Datasheet

LM5041B
www.ti.com SNVS605 –MAY 2009
ELECTRICAL CHARACTERISTICS (continued)
Unless otherwise stated the following conditions apply: V
IN
= 48V, V
CC
= 10V, RT = 26.7 kΩ, R
SET
= 20 kΩ.
(1)
. Limits in
standard type are for T
J
= 25°C only; limits in boldface type apply over the Operating Junction Temperature (T
J
) range of -
40°C to +125°C. Minimum and Maximum limits are specified through test, design, or statistical correlation. Typical values
represent the most likely parametric norm at T
J
= 25°C, and are provided for reference purposes only.
Symbol Parameter Conditions Min Typ Max Units
Error Amplifier
GBW Gain Bandwidth - 3 - MHz
DC Gain - 80 - dB
Input Voltage V
FB
= COMP 0.735 0.75 0.765 V
COMP Sink Capability V
FB
= 1.5V, COMP= 1V 4 8 - mA
Reference Supply
Ref Voltage I
REF
= 0 mA 4.85 5 5.15 V
V
REF
Ref Voltage Regulation I
REF
= 0 to 10 mA - 25 50 mV
Ref Current Limit 15 20 - mA
Current Limit
CS Step from 0 to 0.6V
Time to Onset of OUT Transition
ILIM Delay to Output - 40 - ns
(90%)
C
L
= 0
Cycle by Cycle Threshold Voltage 0.45 0.5 0.55 V
Leading Edge Blanking Time - 50 - ns
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
180 220
Frequency1 RT = 26.7 kΩ 200 kHz
175 225
Frequency2 RT = 7.87 kΩ 515 600 685 kHz
Sync threshold - 3 3.5 V
PWM Comparator
COMP = 2V, CS stepped 0 to 0.4V
Delay to Output - 25 - ns
Time to onset of OUT transition low
(Ts-240ns)
Max Duty Cycle TS = Oscillator Period - - %
/ Ts
Min Duty Cycle COMP = 0V - - 0 %
COMP to PWM Comparator Gain - 0.32 -
COMP Open Circuit Voltage FB = 0V 4.1 4.8 5.5 V
COMP Short Circuit Current FB = 0V, COMP = 0V 0.6 1 1.4 mA
Slope Compensation
Delta increase at PWM Comparator
Slope Comp Amplitude - 110 - mV
to CS
UVLO Shutdown
Under-Voltage Shutdown 2.44 2.5 2.56 V
Under-voltage Shutdown
16 20 24 µA
Hysteresis Current Source
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