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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Special Purpose Regulators

Renesas ISL6539IA

Name: ISL6539IA
Brand: Renesas
SKU: ISL6539IA
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: ISL6539IA

Manufacturer:: Renesas

Category:: Special Purpose Regulators

Package:: 28-SSOP (0.154", 3.90mm Width)

Datasheet:: ISL6539IA.pdf

Description:: IC REG CTRL DDR DRAM 2OUT 28SSOP

Quantity:: RFQ Add To RFQ list

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Product details

Overview

ISL6539IA from Intersil is a wide-input-range dual PWM controller IC designed for synchronous buck DC/DC conversion in DDR memory and graphics chipset power supplies. It delivers two independently adjustable outputs (0.9V–5.5V), supports DDR-I/DDR2 mode with VTT tracking and VDDQ/2 reference generation, and features voltage feed-forward ramp modulation, current-mode control, and 300kHz synchronized PWM operation.

For engineers reviewing the ISL6539IA datasheet, ISL6539IA pinout, ISL6539IA application, or ISL6539IA equivalent, key selection considerations include its dual-channel phase-shift capability (0°/90°/180°), lossless r_DS(ON) current sensing, integrated overvoltage/undervoltage/overcurrent protection per channel, DDR-specific VTT sourcing/sinking capability, and QSOP-28 package compatibility with industrial temperature range (−40°C to +85°C).

Technical Context

The ISL6539IA implements dual independent current-mode PWM controllers with input voltage feed-forward via the VIN pin, enabling stable regulation across 3.3V/5V system rails or 5.0V–15V unregulated inputs. Each channel includes internal error amplifiers with fixed compensation, adaptive dead-time control, and diode emulation logic.

In DDR mode (DDR pin high), Channel 2 transforms into a bidirectional VTT regulator tracking VDDQ/2, while PG2/REF becomes a buffered 1.25V output capable of sourcing 10mA. Phase alignment between channels is dynamically set by VIN voltage level (GND = 0°, 5V = 90°, >4.2V = 180°), minimizing input current ripple.

Key Specifications

Parameter	Value and Actual Design Meaning
Oscillator frequency	300 kHz typical; enables consistent switching timing and EMI control in high-density power designs.
Output voltage range	0.9V to 5.5V per channel; supports DDR2 VDDQ (2.5V), GPU core (1.2V), and I/O rail (3.3V) without external DACs.
VDDQ/2 reference accuracy	±1% at 0–10 mA load; ensures precise termination voltage matching required for DDR signal integrity.
Overvoltage threshold	115% of set point; latches lower MOSFET on to clamp output during fault, preventing DRAM damage.
Soft-start current	4.5 µA typical; charges external capacitor linearly to control inrush current and prevent supply rail collapse.
Input voltage range	3.3V or 5V system rail, or 5.0V–15V unregulated input; eliminates need for pre-regulator in server/motherboard applications.
Operating temperature	−40°C to +85°C; validated for industrial-grade motherboard, graphics card, and FPGA power subsystems.

Pinout & Package

ISL6539IA is housed in a 28-lead QSOP package (M28.15 drawing), Pb-free and RoHS compliant, with exposed pad thermal enhancement. Pin layout supports dual synchronous buck layouts with separate power and signal ground paths.

Pin/Terminal	Circuit Role	Design Meaning
EN1 / EN2	Channel enable inputs	Independent TTL-compatible control: high = active PWM, low = shutdown with <1 µA ICCSN; enables staggered startup sequencing.
VSEN1 / VSEN2	Feedback sense inputs	High-impedance (80 nA bias) inputs monitoring resistive divider output; used for PGOOD, OVP, UVP, and regulation loop.
ISEN1 / ISEN2	Current sense inputs	Monitor r_DS(ON) voltage drop across lower MOSFETs; support lossless sensing or optional external resistor for precision.
UGATE1 / UGATE2 LGATE1 / LGATE2	Upper/lower gate drivers	Integrated 4Ω pull-up / 2.3Ω pull-down drivers; drive standard N-channel MOSFETs without external buffers.
PHASE1 / PHASE2	Switch node connections	Connect to source of upper MOSFET and drain of lower MOSFET; critical for accurate current sampling and bootstrap timing.
PG1 / PG2/REF	Power-good / DDR reference	Open-drain PGOOD1; dual-function PG2/REF: open-drain PGOOD2 in dual mode, 10mA VDDQ/2 buffer in DDR mode.
DDR	Mode select input	TTL-level control: low = independent dual switcher, high = DDR memory power solution with VTT tracking and reference generation.
VIN	Feed-forward & phase control	Provides input-voltage-proportional ramp slope; also selects channel phase shift (0°/90°/180°) when DDR = 1.

Key Features

Feature	Design Value
Dual-mode architecture	Single IC supports both generic dual-output buck (0.9V–5.5V) and full DDR memory power (VDDQ + VTT + VDDQ/2 ref) via DDR pin.
VTT bidirectional regulation	CH2 sinks and sources current to maintain VTT = VDDQ/2 under dynamic DDR bus loading, eliminating need for discrete op-amp solutions.
Lossless current sensing	Uses MOSFET r_DS(ON) as current-sense element; reduces BOM count and PCB area vs. shunt resistors while maintaining ±5% OCP accuracy.
Phase-shift programmability	0°, 90°, or 180° inter-channel offset selected by VIN voltage level in DDR mode; minimizes input capacitor RMS current by up to 41%.
Integrated protection suite	Per-channel OVP (115%), UVP (75%), PGOOD window (±11%), and adjustable OCP via OCSET pins - no external comparators required.

Applications

Graphics Card GPU Core Supply	DDR2 Memory Termination (VTT)
Use Scenario: Powering GPU core voltage (e.g., 1.2V @ 40A) and memory interface (e.g., 2.5V VDDQ) on discrete graphics cards. IC Role / Device Role / Timing Role: Dual-channel synchronous buck controller delivering tightly regulated, fast-transient GPU core and VDDQ rails with shared thermal management. Use Value: Enables single-chip solution for multi-rail GPU power with coordinated soft-start, independent PGOOD signaling, and minimized input ripple via 180° phase shift.	Use Scenario: Providing bidirectional VTT termination voltage for DDR2 SDRAM modules on motherboards or servers. IC Role / Device Role / Timing Role: CH2 operates as a sourcing/sinking VTT regulator tracking VDDQ/2 in real time, with PG2/REF supplying buffered reference to DRAM chips. Use Value: Eliminates discrete op-amp + FET VTT circuit; achieves <10 mV tracking error and ±2A sink/source capability without external components.
Server Motherboard System Regulator	FPGA I/O Bank Supply
Use Scenario: Generating multiple low-noise, high-accuracy rails (e.g., 1.8V, 3.3V, 5V) for CPU VRM support, chipset, and peripheral interfaces. IC Role / Device Role / Timing Role: Dual PWM controller operating in independent mode, each channel configured for distinct output voltage and current rating. Use Value: Reduces component count vs. two discrete controllers; shares VCC bias, thermal footprint, and protection logic while maintaining channel isolation.	Use Scenario: Powering configurable FPGA I/O banks requiring precise voltage matching (e.g., 1.5V, 1.8V, 2.5V) with tight load regulation. IC Role / Device Role / Timing Role: CH1 regulates main I/O rail; CH2 provides auxiliary rail or DDR-compatible termination for high-speed transceivers. Use Value: Supports mixed-voltage I/O standards on single FPGA; leverages internal compensation and feed-forward for <1% load regulation across 0–10A.

Graphics Card GPU Core Supply

DDR2 Memory Termination (VTT)

Use Scenario: Powering GPU core voltage (e.g., 1.2V @ 40A) and memory interface (e.g., 2.5V VDDQ) on discrete graphics cards.

IC Role / Device Role / Timing Role: Dual-channel synchronous buck controller delivering tightly regulated, fast-transient GPU core and VDDQ rails with shared thermal management.

Use Value: Enables single-chip solution for multi-rail GPU power with coordinated soft-start, independent PGOOD signaling, and minimized input ripple via 180° phase shift.

Use Scenario: Providing bidirectional VTT termination voltage for DDR2 SDRAM modules on motherboards or servers.

IC Role / Device Role / Timing Role: CH2 operates as a sourcing/sinking VTT regulator tracking VDDQ/2 in real time, with PG2/REF supplying buffered reference to DRAM chips.

Use Value: Eliminates discrete op-amp + FET VTT circuit; achieves <10 mV tracking error and ±2A sink/source capability without external components.

Server Motherboard System Regulator

FPGA I/O Bank Supply

Use Scenario: Generating multiple low-noise, high-accuracy rails (e.g., 1.8V, 3.3V, 5V) for CPU VRM support, chipset, and peripheral interfaces.

IC Role / Device Role / Timing Role: Dual PWM controller operating in independent mode, each channel configured for distinct output voltage and current rating.

Use Value: Reduces component count vs. two discrete controllers; shares VCC bias, thermal footprint, and protection logic while maintaining channel isolation.

Use Scenario: Powering configurable FPGA I/O banks requiring precise voltage matching (e.g., 1.5V, 1.8V, 2.5V) with tight load regulation.

IC Role / Device Role / Timing Role: CH1 regulates main I/O rail; CH2 provides auxiliary rail or DDR-compatible termination for high-speed transceivers.

Use Value: Supports mixed-voltage I/O standards on single FPGA; leverages internal compensation and feed-forward for <1% load regulation across 0–10A.

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual PWM controller applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
ISL6522CRZ	Single-channel, 300kHz, no DDR mode or VTT capability; lacks PG2/REF, DDR, OCSET2, and phase-shift control.	Suitable only for single-rail applications; cannot replace ISL6539IA in DDR or dual-output systems.	Select only if design requires one regulated output and space/thermal constraints favor smaller SOIC-16 package.
TPS51220ARUKR	TI dual-channel controller with DDR2/3 support, but uses external reference and requires separate VTT driver; no integrated VDDQ/2 buffer.	Supports DDR3 with higher current VTT (±3A), but adds 3–4 external components for reference and tracking.	Prefer when DDR3 compliance and higher VTT current are mandatory; accept added complexity for broader memory compatibility.

Compared with ISL6539IA, ISL6522CRZ offers reduced integration and no DDR functionality, making it unsuitable for memory power; TPS51220ARUKR extends DDR support to DDR3 but increases BOM count and layout area due to external VTT circuitry.

Availability

ISL6539IA is available at Aetrix Electronics and suitable for graphics card power delivery, DDR2 memory subsystems, and industrial motherboard system regulators requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for ISL6539IA 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

Intersil (now part of Renesas Electronics) is a semiconductor company specializing in high-performance analog and power management ICs for computing, communications, and industrial markets.

The ISL6539IA belongs to Intersil's DDR memory power controller product line, engineered specifically to integrate VDDQ regulation, VTT sourcing/sinking, and VDDQ/2 reference generation into a single dual-PWM IC for cost-sensitive, space-constrained DDR-I/DDR2 platforms.

FAQ

What is the maximum input voltage supported by the ISL6539IA?

The ISL6539IA supports an absolute maximum input voltage of +18.0V on the VIN pin. Its recommended operating range is 3.3V or 5.0V system rails, or 5.0V to 15.0V unregulated input. Operation beyond 15.0V is not advised for sustained use, as thermal stress and reliability may degrade outside the validated specification window defined in the FN9144 datasheet. The ISL6539IA maintains stable regulation across this full range using voltage feed-forward ramp modulation.

How does the ISL6539IA implement VTT tracking in DDR mode?

In DDR mode (DDR pin high), the ISL6539IA configures Channel 2 to track VDDQ/2 by connecting the OCSET2 pin to a resistor divider across VDDQ. The internal amplifier buffers this voltage and outputs it on PG2/REF. Simultaneously, Channel 2's error amplifier uses VDDQ/2 as its reference, enabling real-time VTT regulation. The ISL6539IA supports bidirectional current flow on CH2, allowing it to source and sink current as DDR bus states change - a requirement not met by standard buck controllers.

Can the ISL6539IA operate with only one channel enabled?

Yes, the ISL6539IA supports independent channel control via EN1 and EN2 pins. Either channel can be enabled or disabled without affecting the other. When only EN1 is high, CH1 operates normally with full protection and PGOOD1 assertion; CH2 remains in low-power shutdown (<1 µA ICCSN). This allows flexible power sequencing in multi-rail systems and simplifies bring-up testing. Both channels share VCC and thermal design but retain independent feedback, current sensing, and soft-start circuits.

What is the purpose of the VIN pin beyond input voltage sensing?

Beyond providing feed-forward ramp modulation, the VIN pin determines inter-channel phase alignment in DDR mode: grounding VIN sets 0° phase shift, applying 5V sets 90° lag for CH2, and >4.2V sets 180° anti-phase operation. This dynamic control minimizes input capacitor RMS current and improves thermal distribution. In dual-switcher mode, VIN solely serves feed-forward - phase shift is fixed at 180° regardless of VIN voltage. The ISL6539IA's VIN pin thus serves dual functional roles depending on DDR pin state.

Does the ISL6539IA require external compensation components?

No, the ISL6539IA integrates fully compensated error amplifiers for both channels, eliminating the need for external compensation networks in most applications. Internal compensation is optimized for standard LC filter selections and leverages voltage feed-forward and current-mode control to stabilize the loop. Only an optional feed-forward capacitor (Cz) across the top feedback resistor is recommended for enhanced transient response - no poles, zeros, or gain-setting resistors are required externally. This reduces design risk and accelerates time-to-market for ISL6539IA-based power supplies.

ISL6539IA Specifications

Product attributes: Attribute value

Manufacturer:: Renesas

Series:: -

Package/Case:: 28-SSOP (0.154", 3.90mm Width)

Packaging:: Tube

Product Status:: Obsolete

Applications:: Controller, DDR DRAM, SDRAM

Voltage - Input:: 3.3V ~ 18V

Number of Outputs:: 2

Voltage - Output:: 0.9V ~ 5.5V

Operating Temperature:: -40°C ~ 85°C

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 28-SSOP/QSOP

ISL6539IA FAQ

1.How can I place an order for ISL6539IA through Aetrix?

Please submit a Request for Quotation (RFQ) for ISL6539IA 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 ISL6539IA reliable?

The price and inventory of ISL6539IA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ISL6539IA is usually 5 days.

3.What payment methods are accepted for ISL6539IA?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ISL6539IA transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for ISL6539IA?

ISL6539IA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your ISL6539IA 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 ISL6539IA?

For technical support, including ISL6539IA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ISL6539IA requirements.

6.How does Aetrix verify that ISL6539IA is sourced from the original manufacturer or authorized distributors?

All ISL6539IA 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 ISL6539IA meets industry standards.

7.What is the process for return or replacement of ISL6539IA?

All ISL6539IA units undergo pre-shipment inspection (PSI). If there is an issue with ISL6539IA, 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 ISL6539IA part is unused and in its original packaging.

Return procedure for ISL6539IA:

1.Submit a request within 90 days.

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

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