Features
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2-kV ESD Protection
Two Comparators with Common Reference
Tight Threshold Tolerance
Threshold Matched to PTC Characteristic of Incandescent Lamps
Temperature Compensated
NPN Output
Interference and Damage-protection According to VDE 0839
EMI Protection
Reversal Polarity Protection
Load-dump Protection
Automotive
Lamp-outage
Monitor IC
U479B
1. Description
The monolithic integrated bipolar circuit, U479B, is designed as a monitor for lamp fail-
ure in automobiles. The comparator threshold is matched to the PTC characteristic of
incandescent lamps. The threshold is tied to V
4,6
= V
S
– V
T
where V
T
= 8 mV.
If the voltage drop across the shunt resistor, R
sh
, exceeds 8 mV, the output is turned
off, otherwise, the output is turned on. Without supply voltage or open input pin 8, the
output is turned off. A comparator input, which is not used, must be connected to
pin 7.
Figure 1-1.
Schematic and Application Circuit
V
S
2
R
sh
Z
2
-
+
0.6 V
S
-
+
8
-
+
6
1
Lamps
R
1
3
&
&
V
Batt
7
5
OUT1
4
R
sh
OUT2
150
Ω
Rev. 4775B–AUTO–09/05
U479B
3. Absolute Maximum Ratings
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress rating
only and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of this
specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
Parameters
Supply voltage
Current consumption, t = 2 ms
Output current
Input voltage
Reference point pin 7
Power dissipation
T
amb
= 95°C
T
amb
= 60°C
Ambient temperature range
Storage temperature range
Junction temperature
DIP8
SO8
DIP8
SO8
Pin
2, 7
1
3, 5
4, 6
Symbol
V
S
I
1
I
3,5
-V
4,6
P
tot
P
tot
P
tot
P
tot
T
amb
T
stg
T
j
Value
16.5
1.5
20
6
Unit
V
A
mA
V
420
360
690
560
–40 to +95
–55 to +125
150
mW
mW
mW
mW
°C
°C
°C
4. Thermal Resistance
Parameters
Junction ambient
DIP8
SO8
Symbol
R
thJA
R
thJA
Value
110
160
Unit
K/W
K/W
3
4775B–AUTO–09/05
5. Electrical Characteristics
V
S
= 9V to 15V, T
amb
= –40 to +95°C,
Figure 1-1 on page 1,
unless otherwise specified.
Parameters
Supply voltage
Internal Z-diode Z
2
Current consumption
Output saturation voltage
V
S
= 12V
V
S
= 9V, I
3,5
= 10 mA
T
amb
= 25°C
Reference point V
Pin 7
I
3,5
= 3 mA
V
S
= 12V
V
S
= 15V
V
T(15 V)
–
V
T(12 V)
-
∆V
= --------------------------------------------
15 V
–
12 V
Switch identification
Input 1/input 2
Input switch
Switch-on, high to low
Switch-off, low to high
8
4, 6
8
3, 5
Test Conditions
Pin
2, 7
2
1
3, 5
Symbol
V
S
V
Z
I
1
V
sat
Min.
9
20
4.5
6
0.5
Typ.
Max.
15
Unit
V
V
mA
V
Control signal threshold
4, 6
–V
T
–V
T
∆V
V
8
I
I
I
I
t
d(on)
t
d(off)
6.5
7.8
8
9.3
0.45
0.6 V
S
100
5
6
30
9.5
10.8
mV
mV
mV/V
V
nA
µA
µs
µs
Voltage drift
Threshold voltage
Input currents
Delay time
Figure 5-1.
Delay Times
V
4,6
12.00
11.95
V
t
d(off)
V
0
12
6
V
0
10
20
30
40
50
t
d(on)
60 µs
t
4
U479B
4775B–AUTO–09/05
U479B
6. Ordering Information
Extended Type Number
U479B-MY
U479B-MFPY
U479B-MFPG3Y
Package
DIP8
SO8
SO8
Remarks
Pb-free
Tubed, Pb-free
Taped and reeled, Pb-free
7. Package Information
P a c k a g e D IP 8
D im e n s io n s in m m
9 .8
9 .5
1 .6 4
1 .4 4
7 .7 7
7 .4 7
4 .8 m a x
6 .4 m a x
0 .5 m in
0 .5 8
0 .4 8
7 .6 2
8
5
2 .5 4
3 .3
0 .3 6 m a x
9 .8
8 .2
te c h n ic a l d ra w in g s
a c c o rd in g to D IN
s p e c ific a tio n s
1
4
5
4775B–AUTO–09/05
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