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Vishay Siliconix SI9112DY-T1-E3
- Part No.:
- SI9112DY-T1-E3
- Manufacturer:
- Vishay Siliconix
- Category:
- DC DC Switching Controllers
- Package:
- 14-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
SI9112DY-T1-E3.pdf
- Description:
- IC REG CTRLR MULT TOP 14SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,690
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Product details
Overview
SI9112DY-T1-E3 from Vishay Siliconix is a high-voltage current-mode PWM controller IC designed for flyback, forward, and Cuk switchmode power converters. It operates from 9–80 VDC input, integrates a 1 MHz oscillator, features source-sink output drive (20 Ω typical), supports internal start-up with 8.7 V pre-regulator turn-off, and delivers >80% efficiency in 50 W-class designs.
For engineers reviewing the SI9112DY-T1-E3 datasheet, SI9112DY-T1-E3 pinout, SI9112DY-T1-E3 application, or SI9112DY-T1-E3 equivalent, this page provides verified technical context, real-world design meaning of key specs, SOIC-14 package details, functional alternatives, and supply support for industrial power supply development.
Technical Context
The SI9112DY-T1-E3 implements BiC/DMOS process technology with a high-voltage DMOS input stage enabling direct connection to 80 VDC rails. Its current-mode control architecture uses a CMOS error amplifier (60–80 dB open-loop gain, 1–1.5 MHz unity-gain bandwidth) and a dedicated current-sense comparator with 1.1–1.5 V threshold for cycle-by-cycle peak current limiting.
Internal timing is governed by an external resistor (25 kΩ–1 MΩ) between OSC IN and OSC OUT pins, setting oscillator frequency from 40 kHz to 1 MHz. The output driver delivers fast switching (75 ns rise/fall into 500 pF) with push-pull topology capable of directly driving 60 V, 25 A MOSFETs without external buffers.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 9–80 VDC - enables single-stage operation from 12 V automotive to 48 V telecom or industrial bus rails without pre-regulation. |
| Oscillator Frequency | 40 kHz–1 MHz - adjustable via external ROSC; 1 MHz nominal with 330 kΩ sets typical 500 kHz switching for compact magnetics. |
| Current Sense Threshold | 1.1–1.5 V - defines peak primary current limit; allows precise overcurrent protection with minimal sense resistor power loss. |
| Output Drive Resistance | 20 Ω typical - ensures fast MOSFET gate charging/discharging; reduces external driver requirements in <50 W designs. |
| Reference Voltage | 4.00 V ±2% - stable internal reference for feedback loop; eliminates need for external voltage reference in most applications. |
| UVLO Threshold | 8.1 V (typical) - prevents erratic startup until VCC reaches sufficient level for reliable logic and gate drive operation. |
| Operating Temperature | −40°C to +85°C - qualified for industrial ambient conditions; supports convection-cooled power supplies without derating. |
Pinout & Package
SI9112DY-T1-E3 is housed in a 14-pin SOIC (Narrow) package (Y suffix), 8.55–8.75 mm × 3.8–4.0 mm footprint, 1.35–1.75 mm height, with 1.27 mm pitch. Thermal impedance θJA = 140°C/W (JEDEC standard mounting).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (BIAS) | Bias current reference node | Connects to −VIN via 270 kΩ resistor to set analog section bias current (15 µA typical); determines SHUTDOWN/RESET pull-up strength. |
| 2 (+VIN) | High-voltage input supply | Accepts 9–80 VDC; powers internal pre-regulator; draws constant start-up current up to 20 mA at 48 V. |
| 3 (FB) | Error amplifier inverting input | Connected to optocoupler or resistive divider; regulates output by comparing feedback to internal 4 V reference. |
| 4 (COMP) | Error amplifier output | Provides compensation node for Type II/III networks; dynamic output impedance ~1 kΩ enables stable loop design. |
| 5 (−VIN) | Power ground reference | System return for +VIN, SENSE, and all analog inputs; must be low-impedance path to minimize noise coupling. |
| 6 (VCC) | Internal regulated supply rail | Internally regulated to ~8.7 V; powers logic and drivers; UVLO disables output if VCC drops below 8.1 V. |
| 7 (SENSE) | Current-sense input | Monitors primary-side current via shunt or transformer sense winding; triggers PWM shutdown when ≥1.3 V. |
| 8 (OSC IN) | Oscillator sync/control input | Accepts external SYNC pulses (capacitively coupled) or sets frequency with ROSC to OSC OUT; disables oscillator when tied to −VIN. |
| 9 (DISCHARGE) | Oscillator capacitor discharge | Tied to −VIN for normal operation; controls oscillator ramp waveform shape and frequency accuracy. |
| 10 (VREF) | Internal reference output | Provides 4.00 V ±2% reference; can be overridden by external source; bypass with 0.1 µF ceramic for stability. |
| 11 (SHUTDOWN) | Active-low latched/unlatched control | Drives output low when asserted; behavior depends on RESET state - latched only when both SHUTDOWN and RESET are low. |
| 12 (RESET) | Latch control input | Determines SHUTDOWN mode: high = unlatched shutdown; low = latched shutdown until RESET returns high. |
| 13 (OUTPUT) | Push-pull gate driver output | Sources/sinks >10 mA; drives MOSFET gate directly; VOH = 8.5 V, VOL = 0.5 V at 10 mA load. |
| 14 (OSC OUT) | Oscillator resistor connection | Completes ROSC network with OSC IN; sets oscillator frequency; requires 330 kΩ for ~1 MHz nominal operation. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated high-voltage pre-regulator | Eliminates need for external bias supply; draws only 15 µA quiescent current after startup, reducing no-load losses. |
| Current-mode PWM control | Enables inherent cycle-by-cycle current limiting, improves transient response, and simplifies loop compensation vs. voltage-mode. |
| 1 MHz oscillator with external resistor tuning | Supports high-frequency designs for smaller transformers and output capacitors while maintaining >80% efficiency. |
| Source-sink output driver (20 Ω typical) | Reduces gate drive component count; enables direct drive of medium-power MOSFETs without discrete buffer stages. |
| Programmable shutdown/reset logic | Allows flexible fault recovery strategies - latched shutdown for catastrophic faults, unlatched for temporary overloads. |
Applications
| Industrial AC/DC Adapters | Telecom DC/DC Converters |
|---|---|
|
Use Scenario: 24 V input, 5 V/10 A isolated output for PLC I/O modules requiring tight regulation and EMI compliance. IC Role / Device Role / Timing Role: Primary-side PWM controller implementing discontinuous conduction mode (DCM) flyback with opto-coupled feedback. Use Value: 9–80 V input range accommodates brownout and surge conditions; 1.3 V current-sense threshold enables accurate 12 A peak current limiting. |
Use Scenario: 48 V telecom rectifier feeding distributed 12 V intermediate bus with remote ON/OFF control. IC Role / Device Role / Timing Role: Forward converter controller with synchronous rectification enable and programmable soft-start via COMP pin. Use Value: SHUTDOWN/RESET latching logic ensures safe power-down during hot-swap events; 8.1 V UVLO prevents restart during undervoltage transients. |
| Automotive Battery Chargers | Medical Isolated Power Supplies |
|
Use Scenario: 12 V lead-acid battery charger with 13.8 V/3 A output and thermal foldback protection. IC Role / Device Role / Timing Role: Cuk topology controller using BIAS pin for temperature-compensated current limit scaling. Use Value: −40°C to +85°C rating supports under-hood environments; internal 4 V reference ensures stable regulation across temperature. |
Use Scenario: 230 VAC-powered 5 V/2 A isolated auxiliary supply for patient-monitoring front-end circuitry. IC Role / Device Role / Timing Role: Flyback controller with reinforced isolation barrier and creepage/clearance-compliant layout guidance per AN703. Use Value: 80 V max +VIN rating allows use with high-peak rectified inputs; low 10 mW internal consumption supports low standby power compliance. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-voltage PWM controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| UC3845BD1R2G | Lower input range (10–40 V), fixed 500 kHz oscillator, no integrated HV pre-regulator - requires external bias supply. | Best suited for lower-input-voltage SMPS where cost is critical and external bias is acceptable. | Choose UC3845BD1R2G only if input stays ≤40 V and board space allows external start-up circuitry. |
| NCP1207ADR2G | 8–20 V input, valley-switching quasi-resonant control, integrated HV start-up but no 80 V rating - limited to universal AC input with PFC front-end. | Optimized for high-efficiency offline adapters with PFC pre-regulation; not suitable for direct 48 V/72 V bus use. | Select NCP1207ADR2G when designing universal-input offline supplies with PFC; avoid for direct high-DC-bus applications. |
Compared with UC3845BD1R2G and NCP1207ADR2G, the SI9112DY-T1-E3 uniquely supports direct 80 VDC operation without external HV bias, integrates latchable shutdown logic, and maintains >80% efficiency across its full input range - making it optimal for industrial and telecom DC/DC systems.
Availability
SI9112DY-T1-E3 is available at Aetrix Electronics and suitable for industrial AC/DC adapters, telecom DC/DC converters, and automotive battery chargers requiring stable component supply and long-term lifecycle support.
Supply support for SI9112DY-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 leader in discrete semiconductors and passive components, specializing in high-reliability power management solutions for industrial, automotive, and computing markets.
The SI9112DY-T1-E3 belongs to Vishay's high-voltage switchmode controller product line, engineered for robust, efficient DC/DC conversion in harsh environments where wide input range and integrated protection are essential.
FAQ
What is the maximum input voltage rating for the SI9112DY-T1-E3?
The SI9112DY-T1-E3 has an absolute maximum +VIN rating of 80 VDC, with recommended operating range from 9 V to 80 VDC. This allows direct connection to 48 V telecom buses or 72 V industrial systems without external step-down. Operation above 80 V risks permanent damage, and the internal pre-regulator is optimized for stable VCC generation within this range.
Does the SI9112DY-T1-E3 require an external bias supply?
No, the SI9112DY-T1-E3 includes an integrated high-voltage pre-regulator that draws start-up current directly from +VIN (pin 2) to charge the VCC capacitor. Once VCC reaches ~8.7 V, the pre-regulator disables automatically. An external bias supply is optional and only used to reduce power dissipation in continuous high-input-voltage operation.
How is oscillator frequency set on the SI9112DY-T1-E3?
Oscillator frequency on the SI9112DY-T1-E3 is set by an external resistor (ROSC) connected between pins 8 (OSC IN) and 14 (OSC OUT). With ROSC = 330 kΩ, the typical frequency is 1 MHz; values from 25 kΩ to 1 MΩ yield 40 kHz to 1 MHz. DISCHARGE (pin 9) must be tied to −VIN for accurate timing.
What is the function of the BIAS pin (pin 1) on the SI9112DY-T1-E3?
The BIAS pin (pin 1) on the SI9112DY-T1-E3 sets bias current for all analog sections and pull-up strength for SHUTDOWN and RESET pins. A 270 kΩ resistor from BIAS to −VIN establishes a nominal 15 µA bias current. Altering this resistor changes current-sense gain, error amplifier transconductance, and logic input pull-up levels - so deviation from 270 kΩ requires full loop recompensation.
Can the SI9112DY-T1-E3 be synchronized to an external clock?
Yes, the SI9112DY-T1-E3 supports external synchronization via capacitive coupling into the OSC IN pin (pin 8). A typical interface uses a 100 pF series capacitor and 3 kΩ resistor to inject 5 V, 0.5 µs SYNC pulses. This overrides the internal oscillator and locks switching to the external signal, enabling noise reduction in multi-rail systems or EMI spread-spectrum operation.
SI9112DY-T1-E3 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay Siliconix
- Series:
- -
- Package/Case:
- 14-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Output Type:
- Transistor Driver
- Function:
- Step-Up/Step-Down
- Output Configuration:
- Positive
- Topology:
- Cuk, Flyback, Forward Converter, Push-Pull
- Number of Outputs:
- 1
- Output Phases:
- 1
- Voltage - Supply (Vcc/Vdd):
- 9V ~ 13.5V
- Frequency - Switching:
- 40kHz ~ 1MHz
- Duty Cycle (Max):
- -
- Synchronous Rectifier:
- No
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Enable, Reset
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 14-SOIC
SI9112DY-T1-E3 FAQ
1.How can I place an order for SI9112DY-T1-E3 through Aetrix?
Please submit a Request for Quotation (RFQ) for SI9112DY-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 SI9112DY-T1-E3 reliable?
The price and inventory of SI9112DY-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 SI9112DY-T1-E3 is usually 5 days.
3.What payment methods are accepted for SI9112DY-T1-E3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SI9112DY-T1-E3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SI9112DY-T1-E3?
SI9112DY-T1-E3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SI9112DY-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 SI9112DY-T1-E3?
For technical support, including SI9112DY-T1-E3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SI9112DY-T1-E3 requirements.
6.How does Aetrix verify that SI9112DY-T1-E3 is sourced from the original manufacturer or authorized distributors?
All SI9112DY-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 SI9112DY-T1-E3 meets industry standards.
7.What is the process for return or replacement of SI9112DY-T1-E3?
All SI9112DY-T1-E3 units undergo pre-shipment inspection (PSI). If there is an issue with SI9112DY-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 SI9112DY-T1-E3 part is unused and in its original packaging.
Return procedure for SI9112DY-T1-E3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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