Datasheet

LM5041
SNVS248D –AUGUST 2003–REVISED MARCH 2013 www.ti.com
Electrical Characteristics (continued)
Specifications with standard typeface are for T
J
= 25°C, and those with boldface type apply over full Operating Junction
Temperature range. V
IN
= 48V, V
CC
= 10V, RT = 26.7kΩ, R
SET
= 20kΩ) unless otherwise stated.
(1)
Symbol Parameter Conditions Min Typ Max Units
Reference Supply
V
REF
Ref Voltage I
REF
= 0 mA 4.85 5 5.15 V
Ref Voltage Regulation I
REF
= 0 to 10mA 25 50 mV
Ref Current Limit 15 20 mA
Current Limit
ILIM Delay to Output CS Step from 0 to 0.6V 40 ns
Time to Onset of OUT
Transition (90%)
C
L
= 0
Cycle by Cycle Threshold 0.45 0.5 0.55 V
Voltage
Cycle Skip Threshold Resets SS capacitor; auto 0.55 0.6 0.65 V
Voltage restart
Leading Edge Blanking 50 ns
Time
CS Sink Current (clocked) CS = 0.3V 2 5 mA
Soft-Start
Soft-start Current Source 7 10 13 µA
Soft-start to COMP Offset 0.35 0.55 0.75 V
Shutdown Threshold 0.25 0.5 0.75 V
Oscillator
Frequency1 (RT = T
J
= 25°C 180 200 220 kHz
26.7KΩ) 175 225
Frequency2 (RT = 515 600 685 kHz
7.87KΩ)
Sync threshold 3 3.5 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
Max Duty Cycle TS = Oscillator Period (Ts-240ns)/Ts) %
Min Duty Cycle COMP = 0V 0 %
COMP to PWM 0.32
Comparator Gain
COMP Open Circuit FB = 0V 4.1 4.8 5.5 V
Voltage
COMP Short Circuit FB = 0V, COMP = 0V 0.6 1 1.4 mA
Current
Slope Compensation
Slope Comp Amplitude Delta increase at PWM 110 mV
Comparator to CS
UVLO Shutdown
Under-voltage Shutdown 2.44 2.5 2.56 V
Under-voltage Shutdown 16 20 24 µA
Hysteresis Current
Source
Buck Stage Outputs
Output High level 5 (V
REF
) V
Output High Saturation I
OUT
= 10mA 0.5 1 V
REF = V
OUT
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