IKSEMICON ILE4278_13

TECHNICAL DATA
5-V Low-Drop Fixed Voltage Regulator
ILE4278
Features
• Output voltage tolerance ≤ ± 2%, 4%
• Very low current consumption
• Separated reset and watchdog output
• Low-drop voltage
• Watchdog
PDSO-14
• Adjustable watchdog activating threshold
• Adjustable reset threshold
ORDERING INFORMATION
• Overtemperature protection
• Reverse polarity protection
ILE4278D
• Short-circuit proof
• Suitable for use in automotive electronics
• Wide temperature range
• AEC-Q100 Qualified
• ESD Protection : HBM ±8,000V / MM ±400V / CDM ±2,000V
Functional Description
The ILE 4278 is a monolithic integrated low-drop fixed-voltage regulator which can
supply loads up to 200 mA. The device is available in the 14-SOP-225 package. It is
designed to supply microprocessor systems under the severe conditions of automotive
applications and therefore equipped with additional protection functions against over
load, short circuit and over temperature. Of course the ILE 4278 can also be used in
other applications where a stabilized voltage is required.
An input voltage VI in the range of 6V ≤ VI ≤ 28V is regulated to VQ,nom = 5 V with an
accuracy of ± 2%.
An input voltage VI in the range of 28V ≤ VI ≤ 45 V is regulated to VQ,nom = 5 V with an
accuracy of ± 4%.
The device operates in the wide temperature range of Tj = – 40 to 12 5 ℃.
Two additional features are implemented in the ILE 4278 a load dependent watchdog
function as well as a sophisticated reset function including power on reset, under
voltage reset, adjustable reset delay time and adjustable reset switching threshold.
The watchdog function monitors the microcontroller, including time base failures. In
case of a missing rising edge within a certain pulse repetition time the watchdog output
is set to LOW. Programming of the max. repetition time can be done easily by an
external reset delay capacitor. To prevent a reset in case of missing pulses, the
watchdog output WO is separate from the reset output RO for the ILE 4278.
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ILE4278
The watchdog output can be used as an interrupt signal for the microcontroller. In any
case it is possible to connect pin WO and pin RO externally.
When the controller is set to sleep mode or low power mode its current consumption
drops and no watchdog pulses are created. In order to avoid unnecessary wake up
signals due to missing pulses at pin WI the watchdog feature can be disabled as a
function of the load current. The switch off threshold is set by an external resistor to pin
WADJ. The watchdog function can also be used as a timer, which periodically wakes
up the controller. Therefore the pin WADJ has to be connected to the output Q.
The power on reset feature is necessary for a defined start of the microprocessor when
switching on the application. The reset signal at pin RO goes high after a certain delay
timed trd when the output voltage of the regulator has surpassed the reset threshold.
The delay time is set by the external delay capacitor. An under voltage reset circuit
supervises the output voltage. In case VQ falls below the reset threshold the reset
output is set to LOW after a short reset reaction time trr. The reset LOW signal is
generated down to an output voltage VQ of 1 V. In addition the reset switching
threshold can be adjusted by an external voltage divider. This feature is useful with
microprocessors which guarantee a safe operation down to voltages below the
internally set reset threshold of 4.65 V typical.
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ILE4278
Pin Configuration
(top view)
PDSO-14
Figure 1
Pin Definitions and Functions
Pin
Symbol
Function
1
WO
2
WADJ
3, 4, 5, 10, 11, 12
GND
6
D
Reset Delay; connect a capacitor to ground for delay time
adjustment.
7
RADJ
Reset Switching Threshold Adjust; for setting the switching
threshold, connect a voltage divider from output to ground.
If this input is connected to ground, the reset is triggered
at the internal threshold.
8
WI
Watchdog Input; rising edge-triggered input for monitoring
a microcontroller.
9
Q
5 V Output Voltage; block to ground with min.
10uF capacitor, ESR ≤ 5Ω
13
I
Input Voltage; block to ground directly on the IC with ceramic
capacitor.
14
RO
Watchdog Output; the open collector output is connected
to the 5 V output via an integrated resistor of 30 ㏀.
Watchdog Adjust; an external resistor to GND determines the
watchdog activating threshold.
Ground
Reset Output; the open collector output is connected to the
5 V output via an integrated resistor of 30 ㏀.
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ILE4278
Block Diagram
Absolute Maximum Ratings
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Tj = – 40 to 150 ℃
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Test Circuit
VDR = VI -VO Outside the control range
Figure 3
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PDSO-14
June, 2013, Rev. 02