IKSEMICON ILE4268

TECHNICAL DATA
5-V Low-Drop Fixed Voltage Regulator
ILE4268
Features
• Output voltage tolerance < ± 2 %
• Very low current consumption
• Low-drop voltage
• Watchdog
• Settable reset threshold
• Overtemperature protection
• Reverse polarity protection
• Short-circuit proof
• Suitable for use in automotive electronics
• Wide temperature range
Functional Description
This device is a 5-V low-drop fixed-voltage regulator. The maximum input voltage is 45
V. It can deliver an output current of at least 180 mA. The IC is short-circuit proof and
features temperature protection that disables the circuit in the event of impermissibly high
temperatures. The watchdog function is disabled as a function of the load, so that a
controller is not interrupted during sleep mode by a watchdog reset.
Application Description
The IC regulates an input voltage V, in the range 5.5 V < V, < 45 V to Vqrated = 5-O V.
In the event of an output voltage VQ < VRT, a reset signal is generated. The wiring of the
reset switching threshold input enables the value of VRT to be reduced. The reset delay
time can be adjusted using an external capacitor. The integrated watchdog monitors the
connected active controller. If there is no positive-going edge at the watchdog input, the
reset output is set to low. The reset delay capacitor provides a wide adjustment range for
the pulse repetition time. The watchdog function is only activated if the load exceeds 8 mA.
This ensures that a microcontroller is not activated during power-down and the current
drain is not increased. The IC is protected against overload and overtemperature.
1
ILE4268
Pin Configuration
(top view)
Pin Definitions and Functions
Pin
1, 2, 8,
13, 19, 20
Symbol Function
N. C.
Not connected.
3
QRES
4 … 7,
14 … 17
9
GND
DRES
10
SRES
11
W
12
VQ
18
VI
Reset output; the open collector output is connected to the
5-V output via an integrated resistor of 30 kΩ.
Ground
Reset delay; connect a capacitor to ground for delay time
adjustment.
Reset switching threshold; for setting the switching
threshold, output to ground with voltage divider. If this input is
connected to ground, the reset is triggered at an output
voltage of 4.5 V.
Watchdog input; positive-edge-triggered input for monitoring
a microcontroller.
5-V output voltage; block to ground with 22-µF capacitor,
ESR < 3 Ω.
Input voltage; block to ground directly on the IC with ceramic
2
ILE4268
Circuit Description
The control amplifier compares a reference voltage, which is kept highly accurate by
resistance adjustment, to a voltage that is proportional to the output voltage and drives the
base of the series transistor via a buffer. Saturation control as a function of the load
current prevents any over-saturation of the power element. If The externally scaled down
output voltage at the reset threshold input drops below 1.35 V, the external reset delay
capacitor is discharged by the reset generator. If the voltage on the capacitor reaches the
lower threshold VST, a reset signal is generated on the reset output and not cancelled
again until the upper threshold voltage is exceeded. If the reset threshold input is
connected to GND, reset is triggered at an output voltage of 4.5 V. A connected
microcontroller is monitored by the watchdog logic. If pulses are missing, the rest output is
set to low. The pulse sequence time can be set within a wide range with the reset delay
capacitor.
The IC also incorporates a member of internal circuits for protection against:
• Overload
• Overtemperature
• Reverse polarity
Block Diagram
3
ILE4268
Absolute Maximum Ratings
Tj=-40 to 150°C
Parameter
Input
Input voltage
Input current
Symbol
Limit Values
min.
max.
Notes
Vi
Ii
-30
VR
IR
-0.3
7
V
Reset Delay
Voltage
Current
VD
ID
-0.3
7
V
Watchdog
Watchdog input
Vw
-0.3
7
V
-
Reset Input
Reset threshold
VRE
-0.3
7
V
-
Output
Output voltage
Output current
VQ
IQ
-0.3
7
V
Ground
Current
IM
-100
50
mA
-
150
150
°C
°C
—
-50
Reset Output
Voltage Current
Temperatures
Junction temperature Ti
Storage temperature Ts
45
Unit
V
Internally limited
Internally limited
Internally limited
Internally limited
4
ILE4268
Operating Range
Parameter
Symbol
Input voltage
Junction temperature
Vi
Tj
Thermal Resistance
Junction ambient (soldered)
Junction case
RthjA
RthjC
Limit Values
Unit
min.
max.
45
V
-40
150
°C
70
25
Notes
K/W
K/W
Optimum reliability and life time are guaranteed if the junction temperature does not
exceed 125 °C in operating mode. Operation at up to the maximum junction temperature
of 150°C is possible in principle. Note, however, that operation at the maximum permitted
ratings could affect the reliability of the device.
Characteristics
Vi = 13.5 V;- 40 °C ≤ Tj ≤ 125 °C (unless otherwise specified)
Parameter
Symbol
Limit Values
typ.
max.
5.00
5.10
Unit
Test Condition
Output voltage
VQ
min.
4.90
Output current limiting
Current consumption
Iq = Ii - IQ
Current consumption
Iq = Ii - IQ
Drop voltage
Load regulation
IQ
Iq
180
—
250
300
—
450
mA
HA
5mA ≤ IQ ≤ 150mA;
6V ≤ V i≤ 28V;
—
IQ = 0 mA
Iq
—
13
20
mA
IQ = 150 mA
VDR
∆VQ
∆VQ
-
0.25
10
0.5
30
V
mV
IQ= 150mA1)
IQ= 5 to 150mA
—
10
30
mV
Vi = 6 to 28 V
IQ= 150mA
Switching threshold
Switching voltage
Saturation voltage
Saturation voltage
Charging current
VRT
VRE
VR
Vc
Id
4.2
1.28
5
4.5
1.35
0.2
30
12
4.8
1.45
0.5
100
18
1 mA extern
VQ < VRT
Vc = 1.0V
Delay switching
threshold
Delay time
Delay time
Pull-up
VDU
1.4
1.8
2.2
V
V
V
mV
µA
V
td
tt
RR
10
18
15
2
30
25
46
ms
ms
kΩ
Cd = 100 nF
Cd = 100 nF
with resp. to VQ
VDRL
0.2
0.4
0.55
V
—
Supply voltage
regulation
V
Reset Generator
Lower switching
threshold
—
1) Drop
voltage = VI – VQ (measured when the output voltage has dropped 100 mV from the nominal value
obtained at 13.5 V input)
5
ILE4268
Characteristics (cont’d)
Parameter
Symbol
Limit Values
Unit
Test Condition
min.
typ.
max.
ICd
Id
VCd
VDWL
1.5
5
1.6
0.2
3.5
12
1.8
0.4
5.2
18
2.0
0.55
µA
µA
V
V
Vc = 1.0V
Vc = 1.0V
—
TWP
FWT
30
25
55
40
75
60
ms
ms
Q = 100nF
Cd = 100nF
IQ
Vw
2
5
8
—
15
—
mA
Watchdog
Discharge current
Charging current
Switching voltage
Lower switching
threshold
Watchdog periode
Watchdog trigger
time
Activating current
Slew rate
Activates watchdog
V/µs from 20 % up to 80 % VQ
Note: The reset output is low in range from VQ= 1 V to VRT.
Test Circuit
6
ILE4268
Timing (Watchdog Disabled)
Timing of the Watchdog Function
7
ILE4268
Package Dimensions
P-DSO-20-6
8