DC1575A Linear Technology, DC1575A Datasheet - Page 6

• Manufacturer Part Number: DC1575A
• Description: LTC4362-1/LTC4362-2 Overvoltage/Overcurrent Protector With LatchOff/Auto-Retry
• Manufacturer: Linear Technology
• Series: -r

Specifications of DC1575A

• Design Resources: DC1575A Schematic DC1575 Design Files
• Main Purpose: Overvoltage/Overcurrent Protection
• Embedded: No
• Utilized Ic / Part: LTC4362-2
• Primary Attributes: -
• Secondary Attributes: -
• Kit Application Type: Power Management
• Application Sub Type: Overvoltage Protection
• Features: Demonstrates Two Protection Schemes Selected At JP2, Provides Connection For USB Protection
• Lead Free Status / Rohs Status: Not applicable / Not applicable

LTC4362-1/LTC4362-2
BLOCK DIAGRAM
OPERATION
Mobile devices like cell phones and MP3/MP4 players
have highly integrated subsystems fabricated from deep
submicron CMOS processes. The small form factor is
accompanied by low absolute maximum voltage ratings.
The sensitive electronics are susceptible to damage from
transient or DC overvoltage conditions from the power
supply.
Failures or faults in the power adaptor can cause an over-
voltage event. So can hot-plugging an AC adaptor into the
power input of the mobile device (see Application Note
88). Today’s mobile devices derive their power supply or
recharge their internal batteries from multiple alternative
inputs like AC wall adaptors, car battery adaptors and USB
6
IN
GATEP
ON
1V
5μA
200k
+
–
1.8M
5.8V
CONTROL
CHARGE
PUMP
GND
+
–
+
–
+
–
GATE HIGH
COMPARATOR
OVERCURRENT
COMPARATOR
OVERVOLTAGE
COMPARATOR
10μA
GATE HIGH
THRESHOLD
+ –
47mV
ports. A user might unknowingly plug in the wrong adap-
tor, damaging the device with a high or even a negative
power supply voltage.
The LTC4362 protects low voltage electronics from these
overvoltage conditions by controlling an internal N-chan-
nel MOSFET confi gured as a pass transistor. At power-up
(V
age condition causes the delay cycle to continue until a
safe voltage is present. When the delay cycle completes,
an internal high-side switch driver slowly ramps up the
MOSFET gate, powering up the output at a controlled rate
and limiting the inrush current to the output capacitor.
IN
5.8V
5.7V
> 2.1V), a start-up delay cycle begins. Any overvolt-
RESISTOR
SENSE
31mΩ
SENSE
5.8V
500k
PWRGD
436212 BD
OUT
436212fa