Datasheet LT1950 (Analog Devices) - 4

LT1950
ELECTRICAL CHARACTERISTICS The
●
denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25
°
C. COMP = open, FB = 1.4V, ROSC = 249k, SYNC = 0V, SLOPE = open, VREF = 0.1
µ
F, SHDN = VIN, BLANK = 0V, ISENSE = 0V, VIN2 = 15V, GATE = 1nF, BOOST = open, VIN = 15V, VSEC = 0V, unless otherwise specified. PARAMETER CONDITIONS MIN TYP MAX UNITS
Maximum Duty Cycle Clamp VSEC = 1.4V, FB = 1V, COMP = VOH 63 75 87 % VSEC Input Bias Current 0V < VSEC < 2.8V –0.3 –1.0 µA
Note 1:
Absolute Maximum Ratings are those values beyond which the life
Note 4:
Guaranteed by correlation to static test. of a device may be impaired.
Note 5:
This IC includes overtemperature protection that is intended to
Note 2:
The LT1950EGN is guaranteed to meet performance specifications protect the device during momentary overload conditions. Junction from 0°C to 125°C operating junction temperature. Specifications over the temperature will exceed 125°C when overtemperature protection is active. –40°C to 125°C operating junction temperature range are assured by Continuous operation above the specified maximum operating junction design, characterization and correlation with statistical process controls. temperature may impair device reliability. The LT1950IGN is guaranteed over the full –40°C to 125°C operating
Note 6:
Guaranteed but not tested. junction temperature range.
Note 7:
Maximum recommended SYNC frequency = 500kHz.
Note 3:
Rise and Fall times are between 10% and 90% levels.
W U TYPICAL PERFOR A CE CHARACTERISTICS Switching Frequency vs FB Voltage vs Temperature Temperature VIN Shutdown IQ vs Temperature
1.26 240 16 SHDN = 0V 230 14 1.25 220 A) 12 µ 1.24 ( 210 Q 10 1.23 200 8 190 6 FB VOLTAGE (V) 1.22 FREQUENCY (kHz) SHUTDOWN I IN 180 V 4 1.21 170 2 1.20 160 0 –50 –25 0 25 50 75 100 125 –50 –25 0 25 50 75 100 125 –50 –25 0 25 50 75 100 125 TEMPERATURE (°C) TEMPERATURE (°C) TEMPERATURE (°C) 1950 G01 1950 • G02 1950 • G03
Shutdown Threshold vs Maximum I I SENSE Threshold vs SENSE Pin Current vs Temperature Temperature Temperature
1.45 125 270 120 250 1.40 115 230 110 A) µ 210 1.35 105 190 THRESHOLD (mV) 100 170 1.30 CURRENT ( SENSE 95 150 90 I SENSE SHUTDOWN THRESHOLD (V) 1.25 85 130 MAXIMUM I 80 110 1.20 75 90 –50 –25 0 25 50 75 100 125 –50 –25 0 25 50 75 100 125 –50 –25 0 25 50 75 100 125 TEMPERATURE (°C) TEMPERATURE (°C) TEMPERATURE (°C) 1950 • G04 1950 G05 1950 G06 1950fa 4