LM5020
SNVS275F –MAY 2004–REVISED APRIL 2006
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Electrical Characteristics (continued)
Specifications in standard type face are for T
J
= +25°C and those in boldface type apply over the full operating junction
temperature range. Unless otherwise specified: VIN = 48V, VCC = 10V, and RT = 31.6kΩ.
(1)
Symbol Parameter Conditions Min Typ Max Units
CS Sink Impedance (clocked) 35 55 Ω
Soft Start
Softstart Current Source 7 10 13 µA
Softstart to COMP Offset 0.35 0.55 0.75 V
Oscillator
Frequency1 (RT = 31.6k) See
(3)
175 200 225 kHz
Frequency2 (RT = 9.76k) See
(3)
560 630 700 kHz
Sync threshold 2.4 3.2 3.8 V
PWM Comparator
Delay to Output COMP set to 2V, 25 ns
CS stepped 0 to 0.4V,
Time to onset of OUT
transition low
Min Duty Cycle COMP=0V 0 %
Max Duty Cycle (-1 Device) 75 80 85 %
Max Duty Cycle (-2 Device) 50 %
COMP to PWM Comparator Gain 0.33
COMP Open Circuit Voltage 4.3 5.2 6.1 V
COMP Short Circuit Current COMP=0V 0.6 1.1 1.5 mA
Slope Compensation
Slope Comp Amplitude Delta increase at PWM 80 105 130 mV
(LM5020-1 Device Only) Comparator to CS
Output Section
Output High Saturation Iout = 50mA, V
CC
- V
OUT
0.25 0.75 V
Output Low Saturation I
OUT
= 100mA, V
OUT
0.25 0.75 V
Rise Time Cload = 1nF 18 ns
Fall Time Cload = 1nF 15 ns
Thermal Shutdown
Tsd Thermal Shutdown Temp. 165 °C
Thermal Shutdown Hysteresis 25 °C
(3) Specification applies to the oscillator frequency. The operational frequency of the LM5020-2 devices is divided by two.
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