Push-pull driver for isolation transformers
0.5-A switches with programmable current limit
The SN6507 is a high voltage, high frequency push-pull transformer driver providing isolated power in a small solution size. The device comes with the push-pull topology’s benefits of simplicity, low EMI, and flux cancellation to prevent transformer saturation. Further space savings are achieved through duty-cycle control, which reduces component count for wide-input ranges, and by selecting a high switching frequency, reducing the size of the transformer.
The device integrates a controller and two 0.5-A NMOS power switches that switch out of phase. Its input operating range is programmed with precision undervoltage lockouts. The device is protected from fault conditions by over-current protection (OCP), adjustable under-voltage lockout (UVLO), over voltage lockout (OVLO), thermal shutdown (TSD), and break-before-make circuitry.
The programmable Soft Start (SS) minimizes inrush currents and provides power supply sequencing for critical power up requirements. Spread Spectrum Clocking (SSC) and pin-configurable Slew Rate Control (SRC) further reduces radiated and conducted emissions for ultra-low EMI requirements.
The SN6507 is available in a 10-pin HVSSOP DGQ package. The device operation is characterized for a temperature range from –55°C to 125°C.
PART NUMBER | PACKAGE(1) | BODY SIZE (NOM) |
---|---|---|
SN6507 | HVSSOP (10 Pin) | 3.00 mm × 3.00 mm |
Changes from Revision * (March 2022) to Revision A (June 2022)
PIN | DESCRIPTION | ||
---|---|---|---|
NAME | NO. | TYPE(1) | |
SW1 | 1 | O | Open drain output of the first power MOSFET, switch 1. Typically connected to either of the outer terminals of the center tap transformer. Because large currents flow through these pins, their external traces should be kept short. |
GND | 2 | GND | Ground connection of internal control circuits and power MOSFET. Pin 2 and Pin 9 must be shorted on PCB for optimzed emissions and efficiency. |
VCC | 3 | P | The VCC pin is the main supply pin for the power and analog circuits. Short duration, high-current pulses are produced during the turn on and turn off of the power switches. |
EN/UVLO | 4 | I | Enable input and undervoltage lockout (UVLO) programming pin.
|
DC | 5 | I | Duty cycle control pin to compensate input variation. A resistor on this pin to GND sets the duty cycle. If unused, leave the pin floating, the duty cycle is set to the default value (48%). Duty cyle control is disabled in SYNC mode. |
SR | 6 | I | Slew rate control pin to further optimize emission performance. This pin adjusts slew rate of SW1 and SW2 by connecting a resistor to GND. If the pin is left floating, the part switches at the default slew rate. |
CLK | 7 | I | This pin is used to sync the device with an external clock (SYNC mode) or program the switching frequency by connecting the pin to ground through a resistor. If shorted to GND, the part will switch at its default frequency (1MHz typical). If left floating, the part will stop switching. |
SS/ILIM | 8 | I | Multifunction Soft-Start (SS) and Current-Limit (ILIM) input pin.
|
GND | 9 | GND | Ground connection of internal control circuits and power MOSFET. Pin 2 and Pin 9 must be shorted on PCB for optimized emissions and efficiency. |
SW2 | 10 | O | Open drain output of the second power MOSFET, switch 2. Typically connected to either of the outer terminals of the center tap transformer. Because large currents flow through these pins, their external traces should be kept short. |
PowerPAD | 11 | GND | GND pins (Pin 2 and Pin 9) must be electrically connected to the power pad (Pin 11) on the printed circuit board for proper operation. |
MIN | MAX | UNIT | ||
---|---|---|---|---|
Supply voltage (2) | VCC | –0.5 | 60 | V |
Voltage | EN/UVLO | –0.5 | VCC + 0.5 | V |
Voltage | SS/ILIM, CLK, DC | –0.5 | 6 | V |
Output switch voltage | SW1, SW2 | 85 | V | |
Peak output switch current | I(D1)Pk, I(D2)Pk | 1.6 | A | |
Junction temperature, TJ | -55 | 150 | °C | |
Storage temperature range, Tstg | –65 | 150 | °C |