SN6505ADBVR

The SN6505 is a low-noise, low-EMI, push-pull transformer driver designed for small isolated power supplies. This device drives thin, center-tapped transformers with a DC power supply ranging from 2.25V to 5V. Ultra-low noise and EMI can be achieved through the slew rate control of the output switching voltage and spread spectrum clock (SSC). The SN6505 includes an oscillator followed by a gate driver circuit, which provides compensated output signals to drive ground-referenced N-channel power switches. The device contains two 1A power MOSFET switches to ensure normal startup under heavy load conditions. The switching clock can also be provided externally, which ensures accurate positioning of switching harmonics or allows for use with multiple transformer drivers. Internal protection features include a 1.7A current limit, undervoltage lockout, thermal shutdown, and a break-before-make circuit. The SN6505 has a soft-start feature to prevent high inrush currents in large load capacitors during power-up. The SN6505 is available in a small 6-pin SOT23/DBV package. The device operates over a temperature range of -55°C to 125°C.

Applications

• Isolated power supply for CAN, RS-485, RS-422, RS-232, SPI, I2C, and low-power LAN
• Low-noise isolated USB power supply
• Process control
• Telecom power supply
• Radio power supply
• Distributed power supply
• Medical instruments
• Precision instruments
• Low-noise filament power supply

Key features

• Push-pull transformer driver
• Wide input voltage range: 2.25V to 5.5V
• High output drive: 1A at 5V supply
• Low R_ON, 0.25Ω maximum at 4.5V supply
• Ultra-low EMI
• Spread-spectrum clocking
• Precision internal oscillator options: 160kHz (SN6505A) and 420kHz (SN6505B)
• Multi-device synchronization via external clock input
• Slew rate control
• 1.7A current limiting
• Low shutdown current: <1μA
• Thermal shutdown
• Wide temperature range: -55°C to 125°C
• Small 6-pin SOT23 (DBV) package
• Soft-start for inrush current reduction