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Renesas ISL6446IAZ-T7A
- Part No.:
- ISL6446IAZ-T7A
- Manufacturer:
- Renesas
- Category:
- Voltage Regulators - Linear + Switching
- Package:
- 24-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
ISL6446IAZ-T7A.pdf
- Description:
- IC REG TRPL BUCK/LNR SYNC 24QSOP
- Quantity:
- Payment:
- Shipping:
Inventory:221
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Product details
Overview
ISL6446IAZ-T7A 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, programmable 100kHz–2.5MHz switching frequency, and lossless rDS(ON)-based overcurrent protection. Used in ATX power supplies and FPGA/DSP core voltage regulation.
For engineers reviewing the ISL6446IAZ-T7A datasheet, ISL6446IAZ-T7A pinout, ISL6446IAZ-T7A application, or ISL6446IAZ-T7A equivalent, key selection criteria include interleaved ripple reduction, independent soft-start into prebiased loads, PGOOD monitoring of three outputs, and compatibility with 4.5–24V input ranges across QSOP-24 packaging.
Technical Context
The ISL6446IAZ-T7A implements dual synchronous buck converters operating 180° out-of-phase to reduce input RMS current and capacitor stress. Each PWM channel uses voltage-mode control with a 0.6V internal reference, 100ns minimum on-time, and adjustable overcurrent threshold via external resistor-to-drain connection on OCSET pins.
Its linear controller employs a transconductance amplifier (2A/V) driving an external PNP or PMOS pass device, with LCFB feedback referenced to 0.595V (±2.5% over temperature). The PGOOD signal asserts only after both PWM outputs settle within ±10% and the linear output exceeds 75% of nominal - with delay inversely proportional to switching frequency (e.g., 46ms at 1.4MHz).
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 bias or wide-range VIN with internal 5V VCC regulator |
| Output Regulation Accuracy | ±1.5% over line/temperature - ensures stable core voltage for DSP/FPGA logic domains |
| Switching Frequency Range | 100kHz–2.5MHz - enables low-cost 100kHz ATX designs or compact high-frequency layouts up to 2.5MHz |
| Reference Voltage | 0.6V ±0.0185V (–40°C to +85°C) - sets minimum output voltage and defines feedback divider ratio |
| Overcurrent Sensing | Lossless rDS(ON) sensing - eliminates current-sense resistor, reducing BOM cost and PCB area |
| Thermal Shutdown | +150°C with 20°C hysteresis - protects against sustained overload or poor heatsinking in enclosed systems |
| PGOOD Delay | 46ms at 1.4MHz (inversely proportional to fSW) - provides deterministic power sequencing timing without external timers |
Pinout & Package
ISL6446IAZ-T7A is housed in a RoHS-compliant 24-lead QSOP package (M24.15), optimized for thermal performance (θJA = 75°C/W) and surface-mount assembly in space-constrained networking modules.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BOOT1, BOOT2 | Bootstrap supply for high-side gate drivers | Connects to bootstrap capacitors; internal diode anode tied to VCC - enables N-channel high-side FET drive |
| UGATE1, UGATE2 | High-side MOSFET gate drive outputs | Bootstrapped outputs capable of 2.6Ω pull-up / 2Ω pull-down - drives upper FET gates with <25ns rise/fall |
| PHASE1, PHASE2 | Switch node connections | Junction of high-side source, low-side drain, and output inductor - critical for EMI layout and current sensing |
| LGATE1, LGATE2 | Low-side MOSFET gate drive outputs | VCC-referenced drivers with 2.6Ω pull-up / 2Ω pull-down - directly drives N-channel sync rectifiers |
| FB1, FB2 | PWM output voltage feedback inputs | Monitor regulated outputs via resistor dividers; feed error amplifiers and PGOOD/OVP comparators |
| LCFB | Linear controller feedback input | Sets linear output voltage via external divider; threshold = 0.595V ±25mV - enables precision auxiliary rail generation |
| SS1/EN1, SS2/EN2 | Soft-start and enable inputs | 30µA current source charges external capacitor; <1V disables controller - supports independent sequencing and voltage tracking |
| OCSET1, OCSET2 | Overcurrent trip level programming | 110µA current source develops voltage across rDS(ON); trip occurs when PHASE < OCSET during high-side conduction |
| PGOOD | Open-drain power-good status output | Asserts high only when both PWM outputs are within ±10% and linear output >75% - enables system-level power sequencing |
| VIN, VCC | Main input and bias supply rails | VIN powers internal 5V regulator (if >5.5V); VCC supplies gate drivers and logic - decoupling mandatory per datasheet layout guidelines |
Key Features
| Feature | Design Value |
|---|---|
| 180° out-of-phase PWM operation | Reduces input ripple current by ~70% vs. in-phase operation - lowers bulk capacitor requirements and EMI filtering cost |
| Independent soft-start into prebiased loads | Enables safe ramp-up of powered-backplane rails or hot-plug modules without reverse current flow |
| Voltage tracking capability | Allows coordinated startup of multiple rails (e.g., core and I/O) using shared SS/EN network - simplifies sequencing design |
| Lossless current sensing | Eliminates sense resistor and associated power loss - improves efficiency in high-current (>10A) applications |
| Three-output PGOOD monitoring | Single open-drain signal confirms all three regulated outputs meet tolerance - reduces system supervisor IC count |
Applications
| ATX Power Supplies | DSP/FPGA Point-of-Load Regulation |
|---|---|
Use Scenario: Primary +5V and +3.3V rail generation in desktop/server ATX PSUs with tight ripple and transient response requirements. IC Role / Device Role / Timing Role: Dual PWM controller managing interleaved buck stages for main DC outputs; linear controller generates auxiliary +1.2V for chipset. Use Value: 180° phase shift cuts input capacitor RMS current by >50%, enabling smaller, lower-ESR bulk caps and reduced thermal stress. | Use Scenario: Core voltage regulation for high-performance DSPs and FPGAs requiring fast load-step response and precise 0.6–1.2V outputs. IC Role / Device Role / Timing Role: Triple-output controller delivering tightly regulated VCORE, VI/O, and VREF rails with synchronized soft-start and PGOOD coordination. Use Value: Independent SS/EN pins allow staggered startup to limit inrush; high-bandwidth error amplifiers (<15MHz GBW) suppress load transients under 10A/µs steps. |
| Industrial Networking Equipment | DSL/FTTx Line Cards |
Use Scenario: Power management in managed switches and routers where EMI compliance and thermal density constrain design. IC Role / Device Role / Timing Role: Dual PWM + linear controller supplying CPU, PHY, and memory rails with integrated OCP/UVP/OVP protection and thermal shutdown. Use Value: Lossless rDS(ON) current sensing avoids sense resistor losses - critical for 85°C ambient industrial environments. | Use Scenario: Compact power solution for DSLAM line cards requiring multiple isolated, low-noise analog and digital rails. IC Role / Device Role / Timing Role: Generates +5V (PWM1), +3.3V (PWM2), and +1.8V (linear) from single 12V input with minimal external components. Use Value: Programmable 100kHz–2.5MHz frequency allows optimization: low fSW for efficiency in fan-cooled DSLAMs, high fSW for size reduction in fanless FTTx units. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar triple-output controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ISL6446IRZ-T7A | Same die, 24-lead QFN package (5×5mm) - lower θJA (45°C/W) but requires reflow-compatible layout | Better thermal performance in high-power density designs; no lead-frame parasitics for high-frequency gate drive | Select for thermally constrained applications where board space permits QFN; not drop-in compatible with QSOP footprint |
| RTQ2132B-QA | Dual PWM + LDO in 28-pin QFN; 0.6V ref, ±1% accuracy, but no lossless OCP - uses external sense resistor | Lacks rDS(ON) current sensing; adds integrated LDO instead of linear controller requiring external pass device | Choose when integrated LDO simplifies BOM and ±1% accuracy is required; avoid if minimizing sense resistor losses is critical |
Compared with ISL6446IAZ-T7A, the ISL6446IRZ-T7A offers superior thermal dissipation in space-limited layouts, while the RTQ2132B-QA trades lossless OCP for tighter regulation and integrated LDO functionality - making each suitable for distinct thermal, accuracy, and component-count priorities.
Availability
ISL6446IAZ-T7A is available at Aetrix Electronics and suitable for ATX power supplies, DSP/FPGA point-of-load regulation, and industrial networking equipment requiring stable component supply and long-term production continuity.
Supply support for ISL6446IAZ-T7A 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 specializing in microcontrollers, analog power management, and connectivity solutions for industrial, automotive, and communications markets.
The ISL6446IAZ-T7A belongs to Renesas' high-performance multi-rail power controller product line, designed specifically for broadband infrastructure, DSL, and networking applications demanding interleaved efficiency, robust protection, and flexible sequencing.
FAQ
What input voltage configurations does the ISL6446IAZ-T7A support?
The ISL6446IAZ-T7A supports two input configurations: (1) 5.5V–24V applied to VIN, with internal 5V VCC regulator powering gate drivers; or (2) 5V ±10% applied directly to VCC, bypassing the internal regulator. VIN must be decoupled with ceramic capacitor; VCC requires ≥1µF ceramic decoupling. Both configurations are validated per datasheet Table 1 and Absolute Maximum Ratings.
How does the ISL6446IAZ-T7A achieve lossless overcurrent protection?
The ISL6446IAZ-T7A achieves lossless overcurrent protection by using the upper MOSFET's rDS(ON) as the current-sense element. An internal 110µA current source develops a voltage across ROCSET connected between OCSET and the MOSFET drain. When PHASE voltage falls below OCSET during high-side conduction, an overcurrent is detected. This eliminates external sense resistors, reducing power loss and PCB area - confirmed in Electrical Specifications and Functional Description sections of FN7944 Rev 2.00.
Can the ISL6446IAZ-T7A soft-start into a prebiased output voltage?
Yes, the ISL6446IAZ-T7A supports soft-start into prebiased loads on both PWM outputs. When the SS/EN pin voltage ramp exceeds the prebiased output voltage, the FETs begin switching seamlessly from that point. If prebias exceeds the final target, the output is pulled down post-soft-start. This behavior is verified in Figure 14 (prebiased startup) and Functional Description section (page 11) of FN7944 Rev 2.00.
What is the role of the LCFB pin in the ISL6446IAZ-T7A linear controller?
The LCFB pin is the feedback input for the ISL6446IAZ-T7A's linear controller, referenced to an internal 0.595V ±25mV threshold. An external resistor divider sets the linear output voltage (e.g., 1.2V, 1.8V). If unused, LCFB must be tied to VCC to maintain PGOOD functionality. Its leakage current is ≤80nA, ensuring minimal divider error - specified in Electrical Specifications (page 7) and Pin Descriptions (page 2).
How is PGOOD assertion timing determined for the ISL6446IAZ-T7A?
PGOOD assertion for the ISL6446IAZ-T7A begins only after both PWM outputs settle within ±10% of target and the linear output exceeds 75% of nominal. An internal timer then delays PGOOD high by tPGOOD = 0.065 / fSW seconds (e.g., 46ms at 1.4MHz). No independent adjustment is possible - this relationship is fixed and documented in Equation 3 (page 12) and Electrical Specifications (page 8) of FN7944 Rev 2.00.
ISL6446IAZ-T7A Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Renesas
- Series:
- -
- Package/Case:
- 24-SSOP (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- 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
ISL6446IAZ-T7A FAQ
1.How can I place an order for ISL6446IAZ-T7A through Aetrix?
Please submit a Request for Quotation (RFQ) for ISL6446IAZ-T7A 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 ISL6446IAZ-T7A reliable?
The price and inventory of ISL6446IAZ-T7A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ISL6446IAZ-T7A is usually 5 days.
3.What payment methods are accepted for ISL6446IAZ-T7A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ISL6446IAZ-T7A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ISL6446IAZ-T7A?
ISL6446IAZ-T7A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ISL6446IAZ-T7A 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 ISL6446IAZ-T7A?
For technical support, including ISL6446IAZ-T7A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ISL6446IAZ-T7A requirements.
6.How does Aetrix verify that ISL6446IAZ-T7A is sourced from the original manufacturer or authorized distributors?
All ISL6446IAZ-T7A 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 ISL6446IAZ-T7A meets industry standards.
7.What is the process for return or replacement of ISL6446IAZ-T7A?
All ISL6446IAZ-T7A units undergo pre-shipment inspection (PSI). If there is an issue with ISL6446IAZ-T7A, 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 ISL6446IAZ-T7A part is unused and in its original packaging.
Return procedure for ISL6446IAZ-T7A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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