DC1018B-B Linear Technology, DC1018B-B Datasheet - Page 16

• Manufacturer Part Number: DC1018B-B
• Description: LT4356-2 Overvoltage Protection Regulator With Auto-retry, Aux Amplifier Remains On During Shutdown
• Manufacturer: Linear Technology
• Series: -r

Specifications of DC1018B-B

• Design Resources: DC1018B Design File DC1018B Schematic
• Main Purpose: Overvoltage Protection
• Embedded: No
• Utilized Ic / Part: LT4356-2
• Primary Attributes: -
• Secondary Attributes: -
• Kit Application Type: Power Management
• Application Sub Type: Overvoltage Protection
• Features: Triple Layout For D-PAK Or S-8 MOSFETs , LEDs Show Input, Outputs, Fault & Enable
• Lead Free Status / Rohs Status: Not applicable / Not applicable

APPLICATIONS INFORMATION
LT4356-1/LT4356-2
Shutdown
The LT4356 can be shut down to a low current mode when
the voltage at the SHDN pin goes below the shutdown
threshold of 0.6V. The quiescent current drops to 7μA for
the LT4356-1 and 60μA for the LT4356-2 which leaves the
auxiliary amplifi er on.
The SHDN pin can be pulled up to V
up to 60V without damaging the pin. Leaving the pin open
allows an internal current source to pull it up and turn
on the part while clamping the pin to 2.5V. The leakage
current at the pin should be limited to no more than 1μA
if no pull up device is used to help turn it on.
Supply Transient Protection
The LT4356 is guaranteed to be safe from damage with
supply voltages up to 100V. Nevertheless, voltage tran-
sients above 100V may cause permanent damage. During
a short-circuit condition, the large change in current fl owing
through power supply traces and associated wiring can
cause inductive voltage transients which could exceed
100V. To minimize the voltage transients, the power trace
parasitic inductance should be minimized by using wide
traces. A small surge suppressor, D2, in Figure 9, at the
input will clamp the voltage spikes.
16
SMAJ58CA
12V
V
D2*
IN
Figure 8. Overvoltage Regulator with P-Channel MOSFET
Reverse Input Protection
*DIODES INC.
CC
or below GND by
10mΩ
11
12
R
6
7
SNS
V
SHDN
A
IN
SNS
CC
OUT
+
5
Si4435
Q2
GND
R6
10k
10
1N5245
LT4356S
15V
D1
TMR
1
A total bulk capacitance of at least 22μF low ESR electro-
lytic is required close to the source pin of MOSFET Q1. In
addition, the bulk capacitance should be at least 10 times
larger than the total ceramic bypassing capacitor on the
input of the DC/DC converter.
UNDERVOLTAGE
C
0.1μF
TMR
IRLR2908
Figure 9. Overvoltage Regulator with Low-Battery Detection
GATE
Q1
383k
100k
4
R4
R5
R3
10Ω
V
IN
SMAJ58A
OUT
4356 F08
FLT
EN
FB
3
D2
2
8
9
12
11
6
7
V
SHDN
IN
A
R1
59k
R2
4.99k
CC
OUT
+
V
12V, 3A
CLAMPED
AT 16V
OUT
10mΩ
R
SNS
GND
SNS
LT4356S
10
5
IRLR2908
GATE
Q1
TMR
4
R3
10Ω
1
C
47nF
TMR
OUT
4356 F09
FLT
3
EN
FB
2
9
8
R1
59k
R2
4.99k
FAULT
*SANYO 25CE22GA
SHDN
CONVERTER
C
22μF
L
*
DC-DC
V
CC
GND
4356fa