Datasheet

LM5026
www.ti.com SNVS363D –AUGUST 2005–REVISED APRIL 2013
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 = 30.0kΩ, R
SET
= 34.8kΩ) unless otherwise stated
(1)
Symbol Parameter Conditions Min Typ Max Units
Undervoltage Shutdown 0.1 V
Hysteresis
Undervoltage Standby 1.21 1.25 1.29 V
Threshold
Undervoltage Standby 16 20 24 µA
Hysteresis Current
Source
Current Limit
Cycle by Cycle 0.45 0.5 0.55 V
Threshold Voltage
ILIM Delay to Output CS step from 0 to 0.6V Time to 40 ns
onset of OUT transition (90%)
Cgate=0
Leading Edge Blanking 70 100 130 ns
Time
CS Sink Impedance I
CS
= 10mA 30 65 Ω
(clocked)
Over Current Restart
Restart Threshold 2.4 2.55 2.7 V
Fault Charging Current 7.5 10 12.5 µA
Discharging Current 7.5 10 12.5 µA
Soft-Start
Soft-start Current 38 50 58
Source
Soft-stop Current Sink 38 50 58
µA
Soft-start Current 0.6 1 1.3
Source following a
restart event
Oscillator
Frequency1 RT = 30.0 kΩ 180 200 220 kHz
Frequency2 RT = 10.0 kΩ 520 590 660 kHz
SYNC Source Current 200 µA
SYNC Sink Impedance Can sync up to 5 like controllers 100 Ω
minimum
Sync Threshold (falling) 1.4 V
Sync Pulse Width 15 ns
Minimum
PWM Comparator
Delay to Output CS stepped, Time to onset of 40 ns
OUT_A transition low
Mimimum Duty Cycle I
COMP
= 1mA 0 %
Maximum Duty Cycle UVLO=1.3V, COMP = open, V
DCL
80 %
Limit 1 = 2.5V
Maximum Duty Cycle UVLO=1.3V, COMP = open, V
DCL
70 %
Limit 2 = V
RT
x 0.875
Maximum Duty Cycle UVLO=2.92V, COMP = open, 40 %
Limit 3 V
DCL
= 2.5V
SS to PWM Offset 1.4 V
COMP Input Impedance Small signal impedance 1700 Ω
Slope Compensation Delta increase at PWM 75 90 115 mV
Amplitude comparator to CS
Output Section
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