My Inquiry
My Account
Texas Instruments LM3670MF-3.3
- Part No.:
- LM3670MF-3.3
- Manufacturer:
- Texas Instruments
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LM3670MF-3.3.pdf
- Description:
- IC REG BUCK 3.3V 350MA SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:3,913
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LM3670MF-3.3 from Texas Instruments is a fixed-output 3.3 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, automatic PFM/PWM mode transition, and internal soft start - enabling compact power rails in mobile phones and handheld instrumentation.
For engineers reviewing the LM3670MF-3.3 datasheet, LM3670MF-3.3 pinout, LM3670MF-3.3 application, or LM3670MF-3.3 equivalent, key selection considerations include its 3.3 V fixed output tolerance (±6% over 0–350 mA), 15 µA typical quiescent current in PFM mode, 0.1 µA shutdown current, SOT-23-5 package footprint, and compatibility with only three external components: one inductor and two ceramic capacitors.
Technical Context
The LM3670MF-3.3 implements voltage-mode control with input voltage feed-forward to maintain tight line regulation across its 2.5–5.5 V input range. Its integrated PFET/NFET synchronous rectifier enables high efficiency (90–95% at 1–100 mA) without an external diode.
Operation spans three modes: fixed-frequency 1-MHz PWM (70–350 mA), hysteretic PFM (light-load, 15 µA IQ), and shutdown (<0.1 µA). The device supports 100% duty cycle for low-dropout operation and includes undervoltage lockout (2.4 V), thermal shutdown, and cycle-by-cycle current limiting (750 mA peak).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3 V ±6% over 0–350 mA load and full temperature range - ensures stable rail for I/O or peripheral logic without external feedback resistors. |
| Input Voltage Range | 2.5 V to 5.5 V - supports direct connection to single Li-Ion (2.7–4.2 V) or three-cell NiMH/NiCd (3.0–4.5 V) battery packs. |
| Max Load Current | 350 mA continuous - sufficient for powering RF front-ends, microcontroller cores, or sensor subsystems in space-constrained devices. |
| Switching Frequency | 1 MHz typical (550–1300 kHz range) - enables use of small 4.7–10 µH inductors and minimizes EMI filtering requirements. |
| Quiescent Current | 15 µA typical in PFM mode - extends battery life during standby or low-activity states in always-on portable applications. |
| Shutdown Current | 0.1 µA typical - reduces system-level leakage when host MCU disables power via EN pin. |
| Efficiency | 90% at 350 mA (VIN = 3.6 V, VOUT = 3.3 V) - minimizes thermal rise and extends runtime versus linear regulators. |
Pinout & Package
The LM3670MF-3.3 is housed in a 5-pin SOT-23 package (2.90 mm × 1.60 mm body size), optimized for high-density PCB layouts in portable electronics.
| 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 switching noise and supply ripple. |
| GND (Pin 2) | Ground reference | Primary return path for input capacitor, inductor, and output capacitor; must be connected to low-impedance ground plane. |
| EN (Pin 3) | Digital enable | Active-high logic input (VIH ≥1.3 V, VIL ≤0.4 V); pulls low to enter <0.1 µA shutdown state - used for system-level power sequencing. |
| FB (Pin 4) | Feedback node | Internally tied to 3.3 V reference; not externally configurable - eliminates need for resistor divider and simplifies layout for fixed-output variant. |
| SW (Pin 5) | Switching node | Connects to inductor; carries high dv/dt and pulsed current - requires short, wide trace and careful placement to minimize EMI and parasitic inductance. |
Key Features
| Feature | Design Value |
|---|---|
| Internal synchronous rectification | Eliminates external Schottky diode, reducing conduction loss and improving efficiency by 5–10% vs. asynchronous buck topologies at low output voltages. |
| Automatic PFM/PWM mode switching | Seamlessly transitions between high-efficiency light-load PFM (15 µA IQ) and low-noise full-power PWM (1 MHz) without external control or configuration. |
| 100% duty cycle low-dropout operation | Maintains regulated 3.3 V output down to VIN ≈ 3.3 V + ILOAD × (RDSON_P + RINDUCTOR), extending usable battery range near end-of-discharge. |
| Integrated soft-start | Controls inrush current during startup (typical 400 µs with 10 µF COUT and 350 mA load), preventing input rail collapse and system reset events. |
| Overcurrent and thermal protection | Includes cycle-by-cycle current limiting (750 mA peak) and thermal shutdown - safeguards IC and external components under fault or overload conditions. |
Applications
| Mobile Phone Power Rail | Handheld Instrumentation |
|---|---|
Use Scenario: Supplying 3.3 V to baseband processor I/O, display interface, or camera module in slim smartphone designs. IC Role / Device Role / Timing Role: Primary step-down regulator converting battery voltage to stable 3.3 V logic rail with minimal board area and thermal impact. Use Value: Enables use of only three passive components (inductor + two ceramics), reducing BOM count and PCB real estate versus multi-stage or LDO solutions. | Use Scenario: Powering microcontroller peripherals and analog front-end circuitry in battery-operated test meters or data loggers. IC Role / Device Role / Timing Role: Efficient main power converter delivering regulated 3.3 V from aging NiMH cells while maintaining >90% efficiency at partial loads. Use Value: 15 µA PFM quiescent current extends operational time between battery replacements in infrequently used field instruments. |
| PDA System Voltage | Portable Medical Sensor |
Use Scenario: Generating clean 3.3 V supply for touch controller, flash memory, and USB transceiver in legacy PDA platforms. IC Role / Device Role / Timing Role: Fixed-output buck converter operating across wide input range (2.7–4.5 V) as battery discharges, with no external feedback tuning required. Use Value: ±6% output tolerance and built-in soft-start ensure reliable boot-up and stable communication interfaces without additional supervision circuitry. | Use Scenario: Providing isolated 3.3 V rail for low-power biosensor signal conditioning and BLE radio in wearable health monitors. IC Role / Device Role / Timing Role: Low-noise, high-efficiency DC-DC stage supporting ultra-low-power sleep modes and rapid wake-up response. Use Value: 0.1 µA shutdown current and automatic PFM entry allow sub-µA system standby - critical for multi-week battery life in clinical-grade wearables. |
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 | 3.3 V fixed output, 1.8–6.5 V input, 400 mA max, 3.8 MHz switching frequency, 17 µA IQ in PFM mode | Higher switching frequency enables smaller inductors but increases EMI sensitivity; lacks 100% duty cycle mode | Preferred when board space is extremely constrained and higher-frequency filtering is acceptable. |
| AP3012KTR-G1 | 3.3 V fixed output, 2.5–5.5 V input, 300 mA max, 1.5 MHz switching frequency, 25 µA IQ in PFM mode | Lower max current and higher quiescent current; no thermal shutdown or current limit protection | Suitable for cost-sensitive, non-safety-critical applications where 350 mA headroom and robust protection are not required. |
Compared with LM3670MF-3.3, TPS62231DRYR offers higher frequency and current but sacrifices dropout capability and protection features, while AP3012KTR-G1 trades performance and safety for lower cost and simpler qualification - making LM3670MF-3.3 optimal for reliability-critical portable systems requiring full-feature integration in minimal footprint.
Availability
LM3670MF-3.3 is available at Aetrix Electronics and suitable for mobile phone power rails, handheld instrumentation, PDA system voltage, and portable medical sensor applications requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.
Supply support for LM3670MF-3.3 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 and embedded processing technologies, with leadership in power management ICs for portable, industrial, and automotive markets.
The LM3670 product line was designed specifically for ultralow-voltage, battery-powered portable electronics - delivering high efficiency, minimal external component count, and robust protection in sub-3-mm² packages.
FAQ
What is the recommended inductor value for LM3670MF-3.3 in a typical application?
A 4.7 µH or 10 µH shielded surface-mount inductor with ≥800 mA saturation current and <0.3 Ω DC resistance is recommended for LM3670MF-3.3. TI's datasheet specifies 10 µH as optimal for most use cases, balancing ripple current, transient response, and physical size - with Vishay IDC2512NB100M and Coilcraft DO1608C-103 listed as validated options.
Does LM3670MF-3.3 require external feedback resistors to set its output voltage?
No. LM3670MF-3.3 is a fixed-output variant with internal feedback network trimmed to 3.3 V; the FB pin is internally connected and not user-accessible. This eliminates resistor selection, layout complexity, and tolerance drift - unlike the adjustable LM3670 versions which require external R1/R2 dividers.
What is the minimum input voltage required for LM3670MF-3.3 to maintain regulation at full load?
At 350 mA load, LM3670MF-3.3 requires VIN ≥ 3.3 V + 350 mA × (RDSON_P + RINDUCTOR). With typical RDSON_P = 690 mΩ and a 0.2 Ω inductor, minimum VIN is ~4.55 V. However, the device supports 100% duty cycle operation, allowing regulation down to ~3.4 V under light loads - per the datasheet's dropout specification.
How does the EN pin function on LM3670MF-3.3, and what logic levels enable operation?
The EN pin on LM3670MF-3.3 is an active-high digital input. Operation begins when EN voltage exceeds 1.3 V (VIH), and shuts down when pulled below 0.4 V (VIL). In shutdown, LM3670MF-3.3 draws only 0.1 µA typical - making it ideal for MCU-controlled power gating in battery-powered systems.
Can LM3670MF-3.3 operate from a single-cell alkaline battery?
No. LM3670MF-3.3 requires a minimum input voltage of 2.5 V, and a single alkaline cell drops below this threshold early in discharge (nominal 1.5 V, fully discharged ~0.9 V). It is designed for single Li-Ion (2.7–4.2 V) or three-cell NiMH/NiCd (3.0–4.5 V) sources - not primary alkaline or zinc-carbon cells.
LM3670MF-3.3 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- SC-74A, SOT-753
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- 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):
- 3.3V
- 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-3.3 FAQ
1.How can I place an order for LM3670MF-3.3 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3670MF-3.3 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-3.3 reliable?
The price and inventory of LM3670MF-3.3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3670MF-3.3 is usually 5 days.
3.What payment methods are accepted for LM3670MF-3.3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3670MF-3.3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3670MF-3.3?
LM3670MF-3.3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3670MF-3.3 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-3.3?
For technical support, including LM3670MF-3.3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3670MF-3.3 requirements.
6.How does Aetrix verify that LM3670MF-3.3 is sourced from the original manufacturer or authorized distributors?
All LM3670MF-3.3 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-3.3 meets industry standards.
7.What is the process for return or replacement of LM3670MF-3.3?
All LM3670MF-3.3 units undergo pre-shipment inspection (PSI). If there is an issue with LM3670MF-3.3, 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-3.3 part is unused and in its original packaging.
Return procedure for LM3670MF-3.3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM3670MF-3.3 Tags
-
TPS562201DDCR
Texas Instruments
-
MC34063ABD-TR
STMicroelectronics
-
TPS561201DDCR
Texas Instruments
-
MC33063ADR
Texas Instruments
-
MC34063ADR
Texas Instruments
-
TPS560200DBVR
Texas Instruments
-
AP3012KTR-G1
Diodes Incorporated
-
TLV61048DBVR
Texas Instruments
-
AZ34063UMTR-G1
Diodes Incorporated
-
TPS562200DDCR
Texas Instruments
-
AP62300TWU-7
Diodes Incorporated
-
MC34063EBD-TR
STMicroelectronics
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
