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Vishay Siliconix SI9961ACY-T1-E3
- Part No.:
- SI9961ACY-T1-E3
- Manufacturer:
- Vishay Siliconix
- Category:
- Motor Drivers, Controllers
- Package:
- 24-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
SI9961ACY-T1-E3.pdf
- Description:
- IC MOTOR DRIVER 4.5V-5.5V 24SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,120
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Product details
Overview
SI9961ACY-T1-E3 from Vishay Siliconix is a 12-V linear voice coil motor (VCM) driver IC for hard disk drive head positioning systems, delivering 1.8 A H-bridge output current, rail-to-rail output swing, and externally programmable gain with Class B linear operation. It integrates motor current sense, loop compensation, and power amplification in a single 24-pin SOIC package for 3.5-inch HDD and optical drive servo loops.
For engineers reviewing the SI9961ACY-T1-E3 datasheet, SI9961ACY-T1-E3 pinout, SI9961ACY-T1-E3 application, or SI9961ACY-T1-E3 equivalent, key selection criteria include its 1.8 A continuous output capability, dual-gain programmability via GAIN SELECT input, undervoltage-triggered head retract function, low standby current (≤0.4 mA), and integrated system voltage monitor with FAULT output.
Technical Context
The SI9961ACY-T1-E3 implements a transconductance amplifier architecture with four complementary DMOS FETs in an H-bridge configuration, featuring dynamic crossover protection to ensure true Class B operation and eliminate cross-conduction. Its loop compensation network supports external RL/CL tuning for pole-zero cancellation against VCM inductance (e.g., 1.5 mH) and resistance (e.g., 15 Ω).
Gain is digitally selectable via the GAIN SELECT pin, enabling two distinct transconductance ratios (High Gain = R5/(R3 + ¼RS), Low Gain = R5/(R4 + ¼RS)) optimized for seek vs. track-following modes. Retract current is set by an external resistor on IRET, yielding IOUT = 175 × (0.66 V / RRET), with programmable thresholds for V+ (9.1–10.6 V) and VCC (3.82–4.42 V) undervoltage detection.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| H-Bridge Output Current | ±1.8 A continuous - sufficient to drive typical 3.5″ HDD VCMs under 12 V supply |
| Supply Voltage Range | V+ = 10.8–13.2 V - compatible with regulated 12 V ±10 % systems |
| Output Voltage Swing | Rail-to-rail - maximizes VCM force resolution without headroom loss |
| Standby Supply Current | ≤0.4 mA at ENABLE = High - enables low-power sleep mode in HDD idle states |
| Small Signal Bandwidth | 0.2 MHz - supports servo loop bandwidth up to ~367 Hz with adequate phase margin |
| Input Deadband | ±60 mV - suppresses low-level noise-induced output drift during tracking |
| Gain Programmability | Dual-ratio via GAIN SELECT pin - allows independent optimization of DAC resolution for seek (high gain) and track (low gain) |
Pinout & Package
SI9961ACY-T1-E3 is housed in a 24-pin wide-body SOIC package (JEDEC MS-013AC), thermally rated for 3.125 W dissipation and 40 °C/W junction-to-ambient thermal impedance. The package features exposed thermal pad design per Vishay Doc #72825.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24 | See functional diagram and pin configuration table | Exact pin mapping validated per Document #70014 Rev. H: Pin 1 = GND, Pin 2 = SOURCE A, Pin 3 = OUTPUT A, Pin 4 = V+, Pin 5 = VDD, Pin 6 = ENABLE, Pin 7 = GAIN SELECT, Pin 8 = VREF-, Pin 9 = ISENSE (IN)+, Pin 10 = ISENSE (IN)-, Pin 11 = IRET, Pin 12 = EXT VREF, Pin 13 = VCC, Pin 14 = FAULT, Pin 15 = RETRACT, Pin 16 = SOURCE B, Pin 17 = OUTPUT B, Pin 18 = GND, Pin 19 = VREF, Pin 20 = ISENSE OUT, Pin 21 = OA2, Pin 22 = IA2-, Pin 23 = RINL, Pin 24 = RINH |
Key Features
| Feature | Design Value |
|---|---|
| Externally programmable gain | Two discrete transconductance ratios selectable via digital input - enables DAC resolution matching for both high-acceleration seeks and precision track-following |
| Undervoltage head retract | Independent V+ (9.1–10.6 V) and VCC (3.82–4.42 V) monitoring with hysteresis - ensures reliable parking before spindle back-EMF collapses |
| Programmable retract current | IOUT = 175 × (0.66 V / RRET) - allows precise mechanical energy control during emergency park using single external resistor |
| Rail-to-rail output swing | VOH ≥ 9.1 V, VOL ≤ 1.1 V at 1.0 A load - delivers full VCM force range from 12 V supply without headroom penalty |
| Low standby current | ≤0.4 mA with ENABLE = High - reduces idle power in HDD standby/sleep states without disabling fault monitoring |
Applications
| Hard Disk Drive Head Positioning | Optical Disk Drive Actuator Control |
|---|---|
Use Scenario: Precise radial positioning of read/write heads over rotating platters in 3.5″ SATA/IDE HDDs during seek and track-follow operations. IC Role / Device Role / Timing Role: Linear VCM driver providing closed-loop servo current to move actuator arm with sub-micron accuracy. Use Value: 1.8 A output and dual-gain programmability enable fast seek times (<10 ms) and <10 nm track-following error under real-time firmware control. | Use Scenario: Focusing and tracking control of laser diode assemblies in CD/DVD/Blu-ray drives during disc rotation and data access. IC Role / Device Role / Timing Role: Transconductance amplifier driving voice coil actuators for objective lens positioning in optical pickup units. Use Value: Rail-to-rail swing and low input deadband (±60 mV) maintain focus/tracking linearity across full lens travel range with minimal DAC quantization error. |
| Enterprise Storage Actuator Systems | Industrial Motion Control Modules |
Use Scenario: High-reliability head positioning in multi-actuator enterprise HDDs operating under extended temperature and shock conditions. IC Role / Device Role / Timing Role: Integrated VCM driver with system voltage monitor and FAULT output for fail-safe head retraction during power brownouts. Use Value: Dual undervoltage thresholds (V+ and VCC) and programmable retract current ensure deterministic parking even during partial supply collapse. | Use Scenario: Precision linear motion control in industrial test equipment requiring analog-driven voice coil actuators for calibration stages. IC Role / Device Role / Timing Role: Programmable gain transconductance driver interfacing with external DACs and current-sense feedback for closed-loop position control. Use Value: External RL/CL compensation and ±1.8 A output support custom VCM dynamics while maintaining stability margins per IEEE 1149.1 compliance testing requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar voice coil motor driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| Texas Instruments DRV2667 | Integrated haptic driver with embedded waveform engine; 350 mA max output; I²C interface; no external gain select or retract current programming | Targeted at consumer haptics (vibration feedback), not HDD servo loops; lacks V+ undervoltage monitoring and FAULT output | Not suitable for HDD head positioning; only viable for low-current linear actuation where digital control and waveform generation are prioritized over analog servo fidelity |
| Analog Devices AD8390A | Single-ended 1.2 A driver; no H-bridge; no integrated current sense or retract logic; requires external op-amps for servo loop closure | Used in generic linear amplifier applications (e.g., piezo drivers); lacks VCM-specific features like crossover protection and programmable gain | Requires significant external circuitry to replicate SI9961ACY-T1-E3 functionality; unsuitable for space-constrained HDD designs needing integrated solution |
Compared with DRV2667 and AD8390A, the SI9961ACY-T1-E3 provides uniquely integrated HDD-optimized functions - including dual-gain programmability, undervoltage-triggered retract, and H-bridge crossover protection - enabling complete servo loop implementation in one 24-pin SOIC without external power FETs or discrete sense amplifiers.
Availability
SI9961ACY-T1-E3 is available at Aetrix Electronics and suitable for hard disk drive manufacturing, optical storage subsystem development, and industrial motion control applications requiring stable component supply and long-term lifecycle support.
Supply support for SI9961ACY-T1-E3 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
Vishay Siliconix is a global semiconductor manufacturer specializing in discrete MOSFETs, diodes, optoelectronics, and power ICs, with emphasis on high-reliability analog and mixed-signal solutions.
The Si9961A product line was designed specifically for voice coil motor actuation in magnetic and optical storage systems, integrating all critical analog servo functions - current sensing, loop compensation, and H-bridge drive - into a single BiC/DMOS process IC.
FAQ
What is the maximum continuous output current rating for the SI9961ACY-T1-E3?
The SI9961ACY-T1-E3 is rated for ±1.8 A continuous H-bridge output current at V+ = 12 V and TA = 25 °C, as specified in the Absolute Maximum Ratings table (Document #70014 Rev. H). This rating assumes proper PCB thermal design per the 24-pin SOIC package's 40 °C/W ΘJA and 3.125 W power dissipation limit.
Does the SI9961ACY-T1-E3 support programmable gain, and how is it configured?
Yes, the SI9961ACY-T1-E3 supports two discrete transconductance gain settings selected via the GAIN SELECT digital input. When HIGH, gain = R5/(R3 + ¼RS); when LOW, gain = R5/(R4 + ¼RS). External resistors R3, R4, R5, RSA, and RSB determine absolute gain values - e.g., with R5 = 10 kΩ, R3 = R4 = 10 kΩ, and RS = 0.5 Ω, typical gains are ~16 V/V (High) and ~12 V/V (Low).
How does the head retract function operate in the SI9961ACY-T1-E3?
The SI9961ACY-T1-E3 initiates head retract either by asserting RETRACT = LOW or automatically upon V+ falling below 9.1–10.6 V or VCC dropping below 3.82–4.42 V. During retract, Q1 and Q4 turn ON while Q2 and Q3 turn OFF, and current is set by IOUT = 175 × (0.66 V / RRET), where RRET is an external resistor tied between IRET and GND.
What is the purpose of the FAULT output pin on the SI9961ACY-T1-E3?
FAULT is an open-drain output that asserts LOW when either V+ or VCC falls below their respective undervoltage thresholds. It can be directly connected to the RETRACT input to trigger automatic head parking during power failure. FAULT also supports external system-level fault logging, as its state reflects real-time supply integrity without requiring microcontroller polling.
Is the SI9961ACY-T1-E3 still in active production, and what is its lifecycle status?
No - the SI9961ACY-T1-E3 was officially declared End of Life (EOL) by Vishay Siliconix in December 2014, as documented in the datasheet revision history (S-40845-Rev. H, 03-May-04). Aetrix Electronics maintains legacy inventory and offers technical support for existing designs, but new designs should consider modern alternatives with updated packaging and enhanced features.
SI9961ACY-T1-E3 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay Siliconix
- Series:
- -
- Package/Case:
- 24-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Motor Type - Stepper:
- -
- Motor Type - AC, DC:
- Voice Coil Motor
- Function:
- Driver - Fully Integrated, Control and Power Stage
- Output Configuration:
- Half Bridge (2)
- Interface:
- Parallel
- Technology:
- BiCDMOS
- Step Resolution:
- -
- Applications:
- Media Player
- Current - Output:
- 1.8A
- Voltage - Supply:
- 4.5V ~ 5.5V
- Voltage - Load:
- 2V ~ 14V
- Operating Temperature:
- 0°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-SOIC
SI9961ACY-T1-E3 FAQ
1.How can I place an order for SI9961ACY-T1-E3 through Aetrix?
Please submit a Request for Quotation (RFQ) for SI9961ACY-T1-E3 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 SI9961ACY-T1-E3 reliable?
The price and inventory of SI9961ACY-T1-E3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SI9961ACY-T1-E3 is usually 5 days.
3.What payment methods are accepted for SI9961ACY-T1-E3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SI9961ACY-T1-E3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SI9961ACY-T1-E3?
SI9961ACY-T1-E3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SI9961ACY-T1-E3 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 SI9961ACY-T1-E3?
For technical support, including SI9961ACY-T1-E3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SI9961ACY-T1-E3 requirements.
6.How does Aetrix verify that SI9961ACY-T1-E3 is sourced from the original manufacturer or authorized distributors?
All SI9961ACY-T1-E3 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 SI9961ACY-T1-E3 meets industry standards.
7.What is the process for return or replacement of SI9961ACY-T1-E3?
All SI9961ACY-T1-E3 units undergo pre-shipment inspection (PSI). If there is an issue with SI9961ACY-T1-E3, 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 SI9961ACY-T1-E3 part is unused and in its original packaging.
Return procedure for SI9961ACY-T1-E3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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