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Renesas ISL9491AERZ-T
- Part No.:
- ISL9491AERZ-T
- Manufacturer:
- Renesas
- Category:
- Special Purpose Regulators
- Package:
- 16-VQFN Exposed Pad
- Datasheet:
-
ISL9491AERZ-T.pdf
- Description:
- IC REG CONV SATELLIT 1OUT 16QFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,053
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Product details
Overview
ISL9491AERZ-T from Intersil is a single-output LNB supply voltage regulator IC designed for satellite set-top box applications. It integrates a current-mode boost converter and low-noise linear regulator with tone injection, DiSEqC 1.x/2.x support, and VSET-controlled polarization voltage selection (11.0V/12.0V/15.0V/16.0V). It delivers up to 500mA output current with <1.4V dropout at full load and operates across -20°C to +85°C.
For engineers reviewing the ISL9491AERZ-T datasheet, ISL9491AERZ-T pinout, ISL9491AERZ-T application, or ISL9491AERZ-T equivalent, key selection considerations include DiSEqC tone frequency (44kHz), LNB polarization voltage programmability via VSET0/VSET1, integrated fault signaling (open-drain FAULT), thermal shutdown at 130°C, and QFN-16 package compatibility with satellite STB power architectures.
Technical Context
The ISL9491AERZ-T implements a two-stage architecture: a 380–480kHz current-mode boost converter supplies regulated input to an internal linear post-regulator, maintaining minimal dropout (1.2–1.4V) to optimize efficiency. Its EXTM pin accepts external 44kHz DiSEqC tone signals and transfers them symmetrically to VLNB while preserving signal integrity.
Voltage selection is logic-driven via VSET0/VSET1 pins (11.0V/12.0V/15.0V/16.0V), and dynamic current limiting uses ILIMIT resistor programming (e.g., 148kΩ → 350mA threshold). Thermal protection shuts down both boost and LDO stages above 130°C with 20°C hysteresis, and FAULT asserts low on overvoltage, undervoltage, overcurrent, or overtemperature events.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage Range | 11.0V, 12.0V, 15.0V, or 16.0V selectable via VSET0/VSET1 logic - enables vertical/horizontal LNB polarization control in single-tuner satellite systems. |
| Max Output Current | 500mA continuous, 750mA peak - supports standard LNB loads without external pass devices. |
| Dropout Voltage | 1.2V typical at 500mA - minimizes power dissipation in linear stage when paired with boost-adjusted VSW. |
| Tone Frequency Support | 44kHz external DiSEqC tone input - compliant with ISL9491A variant specification for DiSEqC 1.x/2.x command transmission. |
| Thermal Shutdown | 130°C typical activation with 20°C hysteresis - protects die during sustained overload or poor heatsinking. |
| Supply Voltage Range | 8V to 11V (ISL9491A) - defines valid input rail for stable operation in STB 12V-derived power domains. |
| Efficiency | >92% boost stage efficiency - reduces heat generation and improves system-level power budget in compact STB enclosures. |
Pinout & Package
ISL9491AERZ-T is housed in a 16-lead QFN package (4mm × 4mm, L16.4x4, exposed thermal pad), RoHS-compliant with matte tin e3 termination. Pin layout optimized for low-inductance power routing and thermal management in satellite receiver modules.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VCC | Main power supply input | Accepts 8–11V input; powers internal circuitry and bias networks - requires 1µF BYPASS capacitor for internal 5V LDO stability. |
| GATE | Boost FET gate driver output | Drives external N-channel MOSFET; current-mode control ensures stable boost operation under varying LNB load conditions. |
| CS | Current sense input | Monitors boost FET source voltage; triggers pulse-by-pulse overcurrent protection at 445mV threshold to safeguard switching stage. |
| VOUT | LNB output anode connection | Delivers regulated voltage to anode of back diode; must be isolated from VSENSE to prevent reverse conduction into LNB port. |
| VSENSE | LNB output cathode sensing | Connects to cathode of back diode; withstands up to 24V reverse bias - enables safe tone injection and fault detection on VLNB line. |
| EXTM | External DiSEqC tone input | Accepts 44kHz square-wave DiSEqC commands; transfers tone symmetrically to VLNB with 4–8µs rise/fall time for protocol compliance. |
| VSET0 / VSET1 | Output voltage selection inputs | Logic-controlled pins (0/1) that configure four discrete LNB voltages - critical for polarization switching in single-dish, single-tuner configurations. |
| EN | Enable control input | Active-high logic input; disables all regulators and enters low-power shutdown when pulled low - reduces quiescent current to <8mA. |
| FAULT | Open-drain fault indicator | Asserts low on undervoltage, overvoltage (±12%), overcurrent, or overtemperature - provides interrupt-capable status for host microcontroller monitoring. |
| ILIMIT | Linear regulator current limit set | Resistor-to-GND sets dynamic overcurrent threshold (e.g., 148kΩ = 350mA); enables programmable protection without external components. |
| TCAP | Soft-start timing capacitor | 0.1µF capacitor sets output voltage ramp time - prevents inrush current and ensures controlled LNB power-up sequence. |
| PGND / SGND | Power / signal ground returns | Separate ground paths isolate high-current boost switching noise from sensitive analog regulation and sensing circuits. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated Boost + Linear Architecture | Eliminates need for discrete DC/DC and LDO stages - reduces BOM count, PCB area, and design complexity in STB LNB supply designs. |
| DiSEqC 1.x/2.x Tone Injection | 44kHz EXTM input with symmetric VLNB modulation - meets satellite industry standards for antenna switching and positioner control without external modulators. |
| VSET-Controlled Polarization Selection | Four precise output voltages (11.0V/12.0V/15.0V/16.0V) via two logic pins - enables seamless horizontal/vertical LNB bias switching in consumer-grade receivers. |
| Dynamic & Static Current Limiting | Programmable 50ms-on/900ms-off cycling (dynamic) or constant 750mA delivery (static) - protects against sustained shorts while maintaining system responsiveness. |
| Comprehensive Fault Protection | Single open-drain FAULT pin reports UVLO, OVLO, OCL, and OT - simplifies host-side diagnostics and eliminates need for multiple monitoring circuits. |
Applications
| Direct Broadcast Satellite (DBS) Receiver | Single-Tuner Set-Top Box |
|---|---|
|
Use Scenario: Powering and controlling a single LNB in a DBS receiver with motorized dish positioning. IC Role / Device Role / Timing Role: Provides regulated 15.0V/16.0V output and injects 44kHz DiSEqC tone to select satellite positions and polarizations. Use Value: Enables full DiSEqC 2.x functionality including positioner control and multi-satellite switching using one IC and minimal external components. |
Use Scenario: Supplying bias voltage and tone signal to an LNB in a cost-sensitive consumer STB with fixed dish. IC Role / Device Role / Timing Role: Delivers 11.0V/12.0V output and transmits 44kHz tone for basic DiSEqC 1.x switching between vertical/horizontal polarizations. Use Value: Reduces bill-of-materials by integrating boost, LDO, tone injection, and fault reporting - lowers manufacturing cost and improves reliability. |
| LNB Power Module for OEM Designs | DIRECTV SWM-Compatible System |
|
Use Scenario: Embedded LNB supply module in industrial satellite communication equipment requiring extended temperature operation. IC Role / Device Role / Timing Role: Regulates output with ±12% OV/UV fault window and thermal shutdown at 130°C - ensures robust operation in unventilated enclosures. Use Value: Supports -20°C to +85°C ambient range with built-in protections - eliminates need for external thermal sensors or voltage monitors. |
Use Scenario: Enabling DIRECTV SWM (Single Wire Multiswitch) compatibility in third-party satellite receivers. IC Role / Device Role / Timing Role: Generates stable 16.0V output and clean 44kHz tone with <900mV amplitude - meets SWM signal integrity requirements. Use Value: Allows non-DIRECTV hardware to interface with SWM-enabled dishes without proprietary ICs - expands design flexibility for integrators. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LNB supply regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ISL9491ERZ-T | Supports higher output voltages (13.3V/14.3V/18.3V/20.0V) and 22kHz DiSEqC tone; wider VCC range (8–14V). | Targeted at premium STBs requiring higher LNB bias or legacy 22kHz DiSEqC infrastructure. | Select ISL9491ERZ-T when 22kHz tone or >16V LNB operation is required; not drop-in compatible due to different tone frequency and voltage mapping. |
| MAX2221ETA+T | Single-chip LNB supply with 22kHz tone, 13.0–20.0V output, but no VSET logic interface - uses I²C for voltage control. | Requires microcontroller I²C interface instead of GPIO-based VSET; lacks integrated boost controller - needs external inductor. | Choose MAX2221ETA+T only if I²C configurability and smaller footprint outweigh loss of GPIO simplicity and integrated boost stage. |
Compared with ISL9491AERZ-T, ISL9491ERZ-T offers higher voltage capability and 22kHz tone for broader DiSEqC compatibility, while MAX2221ETA+T trades GPIO-based voltage selection for I²C programmability and reduced integration - making ISL9491AERZ-T optimal for cost-sensitive, GPIO-driven 44kHz DiSEqC systems.
Availability
ISL9491AERZ-T is available at Aetrix Electronics and suitable for satellite set-top box power supplies, LNB bias modules, and DiSEqC-compatible antenna control systems requiring stable component supply and long-term obsolescence planning.
Supply support for ISL9491AERZ-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
Intersil Corporation is a leading provider of power management and precision analog solutions, now part of Renesas Electronics, with deep expertise in satellite, broadcast, and consumer power ICs.
The ISL9491AERZ-T belongs to Intersil's LNB supply regulator product line, engineered specifically for single-tuner satellite receiver applications requiring integrated boost conversion, low-noise linear regulation, and DiSEqC-compliant tone injection.
FAQ
What is the maximum output voltage supported by the ISL9491AERZ-T?
The ISL9491AERZ-T supports four discrete output voltages: 11.0V, 12.0V, 15.0V, and 16.0V - selected via logic states on VSET0 and VSET1 pins. These values are specified for the ISL9491A variant and differ from the ISL9491 (which supports 13.3V–20.0V). The 16.0V maximum enables compatibility with higher-voltage LNBs used in certain DIRECTV SWM configurations.
Does the ISL9491AERZ-T support DiSEqC 2.x protocol?
Yes, the ISL9491AERZ-T supports DiSEqC 2.x through its EXTM pin, which accepts externally generated 44kHz tone signals and transfers them symmetrically to the VLNB output. An external DiSEqC tank circuit can be added to meet full DiSEqC 2.x transmit requirements, including burst coding and enhanced command sets beyond DiSEqC 1.x.
How does the ISL9491AERZ-T implement current limiting?
The ISL9491AERZ-T provides dual current limiting modes: dynamic (50ms on / 900ms off cycling) programmed via ILIMIT resistor, and static (constant 750mA delivery) enabled by shorting ILIMIT to GND. Dynamic mode protects against intermittent faults; static mode sustains current during brief overloads - both prevent thermal runaway while maintaining system responsiveness.
What is the purpose of the TCAP pin on the ISL9491AERZ-T?
The TCAP pin on the ISL9491AERZ-T sets soft-start timing by connecting an external capacitor (typically 0.1µF). It controls the rise and fall time of the output voltage during power-up and transitions between voltage levels - preventing inrush current, reducing stress on external components, and ensuring reliable LNB initialization without voltage overshoot or undershoot.
Can the ISL9491AERZ-T be used in DIRECTV SWM systems?
Yes, the ISL9491AERZ-T is DIRECTV SWM compliant per its datasheet. It delivers stable 16.0V output and injects clean 44kHz tone with 400–900mV amplitude and 4–8µs edge rates - meeting SWM signal integrity specifications for single-wire multiswitch operation. Its integrated fault reporting also aligns with SWM system diagnostic requirements.
ISL9491AERZ-T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Renesas
- Series:
- -
- Package/Case:
- 16-VQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Applications:
- Converter, Satellite Set-Top Box Designs
- Voltage - Input:
- 8V ~ 11V
- Number of Outputs:
- 1
- Voltage - Output:
- 11V ~ 16V
- Operating Temperature:
- -20°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-QFN (4x4)
ISL9491AERZ-T FAQ
1.How can I place an order for ISL9491AERZ-T through Aetrix?
Please submit a Request for Quotation (RFQ) for ISL9491AERZ-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 ISL9491AERZ-T reliable?
The price and inventory of ISL9491AERZ-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ISL9491AERZ-T is usually 5 days.
3.What payment methods are accepted for ISL9491AERZ-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ISL9491AERZ-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ISL9491AERZ-T?
ISL9491AERZ-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ISL9491AERZ-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 ISL9491AERZ-T?
For technical support, including ISL9491AERZ-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ISL9491AERZ-T requirements.
6.How does Aetrix verify that ISL9491AERZ-T is sourced from the original manufacturer or authorized distributors?
All ISL9491AERZ-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 ISL9491AERZ-T meets industry standards.
7.What is the process for return or replacement of ISL9491AERZ-T?
All ISL9491AERZ-T units undergo pre-shipment inspection (PSI). If there is an issue with ISL9491AERZ-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 ISL9491AERZ-T part is unused and in its original packaging.
Return procedure for ISL9491AERZ-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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