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Renesas ISL6845IUZ
- Part No.:
- ISL6845IUZ
- Manufacturer:
- Renesas
- Category:
- Power Supply Controllers, Monitors
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
ISL6845IUZ.pdf
- Description:
- IC REG CTRLR BOOST/FLYBACK 8MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,741
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Product details
Overview
ISL6845IUZ from Intersil is a single-ended current mode PWM controller in an 8-lead MSOP package, designed for isolated flyback and boost power converters. It features 8.4V UVLO start threshold, 50% maximum duty cycle, 5.00V ±1.0% reference voltage, 1A peak gate drive, and 25ns CS-to-OUT propagation delay. It operates across –40°C to +105°C for telecom and industrial DC/DC applications.
For engineers reviewing the ISL6845IUZ datasheet, ISL6845IUZ pinout, ISL6845IUZ application, or ISL6845IUZ equivalent, key selection criteria include its 8.4V/7.2V UVLO hysteresis, 50% duty cycle limit, 1A gate driver capability, tight 4.925–5.050V VREF accuracy over temperature, and compatibility with high-frequency (up to 2MHz) timing networks using RTCT.
Technical Context
The ISL6845IUZ implements peak current mode control with a dedicated current sense comparator having 100mV offset and 25ns propagation delay from CS to OUT, enabling fast transient response and inherent cycle-by-cycle overcurrent protection. Its oscillator uses external RT/CT on the RTCT pin to generate a sawtooth waveform programmable up to 2MHz.
It integrates a high-bandwidth error amplifier (90dB open-loop gain, 5MHz unity-gain bandwidth), a trimmed 5.00V reference with ±1.0% line/load/temperature tolerance, and a 1A totem-pole output stage with 20ns rise/fall times into 1nF. The device disables output when VREF falls below 4.65V and re-enables at 4.80V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| UVLO Start Threshold | 8.4V (enables operation only above valid input rail; 0.8V hysteresis prevents chatter) |
| Max Duty Cycle | 48% (limits conduction time per cycle; critical for stability in flyback with DCM/CCM boundary) |
| VREF Accuracy | 4.925–5.050V over line, load, and –40°C to +105°C (ensures <±1.5% output voltage regulation) |
| CS-to-OUT Delay | 25ns typical (minimizes current-sense-to-gate-response latency for precise peak current limiting) |
| Gate Drive Strength | 1A peak sink/source (directly drives medium-power MOSFETs without external buffers) |
| Oscillator Frequency Range | Up to 2MHz (supports compact magnetics and high-density power designs) |
| Error Amp GBW | 5MHz (enables wide-loop bandwidth for fast load transient recovery) |
Pinout & Package
ISL6845IUZ is housed in an 8-lead MSOP package (JEDEC MO-187AA, M8.118), 3.0mm × 3.0mm footprint, 0.65mm pitch, with exposed pad for thermal enhancement. Pin 1 is marked by a dot or beveled corner.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - RTCT | Oscillator timing control | Connects external R (to VREF) and C (to GND) to set switching frequency and max duty cycle |
| 2 - FB | Error amplifier inverting input | Receives scaled output voltage feedback; internal 2.514V reference sets regulation point |
| 3 - CS | Current sense comparator input | Accepts 0–1.0V signal with 100mV offset; triggers PWM shutdown on overcurrent |
| 4 - VREF | 5.00V precision reference output | Stable 5V supply for external circuitry; requires 0.1–3.3µF bypass capacitor to GND |
| 5 - VDD | Main power supply input | Operates from 9–16V; 60µA start-up current enables low-power enable sequencing |
| 6 - OUT | High-current gate driver output | Drives MOSFET gate with 1A peak; 20ns rise/fall into 1nF ensures fast switching transitions |
| 7 - GND | Power and signal reference ground | Must be connected to low-impedance ground plane; separates high-di/dt return paths |
| 8 - COMP | Error amplifier output / PWM comparator input | Interface for loop compensation network between COMP and FB pins |
Key Features
| Feature | Design Value |
|---|---|
| 1A peak gate drive | Eliminates need for external driver stages in sub-100W isolated converters |
| 60µA start-up current | Enables direct connection to auxiliary winding or low-power bias rails without startup resistor loss |
| 25ns CS-to-OUT propagation delay | Reduces minimum detectable overcurrent pulse width, improving short-circuit protection speed |
| Trimmed RTCT discharge current | Ensures accurate deadtime and maximum duty cycle control across temperature and process variation |
| Tight 100mV CS offset tolerance | Maintains consistent current limit threshold across operating conditions without calibration |
Applications
| Telecom Power Supply | Industrial Isolated Flyback |
|---|---|
Use Scenario: 48V input dual-output flyback supplying +1.8V and +3.3V to base station control logic. IC Role / Device Role / Timing Role: Primary-side PWM controller regulating output via optocoupler feedback to FB pin; sets switching frequency and duty cycle via RTCT network. Use Value: 8.4V UVLO ensures reliable start-up from nominal 48V telecom rail; 50% max duty cycle prevents transformer saturation during overload. |
Use Scenario: 24–48V industrial input flyback delivering isolated 12V/500mA for PLC I/O modules. IC Role / Device Role / Timing Role: Current-mode controller providing cycle-by-cycle current limiting and fast transient response to varying sensor loads. Use Value: 25ns CS-to-OUT delay enables robust short-circuit protection; 1A gate drive directly switches 600V/1Ω MOSFETs without buffer. |
| PC Auxiliary Power | Boost Regulator for Datacom |
Use Scenario: +5V standby rail generation from ATX main 12V rail using isolated flyback topology. IC Role / Device Role / Timing Role: Single-ended PWM IC controlling primary switch; FB pin receives opto-coupled feedback from secondary side. Use Value: Tight 4.925–5.050V VREF accuracy maintains ±1.5% output regulation across line/load/temp; low 60µA start-up current minimizes no-load loss. |
Use Scenario: Boost converter generating +12V from 5V bus for optical transceiver modules in datacom equipment. IC Role / Device Role / Timing Role: High-frequency (1–2MHz) current-mode controller driving external N-channel MOSFET in boost configuration. Use Value: 2MHz programmable frequency allows use of small 2.2µH inductors and 10µF ceramic output caps; 20ns rise/fall times minimize switching losses. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar PWM controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| UCC28C42DR | 7.6V/6.8V UVLO, 50% max duty cycle, 1A drive, but 2.5V reference and no integrated 5V VREF output | Requires external reference or feedback divider adjustment; less suitable for designs needing clean 5V bias rail | Choose UCC28C42DR if board already provides stable 2.5V reference and space is constrained-no VREF bypass cap needed |
| TL3845P | 8.4V/7.6V UVLO, 45% max duty cycle, 200mA drive, 2.5V reference, no 5V VREF output | Limited gate drive strength requires external buffer for >1A loads; lower accuracy reference increases output voltage drift | Choose TL3845P only for cost-sensitive, low-power (<15W) flyback where 5V bias is available elsewhere |
Compared with UCC28C42DR and TL3845P, ISL6845IUZ uniquely integrates a precision 5.00V reference and 1A gate driver in an MSOP package-reducing BOM count and improving regulation accuracy in isolated DC/DC designs requiring self-contained biasing.
Availability
ISL6845IUZ is available at Aetrix Electronics and suitable for telecom power supplies, industrial isolated flyback converters, PC auxiliary rails, and datacom boost regulators requiring stable component supply and long-term design continuity.
Supply support for ISL6845IUZ 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 Corporation, now part of Renesas Electronics, is a semiconductor innovator specializing in high-performance analog and power management ICs for industrial, telecom, and computing markets.
The ISL684x family-including ISL6845IUZ-was engineered as a BiCMOS upgrade to legacy 384x controllers, delivering higher frequency, tighter tolerances, and improved gate drive for next-generation isolated power supplies.
FAQ
What is the UVLO behavior of the ISL6845IUZ?
The ISL6845IUZ has a rising UVLO threshold of 8.4V and falling threshold of 7.2V, providing 1.2V hysteresis to prevent oscillation near brownout conditions. Operation begins only when VDD rises above 8.4V, and shuts down when VDD drops below 7.2V. This ensures reliable start-up from 9–16V input ranges common in telecom and industrial systems, and is confirmed in the FN9124.10 datasheet Table "UNDERVOLTAGE LOCKOUT" for ISL6843/ISL6845 variants.
Does the ISL6845IUZ provide an internal voltage reference?
Yes, the ISL6845IUZ provides a 5.00V ±1.0% reference voltage on the VREF pin, specified from –40°C to +105°C with line/load regulation. It delivers up to 10mA and requires a 0.1–3.3µF ceramic bypass capacitor to GND. This integrated reference eliminates the need for external references in feedback networks and bias rails, and is explicitly documented in the "REFERENCE VOLTAGE" section of the FN9124.10 datasheet.
What is the maximum switching frequency supported by the ISL6845IUZ?
The ISL6845IUZ supports adjustable switching frequencies up to 2MHz via external RT and CT components on the RTCT pin. The oscillator produces a sawtooth waveform whose frequency and maximum duty cycle are calculated using published equations in the datasheet. This high-frequency capability enables compact magnetic design and reduced output capacitance in space-constrained applications like datacom modules.
Can the ISL6845IUZ drive a power MOSFET directly?
Yes, the ISL6845IUZ features a 1A peak source/sink totem-pole output on the OUT pin, capable of directly driving medium-power MOSFET gates without external buffers. Rise and fall times are 20ns into a 1nF load, and gate drive performance is validated across temperature. This is confirmed in the "OUTPUT" section of FN9124.10, including peak current and timing specifications.
How does the ISL6845IUZ handle overcurrent protection?
The ISL6845IUZ implements cycle-by-cycle overcurrent protection using its CS pin, which accepts a 0–1.0V signal with a nominal 100mV offset. When the sensed voltage exceeds the internal threshold, the PWM output is disabled within 25ns (typical). This fast propagation delay ensures immediate shutdown during short circuits, and the feature is intrinsic to its peak current mode architecture as described in the Functional Block Diagram and "CURRENT SENSE" specifications.
ISL6845IUZ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Renesas
- Series:
- -
- Package/Case:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Packaging:
- Tube
- 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
ISL6845IUZ FAQ
1.How can I place an order for ISL6845IUZ through Aetrix?
Please submit a Request for Quotation (RFQ) for ISL6845IUZ 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 ISL6845IUZ reliable?
The price and inventory of ISL6845IUZ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ISL6845IUZ is usually 5 days.
3.What payment methods are accepted for ISL6845IUZ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ISL6845IUZ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ISL6845IUZ?
ISL6845IUZ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ISL6845IUZ 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 ISL6845IUZ?
For technical support, including ISL6845IUZ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ISL6845IUZ requirements.
6.How does Aetrix verify that ISL6845IUZ is sourced from the original manufacturer or authorized distributors?
All ISL6845IUZ 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 ISL6845IUZ meets industry standards.
7.What is the process for return or replacement of ISL6845IUZ?
All ISL6845IUZ units undergo pre-shipment inspection (PSI). If there is an issue with ISL6845IUZ, 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 ISL6845IUZ part is unused and in its original packaging.
Return procedure for ISL6845IUZ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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