Can drive series-connected white LED arrays. Troubleshooting & Replacement (SN51DP)
| Pin | Name / Function | Verified Measured Voltage (Example) | Description / Verified Notes | | :--- | :--- | :--- | :--- | | | Power Input (VIN) | 12V | Primary power supply for the IC's internal driver stage. | | 2 | Enable / On/Off Control | 0V (Off) / >2V (On) | A logic-high signal here typically enables the backlight driver. | | 3 | Feedback / Current Sense | Varies | Connected to a current-sensing resistor to monitor LED current for regulation. | | 4 | Over-Current Protection (OCP) | Varies | Monitors the current. If too high, the IC shuts down to protect the circuit. | | 5 | Dimming Control (PWM) | 2.5V (Typical) | Receives a PWM signal to control the brightness of the backlight. | | 6 | Ground (GND) | 0V | Common ground reference for the IC. | | 7 | Oscillator / Timing | Varies | An external resistor or capacitor sets the internal switching frequency. | | 8 | Gate Drive Output | Varies | Drives the external MOSFET that switches the main current through the LED inductor. | | 9 | Over-Voltage Protection (OVP) | ~1.55V (Normal) / 0.8V (Fault) | Monitors the boosted output voltage. Critical for verifying proper operation . | | 10 | Reference / Compensation | 3.1V (Typical) | Often provides an internal voltage reference or compensation network connection. |
The SN51DP is not just limited to TVs; its versatility makes it popular in:
| | Spec | |----------------------------|-----------------------------------| | Package Type | Dual-in-line (DIP) or SMD | | Input Diode Current (IF) | 5 mA – 20 mA | | Output Collector Voltage | 50 V (VCEO) | | Isolation Resistance | ≥ 10,000 MΩ (test voltage: 500 VDC)| | Storage Temperature Range | -55°C to +150°C | sn51dp datasheet verified
A "verified" design follows the datasheet's recommended formulas for external components: Use the formula
Understanding its verified electrical architecture, pin configurations, internal protection mechanisms, and field-tested cross-references ensures safe implementation and fast diagnosis. Core Specifications Overview
The SN51DP is a 10-pin device. The verified pin configuration for typical backlight applications is as follows: Main input voltage (often used for LED driving). Can drive series-connected white LED arrays
Place the input bulk and bypass capacitors as close as possible to the VINcap V sub cap I cap N end-sub PGNDcap P cap G cap N cap D pins to reduce noise spikes.
"Active Low," Elias whispered. "It was inverted."
High-speed digital pulse width modulation with up to 8-bit programmable resolution. | | 3 | Feedback / Current Sense
Technicians often replace old filter capacitors on the boost rail. For instance, swap out problematic or degraded caps with robust, high-voltage
ESD Protection, On-chip Regulator, 1μ A Shutdown Package: SOP-10
The is a high-performance LED backlight driver IC , commonly used in the power supply or scaler boards of modern LED TVs to control the brightness and efficiency of the display panel. The Story of the SN51DP: Reviving a VU LED TV
Current setting pin; fixes the maximum backlight string output current through a precise resistor value. FB
Because the device supports a shutdown current under 1μ A, it is suitable for energy-sensitive, always-on circuits. 4. Comparison with Similar Components