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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > DC DC Switching Controllers

Semtech Corporation SC1159SWTRT

Name: SC1159SWTRT
Brand: Semtech Corporation
SKU: SC1159SWTRT
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SC1159SWTRT

Manufacturer:: Semtech Corporation

Category:: DC DC Switching Controllers

Package:: 28-SOIC (0.295", 7.50mm Width)

Datasheet:: SC1159SWTRT.pdf

Description:: IC REG CTRLR BUCK 28SOIC

Quantity:: RFQ Add To RFQ list

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Product details

Overview

SC1159SWTRT 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 supports high-efficiency core supplies for Pentium® III and AMD Athlon® microprocessors.

For engineers reviewing the SC1159SWTRT datasheet, pinout, applications, or equivalent options, key selection criteria include its 2 A peak gate drive capability, ±1% output voltage accuracy over temperature, 250 ns comparator propagation delay, and support for both bootstrap and ground-referenced high-side driver configurations.

Technical Context

The SC1159SWTRT implements a voltage-mode hysteretic control architecture with user-configurable hysteresis via external resistor divider on VHYST. Its 5-bit VID decoder accepts TTL-compatible inputs (VID0–VID3, VID25) to set reference voltage with 25 mV resolution, meeting VRM 8.5 specifications for CPU core supply sequencing.

It integrates dual 2 A MOSFET drivers (HIGHDR/LOWDR), adaptive deadtime logic preventing shoot-through, current sensing via IOUT/IOUTLO pins, droop compensation using external resistors, and independent UVLO (10 V start, 2 V hysteresis) and OVP (±15% of VREF) protection circuits.

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 CPU 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 microprocessor operation under load and thermal variation.
Gate Drive Current	2 A peak source/sink per driver (HIGHDR/LOWDR) - supports fast switching of low-R_DS(on) N-channel MOSFETs in high-current applications.
Hysteresis Control	User-selectable up to 60 mV via external resistor divider on VHYST pin - allows optimization of transient response vs. switching frequency stability.
Propagation Delay	250 ns max from VSENSE comparator input to driver output - enables tight regulation loop timing for sub-100 ns load step response.
OVP/UVLO Thresholds	OVP at ±15% of VREF; UVLO starts at 10 V with 2 V hysteresis on VIN12V - provides robust fault protection during brown-in/brown-out conditions.
Power Good Output	Open-drain PWRGD asserts low when VSENSE falls >15% below VREF - delivers reliable system-level power sequencing signal to host logic.

Pinout & Package

SC1159SWTRT is housed in a 28-pin SOIC package (SOIC-28W, body width 7.5 mm, JEDEC MS-013AC). Pin pitch is 1.27 mm. Thermal pad not present; standard SOIC thermal resistance applies.

Pin/Terminal	Circuit Role	Design Meaning
IOUT	High-side current sense input	Samples voltage across high-side FET during conduction; output equals 2× sensed voltage for accurate current monitoring.
DROOP	Droop compensation input	Accepts scaled IOUT-derived voltage to reduce load transient undershoot/overshoot via dynamic VOUT offset.
OCP	Overcurrent protection threshold	Compares external resistor-divider voltage against 100 mV internal reference to latch off drivers on fault.
VHYST	Hysteresis setting node	Defines comparator hysteresis as twice voltage difference between VREFB and this pin; max 60 mV.
VREFB	Biased reference buffer output	Provides buffered VREF (±3 mV) for hysteresis and soft-start; sourcing current sets soft-start ramp rate (ISS = IREFB/5).
VSENSE	Feedback input	Monitors regulated output voltage; compared against VREF for error detection in UVLO/OVP/PWRGD functions.
AGND	Analog ground reference	Separate ground for precision analog blocks (reference, comparators, soft-start); must be star-connected to minimize noise coupling.
SOFTST	Soft-start capacitor connection	Charged by internal current source proportional to VREFB; determines controlled VOUT ramp-up time independent of VID setting.
LODRV	Low-side driver output	Direct gate drive output for low-side N-MOSFET; rated for 2 A sink/source; referenced to DRVGND.
LOHIB	Low-side driver enable	Internal logic disables LODRV when high; used for adaptive deadtime control to prevent shoot-through.
DRVGND	Driver ground return	Common return path for LOWDR/LODRV/LOHIB; must be low-inductance connection to power ground plane.
LOWDR	Low-side driver bias supply	Internal regulator output (7 V min) powering low-side driver circuitry; decoupling required at pin.
DRV	High-side driver bias supply	Internal regulator output (7 V min) for floating high-side driver; connects to BOOT via internal Schottky diode.
VIN12V	Main supply input	12 V input powering internal regulators, drivers, and logic; includes 10 V UVLO with 2 V hysteresis.
BOOT	Bootstrap capacitor node	Connects to external bootstrap capacitor; voltage relative to PHASE node powers high-side driver when configured as floating.
HIGHDR	High-side driver output	Direct gate drive output for high-side N-MOSFET; rated for 2 A sink/source; referenced to BOOT or GND depending on configuration.
BOOTLO	Bootstrap mode select	Grounding this pin configures HIGHDR as ground-referenced; leaving open enables floating bootstrap operation.
HISENSE	High-side current sense return	Return path for IOUT current sense amplifier; connects to source of high-side FET in typical layout.
LOSENSE	Low-side current sense return	Return path for low-side current sensing; connects to source of low-side FET in dual-sense configurations.
IOUTLO	Low-side current sense input	Optional input for low-side current sensing; used with LOSENSE for complementary current measurement.
INHIBIT	Enable/disable control	TTL-compatible digital input; low state disables drivers, discharges SOFTST cap, and places IC in low-I_Q mode.
VID25, VID3–VID0	5-bit voltage identification inputs	TTL inputs (0 = GND, 1 = open) selecting VREF from 1.050 V to 1.825 V in 25 mV steps per VRM 8.5 table.
PWRGD	Power-good open-drain output	Asserts low when VSENSE < 0.85×VREF; requires external pull-up for system reset or sequencing logic.

Key Features

Feature	Design Value
Programmable hysteretic control	External resistor divider on VHYST sets hysteresis from 0 to 60 mV - balances switching frequency stability against load transient response speed.
Integrated 5-bit VID DAC	Converts VID0–VID3 + VID25 into precise 25 mV-step output voltage (1.050–1.825 V) - eliminates need for external DAC and simplifies VRM 8.5-compliant CPU supply design.
Adaptive deadtime circuit	Prevents shoot-through by delaying HIGHDR turn-on until LODRV output < 2 V and LOWDR turn-on until PHASE node < 2 V - ensures safe FET commutation without fixed timing overhead.
Current-sense architecture	Uses high-side FET R_DS(on) sampling via IOUT pin with 50 Ω internal switch and external hold capacitor - enables lossless current monitoring without sense resistor power loss.
Droop compensation network	Externally adjustable via DROOP pin and resistor divider - reduces VOUT undershoot during load step-up and overshoot during load step-down for improved dynamic regulation.

Applications

Pentium® III Core Supply	AMD Athlon® Core Supply
Use Scenario: Primary core voltage regulator for Intel Pentium® III processors in server/workstation motherboards requiring VRM 8.5 compliance and tight voltage tolerance. IC Role / Device Role / Timing Role: Synchronous-buck controller generating 1.1 V–1.8 V core voltage with programmable VID interface and fast transient response. Use Value: ±1% output accuracy and 250 ns comparator delay ensure stable CPU operation during rapid load changes typical in multi-threaded workloads.	Use Scenario: Core supply for AMD Athlon® processors in desktop and entry-level server platforms needing high efficiency and precise voltage sequencing. IC Role / Device Role / Timing Role: Hysteretic buck controller delivering 1.1 V–1.8 V with droop compensation and adaptive deadtime for optimal efficiency at 20–40 A loads. Use Value: 2 A gate drivers and integrated OVP/UVP enable robust 95% peak efficiency while maintaining safety margins during thermal stress.
Multi-Processor Core Supply	Voltage Regulator Module (VRM)
Use Scenario: Shared core supply for dual-CPU systems where identical voltage tracking and synchronized soft-start are critical for system stability. IC Role / Device Role / Timing Role: Dual-output capable controller (with companion device) providing matched VREF and coordinated INHIBIT sequencing across multiple SC1159SWTRT units. Use Value: Identical VID decoding and soft-start current (ISS = IREFB/5) ensure simultaneous, ripple-matched power-up of multiple processor cores.	Use Scenario: Central controller in modular VRM designs for embedded computing, telecom line cards, or FPGA-based acceleration platforms. IC Role / Device Role / Timing Role: Programmable VRM 8.5-compliant controller supporting remote voltage adjustment, power-good signaling, and fault reporting via discrete pins. Use Value: PWRGD, INHIBIT, and OCP outputs provide direct interface to system management controllers (SMCs) for real-time health monitoring and graceful shutdown.

Pentium® III Core Supply

AMD Athlon® Core Supply

Use Scenario: Primary core voltage regulator for Intel Pentium® III processors in server/workstation motherboards requiring VRM 8.5 compliance and tight voltage tolerance.

IC Role / Device Role / Timing Role: Synchronous-buck controller generating 1.1 V–1.8 V core voltage with programmable VID interface and fast transient response.

Use Value: ±1% output accuracy and 250 ns comparator delay ensure stable CPU operation during rapid load changes typical in multi-threaded workloads.

Use Scenario: Core supply for AMD Athlon® processors in desktop and entry-level server platforms needing high efficiency and precise voltage sequencing.

IC Role / Device Role / Timing Role: Hysteretic buck controller delivering 1.1 V–1.8 V with droop compensation and adaptive deadtime for optimal efficiency at 20–40 A loads.

Use Value: 2 A gate drivers and integrated OVP/UVP enable robust 95% peak efficiency while maintaining safety margins during thermal stress.

Multi-Processor Core Supply

Voltage Regulator Module (VRM)

Use Scenario: Shared core supply for dual-CPU systems where identical voltage tracking and synchronized soft-start are critical for system stability.

IC Role / Device Role / Timing Role: Dual-output capable controller (with companion device) providing matched VREF and coordinated INHIBIT sequencing across multiple SC1159SWTRT units.

Use Value: Identical VID decoding and soft-start current (ISS = IREFB/5) ensure simultaneous, ripple-matched power-up of multiple processor cores.

Use Scenario: Central controller in modular VRM designs for embedded computing, telecom line cards, or FPGA-based acceleration platforms.

IC Role / Device Role / Timing Role: Programmable VRM 8.5-compliant controller supporting remote voltage adjustment, power-good signaling, and fault reporting via discrete pins.

Use Value: PWRGD, INHIBIT, and OCP outputs provide direct interface to system management controllers (SMCs) for real-time health monitoring and graceful shutdown.

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	Fixed-frequency PWM controller with 3-bit VID (1.1–1.85 V), no hysteretic mode; requires external oscillator; 1.5 A drivers.	Designed for VRM 8.4 compliance; lacks droop compensation and adaptive deadtime; lower gate drive capability limits high-current scalability.	Choose ISL6522CRZ only if fixed-frequency operation and legacy VRM 8.4 support are required; not suitable for VRM 8.5 or >30 A designs.
TPS51116PWR	Single-phase VRM 11.0 controller with 6-bit VID (0.25–1.5 V), integrated MOSFET drivers, and D-CAP™ control; 3 A drivers.	Targets newer Intel mobile CPUs; narrower voltage range excludes Pentium III/Athlon use cases; includes D-CAP for faster transient response but higher complexity.	Choose TPS51116PWR for post-2005 mobile platforms; incompatible with VRM 8.5 VID mapping and 1.8 V+ requirements of SC1159SWTRT applications.

Compared with ISL6522CRZ and TPS51116PWR, SC1159SWTRT uniquely combines VRM 8.5 VID compatibility, hysteretic control for zero-error transient response, and 2 A drivers optimized for discrete high-current FETs - making it the only viable choice for legacy Pentium III/Athlon server and workstation core supplies requiring 1.05–1.825 V programmability.

Availability

SC1159SWTRT is available at Aetrix Electronics and suitable for server systems, workstation power supplies, and multi-processor core voltage regulation requiring stable component supply and long-term industrial lifecycle support.

Supply support for SC1159SWTRT 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 applications.

The SC1159 product line was designed specifically for high-efficiency, VRM 8.5-compliant CPU core voltage regulation in server and workstation platforms, emphasizing programmability, transient response, and integrated protection.

FAQ

What is the maximum output voltage programmable by SC1159SWTRT?

The SC1159SWTRT supports a maximum output voltage of 1.825 V, achieved when all five VID bits (VID0–VID3 and VID25) are set to logic high (open). This value is explicitly defined in the Output Voltage Table on page 11 of the datasheet and aligns with VRM 8.5 specification upper limits for Pentium® III and Athlon® processors.

Does SC1159SWTRT support both bootstrap and ground-referenced high-side driver configurations?

Yes, SC1159SWTRT supports both configurations. Connecting BOOTLO to ground configures the high-side driver as ground-referenced; leaving BOOTLO open enables floating bootstrap operation. The internal Schottky diode between DRV and BOOT facilitates efficient bootstrap charging, and the maximum BOOT-to-ground voltage is rated at 25 V.

How does the SC1159SWTRT implement overvoltage protection?

The SC1159SWTRT monitors VSENSE and triggers overvoltage protection when this voltage exceeds 115% of VREF. Upon detection, a fault latch disables both HIGHDR and LOWDR outputs. The latch remains active until VIN drops below the UVLO threshold (10 V), and a 1 ms deglitch timer prevents false triggering from noise transients.

What is the role of the DROOP pin in SC1159SWTRT?

The DROOP pin in SC1159SWTRT accepts a scaled version of the IOUT-derived current signal to implement droop compensation. This dynamically offsets the target VOUT downward under load, reducing undershoot during load step-up and overshoot during load step-down - improving dynamic regulation without requiring external compensation networks.

Can SC1159SWTRT operate with a 5 V input supply instead of 12 V?

No, SC1159SWTRT requires a 12 V input on the VIN12V pin for proper operation. Its absolute maximum rating for VIN12V is 14 V, and the UVLO circuit activates at 10 V with 2 V hysteresis. While some internal blocks may tolerate lower voltages, the datasheet specifies 12 V as the nominal operating supply for drivers, regulators, and logic - using 5 V will result in functional failure.

SC1159SWTRT Specifications

Product attributes: Attribute value

Manufacturer:: Semtech Corporation

Series:: -

Package/Case:: 28-SOIC (0.295", 7.50mm 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):: 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

SC1159SWTRT FAQ

1.How can I place an order for SC1159SWTRT through Aetrix?

Please submit a Request for Quotation (RFQ) for SC1159SWTRT 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 SC1159SWTRT reliable?

The price and inventory of SC1159SWTRT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SC1159SWTRT is usually 5 days.

3.What payment methods are accepted for SC1159SWTRT?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SC1159SWTRT transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SC1159SWTRT?

SC1159SWTRT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SC1159SWTRT 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 SC1159SWTRT?

For technical support, including SC1159SWTRT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SC1159SWTRT requirements.

6.How does Aetrix verify that SC1159SWTRT is sourced from the original manufacturer or authorized distributors?

All SC1159SWTRT 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 SC1159SWTRT meets industry standards.

7.What is the process for return or replacement of SC1159SWTRT?

All SC1159SWTRT units undergo pre-shipment inspection (PSI). If there is an issue with SC1159SWTRT, 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 SC1159SWTRT part is unused and in its original packaging.

Return procedure for SC1159SWTRT:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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