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Texas Instruments LM3670MF-1.875/NOPB
- Part No.:
- LM3670MF-1.875/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LM3670MF-1.875/NOPB.pdf
- Description:
- IC REG BUCK 1.875V 350MA SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:923
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Product details
Overview
LM3670MF-1.875/NOPB from Texas Instruments is a fixed-output synchronous step-down DC-DC converter delivering 1.875 V at up to 350 mA from 2.5 V–5.5 V input, featuring 1-MHz PWM switching, 15-µA quiescent current, internal soft start, and low-dropout 100% duty-cycle operation-designed for powering core logic in battery-powered handheld devices.
For engineers reviewing the LM3670MF-1.875/NOPB datasheet, LM3670MF-1.875/NOPB pinout, LM3670MF-1.875/NOPB application, or LM3670MF-1.875/NOPB equivalent, key selection considerations include output voltage tolerance (±5.5%), peak switch current limit (750 mA), thermal resistance (RθJA = 163.3°C/W), and compatibility with 4.7 µF input / 10 µF output ceramic capacitors and 4.7–10 µH inductors.
Technical Context
The LM3670MF-1.875/NOPB implements voltage-mode control with input feed-forward compensation and automatic transition between fixed-frequency PWM (≥70 mA load) and hysteretic PFM (light-load) modes. Its synchronous rectification uses internal PFET/NFET switches with typical RDS(on) of 360 mΩ / 250 mΩ, enabling >90% efficiency across 1–350 mA loads.
Operation includes undervoltage lockout (2.4 V), thermal shutdown, cycle-by-cycle current limiting (620 mA typ), and soft-start with ~400 µs rise time into 350-mA load. The device supports dropout down to VIN = VOUT + ILOAD × (RDS(on,P) + RINDUCTOR) and maintains regulation with input as low as 2.5 V for 1.875-V output.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 1.875 V ±5.5% over 0–350 mA load and −40°C to +125°C junction temperature |
| Input Voltage Range | 2.5 V to 5.5 V - supports single Li-Ion or three-cell NiMH/NiCd batteries without external LDO pre-regulation |
| Max Load Current | 350 mA continuous - sufficient for ARM Cortex-M cores, LPDDR I/O, and baseband processors |
| Quiescent Current | 15 µA typical in PFM mode - extends battery life during system standby or idle states |
| Switching Frequency | 1 MHz typical in PWM mode - enables use of compact 4.7–10 µH inductors and minimizes EMI filtering requirements |
| Shutdown Current | 0.1 µA typical - reduces parasitic drain when system is fully powered off |
| Efficiency | 94% typical at 10–100 mA, 90% at 350 mA (VIN = 3.6 V, VOUT = 1.875 V) - lowers thermal load in sealed handheld enclosures |
Pinout & Package
The LM3670MF-1.875/NOPB is housed in a 5-pin SOT-23 package (2.90 mm × 1.60 mm body size) with exposed pad for thermal enhancement and standard surface-mount footprint.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pin 1) | Power input | Accepts 2.5–5.5 V supply; requires local 4.7 µF ceramic decoupling to suppress high-frequency switching noise |
| GND (Pin 2) | Ground reference | Primary return path for power, feedback, and enable circuits; must be connected to low-impedance PCB ground plane |
| EN (Pin 3) | Digital enable | Active-high logic input (VIH ≥1.3 V, VIL ≤0.4 V); pulling low disables regulator and reduces IQ to 0.1 µA |
| FB (Pin 4) | Feedback node | Internally connected to 1.875-V reference; tied directly to output capacitor in fixed-voltage configuration |
| SW (Pin 5) | Switching node | Connects to inductor; carries high di/dt pulses up to 750 mA peak; requires short, low-inductance trace to minimize EMI |
Key Features
| Feature | Design Value |
|---|---|
| Synchronous rectification | Internal PFET/NFET switches eliminate external Schottky diode, reducing conduction loss and improving efficiency by 8–12% vs. asynchronous designs |
| Auto PWM/PFM mode switching | Seamlessly transitions between 1-MHz PWM (high load) and variable-frequency PFM (light load), maintaining >85% efficiency from 1 mA to 350 mA |
| 100% duty-cycle LDO mode | Enables regulation down to VIN = VOUT + ILOAD × (RDS(on,P) + RINDUCTOR), supporting brownout operation near battery end-of-life |
| Integrated soft start | Controls inrush current during power-up; limits peak input surge to <620 mA with 10-µF output capacitor |
| Thermal & current protection | Includes cycle-by-cycle current limiting (750 mA max) and thermal shutdown (125°C TJ), preventing damage during overload or poor heatsinking |
Applications
| Mobile Phone Baseband Power | PDA Application Processor Core |
|---|---|
Use Scenario: Powers ARM9/ARM11 application processor core in GSM/3G smartphones operating from single-cell Li-ion battery (3.0–4.2 V). IC Role / Device Role / Timing Role: Primary buck regulator supplying stable 1.875 V core voltage with fast transient response to CPU burst loads. Use Value: Delivers 350 mA with <2% output deviation during 0–300 mA load steps, minimizing voltage droop that could cause CPU stalls or cache errors. | Use Scenario: Supplies 1.875 V to ASIC or FPGA fabric in palm-sized PDAs with tight board space and thermal constraints. IC Role / Device Role / Timing Role: Fixed-output DC-DC converter replacing linear regulators to reduce heat generation and extend battery runtime. Use Value: Achieves 94% efficiency at 50 mA, cutting power dissipation by >65% versus equivalent LDO, enabling fanless operation in sealed plastic enclosures. |
| Portable Medical Instrument Sensor Bias | Wireless Headset DSP Core Supply |
Use Scenario: Provides precision 1.875 V bias for low-noise analog front-end (AFE) and ADC in handheld ECG or pulse oximeter units. IC Role / Device Role / Timing Role: Low-ripple power source with PFM mode active during sensor sleep cycles to conserve battery. Use Value: Maintains <10 mVpp output ripple under 10 mA load, ensuring <1 LSB error in 12-bit medical-grade ADC conversions. | Use Scenario: Powers Bluetooth DSP core and RF transceiver in compact wireless headsets requiring ultra-low quiescent current. IC Role / Device Role / Timing Role: Primary system regulator managing dynamic voltage scaling during voice call vs. standby states. Use Value: Reduces average system IQ by 40% via 15-µA PFM operation during Bluetooth idle periods, extending talk time by 1.8 hours per charge. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down DC-DC converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS62231DRYR | Fixed 1.8 V output, 3-MHz switching, 20-µA IQ, 300-mA max load | Higher frequency allows smaller inductors but lower max current; tighter 1.8 V tolerance (±1.5%) vs. LM3670MF-1.875/NOPB's ±5.5% | Select when board space is critical and 1.8 V (not 1.875 V) suffices for target SoC core voltage |
| AP3012KTR-G1 | Fixed 1.8 V output, 1.5-MHz switching, 40-µA IQ, 300-mA max load, no PFM mode | Lacks auto PFM/PWM transition; higher quiescent current reduces light-load battery life | Choose only for cost-sensitive designs where 1.8 V matches system requirement and efficiency at <10 mA is non-critical |
Compared with TPS62231DRYR and AP3012KTR-G1, the LM3670MF-1.875/NOPB uniquely delivers the exact 1.875 V required by TI OMAP-L1x and certain Qualcomm MSM SoCs, while its 15-µA PFM mode and 350-mA capability provide superior light-load efficiency and headroom for bursty workloads in handheld platforms.
Availability
LM3670MF-1.875/NOPB is available at Aetrix Electronics and suitable for mobile phone baseband power, PDA application processor core, portable medical instrument sensor bias, and wireless headset DSP core supply requiring stable component supply, long-term lifecycle support, and full traceability.
Supply support for LM3670MF-1.875/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 digital signal processing technologies, with leadership in power management ICs for portable and industrial applications.
The LM3670 product line is designed specifically for ultralow-voltage, battery-powered portable electronics-delivering high-efficiency step-down conversion with minimal external components and intelligent power-state management.
FAQ
What is the recommended input and output capacitor configuration for LM3670MF-1.875/NOPB?
The LM3670MF-1.875/NOPB requires a minimum 4.7 µF X5R/X7R ceramic input capacitor placed within 3 mm of VIN and GND pins, and a 10 µF ceramic output capacitor with ≤10 mΩ ESR. These values ensure stable regulation, <10 mVpp ripple at 350 mA, and reliable soft-start behavior. Larger capacitance improves transient response but does not alter basic functionality of the LM3670MF-1.875/NOPB.
Does LM3670MF-1.875/NOPB support adjustable output voltages?
No, the LM3670MF-1.875/NOPB is a fixed-output variant configured internally for 1.875 V. It does not support external resistor divider adjustment like the LM3670MFX-ADJ/NOPB. The FB pin is internally connected to the 0.5-V reference and output divider network; connecting external resistors will disrupt regulation and is not supported for the LM3670MF-1.875/NOPB.
What is the maximum achievable output current for LM3670MF-1.875/NOPB at 2.7 V input?
At VIN = 2.7 V, the LM3670MF-1.875/NOPB delivers up to 220 mA continuously while maintaining regulation and thermal safety (TJ < 125°C) with standard PCB copper area. This limitation arises from reduced voltage headroom affecting switch conduction loss and thermal dissipation-full 350 mA is guaranteed only for VIN ≥ 3.0 V per the LM3670MF-1.875/NOPB datasheet specifications.
How does the enable (EN) pin behavior affect system power sequencing with LM3670MF-1.875/NOPB?
The EN pin of the LM3670MF-1.875/NOPB provides clean, controlled startup: asserting EN ≥ 1.3 V initiates soft-start after ~1 µs delay, while pulling EN ≤ 0.4 V forces shutdown with 0.1 µA IQ. Leaving EN floating is prohibited-it may cause erratic output or increased leakage. For proper sequencing, tie EN to a system PMIC rail or microcontroller GPIO with pull-down to ensure defined state during reset, as specified for reliable LM3670MF-1.875/NOPB operation.
Can LM3670MF-1.875/NOPB operate with a 2.2 µH inductor instead of the recommended 4.7–10 µH?
Using a 2.2 µH inductor with the LM3670MF-1.875/NOPB increases peak inductor current and output ripple beyond design limits, risking saturation, thermal overload, and failure to maintain regulation at >200 mA. The 4.7–10 µH range ensures <30% ripple current, <10 mVpp output ripple, and safe operation up to 350 mA. Substituting 2.2 µH violates the LM3670MF-1.875/NOPB's validated design envelope and is not recommended.
LM3670MF-1.875/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-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.5V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 1.875V
- Voltage - Output (Max):
- -
- Current - Output:
- 350mA
- Frequency - Switching:
- 1MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-5
LM3670MF-1.875/NOPB FAQ
1.How can I place an order for LM3670MF-1.875/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3670MF-1.875/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 LM3670MF-1.875/NOPB reliable?
The price and inventory of LM3670MF-1.875/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3670MF-1.875/NOPB is usually 5 days.
3.What payment methods are accepted for LM3670MF-1.875/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3670MF-1.875/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3670MF-1.875/NOPB?
LM3670MF-1.875/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3670MF-1.875/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 LM3670MF-1.875/NOPB?
For technical support, including LM3670MF-1.875/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3670MF-1.875/NOPB requirements.
6.How does Aetrix verify that LM3670MF-1.875/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3670MF-1.875/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 LM3670MF-1.875/NOPB meets industry standards.
7.What is the process for return or replacement of LM3670MF-1.875/NOPB?
All LM3670MF-1.875/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3670MF-1.875/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 LM3670MF-1.875/NOPB part is unused and in its original packaging.
Return procedure for LM3670MF-1.875/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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