Datasheet

LM5025C
SNVS568C –SEPTEMBER 2008–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 = 32 kΩ, R
SET
= 27.4 kΩ) unless otherwise stated
(1)
Symbol Parameter Conditions Min Typ Max Units
CS2 Prop CS2 Delay to Output CS2 Step from 0 to 0.6V 50 ns
Time to onset of OUT
Transition (90%)
C
gate
= 0
Cycle by Cycle Threshold 0.45 0.5 0.55 V
Voltage (CS1)
Cycle Skip Threshold Resets SS capacitor; auto 0.45 0.5 0.55 V
Voltage (CS2) restart
Leading Edge Blanking 50 ns
Time (CS1)
CS1 Sink Impedance CS1 = 0.4V 30 50 Ω
(clocked)
CS1 Sink Impedance CS1 = 0.6V 15 30 Ω
(Post Fault Discharge)
CS2 Sink Impedance CS2 = 0.6V 55 85 Ω
(Post Fault Discharge)
CS1 and CS2 Leakage CS = CS Threshold - 100mV 1 µA
Current
Soft-Start
Soft-start Current Source 65 90 115 µA
Normal
Soft-start Current Source 0.5 1 1.5 µA
following a CS2 event
Oscillator
Frequency1 T
A
= 25°C 180 200 220 kHz
T
J
= T
low
to T
high
175 225
Frequency2 RT = 10.8 kΩ 510 580 650 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 91 %
COMP to PWM Offset 0.7 1 1.3 V
COMP Open Circuit 4.3 5.9 V
Voltage
COMP Short Circuit COMP = 0V 0.6 1 1.4 mA
Current
Volt x Second Clamp
Ramp Clamp Level Delta RAMP measured from 2.4 2.5 2.6 V
onset of OUT_A to Ramp peak.
COMP = 5V
UVLO Shutdown
Undervoltage Shutdown 2.44 2.5 2.56 V
Threshold
Undervoltage Shutdown 16 20 24 µA
Hysteresis
Output Section
OUT_A High Saturation MOS Device @ Iout = -10mA, 5 10 Ω
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