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Texas Instruments UCC3975PW
- Part No.:
- UCC3975PW
- Manufacturer:
- Texas Instruments
- Category:
- Power Management - Specialized
- Package:
- 8-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
UCC3975PW.pdf
- Description:
- IC TRNSF CNTRLR DUAL FET 8-TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,380
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Product details
Overview
UCC3975PW from Texas Instruments is a resonant flyback topology piezoelectric transformer (PZT) controller IC for CCFL backlight power supplies, operating from 3 V to 13.5 V, featuring programmable voltage-controlled oscillator (VCO), open lamp protection, dual MOSFET drivers, and 15-µA shutdown current. It targets narrow-profile LCD enclosures in notebook computers and portable displays.
For engineers reviewing the UCC3975PW datasheet, UCC3975PW pinout, UCC3975PW application, or UCC3975PW equivalent, key selection criteria include its flyback-specific driver configuration (OUTP left open, OUTN active), 100-kHz nominal oscillator frequency with ROSC/COSC tuning, 1.5-V error amplifier reference, 1.4–1.6-V open-lamp detection threshold, and TSSOP-8 package compatibility with PZT-based resonant converters requiring precise frequency sweep control.
Technical Context
The UCC3975PW implements a fixed 50% duty-cycle half-wave resonant flyback control architecture using an internal VCO whose frequency sweeps from high (start/strike) to low (regulation) under error amplifier feedback. Its oscillator uses a precision window comparator (0.7 V–1.7 V thresholds) and external RC network (ROSC, COSC, RANGE) to set center frequency and allowable range.
It integrates dual CMOS drivers optimized for flyback: OUTN drives an external N-channel MOSFET while OUTP remains unconnected; startup preconditioning pulls COMP to 0 V for maximum frequency; open lamp detection monitors OPEN/SD pin voltage ≥1.5 V to trigger up to seven retries before entering error shutdown.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Topology Support | Flyback only - OUTP pin left open; OUTN drives single N-MOSFET switch in resonant flyback stage. |
| Oscillator Frequency | 95–105 kHz nominal (ROSC = 24 kΩ, COSC = 470 pF) - sets primary-side resonant timing for PZT drive. |
| Error Amplifier Reference | 1.500 V ±35 mV - used as FB input reference to regulate lamp current via frequency sweep. |
| Open Lamp Threshold | 1.4–1.6 V on OPEN/SD pin - triggers retry sequence if lamp fails to strike; distinct from UCC3976/UCC3977 thresholds. |
| Shutdown Current | 15 µA typical - achieved by pulling OPEN/SD >2.5 V; enables ultra-low-power standby in portable systems. |
| Supply Voltage Range | 3 V to 13.5 V - supports direct battery input (e.g., 3-cell Li-ion or 12-V rail) without external regulator. |
| UVLO Turn-on Threshold | 2.85 V ±150 mV - ensures reliable startup only when system voltage is sufficient for PZT operation. |
Pinout & Package
UCC3975PW is housed in an 8-pin TSSOP (PW) package with 0.65-mm pitch, optimized for compact CCFL backlight designs requiring low profile and thermal efficiency.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1: OPEN/SD | Input | Dual-function pin: open lamp fault detection (≥1.5 V triggers retry) and shutdown enable (>2.5 V forces 15-µA quiescent mode). |
| 2: OSC | Input | VCO timing node - connects external ROSC, COSC, and RANGE resistors to define frequency sweep range and center point. |
| 3: COMP | Output | Error amplifier output - controls VCO frequency; preconditioned to 0 V at startup for max-frequency strike attempt. |
| 4: FB | Input | Inverting input of error amplifier - compared to 1.5-V internal reference to regulate lamp current via frequency modulation. |
| 5: GND | Ground | Common signal and power return - must serve as star ground for RCS sense resistor and PZT feedback network. |
| 6: OUTN | Output | N-channel MOSFET driver - delivers 50% duty-cycle gate signal; low-side switching in flyback topology. |
| 7: OUTP | Not connected | No internal connection - left floating per datasheet; distinguishes UCC3975PW from half-bridge (UCC3976PW) and push-pull (UCC3977PW) variants. |
| 8: VDD | Power | Main supply input - requires local 0.1-µF ceramic + 5–10-µF bulk capacitor; UVLO protects against brownout operation. |
Key Features
| Feature | Design Value |
|---|---|
| Flyback-optimized driver architecture | OUTP unconnected and OUTN configured for single-N-MOSFET flyback switching - eliminates cross-conduction risk and simplifies layout vs. half-bridge/push-pull variants. |
| Programmable VCO with wide sweep range | Frequency controlled by external ROSC/COSC/RANGE network - enables precise tuning to match PZT mechanical resonance (e.g., 67–77 kHz) for reliable lamp strike and regulation. |
| Integrated open lamp protection with retry logic | Seven-attempt auto-retry on OPEN/SD >1.5 V - prevents latch-up during cold-start; cleared only by power cycle or OPEN/SD voltage toggle. |
| Low-quiescent shutdown mode | 15-µA typical shutdown current - extends battery life in portable electronics where display backlight may be disabled for extended periods. |
| Startup preconditioning and frequency sweep | COMP pulled to 0 V at power-up - forces initial high-frequency operation to maximize PZT gain for lamp ignition before transitioning to closed-loop regulation. |
Applications
| Notebook Computer Backlight | Portable Instrument Display |
|---|---|
Use Scenario: Powering CCFL backlights in space-constrained laptop LCD panels where height <3 mm is required. IC Role / Device Role / Timing Role: UCC3975PW acts as the resonant flyback controller, driving a single N-MOSFET to excite a piezoelectric transformer that replaces bulky magnetic HV transformers. Use Value: Enables 30% reduction in board area vs. traditional CCFL inverters by eliminating high-voltage magnetics and supporting ultra-thin mechanical envelopes. | Use Scenario: Providing adjustable brightness backlighting for handheld test equipment with variable ambient light conditions. IC Role / Device Role / Timing Role: UCC3975PW regulates lamp current via analog or burst-mode dimming by modulating VCO frequency through COMP voltage. Use Value: Delivers stable 1–5 mA lamp current across 3–13.5 V input range, maintaining consistent luminance despite battery voltage sag during field use. |
| Portable Electronics Display | Medical Handheld Device Interface |
Use Scenario: Driving CCFLs in ruggedized tablets used in logistics or field service applications with frequent on/off cycling. IC Role / Device Role / Timing Role: UCC3975PW executes automatic lamp strike attempts with built-in open-lamp retry and error shutdown to prevent undetected lamp failure. Use Value: Eliminates need for external microcontroller supervision - reduces BOM count and firmware complexity in cost-sensitive portable designs. | Use Scenario: Backlighting critical diagnostic UIs in battery-powered medical devices requiring fail-safe illumination behavior. IC Role / Device Role / Timing Role: UCC3975PW provides regulated CCFL drive with hardware-enforced safety: UVLO prevents operation below 2.85 V; open-lamp fault halts output after 7 retries. Use Value: Meets IEC 60601-1 auxiliary power reliability requirements without additional monitoring circuitry or software intervention. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar PZT controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| UCC3976PW | Half-bridge topology support; OUTP drives P-MOSFET, OUTN drives N-MOSFET with anti-cross-conduction logic; open-lamp threshold 1.4–1.6 V same as UCC3975PW. | Requires two external MOSFETs and single resonant inductor; suited for higher-efficiency, lower EMI designs where board area allows LRES placement. | Select UCC3976PW when system input voltage and lamp voltage favor half-bridge efficiency and layout permits dual-FET layout. |
| UCC3977PW | Push-pull topology support; both OUT1 and OUT2 drive N-MOSFETs with intentional overlap; open-lamp threshold 1.4–1.6 V same as UCC3975PW. | Requires two matched inductors (L1/L2); delivers higher primary voltage to PZT than flyback or half-bridge - beneficial for low-gain single-layer PZTs. | Select UCC3977PW when PZT gain is insufficient for flyback operation and mechanical layout accommodates dual inductors. |
Compared with UCC3976PW and UCC3977PW, the UCC3975PW offers lowest component count for flyback PZT designs - eliminating one MOSFET, one gate driver path, and associated layout complexity - making it optimal for cost- and space-constrained portable backlight systems where single-switch topology meets performance targets.
Availability
UCC3975PW is available at Aetrix Electronics and suitable for notebook computers, portable instrument displays, and medical handheld device interfaces requiring stable component supply and long-term industrial availability.
Supply support for UCC3975PW 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
Texas Instruments is a global semiconductor company headquartered in Dallas, Texas, delivering analog and embedded processing solutions for industrial, automotive, and personal electronics markets.
The UCC3975PW belongs to TI's dedicated CCFL/PZT controller product line, engineered specifically for resonant piezoelectric transformer-based backlight power conversion in ultra-thin portable displays.
FAQ
What topology does the UCC3975PW support?
The UCC3975PW supports only the resonant flyback topology. Its OUTP pin is internally unconnected, and OUTN drives a single external N-channel MOSFET. This distinguishes it from the UCC3976PW (half-bridge) and UCC3977PW (push-pull), which use both outputs actively. The flyback configuration minimizes component count and PCB footprint for CCFL backlight applications.
How does the UCC3975PW implement open lamp protection?
The UCC3975PW monitors the OPEN/SD pin voltage during startup and operation. If voltage exceeds 1.5 V (within 1.4–1.6 V threshold range), it interprets this as an open lamp condition and initiates up to seven automatic restart attempts. After seven failures, the device enters error shutdown mode until power is cycled or OPEN/SD is toggled between >2.5 V and <0.5 V. This behavior is confirmed in the SLUS499A datasheet Section 7.
What is the function of the COMP pin on the UCC3975PW?
The COMP pin on the UCC3975PW is the output of the internal error amplifier and serves as the control voltage for the VCO. At startup, it is preconditioned to 0 V to force maximum oscillator frequency for lamp striking. During regulation, its voltage (0–2.5 V range) sets the operating frequency to maintain constant lamp current. Exceeding 2.5 V triggers a no-lock condition and restart sequence, as documented in the functional block diagram and state diagram of SLUS499A.
Can the UCC3975PW be used with analog or burst-mode dimming?
Yes, the UCC3975PW supports both analog and burst-mode dimming. Analog dimming is implemented by injecting a control voltage (VCNT) into the feedback network to shift the COMP voltage and thus modulate VCO frequency. Burst-mode dimming uses the OPEN/SD pin to enable/disable the controller at low frequency. The datasheet confirms burst-mode capability in Section 7 ("OPEN/SD: This dual-purpose pin… can also be used to provide burst mode dimming").
What are the absolute maximum ratings for the UCC3975PW?
The UCC3975PW has an absolute maximum VDD supply voltage of 15 V, input voltage range of GND–0.5 V to VDD+0.5 V on all pins except GND, storage temperature range of –65°C to 150°C, and junction temperature range of –40°C to 125°C. These values are specified in the "Absolute Maximum Ratings" table of SLUS499A and define stress limits beyond which permanent damage may occur.
UCC3975PW Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Applications:
- Power Supplies
- Current - Supply:
- 1mA
- Voltage - Supply:
- 3V ~ 13.5V
- Operating Temperature:
- 0°C ~ 70°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-TSSOP
UCC3975PW FAQ
1.How can I place an order for UCC3975PW through Aetrix?
Please submit a Request for Quotation (RFQ) for UCC3975PW 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 UCC3975PW reliable?
The price and inventory of UCC3975PW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for UCC3975PW is usually 5 days.
3.What payment methods are accepted for UCC3975PW?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for UCC3975PW transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for UCC3975PW?
UCC3975PW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your UCC3975PW 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 UCC3975PW?
For technical support, including UCC3975PW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your UCC3975PW requirements.
6.How does Aetrix verify that UCC3975PW is sourced from the original manufacturer or authorized distributors?
All UCC3975PW 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 UCC3975PW meets industry standards.
7.What is the process for return or replacement of UCC3975PW?
All UCC3975PW units undergo pre-shipment inspection (PSI). If there is an issue with UCC3975PW, 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 UCC3975PW part is unused and in its original packaging.
Return procedure for UCC3975PW:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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