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Semtech Corporation SC4612MLTRT
- Part No.:
- SC4612MLTRT
- Manufacturer:
- Semtech Corporation
- Category:
- DC DC Switching Controllers
- Package:
- 12-VFDFN Exposed Pad
- Datasheet:
-
SC4612MLTRT.pdf
- Description:
- IC REG CTLR SYNC BUCK 12MLPD
- Quantity:
- Payment:
- Shipping:
Inventory:4,158
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Product details
Overview
SC4612MLTRT from Semtech is a wide-input synchronous buck switching controller optimized for high-efficiency DC-DC conversion in distributed power systems. It supports 4.5V–28V input, delivers output as low as 0.5V with ±1% reference accuracy, features 1.7A peak gate drive, programmable 100kHz–1.2MHz switching frequency, and implements RDS(on)-based hiccup-mode overcurrent protection on the low-side MOSFET.
For engineers reviewing the SC4612MLTRT datasheet, pinout, applications, or equivalent options, key selection considerations include asynchronous startup behavior into pre-biased rails, DRV-regulated 7.8V gate bias, MLPD-12 package thermal performance, and ILIM-programmable current limit with ±20% trip tolerance under temperature and FET RDS(on) variation.
Technical Context
The SC4612MLTRT operates in voltage-mode control with an externally compensated error amplifier and a fixed-frequency oscillator driven by an external capacitor (COSC). Its asynchronous startup mode disables the low-side MOSFET until SS/EN reaches 1.3V, preventing bus discharge during turn-on into pre-biased outputs.
Overcurrent protection uses low-side RDS(on) sensing with a 100mV typical threshold, adjustable via resistive dividers on the ILIM pin. The device integrates shoot-through prevention (30ns non-overlap), internal bootstrapping for high-side drive, and UVLO with 4.5V turn-on and 400mV hysteresis.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.5V to 28V - supports wide industrial and telecom supply rails without external regulators |
| Output Voltage Range | 0.5V to VIN × Duty Cycle - enables core voltage regulation for modern ASICs and FPGAs |
| Switching Frequency | 100kHz to 1.2MHz - programmable via COSC; higher frequencies reduce inductor size but increase switching loss |
| Gate Drive Current | 1.7A peak - drives large N-channel MOSFETs with fast edge rates to minimize conduction and switching losses |
| Reference Accuracy | ±1% at 0.5V - ensures tight output regulation across -40°C to +125°C junction temperature range |
| Current Limit Method | RDS(on) sensing on low-side MOSFET with hiccup mode - reduces average power dissipation during sustained overload |
| Startup Mode | Asynchronous soft-start - keeps low-side MOSFET off until SS/EN ≥ 1.3V, enabling glitch-free start into pre-biased outputs |
Pinout & Package
SC4612MLTRT is packaged in a thermally enhanced 12-pin MLPD (4mm × 4mm, 0.5mm pitch) with exposed thermal pad. Pin 7 (GND) and the underside thermal pad must be soldered to a dedicated PCB ground plane for optimal thermal performance (θJA = 54.3°C/W).
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| 1, 12 | PHASE | Switch node connection - senses low-side RDS(on) voltage and provides timing for synchronous rectification |
| 2 | OSC | Oscillator timing input - sets switching frequency via external capacitor (100pF–1nF for 100kHz–1.2MHz) |
| 3 | SS/EN | Soft-start and enable input - 25µA current source charges external capacitor; pulled low disables IC |
| 4 | EAO | Error amplifier output - connects to compensation network; open-loop output for external loop control |
| 5 | FB | Feedback input - compares output voltage against 0.5V internal reference; requires resistor divider |
| 6 | VDD | Main bias supply - powers internal circuitry; accepts 4.5V–28V; regulates DRV when >10V |
| 7 | GND | Analog/digital ground - common return for all signals; must connect to thermal pad |
| 8 | DL | Low-side gate driver output - drives N-channel MOSFET source; 1.7A sink/source capability |
| 9 | DRV | Regulated gate drive supply - internally regulated to 7.8V (typ.) from VDD >10V; powers DL and BST |
| 10 | BST | Bootstrap supply - charges high-side floating rail; requires 0.1µF ceramic capacitor to PHASE |
| 11 | DH | High-side gate driver output - drives N-channel MOSFET gate; bootstrapped from BST |
| ILIM | Current limit programming | Adjusts OCP threshold via resistor to DRV or PHASE; internal 20µA current source sets baseline |
Key Features
| Feature | Design Value |
|---|---|
| Asynchronous startup mode | Keeps low-side MOSFET off until SS/EN ≥ 1.3V - prevents output bus discharge and avoids latch-up in pre-biased systems |
| Programmable hiccup OCP | ILIM pin adjusts trip point using external resistors - enables precise current limiting despite MOSFET RDS(on) variance and temperature drift |
| Internally regulated DRV | 7.8V (typ.) regulated output from VDD >10V - ensures consistent gate drive strength independent of input rail fluctuations |
| Shoot-through protection | 30ns minimum non-overlap between DH and DL - eliminates cross-conduction losses and improves efficiency at high frequencies |
| Wide duty cycle range | Supports near-100% duty cycle at lower frequencies - accommodates high VIN/VOUT ratios without requiring external components |
Applications
| Telecom Point-of-Load | Server VRM Core Supply |
|---|---|
Use Scenario: Regulating 0.85V/60A core voltage for high-end server CPUs from a 12V intermediate bus. IC Role / Device Role / Timing Role: Synchronous buck controller managing high-side/low-side N-MOSFETs with 600kHz switching and RDS(on) current sensing. Use Value: Asynchronous startup prevents disturbance to adjacent VRMs sharing the same 12V bus during cold boot sequences. | Use Scenario: Providing 1.0V/40A FPGA I/O supply in a base station radio unit with strict EMI limits. IC Role / Device Role / Timing Role: Voltage-mode PWM controller with 1.2MHz operation and external Type III compensation for phase margin control. Use Value: 1.7A gate drive minimizes MOSFET switching time, reducing high-frequency harmonics that could interfere with RF front-end sensitivity. |
| Mixed-Signal ASIC Bias | Distributed Telecom Power |
Use Scenario: Generating 0.5V analog bias rail for high-speed ADC/DAC cores in optical line cards. IC Role / Device Role / Timing Role: Precision buck controller with ±1% 0.5V reference and low-noise error amplifier output (EAO). Use Value: Tight reference accuracy ensures signal-to-noise ratio remains stable across temperature and load transients. | Use Scenario: Local 3.3V/20A supply in remote radio head units powered from -48V telecom battery backup. IC Role / Device Role / Timing Role: Wide-input (4.5V–28V) controller operating from isolated DC-DC converter output with UVLO hysteresis. Use Value: 400mV UVLO hysteresis prevents oscillation during brown-out conditions on aging telecom batteries. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MP2950GQ-Z | Integrated MOSFETs (40V/30A); no external phase node sensing; fixed 600kHz frequency | Suitable for space-constrained designs where board area is critical; lacks RDS(on) OCP flexibility | Choose MP2950GQ-Z only if discrete MOSFET layout is impractical and fixed frequency suffices |
| LTC3891EMSE#PBF | 40V max input; dual-output capable; includes PMBus interface; ±0.5% reference | Targeted at high-reliability industrial systems requiring telemetry and fault logging | Choose LTC3891EMSE#PBF when digital monitoring, redundancy, or tighter reference accuracy is required |
Compared with MP2950GQ-Z and LTC3891EMSE#PBF, SC4612MLTRT offers superior design flexibility for custom high-current power stages, programmable frequency scaling, and robust asynchronous startup-making it ideal for cost-sensitive telecom infrastructure where discrete FET selection and thermal management are prioritized.
Availability
SC4612MLTRT is available at Aetrix Electronics and suitable for telecom equipment, server/workstation power supplies, and mixed-signal applications requiring stable component supply and long-term manufacturability.
Supply support for SC4612MLTRT 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 sensing.
The SC4612 product line was designed for wide-input, high-efficiency synchronous buck conversion in telecom and computing infrastructure where reliability under pre-biased startup and thermal stress is critical.
FAQ
What is the maximum recommended input voltage for SC4612MLTRT?
The absolute maximum input voltage applied to the VDD pin of SC4612MLTRT is 30V, but the recommended operating range is 4.5V to 28V per the Electrical Characteristics table. Exceeding 28V risks violating the specified operating conditions and may trigger UVLO shutdown or cause long-term reliability degradation due to increased internal power dissipation.
How does SC4612MLTRT implement asynchronous startup, and why is it important?
SC4612MLTRT holds the low-side MOSFET (DL) off until the SS/EN pin voltage reaches 1.3V, allowing only high-side switching during initial ramp-up. This prevents discharge of pre-existing output voltage on shared buses - a critical feature in multi-rail telecom systems where uncontrolled bus collapse could reset adjacent ASICs or violate sequencing requirements.
Can SC4612MLTRT operate with a 3.3V input supply?
No, SC4612MLTRT cannot operate with a 3.3V input supply. Its minimum VDD operating voltage is 4.5V, and the UVLO threshold is 4.5V (typical) with 400mV hysteresis. A 3.3V supply falls below this threshold and will prevent internal bias generation, leaving DH, DL, and all control circuits disabled.
What is the function of the ILIM pin on SC4612MLTRT, and how is it configured?
The ILIM pin on SC4612MLTRT programs the overcurrent protection threshold by adjusting the effective current sense level. It sources ~20µA internally; connecting a resistor from ILIM to DRV raises the trip point, while connecting to PHASE lowers it. Typical configuration uses two resistors (Ra and Rb) to achieve ±20% adjustment range around the 100mV nominal threshold.
Is SC4612MLTRT still recommended for new designs?
No, SC4612MLTRT is marked "NOT RECOMMENDED FOR NEW DESIGN" in the official Semtech datasheet (Revision January 31, 2007). While fully functional and supported for existing production, designers should evaluate newer alternatives such as SC4622 or industry equivalents for improved efficiency, integrated features, and extended lifecycle assurance.
SC4612MLTRT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Semtech Corporation
- Series:
- -
- Package/Case:
- 12-VFDFN Exposed Pad
- 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):
- 4.5V ~ 28V
- Frequency - Switching:
- 100kHz ~ 1.2MHz
- Duty Cycle (Max):
- -
- Synchronous Rectifier:
- Yes
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Current Limit, Enable, Frequency Control, Soft Start
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 12-MLPD (4x3)
SC4612MLTRT FAQ
1.How can I place an order for SC4612MLTRT through Aetrix?
Please submit a Request for Quotation (RFQ) for SC4612MLTRT 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 SC4612MLTRT reliable?
The price and inventory of SC4612MLTRT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SC4612MLTRT is usually 5 days.
3.What payment methods are accepted for SC4612MLTRT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SC4612MLTRT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SC4612MLTRT?
SC4612MLTRT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SC4612MLTRT 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 SC4612MLTRT?
For technical support, including SC4612MLTRT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SC4612MLTRT requirements.
6.How does Aetrix verify that SC4612MLTRT is sourced from the original manufacturer or authorized distributors?
All SC4612MLTRT 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 SC4612MLTRT meets industry standards.
7.What is the process for return or replacement of SC4612MLTRT?
All SC4612MLTRT units undergo pre-shipment inspection (PSI). If there is an issue with SC4612MLTRT, 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 SC4612MLTRT part is unused and in its original packaging.
Return procedure for SC4612MLTRT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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