Linear Technology EN55022B, Manual

Page: 3 / 28

LTM4612
3
4612fc
For more information www.linear.com/LTM4612
ELECTRICAL CHARACTERISTICS
The
l
denotes the specifications which apply over the specified internal
operating temperature range, otherwise specifications are at T
A
= 25°C, V
IN
= 24V, unless otherwise noted (Note 2). Per Typical
Application (front page) configuration.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
I
Q(VIN)
Input Supply Bias Current V
IN
= 36V, V
OUT
= 12V, Switching Continuous
V
IN
= 24V, V
OUT
= 12V, Switching Continuous
Shutdown, RUN = 0, V
IN
= 36V
57
48
50
mA
mA
µA
I
S(VIN)
Input Supply Current V
IN
= 36V, V
OUT
= 12V, I
OUT
= 5A
V
IN
= 24V, V
OUT
= 12V, I
OUT
= 5A
1.85
2.72
A
A
V
INTVCC
Internal V
CC
Voltage V
IN
= 36V, RUN > 2V, I
OUT
= 0A 4.7 5 5.5 V
Output Specifications
I
OUT(DC)
Output Continuous Current Range V
IN
= 24V, V
OUT
= 12V (Note 4) 0 5 A
D
V
OUT(LINE)
V
OUT
Line Regulation Accuracy V
OUT
= 12V, FCB = 0V, V
IN
= 22V to 36V,
I
OUT
= 0A
l
0.05 0.3 %
D
V
OUT(LOAD)
V
OUT
Load Regulation Accuracy V
OUT
= 12V, FCB = 0V, I
OUT
= 0A to 5A (Note 4)
V
IN
= 36V
V
IN
= 24V
l
l
0.3
0.3
0.6
0.6
%
%
V
IN(AC)
Input Ripple Voltage I
OUT
= 0A,
C
IN
= 2
×
10µF X5R Ceramic and 1
×
100µF
Electrolytic, 1
×
10µF X5R Ceramic on V
D
Pins
V
IN
= 24V, V
OUT
= 5V
V
IN
= 24V, V
OUT
= 12V
7.2
3.4
mV
P-P
mV
P-P
V
OUT(AC)
Output Ripple Voltage I
OUT
= 0A,
C
OUT
= 2
×
22µF, 2
×
47µF X5R Ceramic
V
IN
= 24V, V
OUT
= 5V
V
IN
= 24V, V
OUT
= 12V
17.5
12.5
mV
P-P
mV
P-P
f
S
Output Ripple Voltage Frequency I
OUT
= 1A, V
IN
= 24V, V
OUT
= 12V 940 kHz
D
V
OUT(START)
Turn-On Overshoot,
TRACK/SS = 10nF
C
OUT
= 200µF, V
OUT
= 12V, I
OUT
= 0A
V
IN
= 36V
V
IN
= 24V
20
20
mV
mV
t
START
Turn-On Time, TRACK/SS = Open C
OUT
= 300µF, V
OUT
= 12V, I
OUT
= 1A
Resistive Load
V
IN
= 36V
V
IN
= 24V
0.5
0.5
ms
ms
D
V
OUT(LS)
Peak Deviation for Dynamic Load Load: 0% to 50% to 0% of Full Load
C
OUT
= 2
×
22µF Ceramic, 150µF Bulk
V
IN
= 24V, V
OUT
= 12V
153 mV
t
SETTLE
Settling Time for Dynamic Load Step Load: 0% to 50% to 0% of Full Load, V
IN
= 24V 37 µs
I
OUT(PK)
Output Current Limit C
OUT
= 200µF
V
IN
= 36V, V
OUT
= 12V
V
IN
= 24V, V
OUT
= 12V
9
9
A
A
Control Section
V
FB
Voltage at V
FB
Pin I
OUT
= 0A, V
OUT
= 12V
l
0.591 0.6 0.609 V
V
RUN
RUN Pin On/Off Threshold 1 1.5 1.9 V
I
SS / TRACK
Soft-Start Charging Current V
SS/TRACK
= 0V –1 –1.5 –2 µA
V
FCB
Forced Continuous Threshold 0.57 0.6 0.63 V
I
FCB
Forced Continuous Pin Current V
FCB
= 0V –1 –2 µA
t
ON(MIN)
Minimum On-Time (Note 3) 50 100 ns
t
OFF(MIN)
Minimum Off-Time (Note 3) 250 400 ns
R
PLLIN
PLLIN Input Resistor 50 k
W