IK Semicon ILE4278 5-v low-drop fixed voltage regulator Datasheet

Preliminary
TECHNICAL DATA
5-V Low-Drop Fixed Voltage Regulator
ILE 4278
Features
•
•
•
•
•
•
•
•
•
•
•
•
Output voltage tolerance  2%, 4%
Very low current consumption
Separated reset and watchdog output
Low-drop voltage
Watchdog
Adjustable watchdog activating threshold
Adjustable reset threshold
Overtemperature protection
Reverse polarity protection
Short-circuit proof
Suitable for use in automotive electronics
Wide temperature range
P-DSO-14-8
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 overtemperature. 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
accuracy of 2%.
6V  VI  28V is regulated to VQ,nom = 5 V with an
An input voltage V I 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 C.
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
Rev. 00
1
ILE 4278
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. 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.
Rev. 00
2
ILE 4278
Pin Configuration
(top view)
14-SOP
WO
WADJ
GND
GND
GND
D
RADJ
1
2
3
4
5
6
7
14
13
12
11
10
9
8
RO
VΙ
GND
GND
GND
VQ
WΙ
Figure 1
Pin Definitions and Functions
Pin
Symbol Function
1
WO
Watchdog Output; the open collector output is connected to the
5 V output via an integrated resistor of 30 kτ.
2
WADJ
Watchdog Adjust; an external resistor to GND determines the
watchdog activating threshold.
GND
3, 4, 5,
10, 11, 12
Ground
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. 10 ←F capacitor,
ESR  5 τ.
13
I
Input Voltage; block to ground directly on the IC with ceramic
capacitor.
14
RO
Reset Output; the open collector output is connected to the
5 V output via an integrated resistor of 30 kτ.
Rev. 00
3
ILE 4278
Block Diagram
VΙ
9
13
Temperature
Sensor
Protection
Circuit
14
VQ
RO
Reset
Generator
+
-
Control
Amplifier
7
1
Bandgap
Reference
6
Watchdog
2
3-5, 10-12
WADJ
GND
RADJ
WO
D
8
WΙ
Figure 2
Rev. 00
4
ILE 4278
Absolute Maximum Ratings
Tj = – 40 to 150 C
Parameter
Symbol
Limit Values
Unit
Notes
min.
max.
VI
II
– 42
45 V
–
–
–
mA
Internally limited
VQ
IQ
–1
25
V
–
–
–
mA
Internally limited
VRO
IRO
– 0.3
25
V
–
–5
5
mA
–
VD
ID
– 0.3
7
V
–
–2
2
mA
–
Input Voltage I
Voltage
Current
Output Voltage Q
Voltage
Current
Reset Output RO
Voltage
Current
Reset Delay D
Voltage
Current
Reset Switching Threshold Adjust RADJ
Voltage
Current
VRADJ
IRADJ
– 0.3
7
V
–
–
–
mA
Internally limited
VWI
IWI
– 0.3
7
V
–
–
–
mA
Internally limited
VWO
IWO
– 0.3
25
V
–
–5
5
mA
–
Watchdog Input WI
Voltage
Current
Watchdog Output WO
Voltage
Current
Rev. 00
5
ILE 4278
Absolute Maximum Ratings (cont’d)
Tj = – 40 to 150 C
Parameter
Symbol
Limit Values
Unit
Notes
min.
max.
VWADJ
IWADJ
– 0.3
7
V
–
–
–
mA
Internally limited
IGND
– 100
50
mA
–
Junction temperature
Tj
– 40
150
–
Storage temperature
Tstg
– 50
C
C
Watchdog Adjust WADJ
Voltage
Current
Ground GND
Current
Temperatures
150
–
Note: ESD protection according to MIL Std. 883: 2 kV.
Maximum ratings are absolute ratings; exceeding any one of these values may
cause irreversible damage to the integrated circuit.
Operating Range
Parameter
Input voltage
Junction temperature
Symbol
Limit Values
Unit
Notes
min.
max.
VI
Tj
6.0
45
V
–
– 40
125
C
–
Rthj-a
Rthj-pin
–
80
K/W
1)
–
30
K/W
Measured to pin 4
Thermal Resistance
Junction ambient
Junction pin
1)
Package mounted on PCB 80 ⌠ 80 ⌠ 1.5 mm3; 35←Cu ; 5← Sn; Heat Sink Area 6 cm2; zero airflow.
Note: In the operating range the functions given in the circuit description are fulfilled.
Rev. 00
6
ILE 4278
Electrical Characteristics
VI = 13.5 V; – 40 C  Tj  125 C (unless otherwise specified)
Parameter
Symbol
Limit Values
min. typ.
max.
Unit Test Condition
Output voltage
VQ
4.90 5.00
5.10
V
1mA  IQ  150 mA;
6 V  VI  28 V
Output voltage
VQ
4.8
5.0
5.2
V
1 mA  IQ  50 mA;
28 V  VI  45 V
Output current limiting
IQ
Iq,o
200
400
–
mA
–
180
200
←A
VQ = 4.8 V
Tj = 25 C; IQ = 0 mA
Current consumption
Iq = I I – I Q
Iq,o
–
210
230
←A
Current consumption
Iq = I I – I Q
Iq,150
–
5
12
mA
IQ = 0 mA;
Tj = 85 C
IQ = 150 mA
Drop voltage;
VDR = VI – VQ
Vdr
–
0.25
0.5
V
IQ = 150 mA1)
Load regulation
αVQ.lo
– 30 – 5
–
mV
Line regulation
αVQ,li
–
5
20
mV
IQ = 5 to 150 mA;
VI = 6 V
VI = 6 to 28 V
IQ = 5 mA
Reset threshold
VQ,rt
4.5
4.65
4.8
V
RADJ connected to
GND
Reset headroom
αVQ,rt = 180 350 –
(VQ,nom –
VQ,rt)
VRADJ,th 1.28 1.35 1.45
VRO,l
–
0.20 0.40
mV
IQ = 10 mA
V
V
VQ ∫=3.5 V
Rext = 10 kτ=to VQ
VQ ∫=1 V
Current consumption
Iq = I I – I Q
Reset Generator
Reset adjust threshold
Reset low voltage
Reset high voltage
Reset pull-up
Charging current
VRO,h
RRO
ID,c
4.5
–
–
V
–
20
30
46
kτ
Internal connected to VQ
2
5
8
←A
VD = 1.0 V
Rev. 00
7
ILE 4278
Electrical Characteristics (cont’d)
VI = 13.5 V; – 40 C  Tj  125 C (unless otherwise specified)
Parameter
Upper timing threshold
Lower reset timing
threshold
Delay time
Reset reaction time
Symbol
Limit Values
Unit Test Condition
min. typ.
max.
VDU
VDRL
1.5
1.9
2.3
V
–
0.2
0.3
0.4
V
–
trd
trr
12
20
28
ms
0.4
1.0
2.0
←s
CD = 47 nF
CD = 47 nF
VWADJ,th
IQ/IWADJ
dVWI/dt
VWOL
VWOH
RWO
1.28 1.35
1.45
V
Voltage at WADJ
650
720
800
–
IQ  10 mA
5
–
–
V/←s From 20% up to 80% VQ
–
0.2
0.4
V
Rext > 10 kτ to VQ
4.5
–
–
V
–
20
30
46
kτ
Internally connected to
VQ
VD = 1.0 V
VD = 1.0 V
Watchdog
Activating threshold
Current ratio
Slew rate
Watchdog low voltage
Watchdog high voltage
Watchdog pull-up
ID,wc
Discharge current
ID,wd
Upper timing threshold VDU
Lower watchdog timing VDWL
Charge current
2
5
8
0.6
1.3
2.0
←A
←A
1.5
1.9
2.3
V
–
0.5
0.7
0.9
V
–
threshold
Watchdog output pulse
period
TWD,p
42
60
80
ms
Cd = 47 nF
Watchdog output low
time
tWD,l
7
13
19
ms
VQ > VRT
Watchdog trigger time
TWI,tr
35
47
61
ms
Cd = 47 nF
1)
Measured when the output voltage VQ has dropped 100 mV from the nominal value.
Rev. 00
8
ILE 4278
Test Circiut
ΙΙ
C Ι1
1000 µF
Ι WO
VΙ
WO
VΙ
WΙ
VWADJ
9
VQ
ΙQ
C Ι2
470 nF
Ι WADJ WADJ
VWO
13
VW
VD
CQ
10 µF
ILE 4278
1
2
8
3-5,
10-12
GND
6
D
CD
47 nF
Ι GND
RO
14
7
RADJ
Ι RO
VQ
VRO
VRE
VDR = VΙ -VO Outside the control range
Figure 3
Rev. 00
9
ILE 4278
Application Information
Input, Output
The input capacitors CI1 and CI2 are necessary for compensating line influences. Using
a resistor of approx. 1 τ in series with CI1, the LC circuit of input inductance and input
capacitance can be damped. To stabilize the regulation circuit the output capacitor CQ is
necessary. Stability is guaranteed at values CQ ∫ 10 ←F with an ESR  5 τ within the
operating temperature range.
Application Circuit
VΙ
+12 V
C Ι1
CΙ2
13
9
VQ
470 nF
1
ILE 4278
14
8
3-5,
10-12
GND
6
D
WO
R1
CQ
22 µF
RO
WΙ
RADJ
7
2
WADJ
µP
*)
Cooling
Area
CD
47 nF
R WADJ
R2
*) or short to GND
for internal threshold
Figure 4
Rev. 00
10
ILE 4278
Reset Timing
The power-on reset delay time is defined by the charging time of an external capacitor
CD which can be calculated as follows:
CD = (αtrd ⌠ ID,c)/αV
CD = delay capacitor
αtrd = delay time
ID,c = charge current, typical 5 ←A
αV = VDU, typical 1.9 V
VDU = upper delay switching threshold at CD for reset delay time
The reset reaction time trr is the time it takes the voltage regulator to set the reset out
LOW after the output voltage has dropped below the reset threshold. It is typically 1 ←s
for delay capacitor of 47 nF. For other values for CD the reaction time can be estimated
Definitions:
using the following equation:
trr  20 s/F ⌠ CD
Reset Timing (Watchdog Disabled)
VΙ
t
< t rr
VQ
V Q, rt
d V Ι D,c
=
dt
CD
VD
t
V DU
V DRL
t rd
t rr
t
VRO
t
Power-on-Reset
Thermal
Shutdown
Voltage Dip
at Input
Undervoltage
Secondary
Spike
Overload
at Output
Figure 5
Rev. 00
11
ILE 4278
Reset Switching Threshold
The present default value is 4.65 V. When using the ILE 4278 the reset threshold can
be set to 3.5 V < VQ,rt < 4.6 V by connecting an external voltage divider to pin RADJ. The
calculation can be easily done since the reset adjust input current can be neglected. If
this feature is not needed, the pin has to be connected to GND.
VQ,rt = Vref(1 + R1/R2)
Definitions:
VQ,rt = Reset threshold
Vref = comparator reference voltage, typical 1.35 V
(Reset adjust input current  50 nA)
ILE 4278
Ι
13
9
Q
30 kΩ
14
Band-GapReference
RO
Band-GapReference
1.35 V
1.35 V
>1
+
-
R1
7
3 ... 5,
RADJ
10 ... 12
GND
R2
Figure 6
The reset output pin is internally connected to the 5 V output Q via a 30 kτ pull-up
resistor. Down to an output voltage VQ of typical 1 V the reset LOW signal at pin RO is
generated.
For the timing of the reset feature please refer to the data sheet, Figure 5.
Rev. 00
12
ILE 4278
Watchdog Activating
The calculation of the external resistor which adjusts the watchdog switch off threshold
can be done by the following equation.
RWADJ = VWADJ,th ⌠ (IQ/IWADJ)/IQ,act
Definitions:
VWADJ,th = switch off threshold, typical 1.35 V
IQ/IWADJ = current ratio, typical 720
IQ,act = switch off load current
ILE 4278
Ι
Q
Band-GapReference
HIGH
+
-
WADJ
Watchdog
active
LOW
Watchdog
disabled
R WADJ
GND
Figure 7
Rev. 00
13
ILE 4278
Watchdog Timing
The frequency of the watchdog pulses has to be higher than the minimum pulse
sequence which is set by the external reset delay capacitor CD. Calculation can be done
according to the formulas given in Figure 8.
The watchdog output is internally connected to the output Q via a 30 kτ pull-up resistor.
To generate a watchdog created reset signal for the microcontroller the pin WO can be
connected to the reset input of the microcontroller. It is also allowed to parallel the
watchdog out to the reset out.
Timing of the Watchdog Function
VW Ι
t
VΙ
VQ
t
T WD, p
VD
t
T WI, tr
VDU
VDWL
VWO
T WI, tr =
t WD, L
(VDU - VDWL )
Ι D, wd
C D ; T WD, p =
(VDU -VDWL ) (Ι D, wc + Ι D, wd )
Ι D, wc x Ι D, wd
C D ; t WD, L =
t
(VDU - VDWL )
Ι D, wc
t
CD
Figure 8
Rev. 00
14
ILE 4278
Hints for Unused Pins
Symbol
Function
Connect to
RO
Reset output
open
D
Reset delay
open or to output Q
RADJ
Reset switching threshold adjust
GND
WI
Watchdog input
GND
WO
Watchdog output
open
WADJ
Watchdog adjust
1)
2)
to output Q via a 270 kτ resistor:
Watchdog always active
to GND: Watchdog disabled
Rev. 00
15
ILE 4278
Drop Voltage Vdr versus
Output Current IQ
Current Consumption Iq
versus Output Current IQ
mV
700
16
I q mA
14
600
12
500
10
400
8
V dr
VI = 13.5 V
T j = 25 ˚C
Tj = 125 C
300
6
Tj = 25 C
200
4
100
2
0
0
50
100
150
200
250
0
mA
0
50
100
150
200
mA 300
ΙQ
Current Consumption Iq
versus Input Voltage VI
IQ
Output Voltage VQ versus
Input Voltage VI
12
mA
Iq mA
VQ
Tj = 25 ˚C
10
10
8
8
6
6
R L= 33 Ω
R L= 33 Ω
4
4
R L= 50 Ω
2
0
2
R L= 100 Ω
0
10
20
30
40 V 50
VI
0
0
2
4
6
8
V
VΙ
Rev. 00
16
ILE 4278
Charge Current ID,wc and Discharge
Current ID,wd versus Temperature Tj
Ι
8
µA
VD
VΙ = 13.5 V
VD = 1.0 V
7
Switching Voltage VDU, VDWL
and VDRL versus Temperature Tj
3.2
V
2.8
V Ι = 13.5 V
2.4
6
Ι D, wc
5
2.0
4
1.6
3
1.2
2
Ι D, wd
1
0
-40
0
40
80
120
V DU
0.8
V DWL
0.4
V DRL
0
-40
C
0
40
80
Tj
Tj
Output Voltage VQ versus
Temperature Tj
Output Current Limit IQ versus
Input Voltage VI
500
5.2
VQ
120 ˚C 160
IQ
V
5.1
Tj = 25 ˚C
mA
400
VΙ = 13.5 V
5.0
300
4.9
200
4.8
100
4.7
4.6
-40
0
0
40
80
120 ˚C 160
Tj
0
10
20
30
40 V 50
VI
Rev. 00
17
ILE 4278
Package Outlines
P-DSO-14-8
Rev. 00
18
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