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Diodes Incorporated AH9281RTR-G1
- Part No.:
- AH9281RTR-G1
- Manufacturer:
- Diodes Incorporated
- Category:
- Motor Drivers, Controllers
- Package:
- SOT-89-5/6
- Datasheet:
-
AH9281RTR-G1.pdf
- Description:
- IC MOTOR DRIVER PAR SOT89-5
- Quantity:
- Payment:
- Shipping:
Inventory:992
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Product details
Overview
AH9281RTR-G1 from BCD Semiconductor Manufacturing Limited is a two-phase, dual-coil high-voltage smart fan motor driver IC integrating a Hall-effect sensor, dynamic offset correction, and 1200mA peak output drivers. It operates from 2.5V to 16V, supports 5V/12V systems, and delivers integrated tachometer (FG) signal output via open-drain FG/RD pin. Designed for PC/server cooling fans and power supply thermal management, it enables reliable brushless DC fan control with low start-up voltage and locked-rotor auto-restart.
For engineers reviewing the AH9281RTR-G1 datasheet, AH9281RTR-G1 pinout, AH9281RTR-G1 application, or AH9281RTR-G1 equivalent, key selection criteria include its 1200mA peak output current, FG open-drain tachometer interface, SOT-89-5 package thermal performance (θJA = 156°C/W), and -40°C to +125°C operating range - all critical for industrial-grade fan control in constrained thermal environments.
Technical Context
The AH9281RTR-G1 implements a two-phase commutation controller with integrated Hall sensor and dynamic offset cancellation, enabling precise rotor position detection without external biasing. Its output stage uses CMOS logic and power MOSFETs with built-in clamping diodes and thermal shutdown protection.
It features a dedicated FG/RD open-drain output capable of sinking up to 30mA at 12V, compatible with Super I/O or hardware monitoring ICs. The device's magnetic sensitivity (BOP = 0–50 G, BRP = –50–0 G) ensures robust operation across temperature and supply variations.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 2.5V to 16V - supports both 5V and 12V fan systems while tolerating transient overvoltage up to 18V absolute max. |
| Peak Output Current | 1200mA per channel - drives large-diameter or high-inertia fans requiring strong torque at startup. |
| FG/RD Output Type | Open-drain, 30mA sink capability - interfaces directly with 3.3V/5V monitoring logic without level-shifting. |
| Operating Temperature | –40°C to +125°C - qualified for server chassis and power supply environments with localized hot spots. |
| Thermal Resistance θJA | 156°C/W (SOT-89-5) - enables 600mW continuous dissipation at ≤75°C ambient without heatsink. |
| Magnetic Hysteresis | 40G - prevents oscillation during slow-speed or stalled-rotor conditions by ensuring clean commutation transitions. |
| ESD Rating | 6000V HBM - withstands handling and board assembly ESD events without latch-up or parametric shift. |
Pinout & Package
Package: SOT-89-5 - surface-mount, thermally enhanced 5-pin package with exposed thermal pad; footprint compatible with standard SOT-89 pick-and-place tooling and reflow profiles.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (VCC) | Power supply input | Accepts 2.5–16V DC; internal regulation powers Hall sensor and logic; decoupling capacitor required near pin. |
| 2 (GND) | Ground reference | Common return for power, outputs, and Hall sensor; must be low-impedance connection to minimize noise coupling. |
| 3 (FG/RD) | Open-drain tachometer output | Generates pulse train proportional to fan RPM; requires external pull-up (e.g., 4.7kΩ to 3.3V/5V) for logic-level interfacing. |
| 4 (DO) | Phase A output driver | High-current N-channel MOSFET output (1200mA peak); connects to coil 1; includes internal clamp diode. |
| 5 (DOB) | Phase B output driver | High-current N-channel MOSFET output (1200mA peak); connects to coil 2; complements DO for two-phase commutation. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated Hall sensor with dynamic offset correction | Eliminates need for external bias resistors or calibration; maintains accurate commutation across temperature and aging. |
| Low start-up voltage (2.5V min) | Enables fan spin-up under brown-out or battery-backed conditions where supply dips below 5V. |
| Locked-rotor shutdown with auto-restart | Halts drive current on stall detection and attempts recovery every ~5 seconds - prevents thermal damage during obstruction. |
| Built-in output clamping diodes | Suppresses inductive kickback from motor coils without external flyback diodes, reducing BOM count and PCB area. |
| Tachometer (FG) signal generation | Provides real-time RPM feedback synchronized to commutation edges - usable by BMC, EC, or fan control firmware. |
Applications
| PC & Server Cooling Systems | Industrial Power Supply Fans |
|---|---|
|
Use Scenario: Fan speed control in 1U/2U rack servers with multi-zone thermal management. IC Role / Device Role / Timing Role: Dual-coil BLDC driver with integrated Hall sensing and FG tachometer output for closed-loop RPM regulation. Use Value: Enables precise 5V/12V fan control with auto-restart on dust clogging - reduces system downtime and improves thermal margin. |
Use Scenario: Forced-air cooling of high-power AC/DC converters and telecom rectifiers. IC Role / Device Role / Timing Role: High-voltage motor driver delivering 1200mA peak current to sustain airflow under high back-pressure conditions. Use Value: Operates reliably at 125°C ambient with 156°C/W thermal resistance - eliminates need for derating or external heatsinking. |
| Laptop Thermal Management | Embedded Network Equipment Fans |
|
Use Scenario: Dual-fan configuration in thin-and-light notebooks with space-constrained PCB layout. IC Role / Device Role / Timing Role: Compact SOT-89-5 packaged driver providing FG feedback to embedded controller for adaptive fan curves. Use Value: Reduces component count vs. discrete Hall + gate driver solutions - saves >12 mm² board area per fan channel. |
Use Scenario: Fan control in carrier-grade switches and routers with remote monitoring via IPMI/BMC. IC Role / Device Role / Timing Role: Tachometer signal source feeding RPM data to baseboard management controller for predictive maintenance alerts. Use Value: Open-drain FG output interfaces natively with 3.3V Super I/O ICs - avoids level-shifter complexity and timing skew. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar brushless fan motor driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ALLEGRO A3921KLPTR-T | Higher VCC max (40V), but no integrated Hall sensor - requires external rotor position sensing. | Used in higher-voltage industrial blowers; lacks FG output - needs external tach circuitry. | Select when driving >24V fans and external Hall sensors are already present in design. |
| ON Semiconductor NCP1701ADR2G | Lower peak current (800mA), no integrated Hall - relies on external hall latches or back-EMF sensing. | Targeted at cost-sensitive consumer electronics; lacks locked-rotor protection and auto-restart. | Choose only for low-power 5V fans where thermal safety features are managed externally. |
Compared with A3921KLPTR-T and NCP1701ADR2G, AH9281RTR-G1 uniquely integrates Hall sensing, FG output, and auto-restart in a single SOT-89-5 package - simplifying design for 5V/12V server and power supply cooling where reliability and minimal BOM are priorities.
Availability
AH9281RTR-G1 is available at Aetrix Electronics and suitable for PC/server cooling systems, industrial power supply thermal management, and embedded network equipment requiring stable component supply and RoHS-compliant green packaging.
Supply support for AH9281RTR-G1 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
BCD Semiconductor Manufacturing Limited is a China-based fabless semiconductor company specializing in analog and mixed-signal ICs for power management, motor control, and sensor interface applications.
AH9281RTR-G1 belongs to BCD's Smart Fan Driver product line, engineered specifically for high-reliability, low-maintenance brushless fan control in computing and power infrastructure - emphasizing integration, thermal robustness, and system-level fault resilience.
FAQ
What is the function of the FG/RD pin on AH9281RTR-G1?
The FG/RD pin is an open-drain output that provides a frequency-proportional tachometer signal (FG mode) indicating fan rotational speed. It sinks up to 30mA at 12V and requires an external pull-up resistor (typically 4.7kΩ) to a logic-compatible voltage. This signal is used by host controllers for closed-loop speed regulation and failure detection.
Does AH9281RTR-G1 require external flyback diodes for motor coil protection?
No. AH9281RTR-G1 integrates clamping diodes across both DO and DOB output terminals, eliminating the need for external flyback diodes. This reduces PCB area, component count, and potential layout errors associated with inductive kickback suppression in BLDC fan applications.
Can AH9281RTR-G1 operate from a 3.3V supply?
No. The minimum recommended supply voltage is 2.5V, but the device is optimized for 5V and 12V operation. At 3.3V, output drive strength degrades significantly, and magnetic sensitivity may fall outside guaranteed specification - use only within the validated 5V/12V range for reliable commutation and FG accuracy.
How does the locked-rotor protection work in AH9281RTR-G1?
When rotor motion ceases, the Hall sensor detects no field transition, triggering internal logic to disable DO and DOB outputs after a timeout. After ~5 seconds, the IC automatically attempts restart by re-enabling outputs - repeating this cycle until rotation resumes or thermal limits are reached, preventing sustained overheating.
AH9281RTR-G1 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Series:
- -
- Package/Case:
- SOT-89-5/6
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Motor Type - Stepper:
- -
- Motor Type - AC, DC:
- Brushless DC (BLDC)
- Function:
- Driver - Fully Integrated, Control and Power Stage
- Output Configuration:
- Low Side (2)
- Interface:
- On/Off
- Technology:
- CMOS, Power MOSFET
- Step Resolution:
- -
- Applications:
- Fan Motor Driver
- Current - Output:
- 500mA
- Voltage - Supply:
- 2.5V ~ 16V
- Voltage - Load:
- 2.5V ~ 16V
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-89-5
AH9281RTR-G1 FAQ
1.How can I place an order for AH9281RTR-G1 through Aetrix?
Please submit a Request for Quotation (RFQ) for AH9281RTR-G1 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 AH9281RTR-G1 reliable?
The price and inventory of AH9281RTR-G1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AH9281RTR-G1 is usually 5 days.
3.What payment methods are accepted for AH9281RTR-G1?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AH9281RTR-G1 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AH9281RTR-G1?
AH9281RTR-G1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AH9281RTR-G1 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 AH9281RTR-G1?
For technical support, including AH9281RTR-G1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AH9281RTR-G1 requirements.
6.How does Aetrix verify that AH9281RTR-G1 is sourced from the original manufacturer or authorized distributors?
All AH9281RTR-G1 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 AH9281RTR-G1 meets industry standards.
7.What is the process for return or replacement of AH9281RTR-G1?
All AH9281RTR-G1 units undergo pre-shipment inspection (PSI). If there is an issue with AH9281RTR-G1, 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 AH9281RTR-G1 part is unused and in its original packaging.
Return procedure for AH9281RTR-G1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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