Datasheet

LM5025
SNVS265B –DECEMBER 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 = 31.3kΩ, R
SET
= 27.4kΩ) unless otherwise stated
(1)
Symbol Parameter Conditions Min Typ Max Unit
Cycle by Cycle Threshold Voltage 0.22 0.25 0.28 V
(CS1)
Cycle Skip Threshold Voltage Resets SS capacitor; auto restart 0.22 0.25 0.28 V
(CS2)
Leading Edge Blanking Time 50 ns
CS Sink Impedance (clocked) I
CS
= 10mA 30 50 Ω
Soft-Start
Soft-start Current Source Normal 17 22 27 µA
Soft-start Current Source following 0.5 1 1.5 µA
a CS2 event
Oscillator
Frequency1 T
A
= 25°C 180 200 220 kHz
T
J
= T
low
to T
high
175 225
Frequency2 RT = 10.4KΩ 500 580 660 kHz
Sync threshold 2 V
Min Sync Pulse Width 100 ns
Sync Frequency Range 160 kHz
PWM Comparator
Delay to Output COMP step 5V to 0V, 40 ns
Time to onset of OUT_A transition low
Duty Cycle Range 0 80 %
COMP to PWM Offset 0.7 1 1.3 V
COMP Open Circuit Voltage 4.3 5.9 V
COMP Short Circuit Current COMP = 0V 0.6 1 1.4 mA
Volt x Second Clamp
Ramp Clamp Level Delta RAMP measured from onset of 2.4 2.5 2.6 V
OUT_A to Ramp peak,
COMP = 5V
UVLO Shutdown
Undervoltage Shutdown Threshold 2.44 2.5 2.56 V
Undervoltage Shutdown 16 20 24 µA
Hysteresis
Output Section
OUT_A High Saturation MOS Device at Iout = -10mA 5 10 Ω
OUTPUT_A Peak Current Sink Bipolar Device at Vcc/2 3 A
OUT_A Low Saturation MOS Device at Iout = 10mA 6 9 Ω
OUTPUT_A Rise Time C
gate
= 2.2nF 20 ns
OUTPUT_A Fall Time C
gate
= 2.2nF 15 ns
OUT_B High Saturation MOS Device at Iout = -10mA 10 20 Ω
OUTPUT_B Peak Current Sink Bipolar Device at Vcc/2 1 A
OUT_B Low Saturation MOS Device at Iout = 10mA 12 18 Ω
OUTPUT_B Rise Time C
gate
= 1nF 20 ns
OUTPUT_B Fall Time C
gate
= 1nF 15 ns
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