SN6505A_15 Datasheet, PDF (1/30 Pages) Texas Instruments – SN6505 Low-Noise 1-A Transformer Drivers for Isolated Power Supplies

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SN6505A, SN6505B
SLLSEP9A – SEPTEMBER 2015 – REVISED OCTOBER 2015
SN6505 Low-Noise 1-A Transformer Drivers for Isolated Power Supplies
1 Features
•1 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 R_ON 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: <1 μA
• Thermal Shutdown
• Wide Temperature Range: –55°C to 125°C
• Small 6-Pin SOT23/DBV Package
• Soft Start to reduce In-rush current
2 Applications
• 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
• Medical Instruments
• Distributed Supplies
• Medical Instruments
• Precision Instruments
• Low-Noise Filament Supplies
3 Description
The SN6505 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 SN6505 consists of an oscillator followed
by a gate drive circuit that provides the
complementary output signals to drive ground-
referenced 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 1.7A current limiting, under-voltage lockout,
thermal shutdown, and break-before-make circuitry.
SN6505 includes a soft-start feature that prevents
high inrush current during power up with large load
capacitors. The SN6505 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.
Device Information⁽¹⁾
PART NUMBER PACKAGE
BODY SIZE (NOM)
SN6505A
SN6505B
SOT23 (6 Pin)
2.90 mm x 1.60 mm
(1) For all available packages, see the orderable addendum at
the end of the datasheet.
Simplified Schematic
SN6505
4 _GND
D2 ³
VOUT
Enable 5 _EN
VCC ^{2 VCC}
Ext Clock 6 _CLK
D1 ¹
10µF 0.1µF
10µ F
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. PRODUCTION DATA.