LT1506IR-3.3SYNC#TR Linear Technology, LT1506IR-3.3SYNC#TR Datasheet - Page 14
![IC REG SW 4.5A STEPDOWN 3.3V 7DD](/photos/7/33/73397/7-dd-pkg_sml.jpg)
LT1506IR-3.3SYNC#TR
Manufacturer Part Number
LT1506IR-3.3SYNC#TR
Description
IC REG SW 4.5A STEPDOWN 3.3V 7DD
Manufacturer
Linear Technology
Type
Step-Down (Buck)r
Datasheet
1.LT1506CS8-3.3PBF.pdf
(24 pages)
Specifications of LT1506IR-3.3SYNC#TR
Internal Switch(s)
Yes
Synchronous Rectifier
No
Number Of Outputs
1
Voltage - Output
3.3V
Current - Output
4.5A
Frequency - Switching
500kHz
Voltage - Input
4 ~ 15 V
Operating Temperature
-40°C ~ 125°C
Mounting Type
Surface Mount
Package / Case
D²Pak, TO-263 (7 leads + tab)
Lead Free Status / RoHS Status
Contains lead / RoHS non-compliant
Power - Output
-
Other names
LT1506IR3.3SYNCTR
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
LT1506
APPLICATIONS
Keep the connections from the resistors to the shutdown
pin short and make sure that interplane or surface capaci-
tance to the switching nodes are minimized. If high
resistor values are used, the shutdown pin should be
bypassed with a 1000pF capacitor to prevent coupling
problems from the switch node. If hysteresis is desired in
the undervoltage lockout point, a resistor R
added to the output node. Resistor values can be calcu-
lated from:
25k suggested for R
V
Example: output voltage is 5V, switching is to stop if input
voltage drops below 6V and should not restart unless
input rises back to 7.5V. V is therefore 1.5V and V
Let R
14
IN
V = Hysteresis in input voltage level
R
R
= Input voltage at which switching stops as input
HI
FB
LO
voltage descends to trip level
= 25k.
R
R
LO IN
HI
V
V
INPUT
OUT
2 38
2 38
U
LO
C1
V
INFORMATION
R
U
V V
2 3 5
R
R
LO
HI
OUT
A
W
IN
SHDN
LT1506
1
V
Figure 4. Undervoltage Lockout
FB
3.5 A
U
IN
can be
2.38V
= 6V.
0.4V
GND
R
FB
SWITCH NODE CONSIDERATIONS
For maximum efficiency, switch rise and fall times are
made as short as possible. To prevent radiation and high
frequency resonance problems, proper layout of the com-
ponents connected to the switch node is essential. B field
(magnetic) radiation is minimized by keeping catch diode,
switch pin, and input bypass capacitor leads as short as
possible. E field radiation is kept low by minimizing the
length and area of all traces connected to the switch pin
and BOOST pin. A ground plane should always be used
under the switcher circuitry to prevent interplane cou-
pling. A suggested layout for the critical components is
shown in Figure 5. Note that the feedback resistors and
compensation components are kept as far as possible
R
R
HI
FB
25 5 2
25 6 2 38 1 5 5 1
48 5 1 5
2 29
k
k
k
.
LOCKOUT
TOTAL
SHUTDOWN
2 38 25 3 5
.
/ .
.
.
V
48
SW
160
k
. /
k
k
.
A
+
1 5
.
OUTPUT
1506 F04