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Renesas ISL97635IRZS2038
- Part No.:
- ISL97635IRZS2038
- Manufacturer:
- Renesas
- Category:
- LED Drivers
- Package:
- -
- Datasheet:
-
ISL97635IRZS2038.pdf
- Description:
- IC AMP CLASS
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Product details
Overview
ISL97635IRZS2038 from Renesas Electronics is an SMBus-controlled 8-channel LED driver IC designed for LCD backlight systems. It delivers up to 30mA per channel with ±1% typical current matching, supports dynamic headroom control for efficiency optimization, and operates from 6V–24V input to drive up to 72 white LEDs (8×9, 3.5V/30mA) in notebook or automotive display applications.
For engineers reviewing the ISL97635IRZS2038 datasheet, ISL97635IRZS2038 pinout, ISL97635IRZS2038 application, or ISL97635IRZS2038 equivalent, key selection criteria include SMBus 256-level PWM/DC dimming control, selectable 600kHz/1.2MHz boost switching frequency, integrated fault detection (open/short-circuit, OVP, OTP), and QFN-24 (4mm×4mm) thermal performance across –40°C to +85°C.
Technical Context
The ISL97635IRZS2038 implements a current-mode PWM boost converter with dynamic headroom control that monitors the highest forward-voltage LED string via IIN0–IIN7 feedback and regulates VOUT to maintain minimal headroom-reducing power loss in multi-string operation. Its dual-loop architecture features fast current sensing and slower voltage feedback for stable transient response during battery-to-adapter transitions.
Dimming is implemented through four distinct modes: SMBus-programmed 256-step PWM (100Hz–5kHz), external PWMI input (up to 20kHz), DPST-compliant combined SMBus+PWMI modulation, and DC-to-PWM conversion using VPWMO analog input (0.21V–1.21V). All modes preserve 8-channel current matching and support per-channel enable sequencing for RGB scrolling.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 6V to 24V - supports wide-range DC supplies including automotive 12V and industrial 24V rails without external pre-regulation. |
| Max Output Voltage | 34.5V - enables driving up to 9× 3.5V white LEDs or 10× 3.2V LEDs per channel in series. |
| Channel Count | 8 independent current sources - allows full-segment backlight control for high-resolution displays with localized dimming capability. |
| Current Matching | ±1% typical - ensures uniform luminance across all 8 LED strings without manual calibration or binning compensation. |
| Switching Frequency | 600kHz or 1.2MHz (selectable) - balances EMI suppression and inductor size; higher frequency reduces passive component footprint. |
| SMBus Interface | 10–100kHz clock, 3V–5.5V nominal - compatible with standard system management buses for host MCU integration and real-time brightness updates. |
| Thermal Range | –40°C to +85°C ambient - validated for automotive cabin and industrial embedded environments with no derating required. |
Pinout & Package
ISL97635IRZS2038 is housed in a thermally enhanced 24-lead 4mm × 4mm QFN package with exposed thermal pad (PKG DWG L24.4x4D), RoHS-compliant matte tin (e3) termination, and MSL3 moisture sensitivity rating.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SMBCLK / SMBDAT | SMBus interface clock/data bidirectional | Enable firmware-configurable dimming, fault register readback, and device identification over shared system bus. |
| PWMI/EN | Multi-function enable/dimming input | First 40µs pulse enables device; subsequent PWM signal provides audio-noise-free dimming up to 20kHz or triggers DPST mode. |
| IIN0–IIN7 | LED string feedback inputs | Monitor individual string voltages to implement dynamic headroom control and detect open/short faults per channel. |
| RSET | Current programming reference | External resistor sets maximum per-channel LED current (e.g., 36.6kΩ = 20mA); tolerance directly impacts absolute accuracy. |
| LX | Boost switch node | Connects to external inductor and Schottky diode; carries peak currents up to 3.2A; requires low-inductance layout for EMI control. |
| FAULT | Fault disconnect output | Open-drain signal pulls low on detected fault (OVP, OTP, short-circuit); latches until cleared via SMBus or power cycle. |
Key Features
| Feature | Design Value |
|---|---|
| Dynamic Headroom Control | Reduces VOUT to minimum required for highest-VF string, cutting boost losses by up to 15% versus fixed-output designs. |
| Four Dimming Modes | Enables compliance with Intel DPST, noise-sensitive audio environments (20kHz PWMI), and analog sensor interfaces (DC-to-PWM). |
| Per-Channel Fault Detection | Configurable short-circuit thresholds (3.1V or 8V) and open-circuit reporting allow precise failure localization in multi-string arrays. |
| Selectably Sequenced Channels | Software-controlled channel enable order supports RGB scrolling backlight effects without additional timing logic or external drivers. |
| Integrated 5.2V LDO (VDC) | Provides clean internal supply; eliminates need for external bias rail when VIN > 6V, simplifying BOM and layout. |
Applications
| Notebook Display Backlight | Automotive Instrument Cluster |
|---|---|
Use Scenario: High-brightness WLED backlight for 13–15.6-inch laptop panels with adaptive brightness control. IC Role / Device Role / Timing Role: Primary LED current regulator with SMBus-based brightness scaling and thermal foldback. Use Value: ±1% current matching eliminates visible banding; dynamic headroom control extends battery life by reducing boost losses at partial brightness. | Use Scenario: RGB LED backlight for digital instrument clusters requiring sequential channel activation for animation effects. IC Role / Device Role / Timing Role: 8-channel programmable current source enabling per-segment color and intensity control via SMBus commands. Use Value: Selectable channel sequencing allows smooth scrolling animations; -40°C to +85°C operation ensures reliability in under-hood temperature extremes. |
| LCD Monitor Backlight | Traffic Signal Module |
Use Scenario: Dual-scan or local-dimming backlight for 24–32-inch commercial monitors with EMI-sensitive audio subsystems. IC Role / Device Role / Timing Role: High-efficiency LED driver supporting 20kHz external PWM dimming to eliminate audible coil whine. Use Value: External PWMI input enables silent dimming; 600kHz/1.2MHz fSW selection optimizes EMI profile for mixed-signal PCB layouts. | Use Scenario: Red/green/yellow LED array in outdoor traffic signals requiring long-life, fault-tolerant operation. IC Role / Device Role / Timing Role: Fault-aware LED driver with open/short detection and latchable FAULT output for predictive maintenance. Use Value: Integrated OVP, OTP, and string fault detection reduce field failure rates; RoHS-compliant QFN package withstands humidity and thermal cycling. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 8-channel LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS61196RGER | Single 8-channel driver with I²C interface; lacks SMBus alert response and DPST mode; max VOUT = 32V. | Requires external fault handling logic; no native support for Intel DPST-compliant dimming sequences. | Choose for cost-sensitive consumer displays where SMBus ecosystem integration is not required. |
| MAX20057ATP/V+T | 8-channel with SPI interface; includes integrated boost inductor; fixed 1.2MHz fSW; no dynamic headroom control. | Higher BOM cost due to integrated inductor; less efficient at partial brightness due to fixed output regulation. | Prefer for space-constrained designs where board area is prioritized over thermal efficiency and dimming flexibility. |
Compared with TPS61196RGER and MAX20057ATP/V+T, the ISL97635IRZS2038 uniquely combines SMBus alert capability, DPST-compliant dimming, and dynamic headroom control-enabling higher efficiency, lower EMI, and tighter luminance uniformity in automotive and premium notebook backlight systems.
Availability
ISL97635IRZS2038 is available at Aetrix Electronics and suitable for notebook display backlighting, automotive instrument cluster illumination, and industrial LCD monitor applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for ISL97635IRZS2038 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 timing solutions for automotive, industrial, and computing markets.
The ISL97635IRZS2038 belongs to Renesas' high-precision LED driver product line, engineered specifically for energy-efficient, fault-resilient LCD backlight systems demanding tight current matching and intelligent thermal/power management.
FAQ
What is the maximum number of LEDs the ISL97635IRZS2038 can drive per channel?
The ISL97635IRZS2038 can drive up to 9 white LEDs (3.5V/30mA type) or 10 lower-VF LEDs (3.2V/20mA type) per channel, for a total of 72 or 80 LEDs respectively. This is enabled by its 34.5V maximum output voltage and dynamic headroom control, which minimizes voltage overhead while maintaining regulation across all strings. The ISL97635IRZS2038 achieves this with ±1% typical current matching across all 8 channels.
How does the ISL97635IRZS2038 implement dynamic headroom control?
The ISL97635IRZS2038 continuously monitors the lowest voltage among IIN0–IIN7 pins-the point of highest LED forward voltage-and uses that signal as the feedback reference for the boost regulator. This ensures VOUT is regulated just above the required level for the most demanding string, reducing power loss and heat generation. The ISL97635IRZS2038 maintains this cycle-by-cycle regulation while preserving per-channel current accuracy via its 8 independent current sources.
What dimming modes does the ISL97635IRZS2038 support, and how do they differ?
The ISL97635IRZS2038 supports four dimming modes: (1) SMBus-programmed 256-step PWM (100Hz–5kHz), (2) external PWMI input (up to 20kHz), (3) DPST-compliant combined SMBus+PWMI modulation, and (4) DC-to-PWM using VPWMO analog input (0.21V–1.21V). Each mode preserves 8-channel current matching and enables different system-level requirements-such as Intel DPST compliance, audio-noise elimination, or ambient light sensor interfacing-without hardware changes. The ISL97635IRZS2038 selects mode via Register 0x01 configuration.
What fault protection features are integrated into the ISL97635IRZS2038?
The ISL97635IRZS2038 integrates string open-circuit detection, selectable-threshold short-circuit detection (3.1V or 8V), overvoltage protection (OVP), overtemperature protection (OTP), thermal shutdown, and optional input overcurrent protection with master fault disconnect switch. All fault conditions are latched and reported in the Fault/Status register accessible via SMBus. The ISL97635IRZS2038 also provides dedicated FAULT pin output for system-level fault signaling and recovery coordination.
What is the recommended RSET value for 20mA per-channel operation in the ISL97635IRZS2038?
For 20mA per-channel operation, the ISL97635IRZS2038 requires a 36.6kΩ resistor at the RSET pin, calculated using Equation 3 from the datasheet (RSET = 733 / ILEDmax). A 1% tolerance metal-film resistor is recommended to maintain absolute current accuracy within ±3%, as specified in the Electrical Specifications table. The ISL97635IRZS2038's current matching remains ±1% typical regardless of RSET tolerance, ensuring consistent luminance across all 8 channels.
ISL97635IRZS2038 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Renesas
- Series:
- -
- Package/Case:
- -
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Type:
- -
- Topology:
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- Internal Switch(s):
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- Number of Outputs:
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- Voltage - Supply (Min):
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- Voltage - Supply (Max):
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- Voltage - Output:
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- Current - Output / Channel:
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- Frequency:
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- Dimming:
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- Applications:
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- Operating Temperature:
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- Grade:
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ISL97635IRZS2038 FAQ
1.How can I place an order for ISL97635IRZS2038 through Aetrix?
Please submit a Request for Quotation (RFQ) for ISL97635IRZS2038 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 ISL97635IRZS2038 reliable?
The price and inventory of ISL97635IRZS2038 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ISL97635IRZS2038 is usually 5 days.
3.What payment methods are accepted for ISL97635IRZS2038?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ISL97635IRZS2038 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ISL97635IRZS2038?
ISL97635IRZS2038 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ISL97635IRZS2038 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 ISL97635IRZS2038?
For technical support, including ISL97635IRZS2038 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ISL97635IRZS2038 requirements.
6.How does Aetrix verify that ISL97635IRZS2038 is sourced from the original manufacturer or authorized distributors?
All ISL97635IRZS2038 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 ISL97635IRZS2038 meets industry standards.
7.What is the process for return or replacement of ISL97635IRZS2038?
All ISL97635IRZS2038 units undergo pre-shipment inspection (PSI). If there is an issue with ISL97635IRZS2038, 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 ISL97635IRZS2038 part is unused and in its original packaging.
Return procedure for ISL97635IRZS2038:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
ISL97635IRZS2038 Tags
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