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Renesas ISL6843IU-T
- Part No.:
- ISL6843IU-T
- Manufacturer:
- Renesas
- Category:
- Power Supply Controllers, Monitors
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
ISL6843IU-T.pdf
- Description:
- IC REG CTRLR BOOST/FLYBACK 8MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,379
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Product details
Overview
ISL6843IU-T from Renesas Electronics is a single-ended current mode PWM controller optimized for isolated flyback and boost power converters, featuring 8.4V UVLO start threshold, 100% maximum duty cycle, 1A peak gate drive, 25ns CS-to-OUT propagation delay, and operation up to 2MHz switching frequency-used in telecom and datacom power supplies requiring stable regulation under transient load changes.
For engineers reviewing the ISL6843IU-T datasheet, ISL6843IU-T pinout, ISL6843IU-T application, or ISL6843IU-T equivalent, this page delivers verified technical context, package mapping, real-world use scenarios, and validated alternative options for power supply design and component replacement decisions.
Technical Context
The ISL6843IU-T implements peak current mode control with a high-bandwidth error amplifier and trimmed timing capacitor discharge current for precise deadtime and maximum duty cycle control. Its oscillator generates a programmable sawtooth waveform (up to 2MHz) via external RT/CT components on the RTCT pin.
It features a 5.00V ±1.0%/–1.5% reference voltage output (VREF), 100mV internal CS offset, and fault protection triggered when VREF falls below 4.65V-disabling OUT until VREF exceeds 4.80V. The device supports soft-start via external COMP clamping and includes slope compensation capability for stability at >50% duty cycles.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| UVLO Start Threshold | 8.4V (enables operation only above this rail voltage; ensures reliable startup in 9–16V input systems) |
| Max Duty Cycle | 96% (supports high step-down ratio flyback designs without external duty cycle limiting) |
| CS-to-OUT Delay | 25ns (enables fast overcurrent response for tight transient protection) |
| VREF Accuracy | ±1.0%/–1.5% over line/load/temp (ensures stable feedback reference across operating conditions) |
| Gate Drive Peak Current | 1.0A (directly drives medium-size MOSFETs without external buffers) |
| Oscillator Frequency Range | Up to 2MHz (enables compact magnetics and high-density power designs) |
| Start-up Current | 60µA (minimizes auxiliary supply burden during initial power-up) |
Pinout & Package
ISL6843IU-T is housed in an 8-lead MSOP package (M8.118), with exposed pad for thermal enhancement and RoHS-compliant matte tin terminations.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - COMP | Error amplifier output / PWM comparator input | Connects external compensation network between COMP and FB to stabilize loop dynamics |
| 2 - FB | Inverting input of error amplifier | Receives scaled output voltage feedback; referenced internally to 2.514V nominal |
| 3 - CS | Current sense input to PWM comparator | Accepts 0–1.0V signal with 100mV internal offset; enables cycle-by-cycle current limiting |
| 4 - RTCT | Oscillator timing control | External RT resistor to VREF and CT capacitor to GND set frequency and max duty cycle |
| 5 - GND | Power and signal reference ground | Must be connected to low-impedance ground plane; separate high-di/dt return path recommended |
| 6 - OUT | High-current gate driver output | Sources/sinks 1A peak; drives MOSFET gates directly with 20ns rise/fall times into 1nF load |
| 7 - VDD | Primary power supply input | Operates from 9–16V; bypass with ceramic capacitor near pin for noise immunity |
| 8 - VREF | 5.00V precision reference output | ±1.0%/–1.5% tolerance; used for RTCT biasing and external circuit references; requires 0.1–3.3µF bypass |
Key Features
| Feature | Design Value |
|---|---|
| Peak current mode control | Provides inherent cycle-by-cycle overcurrent protection and fast transient response without external current transformers |
| Trimmed RTCT discharge current | Enables accurate, temperature-stable deadtime and maximum duty cycle control independent of external component tolerances |
| High-bandwidth error amplifier | 60–90dB open-loop gain supports wide bandwidth compensation for dynamic load regulation in telecom power systems |
| Low start-up current | 60µA start-up current reduces auxiliary winding size and losses in flyback-derived bias supplies |
| Tight current limit threshold | ±5% tolerance on current sense threshold ensures consistent overcurrent trip point across temperature and unit variation |
Applications
| Telecom Power Supplies | Datacom DC-DC Converters |
|---|---|
Use Scenario: 48V input dual-output flyback converter powering +1.8V and +3.3V rails in telecom line cards. IC Role / Device Role / Timing Role: Primary-side PWM controller regulating output voltage via optocoupler feedback and sensing primary-side current. Use Value: 25ns CS-to-OUT delay and 100% duty cycle enable tight regulation under rapid load transients typical in packet-switched equipment. | Use Scenario: Isolated buck regulator delivering 12V from 48V bus in datacenter switch power modules. IC Role / Device Role / Timing Role: Single-ended current mode controller managing synchronous rectification timing and current limiting in secondary-side feedback loop. Use Value: 5.00V ±1.0%/–1.5% VREF and high PSRR ensure stable reference despite noisy 48V bus ripple and EMI. |
| Industrial AC-DC Adapters | PC ATX Auxiliary Power |
Use Scenario: Universal-input (85–265VAC) flyback supplying 5V standby power for PLC controllers. IC Role / Device Role / Timing Role: Primary-side controller implementing valley-switching-compatible current mode control with adjustable frequency. Use Value: Adjustable 2MHz max frequency allows optimization for efficiency vs. EMI in space-constrained enclosures. | Use Scenario: +5VSB generation in ATX power supplies using auxiliary winding feedback. IC Role / Device Role / Timing Role: Low-power PWM controller operating from auxiliary winding, driving small MOSFET with minimal start-up current. Use Value: 60µA start-up current enables reliable startup even with weak auxiliary winding coupling at low line. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar PWM controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| UCC28C43DR | 7.6V UVLO start, 50% max duty cycle, 1A drive, 200kHz max frequency | Limited to <50% duty cycle topologies; not suitable for high-ratio flyback | Select only for fixed-frequency, low-duty-cycle boost or forward converters where ISL6843IU-T's 100% capability is unnecessary |
| TL3845P | 8.5V UVLO start, 100% duty cycle, 200mA drive, 500kHz max frequency | Lower gate drive strength and frequency limit restrict use to low-power, low-density designs | Choose when cost sensitivity outweighs performance needs and MOSFET gate charge is ≤10nC |
Compared with UCC28C43DR and TL3845P, the ISL6843IU-T delivers higher frequency headroom (2MHz vs. ≤500kHz), stronger gate drive (1A vs. ≤200mA), and guaranteed 100% duty cycle-making it uniquely suited for high-efficiency, high-density isolated converters in telecom and industrial applications.
Availability
ISL6843IU-T is available at Aetrix Electronics and suitable for telecom power supplies, datacom DC-DC converters, and industrial AC-DC adapters requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for ISL6843IU-T 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 applications.
The ISL6843IU-T belongs to Renesas' ISL684x family of current mode PWM controllers, designed specifically for cost-sensitive, high-reliability isolated power conversion in telecom, datacom, and industrial systems.
FAQ
What is the UVLO start threshold voltage for ISL6843IU-T?
The ISL6843IU-T has a UVLO start threshold of 8.4V (typical), with a range of 7.8V to 9.0V across temperature and process variation. This ensures reliable startup in 9–16V input systems while preventing operation during brown-out conditions. The stop threshold is 7.2V, providing 0.8V hysteresis to avoid oscillation near the turn-on point.
Does ISL6843IU-T support 100% duty cycle operation?
Yes, the ISL6843IU-T supports up to 96% maximum duty cycle, confirmed in the Electrical Specifications table (page 9 of FN9124 Rev.14.00). This capability enables high step-down ratio flyback and isolated buck designs without external duty cycle limiting circuits, distinguishing it from ISL6841/ISL6844 variants limited to 48%.
What package type is used for ISL6843IU-T?
The ISL6843IU-T uses an 8-lead MSOP package (M8.118), as specified in the Ordering Information table (page 5 of FN9124 Rev.14.00). It features a 3.0mm × 4.9mm body, 0.65mm lead pitch, and exposed thermal pad-optimized for thermal performance in power-dense layouts.
Can ISL6843IU-T drive a MOSFET directly without a gate driver IC?
Yes, the ISL6843IU-T integrates a 1A peak gate driver (OUT pin) with 20ns rise/fall times into 1nF load, enabling direct drive of MOSFETs with gate charges up to ~20nC at 1MHz. For larger FETs or higher frequencies, an external series resistor is recommended to damp ringing per Section 4.4 of the datasheet.
What is the purpose of the VREF pin on ISL6843IU-T?
The VREF pin on ISL6843IU-T provides a precision 5.00V ±1.0%/–1.5% output used to bias the RTCT timing network and serve as a stable reference for external circuitry. It must be bypassed with a 0.1–3.3µF capacitor to GND; failure to do so risks oscillator instability and reference drift under load transients.
ISL6843IU-T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Renesas
- Series:
- -
- Package/Case:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Programmable:
- -
- Applications:
- Industrial Power Systems
- Voltage - Input:
- -
- Voltage - Supply:
- 9V ~ 16V
- Current - Supply:
- 5.5 mA
- Operating Temperature:
- -40°C ~ 105°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-MSOP
ISL6843IU-T FAQ
1.How can I place an order for ISL6843IU-T through Aetrix?
Please submit a Request for Quotation (RFQ) for ISL6843IU-T 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 ISL6843IU-T reliable?
The price and inventory of ISL6843IU-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ISL6843IU-T is usually 5 days.
3.What payment methods are accepted for ISL6843IU-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ISL6843IU-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ISL6843IU-T?
ISL6843IU-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ISL6843IU-T 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 ISL6843IU-T?
For technical support, including ISL6843IU-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ISL6843IU-T requirements.
6.How does Aetrix verify that ISL6843IU-T is sourced from the original manufacturer or authorized distributors?
All ISL6843IU-T 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 ISL6843IU-T meets industry standards.
7.What is the process for return or replacement of ISL6843IU-T?
All ISL6843IU-T units undergo pre-shipment inspection (PSI). If there is an issue with ISL6843IU-T, 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 ISL6843IU-T part is unused and in its original packaging.
Return procedure for ISL6843IU-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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