LT1956IGN-5#TRPBF Linear Technology, LT1956IGN-5#TRPBF Datasheet - Page 23

• Manufacturer Part Number: LT1956IGN-5#TRPBF
• Description: IC SW REG STP-DWN HI VOLT 16SSOP
• Manufacturer: Linear Technology
• Type: Step-Down (Buck)r

Specifications of LT1956IGN-5#TRPBF

• Internal Switch(s): Yes
• Synchronous Rectifier: No
• Number Of Outputs: 1
• Voltage - Output: 5V
• Current - Output: 1.5A
• Frequency - Switching: 500kHz
• Voltage - Input: 5.5 ~ 60 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 16-SSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Power - Output: -

APPLICATIO S I FOR ATIO
current via the V
output. Output rise time is controlled by the current
through C
is in regulation, Q1 turns off and the circuit operates
normally. R3 is transient protection for the base of Q1.
Using the values shown in Figure 10,
RiseTime
Rise Time
SS
defined by R4 and Q1’s V
REMOVABLE
C
R
47 10
4
pin to maintain a constant dv/dt at the
U
INPUT
•
C
SS
V
BE
3
INPUT
U
0 7
12V
15 10
V
.
OUT
10MQ060N
R3
54k
R4
25k
•
D3
Figure 12. Dual Source Supply with 25 A Reverse Leakage
–
C3
2.2 F
CERAMIC
W
9
Figure 13. Buck Converter with Adjustable Soft-Start
BE
C3
2.2 F
5
. Once the output
V
SHDN
SYNC
IN
BOOST
5
ms
R
2.2k
V
SHDN
SYNC
GND
LT1956
C
IN
U
C
0.022 F
C
GND
BIAS
LT1956
BOOST
R
2.2k
C
V
C
0.022 F
SW
C
C
FB
C
220pF
F
BIAS
V
0.1 F
SW
C
FB
C2
Q1
C
220pF
The ramp is linear and rise times in the order of 100ms are
possible. Since the circuit is voltage controlled, the ramp
rate is unaffected by load characteristics and maximum
output current is unchanged. Variants of this circuit can be
used for sequencing multiple regulator outputs.
DUAL POLARITY OUTPUT CONVERTER
The circuit in Figure 14a generates both positive and
negative 5V outputs with all components under 3mm
height. The topology for the 5V output is a standard buck
converter. The –5V output uses a second inductor L2,
diode D3 and output capacitor C6. The capacitor C4
F
0.1 F
D1
C2
MMSD914TI
R4
47k
18 H
D2
L1
D1
10MQ060N
R3
2k
100 F
18 H
C1
L1
15nF
C
+
SS
MMSD914TI
R1
15.4k
R2
4.99k
R1
15.4k
R2
4.99k
1766 F13
+
5V, 1A
C1
100 F
10V
LT1956/LT1956-5
OUTPUT
5V
1A
ALTERNATE
SUPPLY
1956 F12
23
1956f