Datasheet LT3478, LT3478-1 (Analog Devices) - 8

LT3478/LT3478-1
U U U PI FU CTIO S
exceeds 6A or VOUT exceeds OVP, an internal soft-start
Exposed Pad (Pin 17):
The ground for the IC and the con- latch is set, the power NPN is immediately turned off and verter. The FE package has an Exposed Pad underneath the the SS pin is discharged. The soft-start latch is also set IC which is the best path for heat out of the package. Pin 17 if VIN and/or ⎯S⎯H⎯D⎯N do not meet their turn on thresholds. should be soldered to a continuous copper ground plane The SS pin only recharges when all faults are removed under the device to reduce die temperature and increase and the pin has been discharged below 0.25V. the power capability of the LT3478/LT3478-1.
W BLOCK DIAGRA
SHDN VS L SS SW 11 4 5 16 1, 2 V 10µA OUT VC 6 OVERVOLTAGE DETECT – 9.5mΩ – + 1.4V + 57mV – OVPSET + 100Ω RSENSE RSENSE INRUSH 0.1Ω (EXTERNAL FOR SOFT-START CURRENT (INTERNAL FOR LT3478) VIN UVLO PROTECTION LT3478-1) REF 3 1.24V LED 7 VREF PWM OSC S Q Q1 DETECT 10 R LED PWM – + LED CTRL1 1.05V 12 + SLOPE LED + COMP GM Q2 CTRL2 + + – LED – 13 – 1V Σ PWM + 14 + 1000Ω RS – TO OVERVOLTAGE DETECT CIRCUIT 8 15 17 9 3478 F01 OVPSET RT EXPOSED PAD VC (GND)
Figure 1
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