Datasheet LT1074, LT1076 (Analog Devices) - 4

LT1074/LT1076
ELECTRICAL CHARACTERISTICS Note 1:
Absolute Maximum Ratings are those values beyond which the life
Note 5:
Switch frequency is internally scaled down when the feedback pin of a device may be impaired. voltage is less than 1.3V to avoid extremely short switch on times. During
Note 2:
To calculate maximum switch “on” voltage at currents between testing, VFB is adjusted to give a minimum switch on time of 1µs. low and high conditions, a linear interpolation may be used. R R
Note 6:
I LIM – 1k LIM – 1k LIM ≈ (LT1074), ILIM ≈ (LT1076).
Note 3:
A feedback pin voltage (VFB) of 2.5V forces the VC pin to its low 2k 5.5k clamp level and the switch duty cycle to zero. This approximates the zero
Note 7:
Switch to input voltage limitation must also be observed. load condition where duty cycle approaches zero.
Note 8:
V
Note 4:
Total voltage from V MAX = 40V for the LT1074/76 and 60V for the LT1074HV/76HV. IN pin to ground pin must be ≥ 8V after start- up for proper regulation.
Note 9:
Does not include switch leakage.
W BLOCK DIAGRA
INPUT SUPPLY LT1074 10 A µ 320 A µ 0.3V + 6V 500Ω -POWER µ 6V TO ALL REGULATOR SHUTDOWN CIRCUITRY AND BIAS – CURRENT LIMIT COMP 0.04 + 2.35V CURRENT LIMIT C2 + SHUTDOWN 250 Ω – – I * SHUTDOWN* LIM 4.5V 10k FREQ SHIFT R 100kHz R/S G1 S Q OSCILLATOR LATCH SYNC R 3V(p-p) VIN + 400 Ω 15 Ω Z + C1 A1 ANALOG ERROR MULTIPLIER – X AMP XY PULSE WIDTH 2.21V – Z COMPARATOR SWITCH Y OUTPUT (V ) SW FB V 24V (EQUIVALENT) C LT1076 0.1Ω *AVAILABLE ON PACKAGES WITH PIN COUNTS GREATER THAN 5. 100Ω SWITCH OUTPUT (V ) SW LT1074 • BD01 sn1074 1074fds 4