent, this device is selected for low-noise inverting DC/DC conversion where input/output current ripple suppression, small external component count (15 µH/47 µH inductors, 22 µF capacitors), and shutdown-controlled battery life extension are critical design requirements.
Technical Context
The LM2611AMFX/NOPB implements a fixed-frequency (1.4 MHz) current-mode control architecture with internal slope compensation and cycle-by-cycle peak current limiting. Its functional block includes an integrated 0.5-Ω DMOS switch, error amplifier with −1.23-V reference, ramp generator, and shutdown logic that reduces quiescent current to <1 µA.
It operates exclusively in Cuk topology-requiring separate input (L1) and output (L2) inductors plus a coupling capacitor (CCUK)-to achieve continuous input/output currents, low RMS ripple, and inherent EMI advantage over buck-boost. The NFB pin enables output voltage programming via resistor divider, with bias current ≤6.7 µA and reference tolerance ±25 mV over temperature.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Topology | Cuk inverting converter - requires two inductors and one coupling capacitor; enables continuous input/output current and low ripple. |
| Switching Frequency | 1.4 MHz (±0.4 MHz over temp) - allows use of sub-3 mm × 3 mm inductors and ceramic capacitors without audible noise. |
| Output Voltage Range | Programmable down to −36×VIN(MAX); −5 V at 300 mA demonstrated with 5-V input - supports MR head, CCD, LCD, and GaAs FET bias rails. |
| RDS(ON) | 0.5 Ω typical (Grade A) - minimizes conduction loss and thermal rise in SOT-23 package at 300 mA load. |
| Current Limit | 1.2 A typical (Grade A) - sets maximum switch peak current; limits fault energy and enables stable operation with L1/L2 ≥10 µH. |
| Shutdown Current | <1 µA - extends battery runtime in portable systems by disabling switching and internal bias circuits. |
| Reference Voltage | −1.23 V ±25 mV (−40°C to +85°C) - defines output regulation accuracy; used with external RFB1/RFB2 to set VOUT. |
Pinout & Package
LM2611AMFX/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 θJA = 163.5°C/W on standard 2-layer PCB.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - SW | Switch drain node | Connects to input inductor (L1) and Cuk capacitor (CCUK); carries peak switch current up to 1.2 A. |
| 2 - GND | Analog and power ground | Common return for feedback, shutdown, and internal circuitry; must be low-impedance connection to minimize noise coupling. |
| 3 - NFB | Negative feedback input | Accepts resistor divider from VOUT; −1.23-V internal reference regulates output; bias current ≤6.7 µA affects divider accuracy. |
| 4 - SHDN | Active-high shutdown control | Logic-level input: ≥1.5 V enables operation; ≤0.5 V disables switching and reduces IQ to <1 µA. |
| 5 - VIN | Power input | Supplies internal circuitry and switch; accepts 2.7–14 V; requires local 0.1-µF ceramic bypass within 5 mm. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated DMOS switch | 0.5-Ω RDS(ON) (Grade A) reduces conduction loss and eliminates need for external MOSFET driver or discrete switch. |
| Cuk topology support | Enables simultaneous low input/output current ripple and high efficiency - superior to buck-boost for noise-sensitive analog bias rails. |
| Internal compensation | Fixed Type II/III compensation optimized for 10–22 µH inductors - eliminates external compensation network and simplifies layout. |
| Pulse-skipping mode | Automatically enters hysteretic light-load operation below ~50 mA - maintains regulation while reducing switching losses and IQ. |
| Thermal shutdown | Activates at 163°C junction temperature and recovers at 155°C - protects device during overload or poor heatsinking conditions. |
Applications
| MR Head Bias Supply | Digital Camera CCD Bias |
|---|---|
Use Scenario: Provides stable negative bias voltage to magnetoresistive read heads in HDD preamplifier ICs. IC Role / Device Role / Timing Role: Inverting DC/DC regulator generating −5 V from 5-V system rail with ultra-low output ripple (<1 mVp-p). Use Value: Enables high-sensitivity signal detection by minimizing bias-induced noise and drift in analog front-end amplifiers. |
Use Scenario: Supplies regulated negative voltage to CCD image sensor substrate and gate drivers in portable cameras. IC Role / Device Role / Timing Role: Compact Cuk converter delivering −5 V at 300 mA with minimal EMI impact on pixel clock and analog video paths. Use Value: Reduces dark current and fixed-pattern noise through clean, ripple-free bias - directly improving SNR and dynamic range. |
| LCD Panel Bias Generator | GaAs FET RF Amplifier Bias |
Use Scenario: Generates negative gate voltage for active-matrix LCD source driver ICs requiring dual-rail supplies. IC Role / Device Role / Timing Role: Fixed-frequency inverter producing −5 V from single 5-V supply; supports fast startup and shutdown sequencing. Use Value: Eliminates need for external charge pumps or transformers - reduces BOM cost and board area in thin display modules. |
Use Scenario: Supplies precise negative gate bias to GaAs pHEMT amplifiers in wireless infrastructure and test equipment. IC Role / Device Role / Timing Role: Regulated inverter with tight line/load regulation (0.02%/V) and low thermal drift (−1.23 V ±25 mV). Use Value: Maintains optimal FET operating point across temperature and input variation - preserving gain flatness and PAE stability. |
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, Grade B variant: 0.9-A current limit and 0.7-Ω RDS(ON); lower max output current capability. | Suitable for ≤200 mA loads at −5 V; reduced thermal margin under high ambient or high-VIN conditions. | Select LM2611MFX/NOPB only when load current and thermal budget allow lower performance; not drop-in for 300 mA designs. |
| TPS60403DBVR | Charge pump inverter (no inductors); 60 mA max output; 500-kHz switching; no programmable feedback. | Limited to low-current, low-noise applications where inductor-free design is prioritized over efficiency or output capability. | Choose TPS60403DBVR only for ultra-low-power, space-constrained systems needing ≤60 mA; cannot replace LM2611AMFX/NOPB in 300 mA bias rails. |
Compared with LM2611MFX/NOPB, the LM2611AMFX/NOPB delivers higher output current and lower conduction loss, making it preferred for 300 mA bias applications; versus TPS60403DBVR, it provides 5× higher current and superior regulation but requires inductors - selection depends on whether inductor use is acceptable and how much output current is needed.
Availability
LM2611AMFX/NOPB is available at Aetrix Electronics and suitable for MR head bias, CCD imaging, LCD panel, and GaAs FET RF amplifier applications requiring stable component supply, long-term production continuity, and guaranteed traceable sourcing.
Supply support for LM2611AMFX/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 headquartered in Dallas, Texas, specializing in analog, embedded processing, and power management ICs for industrial, automotive, and consumer markets.
The LM2611AMFX/NOPB belongs to TI's precision inverting DC/DC converter product line, engineered specifically for low-noise, high-efficiency negative bias generation in analog and mixed-signal systems where ripple, regulation accuracy, and thermal reliability are critical.
FAQ
What is the maximum output current capability of the LM2611AMFX/NOPB at −5 V?
The LM2611AMFX/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 thermal management, recommended 15 µH/47 µH inductors, and 22 µF ceramic output capacitance. Peak switch current remains within the 1.2-A Grade A limit under these conditions.
Does the LM2611AMFX/NOPB require external compensation components?
No, the LM2611AMFX/NOPB features fully internal Type II/III compensation optimized for 10–22 µH inductors. No external compensation network is required. However, a feed-forward capacitor (CFF) may be added across RFB1 to improve transient response - this is optional and does not affect basic regulation stability.
Can the LM2611AMFX/NOPB operate from a 12-V input to generate −5 V?
Yes, the LM2611AMFX/NOPB supports input voltages from 2.7 V to 14 V. At 12-V input, it can deliver −5 V at up to 375 mA (per Figure 28), provided inductors and capacitors are sized per TI's Cuk design guidelines and thermal limits are observed. Derating applies above 85°C ambient.
What is the function of the NFB pin on the LM2611AMFX/NOPB?
The NFB pin on the LM2611AMFX/NOPB is the negative feedback input that connects to the output via an external resistor divider. It references an internal −1.23-V precision bandgap, enabling accurate output voltage programming. The pin draws ≤6.7 µA bias current, so resistor values should be ≤50 kΩ to minimize divider error.
How does the LM2611AMFX/NOPB handle light-load conditions?
The LM2611AMFX/NOPB automatically enters pulse-skipping (hysteretic) mode below ~50 mA load. In this mode, it maintains regulation while reducing switching frequency and quiescent current - improving efficiency at light loads without requiring external control. Output ripple increases slightly but remains within specification.
LM2611AMFX/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
LM2611AMFX/NOPB FAQ
1.How can I place an order for LM2611AMFX/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2611AMFX/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 LM2611AMFX/NOPB reliable?
The price and inventory of LM2611AMFX/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2611AMFX/NOPB is usually 5 days.
3.What payment methods are accepted for LM2611AMFX/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2611AMFX/NOPB transactions.
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4.How is shipping managed for LM2611AMFX/NOPB?
LM2611AMFX/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2611AMFX/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 LM2611AMFX/NOPB?
For technical support, including LM2611AMFX/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2611AMFX/NOPB requirements.
6.How does Aetrix verify that LM2611AMFX/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2611AMFX/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 LM2611AMFX/NOPB meets industry standards.
7.What is the process for return or replacement of LM2611AMFX/NOPB?
All LM2611AMFX/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2611AMFX/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 LM2611AMFX/NOPB part is unused and in its original packaging.
Return procedure for LM2611AMFX/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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