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Renesas ISL6446AIAZ
- Part No.:
- ISL6446AIAZ
- Manufacturer:
- Renesas
- Category:
- Voltage Regulators - Linear + Switching
- Package:
- 24-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
ISL6446AIAZ.pdf
- Description:
- IC REG TRPL BUCK/LNR SYNC 24QSOP
- Quantity:
- Payment:
- Shipping:
Inventory:631
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Product details
Overview
ISL6446AIAZ from Renesas Electronics is a triple-output power controller integrating two 180° out-of-phase voltage-mode PWM buck controllers and one linear controller for broadband, DSL, and networking point-of-load regulation. It delivers precise 0.6V reference output with ±1.5% tolerance over temperature and line, programmable 100kHz–2.5MHz switching frequency, and lossless rDS(ON)-based overcurrent protection. Used in ATX power supplies and FPGA/ASIC core voltage regulation.
For engineers reviewing the ISL6446AIAZ datasheet, ISL6446AIAZ pinout, ISL6446AIAZ application, or ISL6446AIAZ equivalent, key selection considerations include interleaved ripple reduction, prebiased soft-start capability, PGOOD timing dependency on fSW, and dual independent enable/soft-start pins (SS1/EN1, SS2/EN2) enabling voltage tracking.
Technical Context
The ISL6446AIAZ implements synchronized 180° out-of-phase operation between its two PWM channels to reduce input RMS current and input capacitor stress. Each PWM uses voltage-mode control with a 0.6V internal reference, high-bandwidth error amplifier (15MHz GBWP), and fast transient response enabled by 5V/µs slew rate and 88dB DC gain.
Its linear controller employs a transconductance amplifier (gm = 2A/V) driving an external PNP or PMOS pass device, with LCFB feedback threshold of 0.570–0.620V and LCDR sink capability of 50mA. Protection includes latch-off overcurrent (programmable via OCSET resistors), thermal shutdown at +150°C, and independent UVP/OVP comparators per PWM channel.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.5V–5.5V or 5.5V–24V - supports dual-supply configuration: direct 5V±10% at VCC or wide-range VIN with internal 5V regulator |
| Output Regulation Reference | 0.6V ±1.5% over -40°C to +85°C - enables precise low-voltage outputs (e.g., 1.2V, 1.8V) with minimal resistor tolerance impact |
| Switching Frequency Range | 100kHz–2.5MHz - set by RT-to-SGND resistor; higher frequencies reduce solution size but limit max duty cycle (e.g., 79% at 2.5MHz) |
| Overcurrent Sensing | Lossless rDS(ON) sensing - eliminates sense resistor, reduces BOM cost and power loss; trip level set by ROCSET and 110µA current source |
| PGOOD Timing | Delay = 0.065/fSW seconds - fixed inverse relationship; e.g., 46ms at 1.4MHz, 125ms at 524kHz - no independent adjustment possible |
| Soft-Start Current | 30µA nominal per SS/EN pin - sets ramp time with external capacitor; supports independent timing and prebiased load startup |
| Thermal Shutdown | +150°C with 20°C hysteresis - protects IC under sustained overload; recovery requires SS/EN <1V or power recycle |
Pinout & Package
ISL6446AIAZ is housed in a 24-lead QSOP (RoHS-compliant, M24.15 package) with exposed pad for thermal performance. Pin layout supports dual-buck interleaving and discrete linear regulator integration.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SS1/EN1, SS2/EN2 | Independent soft-start/enable inputs | 30µA pull-up charges external capacitor; <1V disables controller; enables voltage tracking and prebiased startup |
| FB1, FB2, LCFB | Feedback inputs | Connect to resistor dividers; set output voltage using 0.6V reference; LCFB enables linear regulator output programming |
| OCSET1, OCSET2 | Overcurrent threshold setting | 110µA current source develops voltage across ROCSET; compared to PHASE during UGATE on-time for lossless sensing |
| UGATE1/2, LGATE1/2 | High-side and low-side gate drivers | UGATE drives upper N-MOSFET via bootstrap (BOOT1/2); LGATE drives lower N-MOSFET from VCC rail |
| PGOOD | Open-drain power-good indicator | Pulled low if either PWM output deviates >10% from target or linear output drops <75% of nominal; delay tied to fSW |
Key Features
| Feature | Design Value |
|---|---|
| 180° out-of-phase PWM interleaving | Reduces input ripple amplitude and RMS current by ~30%, allowing smaller input capacitors and lower EMI |
| Programmable switching frequency | 100kHz–2.5MHz range enables trade-off between efficiency (low fSW) and component size (high fSW) |
| Prebiased soft-start capability | Supports seamless ramp from precharged output voltages without overshoot or reverse current - critical for hot-swap and multi-rail sequencing |
| Lossless overcurrent protection | Eliminates external current-sense resistor, reducing cost, board area, and conduction losses in high-current applications |
| Voltage tracking via shared SS/EN | Enables controlled ramp alignment between multiple rails (e.g., core and I/O) using single capacitor or resistor divider network |
Applications
| ATX Power Supplies | DSP/ASIC/FPGA Point-of-Load |
|---|---|
Use Scenario: Primary +5V and +3.3V rail generation in desktop/server ATX PSUs with tight ripple and transient requirements. IC Role / Device Role / Timing Role: Dual PWM controller manages interleaved buck stages; linear controller provides auxiliary bias for fan control or monitoring circuitry. Use Value: 180° phase shift cuts input capacitor RMS current by ~40%, enabling smaller 105°C-rated ceramics instead of bulk electrolytics. | Use Scenario: Core voltage (VDD) and I/O voltage (VDDIO) regulation for Xilinx Kintex or Intel Stratix FPGAs during dynamic load transitions. IC Role / Device Role / Timing Role: ISL6446AIAZ delivers tightly regulated 1.2V/1.8V outputs with fast transient response; PGOOD coordinates system reset sequencing. Use Value: Prebiased soft-start prevents FPGA configuration corruption when powered from partially charged backup rails. |
| Industrial Networking Switches | DSL/FTTx Line Cards |
Use Scenario: Powering Ethernet PHYs, packet processors, and SerDes in managed Layer-3 switches operating in extended temperature environments. IC Role / Device Role / Timing Role: Dual PWM supplies 1.0V CPU core and 2.5V memory interface; linear controller powers analog front-end bias circuits. Use Value: Thermal shutdown at +150°C ensures reliability in sealed chassis with limited airflow; -40°C to +85°C rating meets industrial temp grade. | Use Scenario: Multi-rail power for ADSL2+/VDSL2 line cards requiring +12V analog, +3.3V digital, and +5V PHY supplies. IC Role / Device Role / Timing Role: ISL6446AIAZ integrates all three rails in single IC; OCSET-based protection guards against shorted line transformers. Use Value: Lossless current sensing avoids precision resistor drift issues in long-life telecom equipment with 10+ year field deployment. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar triple-output controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ISL65414IRZ | Single 3-phase controller (not dual PWM + linear); 0.6V ref, 300kHz–1.5MHz fSW; no LCFB/LCDR pins | Designed for CPU VRMs with 3-phase interleaving; lacks linear regulator channel and independent SS/EN pins | Select ISL65414IRZ only for high-current CPU core applications requiring >30A per phase and 3-phase topology. |
| TPS51220ARGER | Dual PWM only (no linear controller); integrated MOSFET drivers; 0.6V ref; 300kHz–1MHz fSW; no OCSET lossless sensing | Targeted at notebook GPU/CPU power; requires external sense resistors; no prebiased soft-start support | Choose TPS51220ARGER for space-constrained portable designs where linear rail is omitted and sense-resistor tolerance is acceptable. |
Compared with ISL6446AIAZ, ISL65414IRZ offers higher per-phase current capability but omits the linear regulator and voltage tracking flexibility, while TPS51220ARGER reduces external component count via integrated drivers yet sacrifices lossless OCP and prebiased startup-making ISL6446AIAZ uniquely suited for telecom and industrial multi-rail systems requiring reliability, sequencing control, and maintenance-free current sensing.
Availability
ISL6446AIAZ is available at Aetrix Electronics and suitable for ATX power supplies, FPGA point-of-load regulation, and industrial networking applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for ISL6446AIAZ 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
Renesas Electronics is a global semiconductor leader delivering microcontrollers, analog, power, and SoC solutions for automotive, industrial, infrastructure, and IoT markets.
The ISL6446AIAZ belongs to Renesas' high-performance power management controller family, designed specifically for multi-rail, high-efficiency DC/DC conversion in broadband access and enterprise networking equipment.
FAQ
What input voltage configurations does the ISL6446AIAZ support?
The ISL6446AIAZ supports two input configurations: (1) 4.5V–5.5V applied directly to VCC for 5V±10% operation, or (2) 5.5V–24V applied to VIN, which powers an internal 5V linear regulator feeding VCC. In the latter case, VIN also serves as the high-side switch input for both PWM channels. The datasheet specifies absolute maximum VIN of +28V relative to PGND.
How does the ISL6446AIAZ achieve lossless overcurrent protection?
The ISL6446AIAZ achieves lossless overcurrent protection by using the upper MOSFET's rDS(ON) as the current-sense element. An internal 110µA current source pulls down the OCSET pin, establishing a voltage threshold. During UGATE on-time, the PHASE node voltage is compared to OCSET; if PHASE falls below OCSET, an overcurrent is detected. This eliminates the need for external sense resistors, reducing cost and power loss - a key feature confirmed in the FN8384 datasheet Section "Protection Mechanisms".
Can the ISL6446AIAZ soft-start into a prebiased output voltage?
Yes, the ISL6446AIAZ supports soft-start into prebiased loads on both PWM outputs. When the SS/EN pin voltage ramps, the upper FETs remain off until the ramp exceeds the prebiased output voltage; then regulation begins seamlessly. This behavior is explicitly verified in Figure 20 ("SOFT-START WITH PREBIAS") and Section "Functional Description" of the FN8384 datasheet, and applies independently to each channel.
What determines the PGOOD delay time for the ISL6446AIAZ?
The PGOOD delay time for the ISL6446AIAZ is determined solely by the switching frequency: tPGOOD = 0.065 / fSW seconds. For example, at 300kHz it is ~217ms; at 1.4MHz it is ~46ms. This inverse relationship is fixed in silicon and cannot be adjusted externally - a design constraint documented in Equation 3 on page 14 of the FN8384 datasheet.
Does the ISL6446AIAZ include thermal protection, and how does it behave?
Yes, the ISL6446AIAZ includes thermal shutdown protection that activates at +150°C junction temperature with 20°C hysteresis. When triggered, the device disables all gate drivers and enters latch-off state. Recovery requires either pulling SS/EN below 1V to reset the fault latch or performing a full power recycle. This behavior is specified in the "Absolute Maximum Ratings" and "Electrical Specifications" tables of the FN8384 datasheet.
ISL6446AIAZ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Renesas
- Series:
- -
- Package/Case:
- 24-SSOP (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Topology:
- Step-Down (Buck) Synchronous (2), Linear (LDO) (1)
- Number of Outputs:
- 3
- Frequency - Switching:
- 100kHz ~ 2.6MHz
- Voltage/Current - Output 1:
- Controller
- Voltage/Current - Output 2:
- Controller
- Voltage/Current - Output 3:
- Controller
- w/LED Driver:
- No
- w/Supervisor:
- No
- w/Sequencer:
- No
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-QSOP
ISL6446AIAZ FAQ
1.How can I place an order for ISL6446AIAZ through Aetrix?
Please submit a Request for Quotation (RFQ) for ISL6446AIAZ 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 ISL6446AIAZ reliable?
The price and inventory of ISL6446AIAZ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ISL6446AIAZ is usually 5 days.
3.What payment methods are accepted for ISL6446AIAZ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ISL6446AIAZ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ISL6446AIAZ?
ISL6446AIAZ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ISL6446AIAZ 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 ISL6446AIAZ?
For technical support, including ISL6446AIAZ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ISL6446AIAZ requirements.
6.How does Aetrix verify that ISL6446AIAZ is sourced from the original manufacturer or authorized distributors?
All ISL6446AIAZ 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 ISL6446AIAZ meets industry standards.
7.What is the process for return or replacement of ISL6446AIAZ?
All ISL6446AIAZ units undergo pre-shipment inspection (PSI). If there is an issue with ISL6446AIAZ, 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 ISL6446AIAZ part is unused and in its original packaging.
Return procedure for ISL6446AIAZ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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