LT1676CS8#TR Linear Technology, LT1676CS8#TR Datasheet - Page 12

• Manufacturer Part Number: LT1676CS8#TR
• Description: IC REG SW STEP DOWN HI EFF 8SOIC
• Manufacturer: Linear Technology
• Type: Step-Down (Buck)r

Specifications of LT1676CS8#TR

• Internal Switch(s): Yes
• Synchronous Rectifier: No
• Number Of Outputs: 1
• Voltage - Output: 1.24 ~ 51 V
• Current - Output: 700mA
• Frequency - Switching: 100kHz
• Voltage - Input: 7.4 ~ 60 V
• Operating Temperature: 0°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Power - Output: -

LT1676
desired V
(The 2.5 A factor is an allowance to minimize error due to
SHDN pin input current.)
Behavior is as follows: Normal operation is observed at the
nominal input voltage of 48V. As the input voltage is
decreased to roughly 43V, switching action will stop, V
will drop to zero, and the LT1676 will draw its V
quiescent currents from the V
input voltage, typically 18V or so at 25 C, the voltage on
12V TO
12
TYPICAL APPLICATIONS
48V
V
IN
C1: PANASONIC HFQ
C2: AVX D CASE TPSD107M010R0080
C4, C5: X7R OR COG/NPO
D1: MOTOROLA 100V, 1A, SMD SCHOTTKY
L1: COILCRAFT DO3316P-224
+
IN
C1
39 F
63V
UVLO voltage minus 1.25V applied across it.
Figure 4a. Minimum Component Count Application
C5
100pF
1
6
SHDN
SYNC
V
LT1676
IN
GND
V
IN
IN
5
4
V
V
SW
supply. At a much lower
FB
V
CC
C
R4
210k
1%
R5
6.19k
1%
U
Figure 5. User Programmable Undervoltage Lockout
2
3
7
8
FOR 3.3V V
R1: 24.3K, R2: 14.7k
L1: 150 H, DO3316P-154
I
+
OUT
: 0mA TO 500mA
R3
22k
5%
D1
MBRS1100
C1
C5
C3
2200pF
X7R
OUT
1
6
SHDN
SYNC
IN
VERSION:
LT1676
and V
GND
V
220 H
IN
L1
C4
100pF
5
4
V
OUT
V
SW
V
CC
FB
CC
C
+
2
3
7
8
R3
C2
100 F
10V
the SHDN pin will drop to the shutdown threshold, and the
part will draw its shutdown current only from the V
The resistive divider of R4 and R5 will continue to draw
power from V
SHDN pin lockout threshold is relatively accurate includ-
ing temperature effects, the SHDN pin shutdown thresh-
old is more coarse, and exhibits considerably more
temperature drift. Nevertheless the shutdown threshold
will always be well below the lockout threshold.)
C3
R1
36.5k
1%
R2
12.1k
1%
1676 F04a
D1
C4
L1
V
5V
0mA to 500mA
OUT
IN
+
. (The user should be aware that while the
C2
R1
R2
1676 F05
90
80
70
60
50
40
30
20
1
V
V
V
V
V
IN
IN
IN
IN
Figure 4b. P
OUT
= 12V
= 24V
= 36V
= 48V
10
I
LOAD
OUT
/P
(mA)
IN
100
Efficiency
IN
1676 F04b
rail.
1000