Datasheet

LM20242
SNVS534E –OCTOBER 2007–REVISED MARCH 2013 www.ti.com
ELECTRICAL CHARACTERISTICS (continued)
Unless otherwise stated, the following conditions apply: V
VIN
= 12V. Limits in standard type are for T
J
= 25°C only, limits in
bold face type apply over the 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
Oscillator
F
SW1
Switching Frequency 1 R
RT
= 49.9 kΩ 675 750 825 kHz
F
SW2
Switching Frequency 2 R
RT
= 249 kΩ 225 250 325 kHz
D
MAX
Maximum Duty Cycle I
LOAD
= 0A 90 %
V
RT
RT pin voltage R
RT
= 250 kΩ 550 mV
Error Amplifier
I
FB
Feedback pin bias current V
FB
= 1V 50 nA
I
COMP(SRC)
COMP Output Source Current V
FB
= 0V 200 400 µA
V
COMP
= 0V
I
COMP(SNK)
COMP Output Sink Current V
FB
= 1V 200 350 µA
V
COMP
= 0.5V
g
m
Error Amplifier DC Transconductance I
COMP
= -50 µA to +50 µA 400 515 600 µmho
A
VOL
Error Amplifier Voltage Gain COMP pin open 2000 V/V
GBW Error Amplifier Gain-Bandwidth Product COMP pin open 7 MHz
Current Limit
I
LIM
Cycle By Cycle Current Limit 3.1 3.7 4.65 A
T
ILIM
Cycle By Cycle Current Limit Delay 150 ns
Enable
V
EN(RISING)
EN Pin Rising Threshold 1.2 1.25 1.3 V
V
EN(HYS)
EN Pin Hysteresis 50 mV
I
EN
EN Source Current V
EN
= 0V, V
VIN
= 12V 2 µA
Thermal Shutdown
T
SD
Thermal Shutdown 170 °C
T
SD(HYS)
Thermal Shutdown Hysteresis 20 °C
Thermal Resistance
θ
JC
Junction to Case 5.6 °C/W
θ
JA
Junction to Ambient 0 LFM airflow 30 °C/W
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