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Analog Devices Inc. LT1507CS8#PBF
- Part No.:
- LT1507CS8#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LT1507CS8#PBF.pdf
- Description:
- IC REG BUCK ADJ 1.5A 8SO
- Quantity:
- Payment:
- Shipping:
Inventory:287
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Product details
Overview
LT1507CS8#PBF from Analog Devices (formerly Linear Technology) is a 500kHz monolithic buck mode switching regulator in an 8-lead SOIC package, delivering up to 1.25A output at 3.3V from a 4V–15V input. It features cycle-by-cycle current limiting, 0.3Ω saturated NPN switch, and shutdown current of 20µA. Used in portable computers and battery-powered systems for efficient voltage conversion.
For engineers reviewing the LT1507CS8#PBF datasheet, LT1507CS8#PBF pinout, LT1507CS8#PBF application, or LT1507CS8#PBF equivalent, key selection criteria include fixed 3.3V output, 500kHz constant-frequency operation, BOOST-pin-driven saturation, thermal shutdown, and compatibility with standard surface-mount inductors and tantalum capacitors.
Technical Context
The LT1507CS8#PBF implements current-mode control with a 500kHz internal oscillator and dual feedback loops - one for output voltage regulation via the SENSE pin, another for cycle-by-cycle peak current sensing. Its bipolar NPN power switch uses BOOST-pin voltage boosting to achieve low 0.3Ω on-resistance and high efficiency across load currents up to 1.25A.
It supports external synchronization from 580kHz to 1MHz via the SYNC pin, includes undervoltage lockout (2.38V) and micropower shutdown (0.4V threshold), and provides frequency foldback and current limit foldback below 1V SENSE voltage to manage short-circuit power dissipation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switching Frequency | 500kHz ±40kHz; enables compact 2–5µH inductors and reduces EMI filtering burden. |
| Output Voltage | Fixed 3.3V ±1.5%; internally trimmed; eliminates external resistor divider for simplified layout. |
| Max Output Current | 1.25A continuous; limited by thermal design and inductor saturation; validated at VIN=5V, VOUT=3.3V. |
| Switch On Resistance | 0.3Ω typical; achieved via BOOST-pin voltage boost; reduces conduction loss vs. conventional bipolar designs. |
| Shutdown Current | 20µA max; enables long battery life in standby; specified at VSHDN=0V, VIN≤12V. |
| Input Voltage Range | 4V to 15V; minimum start-up voltage ~4.3V; supports single-cell Li-ion and multi-cell alkaline/battery inputs. |
| Thermal Shutdown | Active at TJ ≥125°C; protects die during overload or poor PCB heatsinking; auto-recovery on cooldown. |
Pinout & Package
LT1507CS8#PBF is housed in an 8-lead plastic SO (S8) package with standard SOIC-8 footprint (5.0mm × 4.0mm, 1.27mm pitch). Thermal resistance θJA = 120°C/W depending on PCB layout.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BOOST (1) | Boost capacitor drive | Provides >VIN voltage to saturate NPN switch; requires external diode + capacitor (e.g., 3.3nF); enables 0.3Ω RON. |
| VIN (2) | Main power input | Accepts 4V–15V; supplies bias and switch drive; requires local 0.1µF ceramic bypass. |
| VSW (3) | Switch node | Connects to inductor and catch diode anode; swings from GND to VIN; must be clamped to GND via Schottky diode. |
| SHDN (4) | Enable/shutdown control | Logic-level input: >2.38V = active, <0.4V = micropower shutdown; 20µA quiescent in shutdown. |
| SYNC (5) | External clock sync | Accepts 580kHz–1MHz logic-level signal; 10%–90% duty cycle; overrides internal oscillator. |
| GND (6) | Power and signal ground | Common return for VIN, BOOST, SHDN, VC; requires low-impedance connection to minimize noise coupling. |
| SENSE (7) | Output voltage sense | Direct connection to 3.3V output; monitors regulation; triggers foldback if voltage drops below 1.5V. |
| VC (8) | Error amplifier output | Drives current comparator; used for compensation (RC network to GND); clampable to disable regulator. |
Key Features
| Feature | Design Value |
|---|---|
| Constant 500kHz switching | Enables predictable EMI spectrum and consistent inductor sizing; no frequency variation with load or temperature. |
| Saturated NPN switch | 0.3Ω on-resistance reduces conduction loss; achieves >85% efficiency at 1A with 5V→3.3V conversion. |
| Integrated current-mode control | Delivers fast transient response and inherent stability without external compensation; eliminates LC resonance peaking. |
| Two-threshold shutdown | 2.38V UVLO prevents startup until input is stable; 0.4V deep shutdown reduces supply current to 20µA. |
| Short-circuit protection | Combines cycle-by-cycle current limiting with frequency foldback (5:1 reduction below 1V SENSE) to limit power dissipation. |
Applications
| Portable Computers | Battery-Powered Systems |
|---|---|
Use Scenario: Powering 3.3V logic rails (e.g., microcontroller I/O, memory interfaces) from a 5V or 7.2V Li-ion battery pack. IC Role / Device Role / Timing Role: Primary DC/DC buck converter providing regulated 3.3V output with tight load transient response. Use Value: High 500kHz switching allows small 5µH inductor and 100µF tantalum output capacitor; 20µA shutdown extends runtime in sleep modes. | Use Scenario: Supplying 3.3V to wireless sensor nodes operating on AA/AAA batteries with intermittent transmission duty cycles. IC Role / Device Role / Timing Role: Efficient step-down regulator enabling >500-hour battery life under light-load conditions. Use Value: 4V minimum input supports operation down to ~1.0V/cell; 0.3Ω switch minimizes dropout loss at end-of-life battery voltage. |
| Battery Charger Auxiliary Rail | Distributed Power Architecture |
Use Scenario: Generating isolated 3.3V auxiliary supply for charger controller ICs and status LEDs in multi-bay smart chargers. IC Role / Device Role / Timing Role: Secondary non-isolated buck regulator fed from main charger output bus (e.g., 12V). Use Value: Fixed 3.3V output eliminates trimming resistors; thermal shutdown prevents overheating during simultaneous charging events. | Use Scenario: Local point-of-load (POL) regulation on motherboard or backplane cards requiring clean 3.3V for FPGA configuration or interface logic. IC Role / Device Role / Timing Role: Compact, self-contained buck converter replacing discrete MOSFET+controller solutions. Use Value: SOIC-8 package fits dense layouts; SYNC pin allows system-wide clock alignment to reduce beat frequencies. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3605EMS8E#PBF | 4MHz synchronous buck; 3A output; integrated MOSFETs; requires external compensation. | Higher frequency enables smaller inductors but increases gate drive losses; better suited for space-constrained, high-current apps. | Select LTC3605EMS8E#PBF only when >1.25A output or <1µH inductor size is required; not drop-in due to different pinout and control architecture. |
| TPS54331DR | 3.5MHz current-mode buck; 3A output; integrated high-side FET; adjustable output; 4.5–28V input. | Wider input range and higher current rating; lacks BOOST pin; uses MOSFET instead of bipolar switch. | Choose TPS54331DR for industrial inputs >15V or when adjustable output is needed; requires redesign of feedback network and layout. |
Compared with LTC3605EMS8E#PBF and TPS54331DR, the LT1507CS8#PBF offers lower BOM cost and proven reliability in battery-input applications, with simpler external component requirements (no bootstrap capacitor, no external FET drivers), but lower maximum current and fixed 3.3V output.
Availability
LT1507CS8#PBF is available at Aetrix Electronics and suitable for portable computers, battery-powered systems, and distributed power architectures requiring stable component supply, long-lifecycle support, and consistent parametric performance across production batches.
Supply support for LT1507CS8#PBF 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
Analog Devices acquired Linear Technology in 2017 and maintains full technical and manufacturing continuity for legacy Linear products including the LT1507 family.
The LT1507 belongs to Linear's monolithic switching regulator product line, designed specifically for high-efficiency, low-noise DC/DC conversion in portable and battery-sensitive applications where compact size and micropower shutdown are critical.
FAQ
What is the maximum output current capability of the LT1507CS8#PBF?
The LT1507CS8#PBF delivers up to 1.25A continuous output current at 3.3V with VIN=5V, as verified in the Typical Application circuit (TA02) and confirmed by load current vs. input voltage graphs. Actual current depends on thermal design, inductor saturation rating, and PCB copper area; exceeding 1.25A risks thermal shutdown activation.
Does the LT1507CS8#PBF require an external feedback resistor divider?
No, the LT1507CS8#PBF is the fixed 3.3V version and contains internal feedback resistors. Pin 7 is labeled SENSE and connects directly to the output; no external divider is needed. Only adjustable versions (e.g., LT1507CS8) require external R1/R2 networks.
How does the BOOST pin function in the LT1507CS8#PBF?
The BOOST pin (Pin 1) supplies elevated voltage to the NPN switch base driver, enabling saturation and achieving 0.3Ω on-resistance. It requires an external charge pump: a Schottky diode (e.g., 1N914) and capacitor (e.g., 3.3nF) connected between VIN and BOOST. Without BOOST, efficiency drops significantly due to higher VCE(sat).
Can the LT1507CS8#PBF be synchronized to an external clock?
Yes, the LT1507CS8#PBF supports external synchronization via the SYNC pin (Pin 5) over 580kHz–1MHz. The input accepts logic-level signals with 10%–90% duty cycle. Synchronization overrides the internal 500kHz oscillator and is useful for reducing beat frequencies in multi-regulator systems.
What protection features are built into the LT1507CS8#PBF?
The LT1507CS8#PBF integrates full cycle-by-cycle current limiting, thermal shutdown (125°C junction), undervoltage lockout (2.38V on SHDN), and micropower shutdown (0.4V threshold). It also features frequency foldback and current limit foldback when SENSE voltage falls below 1V, enhancing short-circuit survivability.
LT1507CS8#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 4V
- Voltage - Input (Max):
- 16V
- Voltage - Output (Min/Fixed):
- 2.42V
- Voltage - Output (Max):
- 14.88V
- Current - Output:
- 1.5A
- Frequency - Switching:
- 500kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SO
LT1507CS8#PBF FAQ
1.How can I place an order for LT1507CS8#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1507CS8#PBF 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 LT1507CS8#PBF reliable?
The price and inventory of LT1507CS8#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1507CS8#PBF is usually 5 days.
3.What payment methods are accepted for LT1507CS8#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1507CS8#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1507CS8#PBF?
LT1507CS8#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1507CS8#PBF 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 LT1507CS8#PBF?
For technical support, including LT1507CS8#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1507CS8#PBF requirements.
6.How does Aetrix verify that LT1507CS8#PBF is sourced from the original manufacturer or authorized distributors?
All LT1507CS8#PBF 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 LT1507CS8#PBF meets industry standards.
7.What is the process for return or replacement of LT1507CS8#PBF?
All LT1507CS8#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1507CS8#PBF, 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 LT1507CS8#PBF part is unused and in its original packaging.
Return procedure for LT1507CS8#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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