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Texas Instruments LM2661MM/NOPB
- Part No.:
- LM2661MM/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
LM2661MM/NOPB.pdf
- Description:
- IC REG CHG PUMP INV 100MA 8VSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,979
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Product details
Overview
LM2661MM/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 modes - negative voltage inversion or positive voltage doubling - and features selectable 10 kHz/80 kHz internal oscillator frequency via the FC pin for optimized capacitor sizing and ripple control in portable power rails.
For engineers reviewing the LM2661MM/NOPB datasheet, LM2661MM/NOPB pinout, LM2661MM/NOPB application, or LM2661MM/NOPB equivalent, this device is evaluated for low-EMI, inductorless DC/DC conversion in space-constrained battery-powered systems requiring ±VOUT generation from single-supply rails.
Technical Context
The LM2661MM/NOPB implements a four-switch charge-pump topology with CMOS drivers, enabling precise voltage inversion (VOUT ≈ −VIN) or doubling (VOUT ≈ +2VIN) depending on external pin configuration. Its LV pin enables low-voltage operation below 3.5 V by bypassing internal regulation circuitry, while the FC pin selects between 10 kHz and 80 kHz oscillator frequencies - directly determining switching frequency (fSW = fOSC/2) and influencing output impedance and ripple.
Operation requires only two external capacitors: one flying capacitor (CAP+, CAP−) and one output filter capacitor (COUT). The OSC pin supports optional external clock drive (up to 150 kHz) in inverter mode only, and oscillator frequency can be reduced using an external capacitor tied to OSC and GND. Output resistance is dominated by internal switch RON, capacitor ESR, and fOSC - not load-independent ideal behavior.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 1.5 V to 5.5 V - supports direct Li-ion, alkaline, or regulated 3.3 V/5 V rail operation without pre-regulation |
| Output Current | 100 mA - sufficient for op-amp biasing, RS-232 interface supplies, or low-power analog subsystems |
| Oscillator Frequency | 10 kHz or 80 kHz (FC pin-selectable) - higher frequency allows smaller external capacitors and lower output impedance |
| Conversion Efficiency | 88% typical at 100 mA - reduces thermal load and extends battery life in portable instrumentation |
| Output Resistance | 6.5 Ω typical - defines voltage drop under load (e.g., 0.65 V drop at 100 mA), critical for stable negative rail design |
| Quiescent Current | 120 µA typical - enables ultra-low standby power in always-on sensor nodes or medical monitors |
| Operating Temperature | –40°C to +85°C - qualified for industrial and automotive cabin-temperature environments |
Pinout & Package
VSSOP-8 (DGK) package: 3.00 mm × 3.00 mm, 0.65 mm pitch, thermally enhanced for compact PCB layouts in handheld and wearable devices.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 FC | Frequency Control Input | Selects internal oscillator frequency: open = 10 kHz, tied to V+ = 80 kHz; no effect when OSC driven externally |
| 2 CAP+ | Flying Capacitor Positive Terminal | Connects to positive plate of flying capacitor (C1); carries bidirectional high-frequency switching current |
| 3 GND | Power Ground Reference | Primary return path for all internal switches and external capacitors; must be low-inductance connection |
| 4 CAP− | Flying Capacitor Negative Terminal | Connects to negative plate of flying capacitor (C1); forms charge-transfer loop with CAP+ |
| 5 OUT | Inverter Output / Doubler Ground | In inverter mode: negative output rail; in doubler mode: connected to system ground (LV = OUT) |
| 6 LV | Low-Voltage Enable Input | Tie to GND for VIN < 3.5 V to bypass regulator; leave open or tie to GND for VIN ≥ 3.5 V |
| 7 OSC | Oscillator Control Input | Accepts external clock ≤150 kHz (inverter mode only); or external capacitor to reduce frequency; internal 15 pF load |
| 8 V+ | Positive Supply Input | Main power input; in doubler mode, becomes positive output terminal (VOUT ≈ +2VIN) |
Key Features
| Feature | Design Value |
|---|---|
| Inductorless DC/DC Conversion | Eliminates magnetic components, EMI filters, and layout-sensitive inductors - reduces BOM count and board area by >30% vs. inductive converters |
| Dual-Mode Operation (Invert/Doubler) | Single IC supports both negative rail generation (e.g., –5 V for op-amps) and positive boost (e.g., +10 V from +5 V) via pin-strapping - no redesign needed |
| Configurable Oscillator | FC pin selection and OSC pin flexibility allow ripple/noise optimization across load and capacitor constraints - avoids fixed-frequency compromises |
| Parallel Operation Support | Multiple LM2661MM/NOPB units can share one output capacitor while using individual flying capacitors - scales output current without new layout |
| Low Quiescent Power | 120 µA supply current enables >1-year battery life in intermittent-sampling IoT sensors powered by coin cells |
Applications
| Operational Amplifier Bias Rails | RS-232 Interface Power |
|---|---|
|
Use Scenario: Dual-supply op-amps (e.g., TL072, OPA234) require symmetric ±VCC rails from a single 5 V source in portable test equipment. IC Role / Device Role / Timing Role: LM2661MM/NOPB generates stable –5 V rail from +5 V input using inverter configuration with 10 µF ceramic flying/output capacitors. Use Value: Delivers 50 mA at –4.95 V (0.1 Ω effective output impedance with parallel configuration), eliminating need for bulky inductive DC/DC or dual batteries. |
Use Scenario: Isolated RS-232 transceivers (e.g., MAX3232) require ±10 V supplies from 3.3 V microcontroller systems in handheld diagnostics tools. IC Role / Device Role / Timing Role: LM2661MM/NOPB operates in doubler mode (LV = OUT, GND on OUT) to generate +6.6 V from 3.3 V, followed by LDO regulation to ±10 V. Use Value: Enables full RS-232 compliance without external transformers or charge pumps with higher quiescent current (>500 µA). |
| Medical Sensor Signal Conditioning | Portable Audio DAC Supplies |
|
Use Scenario: Low-noise EEG front-end amplifiers demand clean, low-ripple negative supply to minimize common-mode offset drift during battery operation. IC Role / Device Role / Timing Role: LM2661MM/NOPB configured with 80 kHz oscillator and low-ESR tantalum capacitors delivers –3.3 V with <15 mVPP ripple at 20 mA load. Use Value: Ripple reduction versus 10 kHz mode improves SNR by 8 dB in 16-bit ADC signal chains without adding LC filtering stages. |
Use Scenario: High-fidelity portable DACs (e.g., PCM5102A) require isolated analog supplies to prevent digital noise coupling into audio outputs. IC Role / Device Role / Timing Role: LM2661MM/NOPB inverts 3.3 V to –3.3 V for DAC's analog ground reference, with OSC pin filtered to suppress switching harmonics near audio band. Use Value: Achieves –3.3 V ±1% regulation over temperature, enabling THD+N < 0.002% in Class AB headphone amplifiers. |
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 |
|---|---|---|---|
| LM2662MM/NOPB | Pin-compatible upgrade with 90% typical efficiency, 4.5 Ω output resistance, and extended 1.8–6.0 V input range | Better suited for 3.3 V systems with tighter output regulation requirements; supports higher ambient temperatures (TJ up to 125°C) | Select LM2662MM/NOPB when efficiency >90% or input >5.5 V is required; same PCB footprint and external component values |
| MAX680ESA+ | Higher 125 mA output current, 120 kHz fixed oscillator, but requires 4.5–6.0 V input and lacks LV pin for sub-3.5 V operation | Optimized for 5 V industrial interfaces; no low-voltage enable - unsuitable for 1.5–3.3 V battery systems | Choose MAX680ESA+ only for 5 V-only designs needing higher current; incompatible with 1.5–3.3 V inputs or LV-controlled low-VIN operation |
Compared with LM2661MM/NOPB, LM2662MM/NOPB offers measurable efficiency and thermal margin gains at identical layout cost, while MAX680ESA+ trades low-voltage flexibility for raw output capability - making LM2661MM/NOPB the optimal balance for mixed-voltage portable systems.
Availability
LM2661MM/NOPB is available at Aetrix Electronics and suitable for portable medical instruments, handheld test equipment, and RS-232 interface power supplies requiring stable component supply with guaranteed long-term manufacturability.
Supply support for LM2661MM/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 power management technologies, with decades of expertise in precision power conversion and signal chain solutions.
The LM266x series was designed specifically for inductorless, low-EMI DC/DC conversion in space- and power-constrained portable electronics - targeting battery-powered instrumentation, interface ICs, and analog subsystems where size and noise matter.
FAQ
What is the maximum output current specification for the LM2661MM/NOPB?
The LM2661MM/NOPB delivers up to 100 mA of continuous output current in both inverter and doubler configurations, as verified across the full operating temperature range (–40°C to +85°C) and input voltage range (1.5 V to 5.5 V). This rating assumes proper thermal management and use of low-ESR external capacitors; exceeding 100 mA may cause output voltage droop beyond specifications or thermal shutdown in sustained operation.
Can the LM2661MM/NOPB generate a regulated negative output voltage?
The LM2661MM/NOPB itself provides unregulated output - its inverter mode yields approximately –VIN, and doubler mode yields approximately +2VIN. However, it can be combined with an external low-dropout linear regulator (e.g., LP2951) to produce a regulated negative output. TI's reference design in SNVS135E Figure 20 demonstrates this configuration, achieving adjustable –1.5 V to –5.5 V with ±1% accuracy and 5% error-flag monitoring.
Is the LM2661MM/NOPB pin-compatible with the LM2660 family?
Yes - the LM2661MM/NOPB shares identical pinout, electrical characteristics, and functional behavior with the LM2660M/NOPB (SOIC-8) and LM2660MM/NOPB (VSSOP-8). All variants use the same FC, LV, OSC, CAP+, CAP−, OUT, GND, and V+ pin assignments and support identical inverter/doubler configurations, oscillator control, and parallel operation schemes.
What external capacitors are recommended for optimal performance with the LM2661MM/NOPB?
TI recommends low-ESR ceramic or tantalum capacitors: 10 µF X7R ceramics for general use, or 150 µF tantalum (e.g., AVX TPS series) for higher current stability. C1 (flying capacitor) and C2 (output capacitor) should match in value and type. Ceramic capacitors reduce output resistance and ripple more effectively than electrolytics, especially at 80 kHz operation - critical for maintaining <1% voltage droop at 100 mA load.
Does the LM2661MM/NOPB support external clock synchronization?
The LM2661MM/NOPB supports external clock drive on the OSC pin - but only in inverter mode, and only with clocks swinging within 100 mV of V+ and GND (i.e., CMOS-level signals). The external clock frequency must not exceed 150 kHz. In doubler mode, the OSC pin cannot accept external drive and must be left open or connected to an external timing capacitor for frequency reduction.
LM2661MM/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
LM2661MM/NOPB FAQ
1.How can I place an order for LM2661MM/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2661MM/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 LM2661MM/NOPB reliable?
The price and inventory of LM2661MM/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2661MM/NOPB is usually 5 days.
3.What payment methods are accepted for LM2661MM/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2661MM/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2661MM/NOPB?
LM2661MM/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2661MM/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 LM2661MM/NOPB?
For technical support, including LM2661MM/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2661MM/NOPB requirements.
6.How does Aetrix verify that LM2661MM/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2661MM/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 LM2661MM/NOPB meets industry standards.
7.What is the process for return or replacement of LM2661MM/NOPB?
All LM2661MM/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2661MM/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 LM2661MM/NOPB part is unused and in its original packaging.
Return procedure for LM2661MM/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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