My Inquiry
My Account
Texas Instruments LM2671N-ADJ/NOPB
- Part No.:
- LM2671N-ADJ/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
LM2671N-ADJ/NOPB.pdf
- Description:
- IC REG BUCK ADJ 500MA 8PDIP
- Quantity:
- Payment:
- Shipping:
Inventory:4,158
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LM2671N-ADJ/NOPB from Texas Instruments is a monolithic step-down (buck) DC-DC switching regulator IC with adjustable output voltage (1.21 V to 37 V), 500-mA output current capability, 260-kHz fixed-frequency operation, ±1.5% output voltage tolerance, and integrated 0.25-Ω DMOS power switch - used in industrial power supplies, battery-powered equipment, and distributed regulation systems.
For engineers reviewing the LM2671N-ADJ/NOPB datasheet, LM2671N-ADJ/NOPB pinout, LM2671N-ADJ/NOPB application, or LM2671N-ADJ/NOPB equivalent, key selection criteria include input voltage range (6.5 V–40 V), soft-start control via external capacitor, SYNC pin for frequency synchronization, thermal shutdown protection, and feedback accuracy under line/load/temperature variation.
Technical Context
The LM2671N-ADJ/NOPB implements a voltage-mode PWM controller with internal 260-kHz oscillator, fixed-frequency operation enabling predictable EMI filtering, and cycle-by-cycle current limiting. Its DMOS power switch delivers low RDS(ON) (0.25 Ω typ.) to sustain >90% efficiency at full load across wide input ranges.
Feedback is sensed at the FB pin with 1.21 V reference (±1.5% over temperature), requiring two external resistors for output programming. The device supports TTL-compatible ON/OFF control, soft-start via SS pin capacitor, and external clock synchronization through the SYNC pin - with frequency foldback disabled during sync mode.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | 500 mA maximum continuous - ensures stable regulation without derating in compact PCB layouts with minimal copper area. |
| Input Voltage Range | 6.5 V to 40 V - supports wide-range industrial inputs including 12 V, 24 V, and 36 V nominal rails. |
| Output Voltage Range | 1.21 V to 37 V - programmable via resistor divider on FB pin; enables single BOM for multiple output voltages. |
| Switching Frequency | 260 kHz (±10%) - balances size of external inductor/capacitor against EMI and efficiency trade-offs. |
| Feedback Reference | 1.21 V ±1.5% - high-accuracy reference enables tight output regulation across line, load, and temperature. |
| Quiescent Current | 3.6 mA typical - minimizes no-load power loss in always-on systems; drops to 50 µA in shutdown. |
| RDS(ON) | 0.25 Ω typical - reduces conduction losses and thermal stress at 500 mA, eliminating need for heatsinking. |
Pinout & Package
LM2671N-ADJ/NOPB is supplied in an 8-pin PDIP (Plastic Dual In-line Package) with body size 9.81 mm × 6.35 mm. Pin 1 is CB (bootstrap capacitor connection), Pin 5 is ON/OFF (TTL-compatible enable), and Pin 6 is GND (power ground). All NC pins are internally unconnected and must remain floating.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CB (Pin 1) | Bootstrap capacitor node | Connects 100-nF ceramic capacitor to VSW to generate gate drive voltage > VIN for high-side DMOS switch. |
| SS (Pin 2) | Soft-start control | Capacitor-to-GND sets output voltage ramp time; prevents inrush current and overshoot at startup. |
| SYNC (Pin 3) | Frequency synchronization input | Accepts external TTL/CMOS clock ≥275 kHz to align switching frequency; disables frequency foldback when active. |
| FB (Pin 4) | Feedback sense input | Monitors voltage divider output; regulates VOUT by maintaining 1.21 V at this pin. |
| ON/OFF (Pin 5) | Enable/disable control | Logic-high (>1.4 V) enables regulation; logic-low (<0.8 V) forces 50-µA standby mode. |
| VSW (Pin 8) | Switch node output | Drives external inductor and Schottky diode cathode; swings between VIN and ~−0.4 V (diode drop). |
| GND (Pin 6) | Power ground | Primary return path for input/output capacitors and internal circuitry; requires low-inductance PCB connection. |
| VIN (Pin 7) | Input supply | Accepts 6.5–40 V DC; powers internal bias circuits and high-side switch; requires local 22-µF tantalum bypass. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated DMOS power switch | 0.25-Ω RDS(ON) eliminates need for external MOSFET and simplifies layout while sustaining 500-mA load. |
| Fixed 260-kHz oscillator | Enables consistent filter design and predictable EMI spectrum; avoids subharmonic oscillation in buck topology. |
| Soft-start with external capacitor | Programmable startup ramp prevents output overshoot and limits inrush into bulk capacitance. |
| TTL-compatible ON/OFF control | 50-µA standby current and 1.4-V threshold allow direct interface with microcontrollers and logic-level signals. |
| Thermal shutdown + current limit | Protects against sustained overload or short-circuit without external sensing components. |
Applications
| Industrial Power Supply | Battery-Powered Equipment |
|---|---|
Use Scenario: Converting 24 V DC bus to 5 V/3.3 V for PLC I/O modules and sensor interfaces. IC Role / Device Role / Timing Role: Primary step-down regulator delivering regulated 5 V at up to 500 mA with <1.5% output error over temperature. Use Value: Eliminates need for linear preregulator; achieves >90% efficiency to reduce heat buildup in enclosed enclosures. | Use Scenario: Regulating 12 V lead-acid or 3S Li-ion battery pack to 3.3 V for MCU and wireless transceiver. IC Role / Device Role / Timing Role: Buck converter with wide 6.5–40 V input range accommodating battery discharge profiles. Use Value: Soft-start prevents inrush into large RF module capacitance; ON/OFF pin enables MCU-controlled power gating. |
| Distributed DC Power Architecture | Test & Measurement Instrumentation |
Use Scenario: Local point-of-load conversion from 12 V backplane to 1.8 V/2.5 V for FPGA I/O banks. IC Role / Device Role / Timing Role: Adjustable-output buck regulator configured via precision resistor divider for exact rail requirements. Use Value: 1.21 V reference accuracy ensures compliance with tight FPGA VCCIO tolerances across operating conditions. | Use Scenario: Generating stable ±15 V analog supply rails from 24 V input in portable oscilloscopes. IC Role / Device Role / Timing Role: Pre-regulator feeding linear post-regulators; uses SYNC pin to lock switching frequency to system clock. Use Value: Synchronized 260-kHz operation avoids beat frequencies with sampling clocks, reducing measurement noise floor. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2671M-ADJ/NOPB | Same electrical specs but in SOIC-8 package (4.90 mm × 3.91 mm); lower RθJA (105°C/W vs. 95°C/W for PDIP). | Better thermal performance in space-constrained layouts; requires rework of footprint and solder profile. | Select for higher power density or automated assembly; avoid if legacy PDIP compatibility is required. |
| LM2596-ADJ | 3-A output rating, 150-kHz switching frequency, wider input range (4.5–40 V), but larger external component count and no SYNC pin. | Higher current capability suits motor drivers or multi-rail systems; lower frequency increases inductor size and ripple. | Choose when >500 mA load or cost-sensitive BOM dominates; accept trade-off in EMI control and board area. |
Compared with LM2671M-ADJ/NOPB, the LM2671N-ADJ/NOPB offers identical regulation performance but in a through-hole PDIP package ideal for prototyping and high-reliability industrial use; versus LM2596-ADJ, it trades current headroom for tighter feedback accuracy, smaller magnetics, and synchronization capability - making it preferable for noise-sensitive or thermally constrained designs.
Availability
LM2671N-ADJ/NOPB is available at Aetrix Electronics and suitable for industrial power supplies, battery-powered instrumentation, and distributed DC power architectures requiring stable component supply, long-term lifecycle support, and RoHS-compliant through-hole packaging.
Supply support for LM2671N-ADJ/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 and embedded processing chips for industrial, automotive, and communications markets.
The LM2671 series belongs to TI's SIMPLE SWITCHER® power converter family, engineered for ease of use in non-isolated DC-DC buck applications where minimal external components, high efficiency, and robust protection features are critical.
FAQ
What is the minimum input voltage required for stable operation of the LM2671N-ADJ/NOPB?
The LM2671N-ADJ/NOPB requires a minimum input voltage of 6.5 V to ensure proper internal biasing and regulation across all load and temperature conditions. Below this threshold, the device may fail to start or exhibit unstable output voltage due to insufficient gate drive margin for the internal DMOS switch. This value is specified in the Recommended Operating Conditions table of the official datasheet (SNVS008L, Section 7.3).
Can the LM2671N-ADJ/NOPB be synchronized to an external clock, and what are the constraints?
Yes, the LM2671N-ADJ/NOPB supports external clock synchronization via its SYNC pin (Pin 3). The external clock must exceed 275 kHz to prevent erroneous reset of the internal oscillator, and must be TTL- or CMOS-compatible (0 V to >3 V). A 100-pF capacitor and 1-kΩ resistor to ground are recommended for AC coupling. Note that frequency foldback protection is disabled during sync mode.
How does the soft-start function work on the LM2671N-ADJ/NOPB, and what capacitor value is recommended?
The LM2671N-ADJ/NOPB implements soft-start by charging an external capacitor connected from SS (Pin 2) to GND. The ramp time is proportional to capacitance; a 10-nF capacitor yields ~10-ms startup. Larger values increase ramp duration to limit inrush current into downstream capacitance. Leaving SS open disables soft-start, causing immediate full output voltage rise.
What is the purpose of the CB pin on the LM2671N-ADJ/NOPB, and how should it be connected?
The CB (bootstrap capacitor) pin on the LM2671N-ADJ/NOPB provides gate drive voltage for the internal high-side DMOS switch. It must be connected via a 100-nF ceramic capacitor directly to the VSW pin. This bootstrap arrangement elevates the gate voltage above VIN to fully enhance the switch, minimizing RDS(ON) and maximizing efficiency at 500 mA.
Does the LM2671N-ADJ/NOPB include thermal protection, and how does it behave under fault conditions?
Yes, the LM2671N-ADJ/NOPB integrates thermal shutdown protection that disables switching when junction temperature exceeds ~150°C. Recovery occurs automatically once temperature falls below the hysteresis threshold (~140°C). Combined with cycle-by-cycle current limiting, this dual protection prevents permanent damage during sustained overload, short-circuit, or inadequate heatsinking scenarios.
LM2671N-ADJ/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- 8-DIP (0.300", 7.62mm)
- Packaging:
- Bulk
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 6.5V
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- 1.21V
- Voltage - Output (Max):
- 37V
- Current - Output:
- 500mA
- Frequency - Switching:
- 260kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 8-PDIP
LM2671N-ADJ/NOPB FAQ
1.How can I place an order for LM2671N-ADJ/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2671N-ADJ/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 LM2671N-ADJ/NOPB reliable?
The price and inventory of LM2671N-ADJ/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2671N-ADJ/NOPB is usually 5 days.
3.What payment methods are accepted for LM2671N-ADJ/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2671N-ADJ/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2671N-ADJ/NOPB?
LM2671N-ADJ/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2671N-ADJ/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 LM2671N-ADJ/NOPB?
For technical support, including LM2671N-ADJ/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2671N-ADJ/NOPB requirements.
6.How does Aetrix verify that LM2671N-ADJ/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2671N-ADJ/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 LM2671N-ADJ/NOPB meets industry standards.
7.What is the process for return or replacement of LM2671N-ADJ/NOPB?
All LM2671N-ADJ/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2671N-ADJ/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 LM2671N-ADJ/NOPB part is unused and in its original packaging.
Return procedure for LM2671N-ADJ/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM2671N-ADJ/NOPB 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…
