Datasheet

LM21305
www.ti.com SNVS639F –DECEMBER 2009–REVISED MARCH 2013
Electrical Characteristics
(1) (2)(2)
(continued)
Specifications with standard typeface are for T
J
= 25°C, and those in boldface type apply over the full Operating
Temperature Range (T
J
= -40°C to +125°C). Unless otherwise specified, V
IN
= V
PVIN
= V
AVIN
= 12V, V
OUT
= 3.3V, I
OUT
= 0A.
Symbol Parameter Remarks Min Typ Max Unit
V
UVLO-HI-AVIN
AVIN UVLO Rising Threshold 2.84 2.93 2.987 V
V
UVLO-LO-AVIN
AVIN UVLO Falling Threshold 2.66 2.73 2.83 V
V
UVLO-HYS-AVIN
AVIN UVLO Hysteresis Window 195 mV
V
5V0
Internal LDO1 Output Voltage Measured at 5V0 pin, 1kΩ load 4.88 V
Recommended Capacitance
C
OUT-CAP-5V0
Ceramic capacitor 1 µF
connected to 5V0 pin
I
SHORT-5V0
Short Circuit Current of 5V0 pin 31 mA
V
2V5
Internal LDO2 output voltage Measured at 2V5 pin, 1kΩ load 2.47 V
Recommended Capacitance Ceramic capacitor
C
OUT-CAP-2V5
100 nF
connected to 2V5 pin
I
SHORT-2V5
Short Circuit Current of 2V5 pin 47 mA
Measured between 5V0 and
VF
CBOOT-D
CBOOT Diode Forward Voltage 0.76 V
CBOOT @ 10 mA
I
CBOOT
CBOOT Leakage Current V
CBOOT
= 5.5V, not switching 0.65 µA
Startup Time from EN high to
T
STARTUP-DELAY
the beginning of internal soft- 160 µs
start
SS Internal Soft-Start 10% to 90% V
FB
1.41 2.7 4.15 ms
OSCILLATOR
Oscillator Frequency, nominal
F
OSC-NOM
R
FRQ
= 61.9 kΩ, 0.025% 695 750 795 kHz
measured at SW pin
Maximum Oscillator Frequency
F
OSC-MAX
R
FRQ
= 28.4 kΩ 1500 kHz
measured at SW pin
Minimum Oscillator Frequency
F
OSC-MIN
R
FRQ
= 167.5 kΩ 300 kHz
measured at SW pin
Minimum Off-Time measured at f
S
= 1.5 MHz, V
IN
= 3.3V, V
FB
=
T
OFF-MIN
50 ns
SW pin 1V, voltage divider ratio = 3.3
Minimum On-Time measured at f
S
= 1.5 MHz, voltage divider
T
ON-MIN
70 ns
SW pin ratio = 1
LOGIC
V
IH-EN
EN Pin Rising Threshold 1.1 1.2 1.3 V
V
HYST-EN
EN Pin Hysteresis Window 130 200 302 mV
I
EN-IN
EN Pin Input Current V
EN
= 12V 18 23 µA
V
IH-UV-PGOOD
PGOOD UV Rising Threshold Percentage of V
OUT
87.5 93 97.5 %
PGOOD UV Hysteresis
V
HYST-UV-PGOOD
Percentage of V
OUT
-4.2 %
Threshold
I
OL- PGOOD
PGOOD Sink Current V
OL
= 0.2V 3 mA
I
OH- PGOOD
PGOOD Leakage Current V
OH
= 18V 460 nA
THERMAL SHUTDOWN
T
SD
Thermal Shutdown
(4)
160 °C
Thermal Shutdown Hysteresis
T
SD-HYS
10 °C
(4)
(4) Specified by design.
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