SN6505B Low-noise 1-A, 420-kHz transformer driver for isolated power supplies | TI.com

SN6505B
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Low-noise 1-A, 420-kHz transformer driver for isolated power supplies

 

Description

The SN6505x 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 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 1.7 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.

Features

  • 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: <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

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Parametrics

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Part number Order Vin (Min) (V) Vin (Max) (V) Vout (Min) (V) Vout (Max) (V) Iout (A) Soft start Features Switching frequency (Min) (kHz) Switching frequency (Max) (kHz) Rating Operating temperature range (C) Package size: mm2:W x L (PKG) Iout (Max) (A) Shutdown current (Typ) (uA) Switch current limit (Typ) (A) Undervoltage lockout
SN6505B Order now 2.25     5.5     0     16     1     Yes     Enable
Short-circuit protection
Spread spectrum clocking
Thermal shutdown
Slew-rate control    
100     1600     Catalog     -55 to 125     6SOT-23: 5 mm2: 1.6 x 2.9 (SOT-23 | 6)     1.5     1     2     Vin<1.7V    
SN6501 Order now 3     5.5     0     11     0.25     No       410     620     Catalog     -40 to 125     5SOT-23: 5 mm2: 1.6 x 2.9 (SOT-23 | 5)     0.5         0.5      
SN6505A Order now 2.25     5.5     0     16     1     Yes     Enable
Short-circuit protection
Spread spectrum clocking
Thermal shutdown
Slew-rate control    
100     600     Catalog     -55 to 125     6SOT-23: 5 mm2: 1.6 x 2.9 (SOT-23 | 6)     1.5     1     2     Vin<1.7