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Texas Instruments LM2661MMX/NOPB
- Part No.:
- LM2661MMX/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
LM2661MMX/NOPB.pdf
- Description:
- IC REG CHG PUMP INV 100MA 8VSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,579
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Product details
Overview
LM2661MMX/NOPB from Texas Instruments is a CMOS switched-capacitor voltage inverter/doubler IC operating from 1.5 V to 5.5 V input, delivering up to 100 mA output current with 88% typical conversion efficiency at full load and 6.5 Ω typical output resistance. It supports dual configurations - negative voltage inversion or positive voltage doubling - and features selectable 10 kHz/80 kHz internal oscillator frequency via the FC pin, used in portable medical instruments and op-amp dual-rail power supplies.
For engineers reviewing the LM2661MMX/NOPB datasheet, LM2661MMX/NOPB pinout, LM2661MMX/NOPB application, or LM2661MMX/NOPB equivalent, key selection criteria include input voltage range compatibility (1.5–5.5 V), output current capability (100 mA), oscillator frequency control (FC pin logic), LV pin configuration for low-voltage operation, and VSSOP-8 package thermal performance (RθJA = 250 °C/W).
Technical Context
The LM2661MMX/NOPB implements a four-switch charge-pump topology with CMOS-controlled switching sequence to invert or double input voltage without inductors. Its internal oscillator drives synchronous MOSFET switches whose on-resistance (contributing to 6.5 Ω typical ROUT) and timing determine output impedance and ripple.
Functional mode is determined by external pin connections: inversion requires V+ as input and OUT as negative output with LV open or grounded; doubling requires GND as input, V+ as output, and LV tied to OUT. The OSC pin supports external capacitor-based frequency tuning (not external clock in doubler mode) and FC pin selects nominal 10 kHz or 80 kHz oscillator frequency.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 1.5 V to 5.5 V - supports single-cell Li-ion, alkaline, or regulated 3.3 V/5 V rails without external regulation. |
| Output Current | 100 mA - sufficient to power dual-op-amp stages or small analog front-ends without parallel devices. |
| Oscillator Frequency | 10 kHz or 80 kHz (FC pin-selectable) - lower frequency reduces quiescent current (0.12 mA); higher frequency enables smaller external capacitors. |
| Output Resistance | 6.5 Ω typical - defines voltage drop under load (e.g., 0.65 V drop at 100 mA), directly impacted by switch RON, capacitor ESR, and fOSC. |
| Conversion Efficiency | 88% typical at 100 mA - balances power loss across internal switches and external capacitors; drops at light loads due to fixed quiescent current. |
| Package | VSSOP-8 (3.0 mm × 3.0 mm) - compact footprint with 250 °C/W junction-to-ambient thermal resistance, suitable for space-constrained portable designs. |
| Operating Temperature | –40 °C to +85 °C - qualified for industrial and medical environments where ambient temperature varies widely. |
Pinout & Package
VSSOP-8 (DGK) package: 3.00 mm × 3.00 mm body, 0.5 mm pitch, exposed pad not present, RoHS-compliant matte tin lead finish, MSL Level-1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 FC | Oscillator frequency control input | Open = 10 kHz; connected to V+ = 80 kHz; no effect when OSC driven externally (inverter mode only). |
| 2 CAP+ | Positive flying capacitor terminal | Connects to anode of charge-pump capacitor C1; carries bidirectional switching current during charge-transfer cycles. |
| 3 GND | Power ground reference | Primary return path for supply, output, and internal oscillator; must be low-impedance connection to minimize noise coupling. |
| 4 CAP− | Negative flying capacitor terminal | Connects to cathode of C1; completes charge-transfer loop with CAP+; polarity reverses between inverter/doubler modes. |
| 5 OUT | Inverter output / Doubler input reference | In inverter mode: negative voltage output; in doubler mode: tied to GND to establish input reference for positive doubling. |
| 6 LV | Low-voltage enable input | Tied to GND for V+ < 3.5 V to bypass internal regulator; left open or GND for V+ ≥ 3.5 V; must be GND when driving OSC externally. |
| 7 OSC | Oscillator control input | Internal 15 pF node; connect external capacitor to reduce frequency; accepts external clock ≤150 kHz only in inverter mode. |
| 8 V+ | Positive supply input / Doubler output | In inverter mode: main input rail; in doubler mode: positive output node delivering ~2× input voltage. |
Key Features
| Feature | Design Value |
|---|---|
| Inductorless voltage conversion | Eliminates EMI, size, and cost penalties of magnetic components-ideal for EMI-sensitive handheld medical devices. |
| Configurable topology | Single device supports both inverting (VOUT ≈ −VIN) and doubling (VOUT ≈ +2VIN) modes via pin-strapping, reducing BOM count. |
| Low quiescent current | 120 µA typical supply current at 10 kHz enables >1-year battery life in always-on instrumentation with intermittent use. |
| Parallel operation support | Multiple LM2661MMX/NOPB units can share one output capacitor while using individual flying capacitors, scaling output current beyond 100 mA. |
| External frequency tuning | OSC pin accepts external capacitor to precisely set oscillator frequency below 10 kHz-critical for noise-sensitive audio or sensor biasing applications. |
Applications
| Operational Amplifier Dual-Rail Supply | Portable Medical Instrument Biasing |
|---|---|
Use Scenario: Generating ±5 V rails from a single 5 V supply for rail-to-rail op-amps in portable ECG front-ends. IC Role / Device Role / Timing Role: LM2661MMX/NOPB operates in inverter mode to produce −5 V, paired with the 5 V input as +5 V, enabling true bipolar signal conditioning. Use Value: Delivers stable −5 V at 50 mA with <100 mV ripple (using 10 µF ceramic caps), meeting low-noise analog signal chain requirements without inductor-induced interference. | Use Scenario: Powering precision analog sensors and ADC reference buffers in handheld blood glucose meters. IC Role / Device Role / Timing Role: LM2661MMX/NOPB configured as voltage doubler generates +5 V from a 2.7 V lithium coin cell, extending usable battery range. Use Value: Achieves 92% efficiency at 20 mA load, enabling >5000 measurements per battery charge while maintaining tight output regulation via external LDO post-regulation. |
| Laptop Peripheral Interface Supply | Industrial Sensor Signal Conditioning |
Use Scenario: Providing isolated −3.3 V bias for RS-232 transceivers in ultrabook docking stations with strict PCB area constraints. IC Role / Device Role / Timing Role: LM2661MMX/NOPB in inverter mode converts 3.3 V USB power to −3.3 V, synchronized to system clock via FC pin for EMI alignment. Use Value: VSSOP-8 footprint fits within 12 mm² board area; 80 kHz oscillator minimizes capacitor size (2.2 µF ×2) while meeting ±5% output tolerance. | Use Scenario: Generating clean ±12 V rails for programmable gain instrumentation amplifiers in factory-floor vibration analyzers. IC Role / Device Role / Timing Role: Two LM2661MMX/NOPB units cascaded in inverter mode produce −12 V from 6 V input, with shared output capacitor. Use Value: Composite output resistance drops to ~3.3 Ω (half of single-device value), supporting 100 mA total load with <150 mV dropout across temperature. |
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 |
|---|---|---|---|
| LM2660MM/NOPB | Same architecture, pinout, and electrical specs; differs only in part number suffix and TI's internal revision tracking-functionally identical to LM2661MMX/NOPB. | No functional difference; both support inverter/doubler modes, same FC/OSC/LV behavior, and identical VSSOP-8 packaging. | Select LM2660MM/NOPB if legacy design documentation references LM2660; no layout or firmware changes required. |
| MAX680ESA+ | Higher 125 mA output current, 120 kHz fixed oscillator, no FC pin; uses different pinout (SO-8) and requires separate flying capacitor polarity handling. | Not suitable for direct replacement due to non-compatible pin mapping and absence of LV/FC configurability; better for fixed-frequency, higher-current apps. | Choose MAX680ESA+ only when 125 mA output and 120 kHz operation are mandatory and board redesign is acceptable. |
Compared with LM2660MM/NOPB, the LM2661MMX/NOPB offers identical functionality but reflects TI's updated orderable part numbering; versus MAX680ESA+, it provides pin-strappable flexibility and lower quiescent current at the expense of peak output current and fixed oscillator frequency.
Availability
LM2661MMX/NOPB is available at Aetrix Electronics and suitable for portable medical instruments, battery-powered op-amp supplies, and industrial sensor interfaces requiring stable component supply across multi-year production cycles.
Supply support for LM2661MMX/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 and embedded processing solutions, with leadership in power management, signal chain, and high-reliability ICs.
The LM266x series was designed specifically for low-noise, inductorless DC/DC conversion in space- and power-constrained portable electronics, emphasizing efficiency, small footprint, and flexible topology configuration.
FAQ
What is the maximum input voltage the LM2661MMX/NOPB can accept in voltage inverter mode?
The LM2661MMX/NOPB supports a maximum input voltage of 5.5 V in inverter mode when the LV pin is open or grounded. Absolute maximum rating for V+ to GND is 6 V, but continuous operation above 5.5 V risks reliability degradation. For inputs exceeding 5.5 V, external regulation is required before applying to the LM2661MMX/NOPB V+ pin.
Can the LM2661MMX/NOPB generate a regulated negative output voltage?
The LM2661MMX/NOPB itself provides unregulated output. However, it can be combined with an external low-dropout linear regulator like the LP2951 to produce a regulated negative output - for example, −3.3 V or −5 V - by connecting the LM2661MMX/NOPB's inverted output to the LDO's input and configuring feedback resistors per the LP2951 datasheet.
Does the LM2661MMX/NOPB support external clock synchronization?
Yes, but only in voltage inverter mode: the OSC pin accepts an external CMOS-compatible clock signal up to 150 kHz, provided the LV pin is tied to GND. External clocking is explicitly disabled in voltage doubler mode per TI's datasheet, and attempting it may result in undefined operation or failure to start.
What is the purpose of the LV pin on the LM2661MMX/NOPB?
The LV (Low-Voltage Enable) pin bypasses internal regulator circuitry when pulled to GND, optimizing performance for input voltages below 3.5 V. At V+ ≥ 3.5 V, LV may be left open or grounded with no functional impact. In doubler mode, LV must be tied to OUT; in inverter mode with external OSC drive, LV must be grounded.
How does paralleling multiple LM2661MMX/NOPB devices affect output resistance?
Paralleling N identical LM2661MMX/NOPB units - each with its own flying capacitor (CAP+/CAP−) but sharing one output capacitor - reduces composite output resistance to ROUT/N. For example, two devices yield ~3.25 Ω typical ROUT, enabling higher output current while maintaining voltage accuracy under load.
LM2661MMX/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Function:
- Ratiometric
- Output Configuration:
- Positive or Negative
- Topology:
- Charge Pump
- Output Type:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 1.5V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- -Vin, 2Vin, Vin/2
- Voltage - Output (Max):
- -
- Current - Output:
- 100mA
- Frequency - Switching:
- 5kHz, 40kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-VSSOP
LM2661MMX/NOPB FAQ
1.How can I place an order for LM2661MMX/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2661MMX/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 LM2661MMX/NOPB reliable?
The price and inventory of LM2661MMX/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2661MMX/NOPB is usually 5 days.
3.What payment methods are accepted for LM2661MMX/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2661MMX/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2661MMX/NOPB?
LM2661MMX/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2661MMX/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 LM2661MMX/NOPB?
For technical support, including LM2661MMX/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2661MMX/NOPB requirements.
6.How does Aetrix verify that LM2661MMX/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2661MMX/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 LM2661MMX/NOPB meets industry standards.
7.What is the process for return or replacement of LM2661MMX/NOPB?
All LM2661MMX/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2661MMX/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 LM2661MMX/NOPB part is unused and in its original packaging.
Return procedure for LM2661MMX/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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