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Texas Instruments LM3670MF-1.5/NOPB
- Part No.:
- LM3670MF-1.5/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LM3670MF-1.5/NOPB.pdf
- Description:
- IC REG BUCK 1.5V 350MA SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:2,614
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Product details
Overview
LM3670MF-1.5/NOPB from Texas Instruments is a fixed-output 1.5 V synchronous step-down DC-DC converter optimized for ultralow-voltage portable systems powered by single Li-Ion or three-cell NiMH/NiCd batteries. It delivers up to 350 mA load current, operates from 2.5 V to 5.5 V input, features 1-MHz PWM switching, 15-µA quiescent current in PFM mode, and internal soft start - enabling compact power rails in space-constrained handheld devices.
For engineers reviewing the LM3670MF-1.5/NOPB datasheet, LM3670MF-1.5/NOPB pinout, LM3670MF-1.5/NOPB application, or LM3670MF-1.5/NOPB equivalent, key selection criteria include its fixed 1.5 V output tolerance (±5% over full load), 100% duty-cycle low-dropout capability, integrated PFET/NFET synchronous rectification, shutdown current of 0.1 µA, and SOT-23-5 package compatibility with minimal external components (one inductor, two ceramic capacitors).
Technical Context
The LM3670MF-1.5/NOPB uses voltage-mode control with input voltage feed-forward to maintain tight line regulation. Its dual-mode operation-PWM at ≥70 mA and hysteretic PFM below-enables high efficiency across wide load ranges: 94% typical at 10–100 mA and ≥90% at 350 mA (VIN = 3.6 V, VOUT = 1.8 V; extrapolated to 1.5 V per design equivalence).
Internal functional blocks include a 0.5 V reference, error amplifier, 1-MHz oscillator, soft-start ramp generator, undervoltage lockout (2.4 V), cycle-by-cycle current limit (620 mA typ), and thermal shutdown. The FB pin is internally connected to a precision resistor divider for fixed 1.5 V output, eliminating external feedback components.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 1.5 V ±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 direct operation from single Li-Ion (2.7–4.2 V) or three NiMH/NiCd (3.0–4.5 V) cells. |
| Max Load Current | 350 mA - sustained output current with thermal derating above 85°C ambient. |
| Quiescent Current | 15 µA typical in PFM mode - extends battery life during standby or light-load operation. |
| Shutdown Current | 0.1 µA typical - enables ultra-low-power system sleep states when EN is pulled low. |
| Switching Frequency | 1 MHz typical (550–1300 kHz range) - allows use of small 4.7–10 µH inductors and 4.7–10 µF ceramic capacitors. |
| Efficiency | ≥90% at 350 mA (VIN = 3.6 V); ≥94% at 10–100 mA - enabled by internal synchronous rectification (PFET + NFET). |
| Duty Cycle Range | 0–100% - supports low-dropout operation down to VIN ≈ VOUT + ILOAD × (RDSON_P + RINDUCTOR). |
Pinout & Package
SOT-23-5 (DBV) package: 2.90 mm × 1.60 mm body, 0.95 mm height, gull-wing leads, RoHS-compliant, moisture sensitivity level 1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pin 1) | Power input | Connects to input filter capacitor (4.7 µF ceramic); accepts 2.5–5.5 V; supplies internal bias and switch driver. |
| GND (Pin 2) | Ground reference | Primary return path for input capacitor, inductor, and internal circuitry; must be low-impedance PCB plane. |
| EN (Pin 3) | Digital enable | Active-high logic input; >1.3 V enables regulation, <0.4 V forces shutdown (0.1 µA IQ); no pull-up required. |
| FB (Pin 4) | Feedback node | Internally tied to fixed 1.5 V divider; not externally accessible - eliminates external resistors and layout sensitivity. |
| SW (Pin 5) | Switching node | Connects to inductor; carries high di/dt current; requires short, low-inductance trace to minimize EMI and voltage spikes. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated synchronous rectification | Eliminates external Schottky diode, reduces conduction loss, and enables >90% efficiency at 350 mA. |
| Automatic PWM/PFM mode transition | Seamlessly switches between 1-MHz PWM (≥70 mA) and variable-frequency PFM (<70 mA) without external control. |
| 100% duty-cycle low-dropout operation | Maintains regulation even as input drops to ~1.6 V (at 100 mA), critical for battery end-of-life support. |
| Internal soft start | 400 µs typical startup time with 10 µF output capacitor - prevents inrush current and output overshoot. |
| Overcurrent and thermal protection | Cycle-by-cycle current limit (750 mA max peak) and thermal shutdown prevent damage under fault conditions. |
| Minimal external components | Only one inductor (4.7–10 µH) and two ceramic capacitors (CIN = 4.7 µF, COUT = 10 µF) required for full functionality. |
Applications
| Mobile Phone Core Rail | PDA Memory Supply |
|---|---|
Use Scenario: Powering ARM-based application processors and LPDDR memory in slim smartphones with single-cell Li-Ion battery. IC Role / Device Role / Timing Role: Primary 1.5 V core supply regulator delivering stable voltage during burst-mode CPU activity and deep-sleep states. Use Value: 15 µA quiescent current in PFM mode extends standby time; 100% duty cycle sustains regulation down to 2.6 V input, maximizing usable battery capacity. | Use Scenario: Providing clean 1.5 V rail to SRAM and flash memory in legacy PDAs operating from three NiMH cells. IC Role / Device Role / Timing Role: Fixed-output buck converter replacing linear regulators to reduce heat and extend runtime in thermally constrained plastic enclosures. Use Value: 94% efficiency at 50 mA load cuts power dissipation by >60% vs. LDO; SOT-23-5 footprint saves board area versus larger alternatives. |
| Handheld Medical Instrument | Portable Test Equipment |
Use Scenario: Supplying analog front-end and microcontroller in battery-powered glucose meters and pulse oximeters. IC Role / Device Role / Timing Role: Low-noise, low-quiescent-current DC-DC source ensuring accurate sensor readings and long shelf life. Use Value: 0.1 µA shutdown current preserves battery charge during multi-month storage; PFM mode minimizes switching noise near sensitive analog circuits. | Use Scenario: Generating 1.5 V for FPGA configuration and interface logic in handheld oscilloscopes and multimeters. IC Role / Device Role / Timing Role: Compact, high-efficiency point-of-load regulator supporting dynamic load steps from idle to active measurement modes. Use Value: Fast transient response (load step recovery in <100 µs) maintains voltage stability during FPGA reconfiguration; 1-MHz switching avoids audible noise. |
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 | 1.5 V fixed output, 300 mA max, 2.05–6.0 V input, 24 µA IQ, 3.5 MHz switching frequency, WSON-6 package. | Higher switching frequency enables smaller inductors but increases EMI sensitivity; lower max current limits use in high-load scenarios. | Select when board space is extremely constrained and higher-frequency filtering is acceptable. |
| AP3012KTR-G1 | 1.5 V fixed output, 300 mA max, 2.5–5.5 V input, 40 µA IQ, 1.5 MHz switching, SOT-23-5 package, no PFM mode. | Lacks automatic PFM/PWM transition - less efficient at light loads; no 100% duty cycle support limits low-VIN headroom. | Select for cost-sensitive designs where light-load efficiency and battery end-of-life performance are secondary. |
Compared with TPS62231DRYR and AP3012KTR-G1, the LM3670MF-1.5/NOPB offers superior light-load efficiency (15 µA vs. 24–40 µA), true 100% duty-cycle dropout, and identical SOT-23-5 footprint - making it optimal for battery-critical portable systems requiring extended runtime and robust low-input operation.
Availability
LM3670MF-1.5/NOPB is available at Aetrix Electronics and suitable for mobile phones, handheld medical instruments, PDAs, portable test equipment, and battery-powered industrial sensors requiring stable component supply and long-term production continuity.
Supply support for LM3670MF-1.5/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, designing and manufacturing analog ICs, embedded processors, and digital signal processors for industrial, automotive, and consumer markets.
The LM3670MF-1.5/NOPB belongs to TI's miniature DC-DC converter product line, engineered specifically for ultralow-voltage portable electronics that demand high efficiency, minimal external components, and reliable operation from shrinking battery sources.
FAQ
What is the output voltage accuracy of the LM3670MF-1.5/NOPB across load and temperature?
The LM3670MF-1.5/NOPB delivers a fixed 1.5 V output with ±5% tolerance over the full 0–350 mA load range and −40°C to +125°C junction temperature. This specification includes line regulation (0.26%/V), load regulation (0.0014%/mA), and internal reference drift. Measured output remains within 1.425 V to 1.575 V under all recommended operating conditions, as verified in TI's SNVS250F datasheet Section 6.5.
Can the LM3670MF-1.5/NOPB operate with an input voltage lower than 2.5 V?
No - the LM3670MF-1.5/NOPB has a minimum recommended input voltage of 2.5 V per Section 6.3 of the datasheet. Below this, undervoltage lockout (UVLO) activates at 2.4 V (typical), disabling regulation. While 100% duty-cycle operation supports dropout down to ~1.6 V at light loads, the device will not start or sustain regulation below 2.5 V input under normal conditions.
Does the LM3670MF-1.5/NOPB require external feedback resistors?
No - the LM3670MF-1.5/NOPB is a fixed-output variant with internal resistor divider connected to the FB pin. Unlike the adjustable LM3670MX-ADJ version, it requires no external resistors. Pin 4 (FB) is not user-accessible for programming; it is internally biased to set 1.5 V output precisely.
How does the LM3670MF-1.5/NOPB handle thermal overload?
The LM3670MF-1.5/NOPB integrates thermal shutdown circuitry that disables switching and places the device in a safe high-impedance state when junction temperature exceeds 125°C (typical). Once temperature falls below the hysteresis threshold (~110°C), regulation automatically resumes. This protection is independent of current limiting and ensures reliability in sealed or poorly ventilated enclosures.
What inductor value is recommended for the LM3670MF-1.5/NOPB?
Texas Instruments recommends a 4.7 µH or 10 µH shielded surface-mount inductor with ≥800 mA saturation current rating and <0.3 Ω DC resistance. Examples include Coilcraft DO1608C-103 (10 µH) and Vishay IDC2512NB100M (10 µH), both listed in the SNVS250F datasheet Table 3. Inductor selection balances ripple current, size, and EMI - 4.7 µH suits higher-frequency filtering, while 10 µH improves light-load PFM stability.
LM3670MF-1.5/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):
- 1.5V
- 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-1.5/NOPB FAQ
1.How can I place an order for LM3670MF-1.5/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3670MF-1.5/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-1.5/NOPB reliable?
The price and inventory of LM3670MF-1.5/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-1.5/NOPB is usually 5 days.
3.What payment methods are accepted for LM3670MF-1.5/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3670MF-1.5/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3670MF-1.5/NOPB?
LM3670MF-1.5/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3670MF-1.5/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-1.5/NOPB?
For technical support, including LM3670MF-1.5/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3670MF-1.5/NOPB requirements.
6.How does Aetrix verify that LM3670MF-1.5/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3670MF-1.5/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-1.5/NOPB meets industry standards.
7.What is the process for return or replacement of LM3670MF-1.5/NOPB?
All LM3670MF-1.5/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3670MF-1.5/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-1.5/NOPB part is unused and in its original packaging.
Return procedure for LM3670MF-1.5/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM3670MF-1.5/NOPB Tags
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