Datasheet LT1617, LT1617-1 (Analog Devices) - 3

LT1617/LT1617-1
W U TYPICAL PERFOR A CE CHARACTERISTICS Switch Saturation Voltage Feedback Pin Voltage and (VCESAT) Bias Current Quiescent Current
0.60 –1.25 5 25 0.55 VFB = 1.23V NOT SWITCHING 0.50 –1.24 4 23 BIAS CURRENT ( µA) 0.45 VOLTAGE ISWITCH = 500mA 0.40 –1.23 3 21 0.35 VIN = 12V 0.30 –1.22 2 µ 19 ISWITCH = 300mA A) CURRENT SWITCH VOLTAGE (V) 0.25 VIN = 1.2V FEEDBACK VOLTAGE (V) QUIESCENT CURRENT ( 0.20 –1.21 1 17 0.15 0.10 –1.20 0 15 –50 –25 0 25 50 75 100 –50 –25 0 25 50 75 100 –50 –25 0 25 50 75 100 TEMPERATURE (°C) TEMPERATURE (°C) TEMPERATURE (°C) 1617/-1 G01 1617/-1 G02 1617/-1 G03
Switch Off Time Switch Current Limit Shutdown Pin Current
550 400 25 VIN = 12V 350 500 VIN = 1.2V µA) 20 300 LT1617 450 250 15 V 400 IN = 1.2V 200 25°C V 10 IN = 12V 150 350 100°C LT1617-1 VIN = 12V SWITCH OFF TIME (ns) 100 SWITCH CURRENT LIMIT (mA) V 5 300 IN = 1.2V SHUTDOWN PIN CURRENT ( 50 250 0 0 –50 –25 0 25 50 75 100 –50 –25 0 25 50 75 100 0 5 10 15 TEMPERATURE (°C) TEMPERATURE (°C) SHUTDOWN PIN VOLTAGE (V) 1617/-1 G04 1617/-1 G05 1617/-1 G06
U U U PI FU CTIO S SW (Pin 1):
Switch Pin. This is the collector of the internal NPN power switch. Minimize the metal trace area con- VOUT − 1.23 R1= nected to this pin to minimize EMI. 1.23 + 2 •10 6 ( − )
GND (Pin 2):
Ground. Tie this pin directly to the local R2 ground plane.
SHDN (Pin 4):
Shutdown Pin. Tie this pin to 0.9V or higher
NFB (Pin 3):
Feedback Pin. Set the output voltage by to enable the device. Tie below 0.25V to turn off the device. selecting values for R1 and R2 (see Figure 1):
VIN (Pin 5):
Input Supply Pin. Bypass this pin with a capacitor as close to the device as possible. 3