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Texas Instruments LM2685MTCX/NOPB
- Part No.:
- LM2685MTCX/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Regulators - Linear + Switching
- Package:
- 14-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM2685MTCX/NOPB.pdf
- Description:
- IC REG DL CHRPMP/LINEAR 14TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,601
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Product details
Overview
LM2685MTCX/NOPB from Texas Instruments is a dual-output regulated switched-capacitor voltage converter that functions as a +5V LDO regulator, voltage doubler (2.85V–5.4V input), and inverting charge pump to generate −5V. It delivers 50mA at +5V (±5%) and 15mA at −5V with 80% typical efficiency at 25mA, operating from 2.85V to 6.5V input in battery-powered portable instrumentation.
For engineers reviewing the LM2685MTCX/NOPB datasheet, LM2685MTCX/NOPB pinout, LM2685MTCX/NOPB application, or LM2685MTCX/NOPB equivalent, key selection criteria include independent shutdown control (CE/SDP/SDN), TSSOP-14 package compatibility, VPSW/VNSW load-disconnect switches, and dual regulated/unregulated output architecture for split-rail analog circuitry.
Technical Context
The LM2685MTCX/NOPB integrates three functional blocks: a voltage doubler (with internal CMOS switch array and Schottky-assisted startup), a low-dropout +5V regulator fed by VDBL, and an unregulated inverting charge pump deriving VNEG from V05. Its 130 kHz fixed-frequency oscillator minimizes output impedance and ripple while enabling compact external capacitor sizing.
Shutdown logic supports hierarchical power management: CE or SDP disables all blocks and both PSW/NSW switches; SDN disables only the inverter stage, preserving +5V output. Output regulation relies on internal feedback for V05, while VNEG droop is determined by switch RDS(on) and capacitor ESR-no closed-loop control.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.85V to 6.5V - supports single-cell Li-ion, 3.3V logic rails, and legacy 5V systems without external LDO pre-regulation. |
| +5V Output Current | 50mA max - sufficient for op-amp biasing, ADC reference buffers, and small-signal analog stages in handheld devices. |
| −5V Output Current | 15mA max - enables rail-to-rail op-amp operation and analog front-end conditioning where negative supply is required. |
| Regulation Accuracy | ±5% at V05 (4.797V–5.303V) - meets standard TTL/CMOS interface and analog IC biasing requirements across full temperature range. |
| Switching Frequency | 130 kHz typical - balances capacitor size, EMI, and efficiency; allows use of low-cost 2.2µF ceramic or tantalum capacitors. |
| Quiescent Current | 800 µA typical - extends battery life in always-on monitoring circuits; drops to 6 µA in shutdown mode. |
| Package | TSSOP-14 - surface-mount footprint compatible with automated assembly; thermal resistance θJA = 140°C/W supports moderate power dissipation. |
Pinout & Package
LM2685MTCX/NOPB is housed in a 14-pin Thin Shrink Small Outline Package (TSSOP) with exposed pad for thermal enhancement and standard JEDEC MO-153 compliance. Pin pitch is 0.65 mm; body dimensions are 5.0 mm × 4.4 mm × 1.2 mm.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Power supply input | Main input rail (2.85V–6.5V); feeds doubler and LDO regulator stages. |
| GND | Ground reference | Common return for all internal blocks and external capacitors; must be low-impedance. |
| VNEG | Inverted output | Unregulated −5V output derived from V05; voltage droops under load due to switch RDS(on) and capacitor ESR. |
| VNSW | Switched negative output | VNEG routed through NSW switch; disconnects load when SDN = high. |
| CE | Chip enable | Active-high global shutdown; disables all blocks and opens both PSW and NSW switches. |
| SDP | Positive shutdown | Active-high positive-side shutdown; functionally identical to CE but inverted polarity logic. |
| SDN | Negative shutdown | Active-high negative-side shutdown; disables only inverter stage, leaving V05/VPSW active. |
| C2− / C2+ | Inverter capacitor terminals | Connect external 2.2µF charge-pump capacitor (C2); polarity critical for correct inversion sequence. |
| V05 | +5V regulated output | Stable +5V output from LDO stage; used directly or via VPSW switch for load isolation. |
| VPSW | Switched positive output | V05 routed through PSW switch; enables load disconnect without affecting regulator operation. |
| VDBL | Voltage doubler output | Doubled input (2×VIN) up to 5.4V; serves as LDO input; not intended for direct loading above 50mA total. |
| C1+ / C1− | Doubler capacitor terminals | Connect external 2.2µF doubling capacitor (C1); timing and efficiency depend on ESR and capacitance. |
Key Features
| Feature | Design Value |
|---|---|
| Independent shutdown controls | CE, SDP, and SDN pins allow selective disabling of entire device, +5V path only, or −5V path only-enabling flexible power sequencing in multi-rail systems. |
| VPSW/VNSW load-disconnect switches | Integrated low-RDS(on) MOSFET switches isolate loads from V05 and VNEG, preventing backfeed and enabling hot-swap capability in modular designs. |
| Startup-assisted voltage doubler | Internal Schottky diode (D1) ensures reliable oscillator startup even with slow input ramps (<10V/ms), eliminating need for external startup circuitry. |
| Low-noise +5V LDO output | Regulated V05 output exhibits <1.0% load regulation and <0.25%/V line regulation-suitable for precision analog references and sensor signal chains. |
| Thermal shutdown protection | Internal thermal limiter triggers at ~150°C junction temperature, forcing shutdown to prevent permanent damage during sustained overload or poor PCB thermal design. |
Applications
| Portable Medical Sensors | Handheld Test Equipment |
|---|---|
Use Scenario: Battery-powered ECG front-end requiring ±5V rails for op-amp biasing and ADC reference generation. IC Role / Device Role / Timing Role: Dual-output voltage converter providing isolated +5V (regulated) and −5V (unregulated) supplies from a single 3.7V Li-ion cell. Use Value: Eliminates need for discrete DC/DC converters or transformer-based solutions, reducing BOM count and board area while maintaining analog signal integrity. | Use Scenario: Digital multimeter with analog input stage needing clean dual supplies for rail-to-rail input amplifiers. IC Role / Device Role / Timing Role: Charge-pump voltage converter generating stable ±5V outputs synchronized to internal 130 kHz oscillator for low-noise analog conditioning. Use Value: Enables true bipolar measurement capability without external inductors or magnetics, improving portability and EMI performance. |
| Industrial Data Loggers | Wireless Sensor Nodes |
Use Scenario: Low-power environmental monitor using precision analog sensors and 16-bit ADCs requiring symmetric supply rails. IC Role / Device Role / Timing Role: Regulated +5V source and inverting charge pump delivering −5V for op-amp offset nulling and sensor excitation circuits. Use Value: Achieves <0.3% load regulation and 80% conversion efficiency at 25mA, extending battery life while meeting industrial-grade accuracy specs. | Use Scenario: Zigbee-enabled temperature/humidity node with RF transceiver and analog sensor interface. IC Role / Device Role / Timing Role: Dual-output converter supplying +5V to MCU peripherals and −5V to RF front-end bias networks, controlled via SDN for sleep-mode current reduction. Use Value: 6 µA shutdown current and independent SDN control cut system standby power by >95%, enabling multi-year battery operation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-output switched-capacitor voltage converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX680ESA+ | Single-output ±5V inverter only; no +5V regulator or voltage doubler; 12-pin SOIC package; 125 kHz switching frequency. | Lacks regulated +5V output and independent shutdown controls-requires external LDO for precision VCC rail. | Select when only bipolar supply is needed and board space permits larger SOIC footprint; avoid if V05 regulation or programmable shutdown is required. |
| TPS60403DBVR | Single-output −5V inverter with 60 mA output; no +5V regulator or doubler; SOT-23-6 package; 1 MHz switching frequency. | Higher frequency enables smaller capacitors but lacks dual-output architecture and shutdown flexibility of LM2685MTCX/NOPB. | Choose for ultra-compact designs needing only negative rail; not suitable as drop-in replacement due to missing V05, VDBL, and multi-shutdown functionality. |
Compared with MAX680ESA+ and TPS60403DBVR, LM2685MTCX/NOPB uniquely integrates regulated +5V generation, voltage doubling, and inverting functions in one TSSOP-14 package with three independent shutdown inputs-making it the only solution supporting simultaneous rail generation and granular power-domain control in space-constrained portable systems.
Availability
LM2685MTCX/NOPB is available at Aetrix Electronics and suitable for portable medical sensors, handheld test equipment, industrial data loggers, wireless sensor nodes, and 3.3V-to-5V conversion applications requiring stable component supply and long-term sourcing continuity.
Supply support for LM2685MTCX/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 digital signal technologies, with decades of expertise in power management ICs.
The LM2685MTCX/NOPB belongs to TI's switched-capacitor voltage converter product line, designed specifically for compact, inductorless dual-rail generation in battery-powered portable electronics where size, efficiency, and supply flexibility are critical.
FAQ
What is the maximum continuous output current supported by LM2685MTCX/NOPB at its +5V regulated output?
The LM2685MTCX/NOPB supports up to 50mA of continuous output current at the V05 (+5V) pin under specified conditions (2.85V ≤ VIN ≤ 6.5V, no load on VDBL). This rating assumes proper external capacitor selection (2.2µF C1/C2, 4.7µF C4) and ambient temperature ≤85°C. Exceeding this current may cause V05 regulation loss or thermal shutdown activation.
Does LM2685MTCX/NOPB provide regulation on both its +5V and −5V outputs?
No-only the +5V output at V05 is regulated via an internal LDO stage. The −5V output at VNEG is generated by an unregulated inverting charge pump; its voltage droops under load due to internal switch RDS(on) and external capacitor ESR. For stable −5V operation, load current must remain ≤15mA and low-ESR capacitors (≤0.3Ω) must be used per the datasheet recommendations.
Can LM2685MTCX/NOPB operate from a 3.3V input supply?
Yes-LM2685MTCX/NOPB operates over an input range of 2.85V to 6.5V, making 3.3V fully compatible. At 3.3V input, the voltage doubler produces ~6.6V at VDBL (within safe limits), which the LDO regulates to 5V at V05. Efficiency remains >80% at 25mA load, and all shutdown functions (CE/SDP/SDN) retain full functionality across this input range.
What is the purpose of the VPSW and VNSW pins on LM2685MTCX/NOPB?
VPSW and VNSW are switched outputs tied internally to V05 and VNEG via MOSFET switches PSW and NSW. They enable load disconnection without disrupting internal regulation-driving SDP high opens PSW (isolating V05 loads), while driving SDN high opens NSW (isolating VNEG loads). This supports power domain isolation in multi-stage analog systems and prevents backfeed during partial shutdown.
Is LM2685MTCX/NOPB still in active production or obsolete?
LM2685MTCX/NOPB is marked obsolete by Texas Instruments per the official datasheet revision history (SNVS055C, April 2013), but Aetrix Electronics maintains legacy inventory and offers lifecycle management support-including last-time-buy planning, cross-reference assistance, and technical documentation archiving-to ensure continuity for existing designs still utilizing this dual-output switched-capacitor converter.
LM2685MTCX/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 14-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Topology:
- Charge Pump (1), Linear (LDO) (1)
- Number of Outputs:
- 2
- Frequency - Switching:
- 130kHz
- Voltage/Current - Output 1:
- ±5V, 5.7V ~ 13V, 50mA
- Voltage/Current - Output 2:
- 5V, 50mA
- Voltage/Current - Output 3:
- -
- w/LED Driver:
- No
- w/Supervisor:
- No
- w/Sequencer:
- No
- Voltage - Supply:
- 2.85V ~ 6.5V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 14-TSSOP
LM2685MTCX/NOPB FAQ
1.How can I place an order for LM2685MTCX/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2685MTCX/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 LM2685MTCX/NOPB reliable?
The price and inventory of LM2685MTCX/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2685MTCX/NOPB is usually 5 days.
3.What payment methods are accepted for LM2685MTCX/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2685MTCX/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2685MTCX/NOPB?
LM2685MTCX/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2685MTCX/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 LM2685MTCX/NOPB?
For technical support, including LM2685MTCX/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2685MTCX/NOPB requirements.
6.How does Aetrix verify that LM2685MTCX/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2685MTCX/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 LM2685MTCX/NOPB meets industry standards.
7.What is the process for return or replacement of LM2685MTCX/NOPB?
All LM2685MTCX/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2685MTCX/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 LM2685MTCX/NOPB part is unused and in its original packaging.
Return procedure for LM2685MTCX/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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