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Semtech Corporation SC1159SW
- Part No.:
- SC1159SW
- Manufacturer:
- Semtech Corporation
- Category:
- DC DC Switching Controllers
- Package:
- 28-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
SC1159SW.pdf
- Description:
- IC FET CTLR LINEAR DDR SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,534
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Product details
Overview
SC1159SW from Semtech is a programmable synchronous-buck DC/DC controller with hysteretic regulation, VRM 8.5 VID interface, and integrated 5-bit DAC for output voltage programming from 1.050 V to 1.825 V in 25 mV steps. It features adaptive deadtime control, overvoltage/overcurrent protection, power-good signaling, and dual 2 A MOSFET drivers-designed specifically for Pentium® III and AMD Athlon® core supplies in server/workstation platforms.
For engineers reviewing the SC1159SW datasheet, pinout, applications, or equivalent options, key selection considerations include its VRM 8.5 VID compatibility, ±1% output voltage accuracy over temperature, 250 ns comparator propagation delay, 95% peak efficiency at 40 A, and support for both ground-referenced and bootstrap high-side driver configurations.
Technical Context
The SC1159SW implements a fixed-frequency hysteretic control architecture where output voltage regulation is achieved via a comparator comparing VSENSE against a temperature-compensated bandgap reference (VREFB), with hysteresis set externally via the VHYST pin. Its 5-bit VID decoder interprets TTL-compatible inputs (VID0–VID3, VID25) to select one of 32 discrete output voltages aligned with VRM 8.5 specifications.
Current sensing uses high-side FET RDS(on) sampling with internal 50 Ω switch and external 0.033 μF hold capacitor; droop compensation adjusts VOUT dynamically using IOUTLO feedback to reduce load transient undershoot/overshoot. The adaptive deadtime circuit prevents shoot-through by enforcing turn-off sequencing based on VPHASE and low-side gate voltage thresholds.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage Range | 1.050 V to 1.825 V in 25 mV increments via 5-bit VID interface - enables precise microprocessor core voltage selection per VRM 8.5 spec. |
| Voltage Accuracy | ±1% over full input/output range and junction temperature (0°C to +125°C) - ensures stable CPU operation under thermal and load variation. |
| Driver Peak Current | 2 A source/sink per high- and low-side driver - supports fast switching of low-RDS(on) N-channel MOSFETs like FDB6035AL/FDB7030BL. |
| Hysteresis Range | Adjustable up to 60 mV via external resistor divider on VHYST pin - allows tuning of regulation bandwidth and noise immunity. |
| Propagation Delay | 250 ns max from comparator input to driver output - enables high-speed transient response critical for CPU load steps. |
| Efficiency | Up to 95% at 40 A output - reduces thermal stress and improves power density in multi-processor server supplies. |
| Overvoltage Threshold | 15% above VREF (e.g., 1.15 × 1.5 V = 1.725 V) - latches off drivers to protect CPU during fault conditions. |
Pinout & Package
SC1159SW is housed in a 28-pin SOIC package (SOIC-28W, body width 7.5 mm, lead pitch 1.27 mm), rated for operation from –40°C to +125°C junction temperature.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| IOUT | High-side current sense output | Provides 2× scaled voltage proportional to high-FET conduction voltage - used for OCP threshold setting and droop compensation. |
| DROOP | Droop compensation input | Accepts scaled IOUT signal to dynamically offset VREF and reduce load transient undershoot/overshoot. |
| OCP | Overcurrent protection threshold | Compares external resistor-divider voltage against 100 mV reference - triggers latch-off on high-side short or overload. |
| VHYST | Hysteresis control input | Sets comparator hysteresis width as twice the voltage difference between VREFB and this pin - tunes regulation stability. |
| VREFB | Bandgap reference buffer output | Low-impedance buffered VREF (±3 mV accuracy); drives hysteresis divider and soft-start current source (ISS = IREFB/5). |
| VSENSE | Feedback input | Monitors output voltage via external resistor divider - compared against VREF to regulate VOUT within ±1%. |
| AGND | Analog ground reference | Separate ground return for precision analog circuits (reference, comparators, VID decoder) - minimizes noise coupling from power paths. |
| SOFTST | Soft-start capacitor connection | Charged by internal current source proportional to VREF - ensures consistent ramp time across all VID settings. |
| LODRV | Low-side driver output | Direct gate drive for low-side N-MOSFET; 2 A peak rating supports fast turn-on/turn-off with minimal losses. |
| HIGHDR | High-side driver output | Gate drive for high-side N-MOSFET; configurable as ground-referenced or floating bootstrap mode via BOOT/BOOTLO pins. |
| VIN12V | +12 V supply input | Powers internal regulators (DRV, PREREG); UVLO activates below 10 V with 2 V hysteresis for noise immunity. |
| VID0–VID3, VID25 | VRM 8.5 voltage identification inputs | TTL-compatible inputs (0 = GND, 1 = open) selecting one of 32 output voltages - compatible with Pentium III/Athlon CPU VID protocols. |
| PWRGD | Open-drain power-good output | Pulled low when VSENSE falls >15% below VREF - signals system controller that output is within regulation tolerance. |
Key Features
| Feature | Design Value |
|---|---|
| Programmable hysteretic control | Enables adjustable regulation bandwidth and transient response without external compensation components. |
| Integrated 5-bit VID DAC | Eliminates need for external DAC or resistor ladder - directly interfaces with CPU VID bus for dynamic voltage scaling. |
| Adaptive deadtime circuit | Prevents shoot-through by synchronizing high/low driver turn-on with VPHASE and DL voltage thresholds - improves reliability at high switching frequencies. |
| On-chip power-good and OVP | Reduces BOM count and board space by integrating fault detection and latch-off logic - simplifies system-level power sequencing. |
| 2 A peak MOSFET drivers | Drives low-RDS(on) discrete MOSFETs without external buffers - maintains high efficiency up to 40 A output current. |
Applications
| Server Core Supply | Workstation CPU Power |
|---|---|
Use Scenario: Dual-socket x86 server motherboard delivering regulated 1.5 V @ 40 A to two Pentium® III processors. IC Role / Device Role / Timing Role: Primary synchronous-buck controller managing phase alignment, droop compensation, and VID-based voltage scaling for CPU cores. Use Value: Achieves 95% efficiency at full load and ±1% output accuracy across –40°C to +85°C ambient - reduces cooling requirements and improves system uptime. | Use Scenario: High-end engineering workstation powering AMD Athlon® processor with dynamic voltage/frequency scaling. IC Role / Device Role / Timing Role: VRM 8.5-compliant controller executing real-time VID updates during CPU P-state transitions. Use Value: 250 ns comparator delay and adaptive deadtime enable sub-100 ns load-step response - prevents CPU clock instability during burst workloads. |
| Multi-Processor Module | Voltage Regulator Module (VRM) |
Use Scenario: Compact VRM daughterboard supplying 1.1 V @ 30 A to four-core microprocessor in telecom baseband unit. IC Role / Device Role / Timing Role: Central controller coordinating parallel buck phases, current sharing, and unified OCP fault reporting. Use Value: Integrated IOUTLO current-sense path and DROOP pin allow precise per-phase current monitoring and coordinated droop - eliminates need for external current-sense amplifiers. | Use Scenario: Standardized plug-in VRM module compliant with Intel VRM 8.5 specification for OEM motherboard integration. IC Role / Device Role / Timing Role: Reference design controller implementing full VRM 8.5 feature set including VID decoding, PWRGD signaling, and thermal-aware shutdown. Use Value: Pin-compatible layout with documented SOIC-28 footprint and verified thermal derating up to +125°C TJ - accelerates qualification and reduces design risk. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous-buck controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ISL6522CRZ | Uses PWM (not hysteretic) control; requires external compensation; 3-bit VID (8 levels) vs. SC1159SW's 5-bit (32 levels). | Targeted at lower-cost single-core systems; lacks droop compensation and adaptive deadtime. | Choose ISL6522CRZ only if VRM 8.5 compliance and fine-grained voltage resolution are not required. |
| TPS51020PWR | Integrates gate drivers and MOSFETs; fixed 1.5 V output; no VID interface; uses voltage-mode PWM with external loop compensation. | Designed for space-constrained embedded applications - not suitable for programmable CPU core supplies. | TPS51020PWR is not a functional substitute; use only for non-VRM, fixed-output point-of-load designs. |
Compared with ISL6522CRZ and TPS51020PWR, the SC1159SW delivers superior voltage granularity (32 vs. 8 or 1 level), native VRM 8.5 protocol support, and hysteretic control for zero-phase-margin stability - making it uniquely suited for high-performance CPU core regulation where transient response and VID flexibility are mandatory.
Availability
SC1159SW is available at Aetrix Electronics and suitable for server systems, workstation CPU power supplies, and voltage regulator modules requiring stable component supply, long-term lifecycle support, and traceable sourcing for industrial and computing applications.
Supply support for SC1159SW 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 fabless semiconductor company specializing in high-performance analog and mixed-signal ICs for power management, RF, and sensing applications.
The SC1159SW belongs to Semtech's VRM-compliant power controller product line, engineered specifically to meet Intel and AMD microprocessor voltage regulation specifications for enterprise-class computing platforms.
FAQ
What is the maximum output current supported by the SC1159SW controller?
The SC1159SW itself does not deliver output current-it controls external high- and low-side MOSFETs. In typical evaluation board configurations (e.g., with FDB6035AL/FDB7030BL), it supports up to 40 A continuous output current while maintaining ≤95% efficiency and <±3% regulation across load steps. Actual current capability depends on MOSFET selection, PCB layout, and thermal design.
Does the SC1159SW support VRM 9.0 or later specifications?
No, the SC1159SW is explicitly designed for VRM 8.5 compliance, as confirmed by its 5-bit VID interface (VID0–VID3 + VID25), output voltage range (1.050 V–1.825 V), and timing parameters aligned with VRM 8.5 documentation. It does not support VRM 9.0's 6-bit VID, extended voltage ranges, or new sequencing requirements.
How is hysteresis configured on the SC1159SW?
Hysteresis on the SC1159SW is set by connecting a resistor divider between VREFB and AGND, with the center tap routed to the VHYST pin. The hysteresis width equals twice the voltage difference between VREFB and VHYST, and is adjustable up to 60 mV. This configuration avoids external op-amps or compensation networks required by PWM controllers.
Can the SC1159SW operate with a 5 V input instead of 12 V?
Yes-the SC1159SW VIN12V pin accepts 5 V to 14 V, but undervoltage lockout activates below 10 V. When powered from +5 V, internal regulators (DRV, PREREG) may not achieve minimum 7 V drive voltage, degrading high-side driver performance. For reliable operation, +12 V is recommended per datasheet test conditions and typical application circuits.
What is the function of the IOUTLO pin on the SC1159SW?
The IOUTLO pin on the SC1159SW provides a low-side current sense signal derived from the same sampling network used for high-side sensing. It outputs a voltage proportional to load current (scaled 1:1 relative to IOUT), enabling accurate droop compensation and current monitoring without additional sense resistors - supporting precise load-line implementation in VRM designs.
SC1159SW Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Semtech Corporation
- Series:
- -
- Package/Case:
- 28-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tube
- 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):
- 11.4V ~ 13V
- Frequency - Switching:
- -
- Duty Cycle (Max):
- -
- Synchronous Rectifier:
- Yes
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Current Limit, Power Good, Soft Start
- Operating Temperature:
- 0°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-SO
SC1159SW FAQ
1.How can I place an order for SC1159SW through Aetrix?
Please submit a Request for Quotation (RFQ) for SC1159SW 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 SC1159SW reliable?
The price and inventory of SC1159SW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SC1159SW is usually 5 days.
3.What payment methods are accepted for SC1159SW?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SC1159SW transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SC1159SW?
SC1159SW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SC1159SW 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 SC1159SW?
For technical support, including SC1159SW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SC1159SW requirements.
6.How does Aetrix verify that SC1159SW is sourced from the original manufacturer or authorized distributors?
All SC1159SW 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 SC1159SW meets industry standards.
7.What is the process for return or replacement of SC1159SW?
All SC1159SW units undergo pre-shipment inspection (PSI). If there is an issue with SC1159SW, 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 SC1159SW part is unused and in its original packaging.
Return procedure for SC1159SW:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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