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Allegro MicroSystems A8290SETTR-T
- Part No.:
- A8290SETTR-T
- Manufacturer:
- Allegro MicroSystems
- Category:
- Special Purpose Regulators
- Package:
- 28-VFQFN Exposed Pad
- Datasheet:
-
A8290SETTR-T.pdf
- Description:
- IC REG CONV RECVRS 1OUT 28QFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,909
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Product details
Overview
A8290SETTR-T from Allegro MicroSystems is a discontinued monolithic LNB supply and control voltage regulator IC designed for analog/digital satellite receivers. It integrates a tracking boost converter (352 kHz typical), linear regulator (≤1 V drop at 500 mA), I²C-compatible interface (400 kHz), 22 kHz tone generation/detection, and DiSEqC™-compatible bypass FET - delivering 13/18 V LNB power and bidirectional coaxial control over single cable.
For engineers reviewing the A8290SETTR-T datasheet, A8290SETTR-T pinout, A8290SETTR-T application, or A8290SETTR-T equivalent, this page provides verified technical context, real-world timing behavior (e.g., 500 µs 13→18 V rise time), fault diagnostics (OCP, TSD, UVLO, cable disconnect), and design-critical package thermal data (RθJA = 32°C/W on 4-layer PCB) to support legacy system maintenance and replacement analysis.
Technical Context
The A8290SETTR-T implements a current-mode tracking boost converter synchronized to its internal 22 kHz tone oscillator (fSW = 352 kHz typical), minimizing passive size while maintaining ≤3% LNB voltage setpoint accuracy across 0–500 mA load. Its linear stage delivers up to 900 mA output with programmable slew rate via external TCAP capacitor (10 nF typical).
DiSEqC™ functionality is fully integrated: four tone generation modes (internal/external, gated/clocked), 300–400 mVPP tone detect sensitivity, and a dedicated bypass FET (RDS(on) ≤ 1 Ω) that reduces output impedance during tone transmission. Fault monitoring includes latched OCP (48 ms timeout), thermal shutdown (165°C), VIN UVLO (7.35 V), and cable disconnect detection (VCAD = 22.8 V).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| LNB Output Voltage | 16 programmable levels (13 V / 18 V standard); ±3% accuracy ensures compliance with EN 50494/50600 LNB specs |
| Boost Switching Frequency | 352 kHz typical; enables compact 33 µH inductor and minimizes EMI in satellite receiver front-end |
| Output Current Limit | 900 mA typical with 48 ms timer; protects against sustained short circuits without latch-off |
| Tone Frequency | 22 kHz ±10% (20–24 kHz); factory-trimmed for DiSEqC™ 1.x/2.0 tone encoding/decoding |
| I²C Interface Speed | Up to 400 kHz; supports fast register read/write for real-time LNB reconfiguration and status polling |
| Thermal Resistance | RθJA = 32°C/W on 4-layer PCB; requires exposed pad (PAD) soldered to ground plane for safe operation at full load |
| Startup Supply Current | 19.0 mA typical at VIN = 12 V, ILOAD = 0 mA; enables low-power standby mode in STB systems |
Pinout & Package
Package: 28-pin QFN (ET), 5 mm × 5 mm, 0.90 mm height, exposed thermal pad (PAD). RoHS-compliant, matte tin leadframe plating.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 BOOST | Tracking supply voltage to linear regulator | Drives linear stage input; voltage tracks LNB output within 800 mV to minimize dissipation |
| 2 VCP | Gate supply voltage for linear regulator | Generated by internal charge pump; enables high-side NMOS control of LNB output |
| 3 TCAP | Capacitor connection for slew rate control | External capacitor (e.g., 10 nF) sets LNB voltage rise/fall time; critical for avoiding OCP during transitions |
| 5 TDO | Tone detect output (open-drain) | Asserts low when 22 kHz tone detected; used for DiSEqC™ 2.0 command synchronization |
| 6 EXTM | External modulation input | Accepts 22 kHz logic signal for tone generation option 3/4; enables external MCU-controlled DiSEqC™ bursts |
| 10 SDA | I²C-compatible data line | Bi-directional open-drain interface; reads status registers (fault flags) and writes control bits (VSEL, TMODE) |
| 11 ADD | Address select input | Configures one of four I²C addresses (0001000 to 0001011) to avoid bus conflicts in multi-LNBR systems |
| 12 SCL | I²C-compatible clock input | Master-generated clock up to 400 kHz; defines timing for register access and interrupt acknowledgment |
| 14 IRQ | Interrupt request (open-drain) | Active-low flag indicating fault (OCP, TSD, VUV) or power-on; requires external pull-up for shared interrupt bus |
| 22 BFO | Bypass FET output | Connects to LNB return path; enables low-impedance tone injection during DiSEqC™ transmit |
| 24 BFI | Bypass FET input | Connects to LNB supply line; forms bidirectional FET pair with BFO for minimal insertion loss |
| 26 LX | Inductor drive point | Switch node for integrated boost MOSFET; connects to 33 µH inductor and 220 nF boost capacitor |
| 27 GNDLX | Boost switch ground | Separate ground pin for boost circuitry; isolates high di/dt noise from signal ground (GND) |
| 28 LNB | Main output voltage to LNB | Delivers regulated 13/18 V to satellite LNB; includes reverse current protection (1–5 mA max) |
| PAD | Exposed thermal pad | Mandatory connection to PCB ground plane; primary thermal path for RθJA = 32°C/W performance |
Key Features
| Feature | Design Value |
|---|---|
| Integrated DiSEqC™ tone generator & detector | Four configurable tone modes (internal/external, gated/clocked); 300–400 mVPP detection threshold meets EN 50600 Class A |
| Programmable LNB output slew rate | Adjustable rise/fall time via TCAP pin capacitor; prevents false OCP triggering during 13↔18 V transitions |
| Auto-recovering short-circuit protection | 900 mA current limit with 48 ms timeout; disables output then clears automatically after host re-enables ENB bit |
| Dual-ground architecture (GND/GNDLX) | Separates analog/signal ground from boost-switch ground; reduces noise coupling into sensitive LNB bias path |
| Comprehensive fault diagnostics | Latched status bits for OCP, TSD, VIN UVLO, cable disconnect, and power-not-good (PNG); readable via I²C |
| Low-noise linear regulation | ≤30 mVPP ripple/noise on LNB output; achieved via high PSRR and integrated compensation |
Applications
| Direct Broadcast Satellite (DBS) Receiver | Digital Video Broadcasting – Satellite (DVB-S/S2) |
|---|---|
|
Use Scenario: Set-top box powering and controlling Ku-band LNB via coaxial cable for single-tuner reception. IC Role / Device Role / Timing Role: Single-chip LNB supply and DiSEqC™ transceiver; generates 22 kHz tone, detects incoming commands, regulates 13/18 V output. Use Value: Eliminates discrete boost + linear + tone circuitry; reduces BOM count by ≥12 components while meeting EN 50494 emission limits. |
Use Scenario: Integrated satellite tuner module in professional broadcast equipment requiring dual-polarization switching. IC Role / Device Role / Timing Role: LNB voltage controller with fast 500 µs 13→18 V transition; supports DiSEqC™ 2.0 positioner queries via TDO-synchronized interrupts. Use Value: Enables sub-100 ms polarization switching; integrated cable disconnect detection prevents false "no signal" alarms during antenna movement. |
| Multi-Switch Distribution System | Legacy Cable TV Headend LNB Management |
|
Use Scenario: 4-output multi-switch feeding multiple receivers from single dish; each output uses A8290SETTR-T for independent LNB control. IC Role / Device Role / Timing Role: Independent LNB regulator per port; uses ADD pin to assign unique I²C address; shares IRQ line for centralized fault monitoring. Use Value: Prevents cross-port interference during simultaneous DiSEqC™ commands; 48 ms OCP timer avoids cascading shutdowns under partial faults. |
Use Scenario: Retrofit upgrade of aging headend amplifiers to support modern DiSEqC™-controlled LNB arrays. IC Role / Device Role / Timing Role: Drop-in replacement for discrete LNB supplies; retains existing PCB layout while adding tone detection and I²C telemetry. Use Value: Enables remote diagnostics (cable disconnect, thermal overload) via existing SNMP infrastructure; no firmware changes required. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LNB supply and control applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| A8295SETTR-T | Successor Generation 5 device; higher efficiency (lower RDS(on) BOOST), extended temperature range (–40°C to 105°C), and enhanced DiSEqC™ 2.0 timing compliance. | Required for new designs targeting EN 50600 Class B emissions; supports faster 13↔18 V transitions (350 µs) and lower quiescent current (12 mA). | Select A8295SETTR-T for new designs needing production support, wider temp range, or stricter EMI requirements; not pin-compatible with A8290SETTR-T. |
| MAX2181AETM+ | Maxim Integrated LNB supply; 300 kHz boost frequency, 1.2 A current limit, integrated 22 kHz oscillator, but lacks tone detection and DiSEqC™ bypass FET. | Suitable for basic LNB power only; requires external tone detector and FET for full DiSEqC™ compliance; different I²C register map and fault reporting. | Choose MAX2181AETM+ only if tone detection and DiSEqC™ 2.0 decode are unnecessary; verify external component additions for full functionality. |
Compared with A8290SETTR-T, A8295SETTR-T offers improved thermal performance and DiSEqC™ timing for new designs, while MAX2181AETM+ provides LNB power only and requires external circuitry for full satellite control - making A8290SETTR-T uniquely suited for legacy DiSEqC™-enabled systems where integrated tone detection and bypass FET are mandatory.
Availability
A8290SETTR-T is available at Aetrix Electronics and suitable for satellite receiver repair, legacy STB refurbishment, and DiSEqC™-based antenna positioning systems requiring stable component supply for long-lifecycle maintenance.
Supply support for A8290SETTR-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
Allegro MicroSystems is a U.S.-based designer of high-performance power ICs and magnetic sensors, specializing in automotive, industrial, and communications applications since 1989.
The A8290 product line was developed specifically for satellite TV infrastructure, integrating LNB power regulation, DiSEqC™ control, and fault diagnostics into a single QFN package to replace multi-chip solutions in set-top boxes and multi-switches.
FAQ
Is the A8290SETTR-T still in production?
No, the A8290SETTR-T is a discontinued product. Allegro MicroSystems ceased production as of December 14, 2017, and no new samples or production lots are available. Aetrix Electronics maintains limited legacy stock for repair and maintenance of existing satellite receiver systems, but it is not recommended for new design-in.
What is the function of the TCAP pin on the A8290SETTR-T?
On the A8290SETTR-T, the TCAP pin connects to an external capacitor (typically 10 nF) that controls the slew rate of the LNB output voltage during 13↔18 V transitions. This prevents false triggering of the 900 mA overcurrent protection by limiting dV/dt; the capacitor value directly determines rise/fall time per the formula CTCAP = (ITCAP × 6) / SR.
Does the A8290SETTR-T support DiSEqC™ 2.0 decoding?
Yes, the A8290SETTR-T supports DiSEqC™ 2.0 decoding via its integrated 22 kHz tone detector. The TDO pin outputs an open-drain active-low signal when a valid 22 kHz tone is received, with guaranteed detection thresholds of 300–400 mVPP and rejection of out-of-band signals below 100 mVPP, meeting EN 50600 requirements.
Can the A8290SETTR-T be used without an I²C controller?
The A8290SETTR-T requires I²C communication for configuration and status monitoring, but basic LNB power can be enabled using the EXTM pin and hardware-addressed mode. However, full functionality-including voltage selection, tone mode control, and fault reading-depends on the I²C interface; standalone operation without I²C is not supported.
What thermal management is required for the A8290SETTR-T at full load?
The A8290SETTR-T requires its exposed thermal pad (PAD) to be soldered to a minimum 2 cm² copper area on a 4-layer PCB to achieve the specified RθJA of 32°C/W. At 900 mA output and 18 V LNB voltage, junction temperature must be kept below 150°C; derating is necessary above 60°C ambient unless additional heatsinking is applied.
A8290SETTR-T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Allegro MicroSystems
- Series:
- -
- Package/Case:
- 28-VFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Applications:
- Converter, Analog and Digital Satellite Receivers
- Voltage - Input:
- 8V ~ 16V
- Number of Outputs:
- 1
- Voltage - Output:
- 12.7V ~ 20.4V
- Operating Temperature:
- -20°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-QFN (5x5)
A8290SETTR-T FAQ
1.How can I place an order for A8290SETTR-T through Aetrix?
Please submit a Request for Quotation (RFQ) for A8290SETTR-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 A8290SETTR-T reliable?
The price and inventory of A8290SETTR-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for A8290SETTR-T is usually 5 days.
3.What payment methods are accepted for A8290SETTR-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for A8290SETTR-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for A8290SETTR-T?
A8290SETTR-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your A8290SETTR-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 A8290SETTR-T?
For technical support, including A8290SETTR-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your A8290SETTR-T requirements.
6.How does Aetrix verify that A8290SETTR-T is sourced from the original manufacturer or authorized distributors?
All A8290SETTR-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 A8290SETTR-T meets industry standards.
7.What is the process for return or replacement of A8290SETTR-T?
All A8290SETTR-T units undergo pre-shipment inspection (PSI). If there is an issue with A8290SETTR-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 A8290SETTR-T part is unused and in its original packaging.
Return procedure for A8290SETTR-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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