My Inquiry
My Account
Analog Devices Inc. LT1507CS8-3.3#PBF
- Part No.:
- LT1507CS8-3.3#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LT1507CS8-3.3#PBF.pdf
- Description:
- IC REG BUCK 3.3V 1.5A 8SO
- Quantity:
- Payment:
- Shipping:
Inventory:104
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LT1507CS8-3.3#PBF from Analog Devices (formerly Linear Technology) is a fixed 3.3V, 500kHz monolithic buck switching regulator with integrated 1.5A NPN power switch, 0.3Ω on-resistance, and current-mode control architecture. It operates from 4V to 15V input, delivers up to 1.25A output, and features cycle-by-cycle current limiting, thermal shutdown, and 20µA shutdown current. Used in portable computers and battery-powered systems requiring compact, efficient DC/DC conversion.
For engineers reviewing the LT1507CS8-3.3#PBF datasheet, LT1507CS8-3.3#PBF pinout, LT1507CS8-3.3#PBF application, or LT1507CS8-3.3#PBF equivalent, key selection criteria include its fixed 3.3V output, 500kHz constant-frequency operation, BOOST-pin-assisted saturation for high efficiency, 8-pin SOIC package, and compatibility with standard surface-mount inductors and tantalum capacitors.
Technical Context
The LT1507CS8-3.3#PBF implements a current-mode, constant-frequency buck topology with an internal 500kHz oscillator and dual-loop control: an error amplifier sets the peak switch current threshold via the VC pin, while a current-sense amplifier monitors switch conduction on a cycle-by-cycle basis. This architecture enables fast transient response and stable loop compensation without external slope compensation below 700kHz.
Its bipolar NPN power switch uses BOOST-pin-driven voltage boosting (≥VIN + 5V) to achieve saturated operation-reducing voltage drop to ~0.3Ω-and enabling >85% efficiency at full load. The SENSE pin (FB/SENSE, Pin 7) connects directly to the regulated 3.3V output, eliminating external feedback resistors, and also provides foldback protection: frequency reduces 5:1 and current limit drops below 1.5V SENSE voltage during overload or short-circuit conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3V ±1.5% (3.25V–3.35V), internally trimmed - eliminates external resistor divider and associated tolerance drift. |
| Switching Frequency | 500kHz ±8% (460–540kHz), constant and temperature-stable - enables use of small 2–5µH inductors and low-ESR ceramic/tantalum output capacitors. |
| Max Output Current | 1.25A continuous at VIN = 5V, VOUT = 3.3V - limited by thermal design and inductor saturation; derates at higher VIN or ambient temperature. |
| Switch On Resistance | 0.3Ω typical (0.4Ω max) with BOOST ≥ VIN + 5V - enables high efficiency (>85%) and low conduction loss without MOSFET-level gate drive complexity. |
| Shutdown Current | 20µA typical (50µA max) at VSHDN = 0V - supports ultra-low-power sleep modes in battery-operated devices. |
| Input Voltage Range | 4V to 15V - supports single-cell Li-ion (4.2V fully charged) through multi-cell configurations; minimum start-up voltage is ~4.3V at full load. |
| Efficiency @ 1A | ~90% at VIN = 5V, VOUT = 3.3V - achieved via saturated bipolar switch and low quiescent current (4mA active, 20µA shutdown). |
Pinout & Package
LT1507CS8-3.3#PBF is housed in an 8-lead plastic SO (S8) package, RoHS-compliant and lead-free (#PBF suffix). Thermal resistance θJA = 120°C/W (typical, dependent on PCB layout), with maximum junction temperature of 125°C.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BOOST (1) | Boost capacitor drive node | Accepts external diode-capacitor charge pump to generate ~VIN+5V; required to saturate internal NPN switch and achieve 0.3Ω RON. |
| VIN (2) | Main power input | Supplies bias and switch current; operates from 4V–15V; requires local 0.1µF ceramic bypass capacitor. |
| VSW (3) | Switch collector node | Connects to inductor; swings from VIN (ON) to ~–0.7V (OFF, clamped by catch diode); must be externally clamped to GND. |
| SHDN (4) | Enable/disable control | Logic-compatible input: >2.38V = UVLO enabled, <0.4V = full shutdown (20µA IQ); open = ON. |
| SYNC (5) | External clock synchronization | Accepts 580kHz–1MHz logic-level signal (10–90% duty); overrides internal 500kHz oscillator for EMI reduction or system clock alignment. |
| GND (6) | Analog/digital ground reference | Common return for all internal circuits; requires low-impedance connection to power ground plane. |
| FB/SENSE (7) | Output voltage sense input | Internally connected to 3.3V output; used for regulation and foldback protection - voltage <1.5V reduces current limit, <1V reduces frequency 5:1. |
| VC (8) | Error amplifier output / current limit setpoint | Provides access to control loop; sets peak switch current; used for compensation (type II/III), current clamping, or external override. |
Key Features
| Feature | Design Value |
|---|---|
| Constant 500kHz switching frequency | Enables predictable EMI filtering and consistent inductor sizing; stable across temperature and line/load without external timing components. |
| Saturated bipolar NPN switch (0.3Ω) | Delivers MOSFET-like conduction efficiency using cost-effective bipolar process - no gate driver needed, minimal die area, high current density. |
| Integrated cycle-by-cycle current limiting | Protects against short-circuit and overload without external sensing; limits peak switch current to 1.5A (min) and folds back under fault conditions. |
| BOOST-pin-assisted saturation | Uses external capacitor/diode to elevate base drive above VIN, reducing VCE(sat) and improving efficiency over wide input range. |
| Two-threshold shutdown pin | Provides accurate undervoltage lockout (2.38V) and deep micropower shutdown (0.4V), supporting robust power sequencing and battery preservation. |
Applications
| Portable Computing Power | Battery-Powered Instrumentation |
|---|---|
Use Scenario: Step-down conversion from 5V USB or Li-ion battery (4.2V) to clean 3.3V for microcontrollers, FPGAs, and sensors in handheld test equipment. IC Role / Device Role / Timing Role: Primary DC/DC converter providing regulated 3.3V rail with fast load transient response and low quiescent current during sleep. Use Value: Enables >90% efficiency at 1A, 20µA shutdown current extends battery life, and 500kHz operation allows compact 5µH inductor and 100µF tantalum output capacitor. | Use Scenario: Power supply for low-power data loggers operating from primary alkaline or lithium thionyl chloride cells (3.6V–6V nominal). IC Role / Device Role / Timing Role: Fixed-output buck regulator delivering stable 3.3V to RF transceivers and precision ADCs despite falling battery voltage. Use Value: Operates down to 4V input, maintains regulation across battery discharge curve, and foldback protection prevents thermal runaway during sensor fault conditions. |
| Distributed Power Architecture | Battery Charger Auxiliary Rail |
Use Scenario: Local point-of-load (POL) conversion in industrial controllers where 12V or 5V backplane supplies power to isolated 3.3V logic domains. IC Role / Device Role / Timing Role: Compact, self-contained buck converter replacing linear regulators to reduce heat and improve system efficiency. Use Value: 8-pin SOIC footprint fits tight board spaces; BOOST-capacitor interface simplifies layout vs. synchronous buck ICs; thermal shutdown ensures reliability under sustained overload. | Use Scenario: Generating 3.3V auxiliary supply from charger IC's 5V output to power fuel gauges, status LEDs, and communication interfaces. IC Role / Device Role / Timing Role: Secondary regulator decoupling charger control circuitry from main charging path to avoid noise coupling and ensure accurate voltage monitoring. Use Value: Low EMI due to constant frequency and internal current-mode control; SENSE pin direct connection eliminates feedback resistor errors; shutdown pin enables coordinated power-down with charger state machine. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT1375CS8-3.3 | Same pinout, 500kHz, but wider 5.5V–25V input range; higher minimum input voltage; slightly lower efficiency at 5V input. | Not suitable for 4V–5V battery inputs; better for 12V/24V industrial rails. | Select LT1507CS8-3.3#PBF when input starts at 4V; choose LT1375CS8-3.3 only if higher input voltage range is required. |
| TPS5430DDAR | 3.3V adjustable (requires external resistors); 500kHz sync-capable; MOSFET-based; 3.5V–36V input; 3A rating. | Higher current capability and input range, but larger solution size and no fixed 3.3V option. | Choose TPS5430DDAR for >1.25A loads or >15V inputs; LT1507CS8-3.3#PBF offers simpler BOM and smaller footprint for ≤1.25A, 4V–15V apps. |
Compared with LT1375CS8-3.3, the LT1507CS8-3.3#PBF delivers superior efficiency and start-up capability at low input voltages (down to 4V), while the TPS5430DDAR provides higher current and input voltage headroom at the cost of added external components and board area.
Availability
LT1507CS8-3.3#PBF is available at Aetrix Electronics and suitable for portable computing, battery-powered instrumentation, and distributed power applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for LT1507CS8-3.3#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, Inc. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors.
The LT1507 product line was designed specifically for compact, high-efficiency buck conversion in space-constrained, battery-sensitive applications - emphasizing low quiescent current, fixed-output simplicity, and robust fault protection without external complexity.
FAQ
What is the maximum continuous output current of the LT1507CS8-3.3#PBF?
The LT1507CS8-3.3#PBF delivers up to 1.25A continuous output current at VIN = 5V and VOUT = 3.3V under typical PCB thermal conditions. This value decreases with higher input voltage (due to increased power dissipation) or elevated ambient temperature. The internal switch current limit is 1.5A minimum, but practical output is constrained by thermal limits and inductor saturation - verified in the "Maximum Load Current" graphs of the LT1507 datasheet.
Does the LT1507CS8-3.3#PBF require an external feedback resistor network?
No. The LT1507CS8-3.3#PBF is the fixed 3.3V version: internal resistor dividers set the output, and Pin 7 functions as SENSE - connected directly to the output. Unlike adjustable variants (e.g., LT1507CS8), no external FB resistors are needed, reducing BOM count, layout area, and potential tolerance-induced output error.
How does the BOOST pin function in the LT1507CS8-3.3#PBF, and what happens if it's left unconnected?
The BOOST pin (Pin 1) drives an external charge-pump capacitor to generate ~VIN + 5V, enabling saturation of the internal NPN switch and achieving 0.3Ω on-resistance. If left unconnected or improperly biased, the switch operates in linear mode, increasing VCE to ~1.5V and reducing efficiency to ~70%. Always connect BOOST to VIN via a Schottky diode (e.g., 1N5818) and 10nF–33nF capacitor to GND per the typical application schematic.
Can the LT1507CS8-3.3#PBF be synchronized to an external clock, and what is the valid frequency range?
Yes. The SYNC pin (Pin 5) accepts logic-level signals from 580kHz to 1MHz with 10–90% duty cycle, overriding the internal 500kHz oscillator. This feature enables EMI reduction through frequency dithering or system-level clock domain alignment. For frequencies above 700kHz and duty cycles >50%, external slope compensation may be required to maintain stability - consult the Applications Information section of the LT1507 datasheet.
What protection features are built into the LT1507CS8-3.3#PBF?
The LT1507CS8-3.3#PBF integrates cycle-by-cycle current limiting, full thermal shutdown (125°C junction), and dual-threshold shutdown pin (2.38V UVLO, 0.4V deep shutdown). Additionally, it features foldback protection: when SENSE voltage drops below 1.5V, peak switch current limit reduces; below 1V, switching frequency folds back ~5:1 - collectively minimizing power dissipation in IC, diode, and inductor during short-circuit events.
LT1507CS8-3.3#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:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 4V
- Voltage - Input (Max):
- 16V
- Voltage - Output (Min/Fixed):
- 3.3V
- Voltage - Output (Max):
- -
- 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
LT1507CS8-3.3#PBF FAQ
1.How can I place an order for LT1507CS8-3.3#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1507CS8-3.3#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 LT1507CS8-3.3#PBF reliable?
The price and inventory of LT1507CS8-3.3#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1507CS8-3.3#PBF is usually 5 days.
3.What payment methods are accepted for LT1507CS8-3.3#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1507CS8-3.3#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1507CS8-3.3#PBF?
LT1507CS8-3.3#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1507CS8-3.3#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 LT1507CS8-3.3#PBF?
For technical support, including LT1507CS8-3.3#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1507CS8-3.3#PBF requirements.
6.How does Aetrix verify that LT1507CS8-3.3#PBF is sourced from the original manufacturer or authorized distributors?
All LT1507CS8-3.3#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 LT1507CS8-3.3#PBF meets industry standards.
7.What is the process for return or replacement of LT1507CS8-3.3#PBF?
All LT1507CS8-3.3#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1507CS8-3.3#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 LT1507CS8-3.3#PBF part is unused and in its original packaging.
Return procedure for LT1507CS8-3.3#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT1507CS8-3.3#PBF 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…
