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Semtech Corporation SC1103CS.TR
- Part No.:
- SC1103CS.TR
- Manufacturer:
- Semtech Corporation
- Category:
- DC DC Switching Controllers
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
SC1103CS.TR.pdf
- Description:
- IC REG CTRLR BUCK 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,596
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Product details
Overview
SC1103CS.TR from Semtech is an asynchronous voltage-mode PWM controller IC for 12V-input buck DC/DC converters, featuring 200kHz fixed-frequency operation, 1% reference voltage accuracy, 500mA high-side gate drive, and integrated current-limit protection. It enables compact, low-cost 2.5V/10A core supplies using external N-channel MOSFETs and bootstrapped high-side drive.
For engineers reviewing the SC1103CS.TR datasheet, pinout, applications, or equivalent options, key selection considerations include its SO-8 package with dedicated PGND/GND separation, bootstrap-based high-side drive architecture, pulse-by-pulse current sensing via differential CS(±) inputs, and under-voltage lockout at 3.8V.
Technical Context
The SC1103CS.TR implements a fixed-frequency voltage-mode control loop with an internally compensated error amplifier and triangle-wave oscillator. Its current-sense architecture uses differential inputs (CS(+) and CS(−)) to monitor voltage drop across an external sense resistor or PCB trace, enabling accurate pulse-by-pulse limiting independent of input voltage or duty cycle.
It employs a bootstrap high-side driver (DH/BST pins) requiring no P-channel MOSFET, supporting efficient N-channel high-side switching in buck topologies. The device separates power ground (PGND) and signal ground (GND) to minimize noise coupling into the feedback and error amplifier paths.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Operating Frequency | Fixed 200kHz - balances efficiency, magnetic component size, and EMI performance in mid-power buck designs. |
| Reference Voltage | 1.25V ±1% - enables precise output regulation with minimal external resistor tolerance impact on VOUT accuracy. |
| Current Sense Inputs | Differential CS(+) and CS(−) - rejects common-mode noise and allows Kelvin sensing for accurate pulse-by-pulse current limiting. |
| High-Side Drive | 500mA peak sink/source - directly drives N-channel MOSFET gates without external level shifters or drivers. |
| UVLO Threshold | 3.8V (rising), 3.6V (falling) - prevents erratic startup/shutdown during brown-out conditions on 12V rail. |
| Input Voltage Range | 5V to 12V - supports wide 12V nominal input with margin for ripple and transient excursions. |
| Thermal Limit | 125°C junction max - defines safe continuous operation limit with appropriate PCB copper area and θJA = 165°C/W. |
Pinout & Package
SC1103CS.TR is housed in an SO-8 surface-mount package with exposed thermal pad (JEDEC MS-012AA), optimized for thermal dissipation in power supply applications. Pin 4 (PGND) and Pin 8 (GND) are physically separate terminals to isolate high-current power return from sensitive analog ground.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VCC (Pin 1) | IC supply input | Accepts 5–12V; requires local 0.1µF ceramic decoupling to GND; powers internal bias and logic. |
| CS(−) (Pin 2) | Negative current sense input | Differential input for Kelvin sensing of external current-sense resistor; referenced to PGND. |
| CS(+) (Pin 3) | Positive current sense input | Differential input paired with CS(−); enables noise-immune current monitoring and overcurrent shutdown. |
| PGND (Pin 4) | Power ground return | Low-impedance return path for high-current switch node (DH) and current-sense circuitry; must connect near power components. |
| DH (Pin 5) | High-side gate driver output | Drives N-channel MOSFET gate with 500mA peak current; operates only when BST voltage is valid. |
| BST (Pin 6) | Bootstrap supply connection | Connects to flying capacitor between DH and SW node; generates ~12V gate drive above SW for N-MOSFET. |
| FB (Pin 7) | Feedback input | Inverting input of error amplifier; sets output voltage via resistive divider (VREF × (1 + Ra/Rb) = VOUT). |
| GND (Pin 8) | Signal ground reference | Analog ground for FB, error amp, oscillator, and UVLO; must be isolated from PGND and tied to output capacitor ground. |
Key Features
| Feature | Design Value |
|---|---|
| Asynchronous N-MOSFET high-side drive | Eliminates need for expensive P-channel FET or external high-side driver IC in buck converters. |
| Differential current sense inputs | Enables accurate, noise-resistant current limiting without additional op-amps or filtering components. |
| Internally compensated error amplifier | Reduces external compensation parts; simplifies design of stable 200kHz voltage-mode control loop. |
| Temperature-compensated 1.25V reference | Ensures consistent output regulation across −40°C to +125°C ambient operating range. |
| Separate PGND and GND pins | Prevents switching noise from corrupting feedback and reference signals, improving load/line regulation. |
Applications
| Pentium® P55 Core Supply | Low-Cost Microprocessor Supplies |
|---|---|
Use Scenario: Delivering stable 2.5V/10A to Intel Pentium P55 processor core under dynamic load transients. IC Role / Device Role / Timing Role: Primary voltage-mode PWM controller managing synchronous buck conversion with bootstrap high-side drive. Use Value: Achieves >90% efficiency at full load while maintaining ±1% output regulation via 1.25V reference and differential current sensing. | Use Scenario: Powering embedded microcontrollers in cost-sensitive industrial controllers with 12V input rails. IC Role / Device Role / Timing Role: Fixed-frequency buck controller implementing simple, low-BOM-count DC/DC regulation. Use Value: Reduces total solution size and BOM count by integrating oscillator, error amp, and 500mA gate driver in SO-8 package. |
| Peripheral Card Supplies | Industrial Power Supplies |
Use Scenario: Generating 3.3V/5A for PCI/PCIe add-in cards where space and thermal constraints limit heatsink use. IC Role / Device Role / Timing Role: Asynchronous PWM controller driving external N-MOSFET in non-synchronous buck topology. Use Value: Enables compact layout with minimal high-current loop area due to dedicated PGND pin and bootstrap architecture. | Use Scenario: Providing regulated 1.8V–5V outputs in DIN-rail mounted programmable logic controllers (PLCs). IC Role / Device Role / Timing Role: Robust voltage-mode controller with UVLO, thermal shutdown, and current limiting for harsh environments. Use Value: Maintains reliable operation across −40°C to +85°C with 125°C junction limit and RoHS-compliant lead-free SO-8 package. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar PWM controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| UC3843BD1R2G | Current-mode control, 250kHz max, no integrated bootstrap driver; requires external high-side driver or P-FET. | Less suitable for compact N-MOSFET buck designs; better for flyback or boost where current-mode stability matters. | Select UC3843BD1R2G only if current-mode control or higher frequency (>200kHz) is required and board space permits external drive circuitry. |
| TL5001CDR | Voltage-mode like SC1103CS.TR but lacks differential CS inputs; single-ended current sense; lower drive strength (200mA). | Not recommended for high-current (>5A) or noisy environments where Kelvin sensing improves reliability. | Choose TL5001CDR for simpler, lower-power 12V-to-3.3V/3A supplies where cost is primary and layout noise is minimal. |
Compared with UC3843BD1R2G and TL5001CDR, the SC1103CS.TR delivers superior integration for N-MOSFET buck converters-its dedicated bootstrap driver, differential current sense, and SO-8 thermal pad enable smaller, more robust 10A designs without external level shifters or noise-filtering components.
Availability
SC1103CS.TR is available at Aetrix Electronics and suitable for Pentium® P55 core supplies, low-cost microprocessor power rails, and industrial DC/DC conversion requiring stable component supply, RoHS compliance, and long-term manufacturability.
Supply support for SC1103CS.TR 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
Semtech Corporation is a U.S.-based semiconductor company specializing in high-performance analog and mixed-signal ICs for power management, protection, and signal integrity.
The SC1103CS.TR belongs to Semtech's legacy power management controller family, designed specifically for cost-sensitive, medium-current DC/DC buck converters in computing and industrial applications.
FAQ
What is the maximum output current supported by the SC1103CS.TR in a typical buck application?
The SC1103CS.TR itself does not deliver output current-it controls external MOSFETs. In the documented 12V-to-2.5V application, it supports up to 10A output using IRLR3103 MOSFETs and proper thermal layout. Actual current capability depends on MOSFET selection, inductor rating, and PCB copper area for heat dissipation. The SC1103CS.TR's 500mA gate driver ensures robust switching of logic-level N-channel devices at 200kHz.
Does the SC1103CS.TR require an external bootstrap diode, and what type is recommended?
Yes-the SC1103CS.TR requires an external bootstrap diode connected between VCC and BST to charge the bootstrap capacitor during low-side conduction. A fast-switching, low-forward-voltage Schottky diode such as LL4148 or MBR0520L is recommended. The diode must handle peak currents during capacitor recharge and exhibit low leakage to maintain BST voltage during high-duty-cycle operation.
How does the SC1103CS.TR implement overcurrent protection, and is it latch-off or hiccup mode?
The SC1103CS.TR implements frequency-shift overcurrent protection: when current sense voltage exceeds threshold, the oscillator frequency drops to reduce average power and prevent thermal runaway. It is not latch-off or hiccup mode-operation resumes automatically once fault condition clears. This behavior is confirmed in the "Electrical Characteristics" table under "Frequency Shift Over-Current Protection" and application notes describing foldback response.
Can the SC1103CS.TR be used with input voltages below 5V, such as 3.3V?
No-the SC1103CS.TR has a minimum VCC operating voltage of 5V per Absolute Maximum Ratings and Electrical Characteristics tables. Operation below 5V is outside specification and may result in undefined behavior, including failure to start or unstable regulation. For sub-5V input applications, a different controller such as the SC1102 or discrete biasing solution is required.
What is the purpose of separating PGND and GND pins on the SC1103CS.TR, and how should they be routed?
PGND (Pin 4) carries high di/dt return current from the DH driver and current-sense circuitry, while GND (Pin 8) serves as the quiet reference for FB, error amplifier, and oscillator. They must be connected to separate copper regions on the PCB: PGND ties to input capacitor and MOSFET source; GND connects to the ground side of the feedback divider and output capacitors. A single-point "star" connection between these grounds should occur near the output capacitor to avoid noise injection into analog circuits.
SC1103CS.TR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Semtech Corporation
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Output Type:
- Transistor Driver
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Number of Outputs:
- 1
- Output Phases:
- 1
- Voltage - Supply (Vcc/Vdd):
- 3.8V ~ 12V
- Frequency - Switching:
- 200kHz
- Duty Cycle (Max):
- 95%
- Synchronous Rectifier:
- No
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- -
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SO
SC1103CS.TR FAQ
1.How can I place an order for SC1103CS.TR through Aetrix?
Please submit a Request for Quotation (RFQ) for SC1103CS.TR 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 SC1103CS.TR reliable?
The price and inventory of SC1103CS.TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SC1103CS.TR is usually 5 days.
3.What payment methods are accepted for SC1103CS.TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SC1103CS.TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SC1103CS.TR?
SC1103CS.TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SC1103CS.TR 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 SC1103CS.TR?
For technical support, including SC1103CS.TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SC1103CS.TR requirements.
6.How does Aetrix verify that SC1103CS.TR is sourced from the original manufacturer or authorized distributors?
All SC1103CS.TR 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 SC1103CS.TR meets industry standards.
7.What is the process for return or replacement of SC1103CS.TR?
All SC1103CS.TR units undergo pre-shipment inspection (PSI). If there is an issue with SC1103CS.TR, 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 SC1103CS.TR part is unused and in its original packaging.
Return procedure for SC1103CS.TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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