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Texas Instruments LM2670S-ADJ
- Part No.:
- LM2670S-ADJ
- Manufacturer:
- Texas Instruments
- Package:
- TO-263-8, D2PAK (7 Leads + Tab), TO-263CA
- Datasheet:
-
LM2670S-ADJ.pdf
- Description:
- IC REG BUCK ADJ 3A TO263
- Quantity:
- Payment:
- Shipping:
Inventory:2,491
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Product details
Overview
LM2670S-ADJ from Texas Instruments is a monolithic step-down (buck) DC/DC switching regulator IC delivering up to 3A output current with adjustable output voltage (1.2V–37V), 8V–40V input range, 260kHz fixed internal oscillator, and ±2% output voltage tolerance over full line/load/temperature. It integrates a 150mΩ DMOS high-side switch and supports external synchronization (280–400kHz) for EMI-sensitive communications and radio equipment.
For engineers reviewing the LM2670S-ADJ datasheet, LM2670S-ADJ pinout, LM2670S-ADJ application, or LM2670S-ADJ equivalent, key selection criteria include its adjustable output architecture, thermal shutdown and current limiting protection, 50µA standby quiescent current in shutdown mode, and compatibility with standard off-the-shelf inductors and Schottky diodes for rapid design implementation.
Technical Context
The LM2670S-ADJ implements a voltage-mode PWM control architecture with an internal 260kHz ramp oscillator and error amplifier driving a high-side DMOS switch. Its feedback loop senses output voltage via an external resistor divider connected to the FB pin, referencing a precise 1.21V internal bandgap (±1.7% over temperature). The SYNC pin enables frequency locking to external clocks above 280kHz, disabling internal foldback during sync operation.
It operates in continuous conduction mode (CCM) across its rated 3A load, with built-in thermal shutdown, cycle-by-cycle current limiting (typ. 4.5A), and ON/OFF enable logic with 1.4V threshold. The CBOOST pin supplies gate drive boost for the high-side FET, requiring a 100nF ceramic capacitor tied to the SW node to sustain low RDS(ON) (0.17Ω typ.) and >90% efficiency at full load.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | 3A continuous - supports industrial and telecom loads without external current boosting. |
| Input Voltage Range | 8V to 40V - compatible with 12V/24V/36V battery and industrial bus systems. |
| Output Voltage Range | 1.2V to 37V adjustable - set via external resistor divider on FB pin; no fixed-output constraint. |
| Feedback Reference Voltage | 1.21V ±1.7% - determines output accuracy; VOUT = 1.21 × (1 + R1/R2). |
| Switch RDS(ON) | 0.17Ω typical - minimizes conduction loss and enables >88% efficiency at 3A/12VIN. |
| Standby Quiescent Current | 50µA - enables ultra-low-power shutdown for battery-backed systems. |
| Synchronization Range | 280kHz to 400kHz - allows EMI filtering consistency and spectrum positioning in RF designs. |
| Junction Temperature Range | –40°C to 125°C - supports operation in automotive under-hood and industrial ambient environments. |
Pinout & Package
LM2670S-ADJ is available in KTW (TO-263-7), NDZ (TO-220-7), and NHM (VSON-14) packages. This part uses the KTW package: 7-pin TO-263 with exposed thermal pad, 10.1mm × 15.24mm footprint, and vertical mounting capability.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (SW) | Switch Output | Drain of internal high-side DMOS FET; connects to inductor and Schottky diode cathode; switches between VIN and ~–0.5V (diode drop). |
| 2 (VIN) | Input Supply | Main power input (8–40V); must be bypassed with low-ESR capacitor placed adjacent to pin for stable high-frequency operation. |
| 3 (CBOOST) | Bootstrap Capacitor | Connects 100nF ceramic capacitor to SW pin to generate gate drive voltage >VIN for full FET enhancement. |
| 4 (GND) | Power Ground | Common return for input/output capacitors, thermal pad, and internal circuitry; requires low-inductance PCB ground plane. |
| 5 (SYNC) | Sync Clock Input | Accepts TTL/CMOS clock >280kHz; overrides internal oscillator; disables current-limit foldback when active. |
| 6 (FB) | Feedback Input | Senses output voltage via resistor divider; internal 1.21V reference sets regulation point; bias current <85nA minimizes divider error. |
| 7 (ON/OFF) | Enable Control | Logic-level enable: >1.4V = ON, <0.8V = OFF; internal 20µA pull-up; 50µA shutdown current. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 150mΩ High-Side DMOS Switch | Eliminates need for external MOSFET and driver; reduces BOM count and layout complexity for 3A buck conversion. |
| External Sync Capability (280–400kHz) | Enables deterministic ripple frequency placement for EMI compliance in comms/radio systems without changing inductor size. |
| ±2% Output Voltage Tolerance | Guaranteed over full line (8–40V), load (100mA–3A), and temperature (–40°C to 125°C) - reduces need for post-regulation trimming. |
| Thermal Shutdown & Cycle-by-Cycle Current Limit | Protects against overload and ambient overheating; current limit threshold is 4.5A typical, with hysteresis for safe recovery. |
| WEBENCH® Power Designer Integration | Generates complete schematics, BOMs, efficiency plots, and thermal simulations directly from TI's online tool - no manual calculations required. |
| 50µA Standby Quiescent Current | Extends battery life in always-on systems; achieved by disabling internal oscillator, bias circuits, and gate drivers in shutdown mode. |
Applications
| Industrial Motor Drive Power Supply | Telecom Line Card Preregulator |
|---|---|
|
Use Scenario: Provides isolated 5V/3.3V bias rails for gate drivers and microcontrollers in 24V-powered motor control modules. IC Role / Device Role / Timing Role: Primary step-down regulator converting unregulated 24V bus to stable 5V; operates in CCM with 260kHz switching for predictable EMI profile. Use Value: 3A output headroom accommodates peak gate charge currents; thermal shutdown prevents damage during stall conditions. |
Use Scenario: Generates 3.3V/5V intermediate rail from –48V telecom supply for FPGA, PHY, and management ICs on line cards. IC Role / Device Role / Timing Role: High-efficiency preregulator preceding LDOs; synchronized to system clock (300kHz) to avoid beat frequencies with data lanes. Use Value: External sync eliminates variable-frequency ripple interference with high-speed serial links (e.g., SGMII, CPRI). |
| Battery-Powered Test Equipment | RF Transceiver Power Management |
|
Use Scenario: Powers analog front-end and ADC/DAC subsystems in portable handheld testers operating from 12V Li-ion packs. IC Role / Device Role / Timing Role: Adjustable-output buck converter set to 2.5V/3.3V; enabled/disabled via microcontroller GPIO to conserve battery. Use Value: 50µA shutdown current extends runtime between charges; ±2% tolerance ensures ADC reference stability. |
Use Scenario: Supplies clean 12V and 5V rails to PA stages and mixer ICs in software-defined radio (SDR) transceivers. IC Role / Device Role / Timing Role: Dual-rail generator using two LM2670S-ADJ units; one synced to LO frequency to align ripple harmonics away from receive band. Use Value: Precise sync control enables spectral shaping of switching noise - critical for meeting FCC Part 15 radiated emissions limits. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2596S-ADJ | Lower 1.5A output current, 150kHz fixed frequency, no sync input, higher RDS(ON) (0.22Ω). | Not suitable for 3A continuous loads or EMI-critical sync applications; limited to cost-sensitive, lower-power designs. | Select LM2596S-ADJ only if load current ≤1.5A and sync capability is unnecessary. |
| TPS54302DDAR | 3A synchronous buck, 2.5–6V input, integrated high/low-side FETs, 2.2MHz switching, no external sync. | Requires lower input voltage; unsuitable for 8–40V industrial buses; higher frequency demands smaller magnetics but increases switching loss. | Choose TPS54302DDAR for compact 5V-input systems where board space is constrained and 40V input tolerance is not required. |
Compared with LM2596S-ADJ and TPS54302DDAR, the LM2670S-ADJ uniquely balances wide 8–40V input support, 3A output, external sync, and thermal robustness - making it optimal for industrial and telecom power conversion where reliability and EMI control are non-negotiable.
Availability
LM2670S-ADJ is available at Aetrix Electronics and suitable for industrial motor drives, telecom line cards, battery-powered test equipment, and RF transceiver power supplies requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.
Supply support for LM2670S-ADJ 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-reliability power conversion solutions.
The LM2670 series belongs to TI's SIMPLE SWITCHER® portfolio - designed specifically for engineers needing fast, robust, and easy-to-implement DC/DC buck regulators without complex compensation or layout sensitivity.
FAQ
What is the minimum input voltage required for stable operation of the LM2670S-ADJ?
The LM2670S-ADJ requires a minimum input voltage of 8V to ensure proper gate drive for the internal DMOS switch and stable regulation across its full output range. Below 8V, the bootstrap circuit cannot maintain sufficient gate voltage, causing dropout or erratic switching behavior. This specification is verified across –40°C to 125°C junction temperature.
How does the LM2670S-ADJ achieve ±2% output voltage accuracy?
The LM2670S-ADJ achieves ±2% output voltage accuracy through a precision 1.21V internal bandgap reference (±1.7% over temperature) and low-input-bias-current feedback amplifier (<85nA). Combined with tight tolerance on internal error amplifier gain and external resistor divider selection, this ensures VOUT = 1.21 × (1 + R1/R2) remains within ±2% across full line, load, and temperature ranges.
Can the LM2670S-ADJ operate without an external Schottky diode?
No - the LM2670S-ADJ is a nonsynchronous buck controller and requires an external Schottky diode connected from SW pin to GND (cathode to SW). Unlike synchronous converters, it lacks a low-side FET; the diode provides the return path for inductor current during switch-off time. Omitting it causes catastrophic failure due to unclamped inductive kickback.
What is the purpose of the CBOOST pin on the LM2670S-ADJ?
The CBOOST pin on the LM2670S-ADJ connects a 100nF ceramic capacitor to the SW node to form a bootstrap circuit that generates a gate drive voltage ~VIN + 10V for the internal high-side DMOS FET. This ensures full enhancement of the 150mΩ switch, minimizing conduction losses and sustaining >88% efficiency at 3A load - a function critical to its high-current performance.
Does the LM2670S-ADJ support forced continuous conduction mode (FCCM)?
No - the LM2670S-ADJ operates in natural continuous conduction mode (CCM) at full load and transitions to discontinuous conduction mode (DCM) at light loads. It does not include a dedicated FCCM pin or control feature. DCM operation reduces light-load efficiency but improves transient response and eliminates subharmonic oscillation without external slope compensation.
LM2670S-ADJ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- TO-263-8, D2PAK (7 Leads + Tab), TO-263CA
- Packaging:
- Tube
- Product Status:
- Obsolete
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 8V
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- 1.2V
- Voltage - Output (Max):
- 37V
- Current - Output:
- 3A
- Frequency - Switching:
- 260kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- TO-263 (DDPAK-7)
LM2670S-ADJ FAQ
1.How can I place an order for LM2670S-ADJ through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2670S-ADJ 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 LM2670S-ADJ reliable?
The price and inventory of LM2670S-ADJ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2670S-ADJ is usually 5 days.
3.What payment methods are accepted for LM2670S-ADJ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2670S-ADJ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2670S-ADJ?
LM2670S-ADJ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2670S-ADJ 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 LM2670S-ADJ?
For technical support, including LM2670S-ADJ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2670S-ADJ requirements.
6.How does Aetrix verify that LM2670S-ADJ is sourced from the original manufacturer or authorized distributors?
All LM2670S-ADJ 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 LM2670S-ADJ meets industry standards.
7.What is the process for return or replacement of LM2670S-ADJ?
All LM2670S-ADJ units undergo pre-shipment inspection (PSI). If there is an issue with LM2670S-ADJ, 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 LM2670S-ADJ part is unused and in its original packaging.
Return procedure for LM2670S-ADJ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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