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onsemi CS51411GDR8
- Part No.:
- CS51411GDR8
- Manufacturer:
- onsemi
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
CS51411GDR8.pdf
- Description:
- IC REG BUCK ADJ 1.5A 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,618
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Product details
Overview
CS51411GDR8 from onsemi is a 1.5 A, 260 kHz fixed-frequency buck regulator IC with V² control architecture, external BOOST capacitor support, and SYNC capability. It operates from 4.5 V to 40 V input, delivers ultrafast transient response, and integrates an on-chip NPN power switch for step-down DC-DC conversion in industrial power supplies and embedded systems.
For engineers reviewing the CS51411GDR8 datasheet, pinout, applications, or equivalent options, key selection considerations include its 260 kHz switching frequency, SYNC input compatibility, BOOST-driven NPN saturation voltage ≤0.7 V at 1.5 A, thermal shutdown at 185 °C, and functional pin-compatibility with LT1375 for drop-in replacement in legacy designs.
Technical Context
The CS51411GDR8 implements V² control architecture, where both PWM comparator inputs derive from output voltage feedback - one via fast AC-coupled path (FFB) with slope compensation, the other via slow DC error path (SFB) through the transconductance error amplifier. This decouples transient response from error amplifier bandwidth.
It features cycle-by-cycle current limiting with foldback (1.5 A typical foldback threshold), frequency foldback to 65 kHz under short circuit, and a dedicated SYNC pin accepting TTL-compatible 305–470 kHz external clocks. The BOOST pin enables bootstrapped base drive to minimize NPN saturation voltage and on-chip power dissipation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switching Frequency | 260 kHz ±13.5% - enables compact magnetics and EMI filtering; factory-trimmed, no external components required. |
| Output Current | 1.5 A continuous - delivered by integrated NPN transistor with BOOST-assisted saturation. |
| Input Voltage Range | 4.5 V to 40 V - supports wide industrial input rails including 12 V, 24 V, and 36 V systems. |
| VFB Foldback Threshold | 0.29 V to 0.36 V - triggers frequency and current limit foldback during overload/short circuit to reduce power dissipation. |
| Saturation Voltage | 0.4 V to 1.0 V at 1.5 A - minimized via BOOST pin drive; directly lowers conduction loss and junction temperature. |
| Shutdown Quiescent Current | 20 µA typical - enables low-power sleep mode when SHDNB is pulled low. |
| Thermal Shutdown Trip | 175 °C to 195 °C - protects device under sustained overload; hysteresis of 42 °C prevents oscillation. |
Pinout & Package
CS51411GDR8 is housed in an SOIC-8 (D suffix, Case 751) package with gull-wing leads, Pb-free and RoHS compliant. Thermal pad is not present; standard SOIC-8 PCB footprint applies.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BOOST | Bootstrap drive supply | Provides elevated base drive voltage to NPN switch; reduces saturation voltage and improves efficiency at high VIN. |
| VIN | Main power input | Supplies collector of internal NPN switch and bias circuitry; rated up to 40 V with −0.3 V reverse tolerance. |
| VSW | Switch emitter node | Connects to inductor; swings negative to −1.0 V (t < 50 ns); requires external catch diode and low-inductance layout. |
| SHDNB | Active-low shutdown | TTL-compatible input; pulls IC into sleep mode (<85 µA) when voltage <1.0 V; internal pull-up active when floating. |
| GND | Power return | Common reference for all internal circuits and power switch emitter; must be low-impedance connection. |
| VFB | Feedback input | Inverting input of error amplifier; regulates output via resistor divider; triggers foldback below 0.29 V. |
| VC | Error amplifier output | Provides access to transconductance amplifier output; used for compensation (e.g., 0.1 µF to GND). |
| SYNC | External clock input | Accepts 305–470 kHz TTL pulses; synchronizes switching to reduce beat frequencies and EMI in multi-rail systems. |
Key Features
| Feature | Design Value |
|---|---|
| V² control architecture | Enables >10 kHz closed-loop bandwidth and load transient recovery independent of error amplifier speed. |
| BOOST-driven NPN switch | Reduces saturation voltage to ≤0.7 V at 1.5 A, lowering conduction loss and enabling higher efficiency at high VIN. |
| SYNC input with 305–470 kHz range | Allows deterministic timing alignment across multiple converters to suppress subharmonic noise and simplify EMI filtering. |
| Frequency and current foldback | Reduces switching frequency to 65 kHz and peak current to ~1.5 A under short circuit, limiting power dissipation and thermal stress. |
| Soft-start via VC pin | Uses internal error amplifier source current to charge external compensation capacitor; eliminates need for dedicated soft-start pin or circuitry. |
Applications
| Industrial Power Supply | Automotive Body Control Module |
|---|---|
Use Scenario: 24 V battery-fed 5 V/1.5 A rail powering microcontrollers, CAN transceivers, and sensors in harsh environments. IC Role / Device Role / Timing Role: Primary buck regulator providing regulated 5 V output with robust overcurrent and thermal protection. Use Value: V² control ensures stable regulation during cold-crank (4.5 V input) and load dumps (40 V transients); SYNC allows synchronization with other rails to meet CISPR-25 Class 5 EMI limits. | Use Scenario: 12 V automotive input converted to 3.3 V for infotainment MCU and memory subsystems. IC Role / Device Role / Timing Role: Fixed-frequency buck controller delivering low-noise, high-efficiency 3.3 V supply with fast transient response to burst-mode processor loads. Use Value: BOOST pin operation minimizes dropout and conduction loss at 12 V input; thermal shutdown at 185 °C ensures reliability under hood temperature extremes. |
| Programmable Logic Controller (PLC) I/O Module | Point-of-Load Converter for FPGA Core Rail |
Use Scenario: DIN-rail mounted PLC with isolated 24 V input powering digital I/O drivers and communication interfaces. IC Role / Device Role / Timing Role: Non-isolated buck stage generating 5 V for logic and interface ICs; operates continuously across −40 °C to +70 °C ambient. Use Value: 260 kHz switching enables small 10 µH inductors and ceramic output capacitors; pin-compatibility with LT1375 simplifies migration from legacy designs. | Use Scenario: FPGA development board requiring tightly regulated 1.2 V core supply with fast dynamic response to logic switching. IC Role / Device Role / Timing Role: Secondary buck regulator stepping down from intermediate 5 V rail to FPGA core voltage using external feedback divider. Use Value: V² architecture achieves <10 µs recovery from 1 A load step; VC pin accessibility enables precise loop compensation for stability with low-ESR MLCC output filters. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT1375CS8#PBF | Pin-compatible, same SOIC-8 footprint and pinout; 1.5 A rating, 250 kHz nominal frequency; no BOOST pin - uses external bootstrap diode/capacitor. | Requires external bootstrap network; lacks integrated SYNC input; slightly lower PSRR and reference accuracy. | Preferred where legacy LT1375 design reuse is critical and external bootstrap is acceptable. |
| MP2307DN-LF-Z | Monolithic synchronous buck; 2 A rating, 340 kHz switching; no SYNC or BOOST pins; different pinout and control architecture (current mode). | Higher efficiency due to synchronous rectification; no external catch diode needed; lacks V² transient performance and foldback protection. | Chosen when higher output current, smaller solution size, and synchronous efficiency outweigh need for ultrafast transient response. |
Compared with LT1375CS8#PBF, CS51411GDR8 offers integrated BOOST drive and SYNC capability without external components; compared with MP2307DN-LF-Z, it provides superior transient response and robust foldback protection but requires an external diode and has lower max current.
Availability
CS51411GDR8 is available at Aetrix Electronics and suitable for industrial power supplies, automotive body control modules, and programmable logic controller I/O modules requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for CS51411GDR8 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
onsemi is a global semiconductor supplier delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.
The CS5141X product line was designed specifically for high-reliability, wide-input-voltage buck conversion in industrial and automotive environments, emphasizing ultrafast transient response, thermal robustness, and ease of loop compensation via V² architecture.
FAQ
What is the maximum input voltage rating for the CS51411GDR8?
The CS51411GDR8 supports an absolute maximum input voltage of 40 V on the VIN pin, with a recommended operating range of 4.5 V to 40 V. Exceeding 40 V may damage the internal NPN power switch and bias circuitry. The device includes built-in protection against overvoltage stress during transients, but sustained operation above 40 V is not permitted per the Absolute Maximum Ratings table in the datasheet.
Does the CS51411GDR8 require an external catch diode?
Yes, the CS51411GDR8 requires an external catch diode connected from VSW to GND. Because it uses an NPN transistor with emitter-connected VSW output, the device cannot provide synchronous rectification. A Schottky diode such as 1N5821 or equivalent is recommended to minimize forward voltage drop and improve efficiency, especially at light loads.
How does the BOOST pin improve efficiency in the CS51411GDR8?
The BOOST pin in the CS51411GDR8 supplies elevated base drive voltage to the internal NPN switch, reducing its saturation voltage (typically ≤0.7 V at 1.5 A). This directly lowers conduction loss - especially beneficial at high input voltages - and decreases on-chip power dissipation. A standard 0.1 µF capacitor and 1N4148 diode form the bootstrap network, referenced to the regulated output.
Is the CS51411GDR8 pin-compatible with the LT1375?
Yes, the CS51411GDR8 is functionally pin-compatible with the LT1375 in SOIC-8 packages. Pin assignments for BOOST, VIN, VSW, SHDNB, GND, VFB, VC, and SYNC match LT1375's VIN, VOUT, SW, SHDN, GND, FB, COMP, and SYNC respectively. No PCB changes are required for direct replacement, though minor compensation tuning may optimize performance due to V² vs. voltage-mode differences.
What happens to the CS51411GDR8 during a short-circuit condition?
During a short circuit, the CS51411GDR8 activates dual-foldback protection: VFB falling below 0.29 V reduces switching frequency to ~65 kHz (25% of nominal) and lowers current limit to ~1.5 A. This significantly cuts power dissipation in both the IC and external components. The device remains operational but limits energy transfer, preventing thermal runaway while maintaining safe junction temperatures.
CS51411GDR8 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 4.5V
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- 1.27V
- Voltage - Output (Max):
- 38V
- Current - Output:
- 1.5A
- Frequency - Switching:
- 260kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
CS51411GDR8 FAQ
1.How can I place an order for CS51411GDR8 through Aetrix?
Please submit a Request for Quotation (RFQ) for CS51411GDR8 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 CS51411GDR8 reliable?
The price and inventory of CS51411GDR8 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CS51411GDR8 is usually 5 days.
3.What payment methods are accepted for CS51411GDR8?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for CS51411GDR8 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for CS51411GDR8?
CS51411GDR8 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your CS51411GDR8 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 CS51411GDR8?
For technical support, including CS51411GDR8 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CS51411GDR8 requirements.
6.How does Aetrix verify that CS51411GDR8 is sourced from the original manufacturer or authorized distributors?
All CS51411GDR8 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 CS51411GDR8 meets industry standards.
7.What is the process for return or replacement of CS51411GDR8?
All CS51411GDR8 units undergo pre-shipment inspection (PSI). If there is an issue with CS51411GDR8, 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 CS51411GDR8 part is unused and in its original packaging.
Return procedure for CS51411GDR8:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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