Ⅰ. SN6505BDBVR Description
Ⅱ. SN6505BDBVR Pinout
Ⅲ. SN6505BDBVR 3D Model
Ⅳ. SN6505BDBVR Specifications
Ⅴ. SN6505BDBVR Feature
Ⅵ. SN6505BDBVR Applications
Ⅶ. SN6505BDBVR Layout
Ⅷ. SN6505BDBVR Package Information
Ⅸ. SN6505BDBVR Datasheet
The SN6505BDBVR is a low-noise, low-EMI push-pull transformer driver, specifically designed for small form factor, isolated power supplies. It drives low-profile, center-tapped transformers from a 2.25 V to 5 V DC power supply. Ultra-low noise and EMI are achieved by slew rate control of the output switch voltage and through Spread Spectrum Clocking (SSC). The SN6505x consists of an oscillator followed by a gate drive circuit that provides the complementary output signals to drive groundreferenced N-channel power switches. The device includes two 1-A Power-MOSFET switches to ensure start-up under heavy loads. The switching clock can also be provided externally for accurate placement of switcher harmonics, or when operating with multiple transformer drivers. The internal protection features include a 1.7 A current limiting, under-voltage lockout, thermal shutdown, and break-before-make circuitry. SN6505x includes a soft-start feature that prevents high inrush current during power up with large load capacitors. SN6505A has a 160 kHz internal oscillator for applications that need to minimize emissions whereas SN6505B has a 420 kHz internal oscillators for applications that require higher efficiency and smaller transformer size. The SN6505x is available in a small 6-pin SOT23/DBV package. The device operation is characterized for a temperature range from –55°C to 125°C.
Pin Functions :
Open drain output of the first power MOSFETs. Typically connected to the outer terminals of the center tap transformer. Because large currents flow through these pins, their external traces should be kept short.
This is the device supply pin. It should be bypassed with a 4.7 μF or greater, low ESR capacitor. When VCC ≤ 2.25 V, an internal undervoltage lockout circuit trips and turns both outputs off.
Open drain output of the second power MOSFETs. Typically connected to the outer terminals of the center tap transformer. Because large currents flow through these pins, their external traces should be kept short.
GND is connected to the source of the power MOSFET switches via an internal sense circuit. Because large currents flow through it, the GND terminals must be connected to a low-inductance quality ground plane.
The EN pin turns the device on or off. Grounding or leaving this pin floating disables all internal circuitry. If unused this pin should be tied directly to VCC.
This pin is used to run the device with external clock. Internally it is pulled down to GND. If valid clock is not detected on this pin, the device shifts automatically to internal clock.
1. SN6505BDBVR Symbol
2. SN6505BDBVR Footprint
3. SN6505BDBVR 3D Model
Switching Frequency (kHz)
Input Voltage (V)
2.25 to 5.5
Output Current (A)
Minimum Operating Supply Voltage (V)
Maximum Operating Supply Voltage (V)
Maximum Supply Current (mA)
Minimum Operating Temperature (°C)
Maximum Operating Temperature (°C)
Tape and Reel
Standard Package Name
• Push-pull driver for transformers
• Wide input voltage range: 2.25 V to 5.5 V
• High output drive: 1 A at 5 V supply
• Low RON 0.25 Ω max at 4.5 V supply
• Ultra-low EMI
• Spread spectrum clocking
• Precision internal oscillator options: 160 kHz (SN6505A) and 420 kHz (SN6505B)
• Synchronization of multiple devices with external clock input
• Slew-rate control
• 1.7 A Current-limit
• Low shutdown current
• Isolated power supply for CAN, RS-485, RS-422, RS-232, SPI, I2C, low-power LAN
• Low-noise isolated USB supplies
• Process control
• Telecom supplies
• Radio supplies
• Distributed supplies
• Medical instruments
• Precision instruments
• Low-noise filament supplies
Typical Application ：
• The VIN pin must be buffered to ground with a low-ESR ceramic bypass-capacitor. The recommended capacitor value can range from 1 μF to 10 μF. The capacitor must have a voltage rating of 10 V minimum and a X5R or X7R dielectric.
• The optimum placement is closest to the VIN and GND pins at the board entrance to minimize the loop area formed by the bypass-capacitor connection, the VIN terminal, and the GND pin. See Figure 11-1 for a PCB layout example.
• The connections between the device D1 and D2 pins and the transformer primary endings, and the connection of the device VCC pin and the transformer center-tap must be as close as possible for minimum trace inductance.
• The connection of the device VCC pin and the transformer center-tap must be buffered to ground with a low-ESR ceramic bypass-capacitor. The recommended capacitor value can range from 1μF to 10 μF. The capacitor must have a voltage rating of 16 V minimum and a X5R or X7R dielectric.
• The device GND pins must be tied to the PCB ground plane using two vias for minimum inductance.
• The ground connections of the capacitors and the ground plane should use two vias for minimum inductance.
• The rectifier diodes should be Schottky diodes with low forward voltage in the 10 mA to 100 mA current range to maximize efficiency.
• The VOUT pin must be buffered to ISO-Ground with a low-ESR ceramic bypass-capacitor. The recommended capacitor value can range from 1μF to 10 μF. The capacitor must have a voltage rating of 16 V minimum and a X5R or X7R dielectric.