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Texas Instruments LM3670MF-1.2/NOPB
- Part No.:
- LM3670MF-1.2/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LM3670MF-1.2/NOPB.pdf
- Description:
- IC REG BUCK 1.2V 350MA SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:14,780
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Product details
Overview
LM3670MF-1.2/NOPB from Texas Instruments is a fixed-output 1.2 V, 350-mA synchronous step-down DC-DC converter in SOT-23-5 package, operating from 2.5 V to 5.5 V input and delivering up to 95% efficiency at 100 mA load. It features automatic PWM/PFM mode switching, 15 µA quiescent current, internal soft start, and low-dropout 100% duty-cycle operation-designed for powering core logic and I/O rails in battery-powered handheld devices.
For engineers reviewing the LM3670MF-1.2/NOPB datasheet, LM3670MF-1.2/NOPB pinout, LM3670MF-1.2/NOPB application, or LM3670MF-1.2/NOPB equivalent, key selection criteria include its fixed 1.2 V output tolerance (±4.5%), 1-MHz switching frequency enabling compact 4.7 µF/10 µF/10 µH external component set, shutdown current of 0.1 µA, and thermal performance validated across –40°C to +125°C junction temperature range.
Technical Context
The LM3670MF-1.2/NOPB implements voltage-mode control with input-voltage feed-forward compensation and internal synchronous rectification using integrated PFET and NFET switches. Its dual-mode operation-PWM at ≥70 mA loads (1-MHz fixed frequency) and hysteretic PFM at light loads-enables high efficiency across full load range without external mode control.
It integrates undervoltage lockout (2.4 V threshold), cycle-by-cycle current limiting (750 mA peak switch limit), thermal shutdown, and soft-start ramp (400 µs typical with 10 µF COUT). The FB pin is internally tied to the 0.5 V reference for fixed 1.2 V output, eliminating external resistor divider requirements.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 1.2 V ±4.5% over 0–350 mA load and –40°C to +125°C, enabling direct supply to 1.2 V core logic without feedback tuning. |
| Input Voltage Range | 2.5 V to 5.5 V-supports single Li-Ion (2.7–4.2 V) or three-cell NiMH/NiCd (3.0–4.5 V) batteries with margin for dropout. |
| Max Load Current | 350 mA continuous-sufficient for microcontroller cores, RF transceivers, and sensor interfaces in portable systems. |
| Switching Frequency | 1 MHz typical-permits use of small 4.7 µF ceramic input and 10 µF ceramic output capacitors plus 4.7–10 µH inductors. |
| Quiescent Current | 15 µA typical in PFM mode-extends battery life during standby in always-on subsystems like real-time clocks or wake-on-event circuits. |
| Shutdown Current | 0.1 µA typical-minimizes leakage when system is powered off, critical for multi-week shelf-life in consumer electronics. |
| Efficiency | 94% typical at 100 mA (VIN = 3.6 V, VOUT = 1.2 V)-reduces thermal load and extends runtime versus LDO alternatives. |
| Duty Cycle | Up to 100%-maintains regulation down to VIN = VOUT + ILOAD × (RDSON_P + RINDUCTOR), supporting brownout resilience. |
Pinout & Package
LM3670MF-1.2/NOPB is housed in a 5-pin SOT-23 package (2.90 mm × 1.60 mm body size) with exposed pad not electrically connected. Thermal resistance RθJA = 163.3°C/W enables operation up to +85°C ambient without forced airflow.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pin 1) | Power input | Connects to input filter capacitor (≥4.7 µF ceramic); must withstand 6 V absolute max and supply peak switch current. |
| GND (Pin 2) | Ground reference | Primary return path for PFET/NFET switching currents; requires low-inductance PCB connection to minimize noise. |
| EN (Pin 3) | Digital enable | Active-high logic input (VIH ≥1.3 V, VIL ≤0.4 V); pulls low to achieve 0.1 µA shutdown current. |
| FB (Pin 4) | Feedback node | Internally connected to 0.5 V reference for 1.2 V output; no external resistors required-simplifies layout and reduces BOM count. |
| SW (Pin 5) | Switching node | Drives external inductor; carries high di/dt current-requires short, wide trace and ground plane clearance to reduce EMI. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated synchronous rectification | Eliminates external Schottky diode, reducing conduction loss and improving efficiency by 8–12% vs. asynchronous buck at 1.2 V output. |
| Automatic PWM/PFM transition | Seamlessly shifts between 1-MHz PWM (≥70 mA) and variable-frequency PFM (<70 mA), maintaining >85% efficiency from 1 mA to 350 mA load. |
| Internal soft start | 400 µs typical startup time with 10 µF COUT-limits inrush current to <620 mA, preventing input rail collapse during power-up. |
| Low-dropout 100% duty cycle | Enables regulation when VIN drops to ~1.25 V (at 350 mA), extending usable battery life beyond conventional buck converters. |
| Only three external components | Requires just one inductor (4.7–10 µH) and two ceramic capacitors (4.7 µF CIN, 10 µF COUT)-reducing footprint, cost, and design validation effort. |
Applications
| Mobile Phone Baseband Core Supply | Wearable Sensor Hub Power Rail |
|---|---|
Use Scenario: Powers ARM Cortex-M4 core and on-chip peripherals in LTE-enabled smartphones during active data transmission and idle monitoring. IC Role / Device Role / Timing Role: Primary 1.2 V core regulator delivering stable voltage under dynamic 10–350 mA load steps with <20 mV transient deviation. Use Value: 94% efficiency at 150 mA extends talk time by 18 minutes per charge versus LDO; 15 µA PFM current preserves battery during 72-hour standby. | Use Scenario: Supplies ultra-low-power MCU and MEMS accelerometer/gyroscope in fitness trackers worn continuously for 7+ days. IC Role / Device Role / Timing Role: Always-on 1.2 V rail with automatic PFM entry during motion-sensing sleep cycles (1–5 mA average load). Use Value: 0.1 µA shutdown current enables firmware-initiated deep-sleep modes; 100% duty cycle sustains operation until battery reaches 1.25 V. |
| Portable Medical Pulse Oximeter | Bluetooth LE Audio Earbud Codec Supply |
Use Scenario: Provides regulated 1.2 V to ADC, LED drivers, and digital signal processor in battery-operated fingertip oximeters requiring FDA-grade reliability. IC Role / Device Role / Timing Role: Safety-critical power stage with thermal shutdown and current limiting-prevents overheating during extended measurement sessions. Use Value: Integrated protection eliminates need for external fault monitoring; ±4.5% output tolerance meets ISO 80601-2-61 accuracy requirements for analog front-end biasing. | Use Scenario: Powers 1.2 V digital audio codec and Bluetooth radio in true wireless stereo earbuds with space-constrained 12 mm × 10 mm PCB. IC Role / Device Role / Timing Role: Compact, high-frequency buck converter enabling 2.0 mm² solution size with 4.7 µF/10 µF/4.7 µH passive set. Use Value: 1-MHz operation allows use of 0603-size capacitors and 2.5 mm × 2.0 mm shielded inductor-critical for miniaturized acoustic cavities. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS62231DRYR | Fixed 1.2 V output, 300 mA max, 3-MHz switching, 17 µA IQ, SOT-563 package (1.6 mm × 1.6 mm) | Higher frequency enables smaller passives but lower max current; tighter output tolerance (±1.5%) | Select when board area is constrained and load never exceeds 300 mA-ideal for sub-10 mm² wearables. |
| AP63202WS6-7 | Fixed 1.2 V output, 2 A max, 1.5-MHz switching, 25 µA IQ, SOT-23-6 package with PG pin | Higher current capability and power-good indicator; larger package and higher quiescent current | Select when future-proofing for higher-current derivatives or requiring power-status signaling in multi-rail systems. |
Compared with TPS62231DRYR and AP63202WS6-7, LM3670MF-1.2/NOPB offers optimal balance of 350 mA capability, 15 µA light-load IQ, and minimal external component count in the industry-standard SOT-23-5 footprint-making it preferred for cost-sensitive, battery-life-critical handheld designs where 300–350 mA peak load is typical.
Availability
LM3670MF-1.2/NOPB is available at Aetrix Electronics and suitable for mobile phones, wearable health monitors, and portable medical instruments requiring stable component supply with guaranteed long-term manufacturability and consistent parametric performance.
Supply support for LM3670MF-1.2/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 ICs, with decades of expertise in high-efficiency DC-DC conversion for portable electronics.
The LM3670 product line delivers miniature, low-quiescent-current step-down converters optimized for ultralow-voltage circuits powered by single-cell Li-Ion or multi-cell NiMH/NiCd batteries-targeting space- and energy-constrained handheld and wearable applications.
FAQ
What is the maximum output current capability of the LM3670MF-1.2/NOPB?
The LM3670MF-1.2/NOPB delivers up to 350 mA continuous output current under recommended operating conditions (VIN = 2.5 V to 5.5 V, TA ≤ +85°C). This rating accounts for thermal limits and internal current limiting (750 mA peak switch current), making LM3670MF-1.2/NOPB suitable for powering microcontroller cores and peripheral interfaces in handheld devices without external current boosting.
Does the LM3670MF-1.2/NOPB require external feedback resistors to set the 1.2 V output?
No. The LM3670MF-1.2/NOPB has an internally trimmed feedback network configured for fixed 1.2 V output. Pin 4 (FB) connects directly to the internal 0.5 V reference-no external resistors are needed. This simplifies layout, reduces component count, and ensures consistent output accuracy without resistor tolerance drift affecting LM3670MF-1.2/NOPB performance.
How does the LM3670MF-1.2/NOPB manage efficiency across varying load conditions?
The LM3670MF-1.2/NOPB automatically transitions between PWM mode (≥70 mA load, 1-MHz fixed frequency) and PFM mode (<70 mA load, variable frequency) to maintain high efficiency. At 100 mA, LM3670MF-1.2/NOPB achieves 94% efficiency; at 1 mA, PFM mode reduces quiescent current to 15 µA while sustaining >85% efficiency-extending battery life across active and standby states.
What thermal performance can be expected from the LM3670MF-1.2/NOPB in a standard 2-layer PCB layout?
In a standard 2-layer PCB with 1-in² copper pour connected to GND pin, LM3670MF-1.2/NOPB exhibits RθJA = 163.3°C/W. At 350 mA load and 3.6 V input, power dissipation is ~180 mW, resulting in ~30°C junction-to-ambient rise-well within the +125°C max TJ rating. No heatsink or airflow is required for operation up to +85°C ambient.
Can the LM3670MF-1.2/NOPB operate with input voltage below 2.5 V?
No. The LM3670MF-1.2/NOPB has a 2.4 V undervoltage lockout (UVLO) threshold and is specified for 2.5 V to 5.5 V input operation. Below 2.5 V, the device disables output and enters shutdown. However, LM3670MF-1.2/NOPB supports 100% duty cycle operation-when VIN drops to ~1.25 V (at 350 mA), it maintains regulation until UVLO triggers, maximizing usable battery capacity.
LM3670MF-1.2/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):
- 1.2V
- 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-1.2/NOPB FAQ
1.How can I place an order for LM3670MF-1.2/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3670MF-1.2/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-1.2/NOPB reliable?
The price and inventory of LM3670MF-1.2/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-1.2/NOPB is usually 5 days.
3.What payment methods are accepted for LM3670MF-1.2/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3670MF-1.2/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3670MF-1.2/NOPB?
LM3670MF-1.2/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3670MF-1.2/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-1.2/NOPB?
For technical support, including LM3670MF-1.2/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3670MF-1.2/NOPB requirements.
6.How does Aetrix verify that LM3670MF-1.2/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3670MF-1.2/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-1.2/NOPB meets industry standards.
7.What is the process for return or replacement of LM3670MF-1.2/NOPB?
All LM3670MF-1.2/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3670MF-1.2/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-1.2/NOPB part is unused and in its original packaging.
Return procedure for LM3670MF-1.2/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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