1
Features
10 kV ESD Protection
Two Comparators with Common Reference
Tight Threshold Tolerance
Constant Threshold
NPN Output
Interference and Damage-protection According to VDE 0839 and ISO/CD 7637
EMI Protection
Reversal Polarity Protection
Load-dump Protection
Description
The bipolar U4793B is designed to monitor overload or a short circuit in automotive or
industrial applications. The threshold is tied to V
4,6
= V
S
- V
T
where V
T
= 44.5 mV. It is
independent of the supply voltage, V
S.
If the voltage drop across shunt resistor, R
sh
,
exceeds this value, the output is turned on, otherwise the output is turned off.
Without supply voltage or open input Pin 8, the output is turned off. The output break-
down voltage is determined by the Z-diodes Z
3
and Z
5
with a typical value of V
Z
= 22 V.
An unused comparator input must be connected to Pin 7.
Block Diagram
Figure 1. Schematic and Application Circuit
-
+
-
+
-
+
&
&
Z
2
2
7
4
8
6
5
3
1
R1
150
W
VS
V
Batt
R
sh
R
sh
Load
0.6 VS
OUT1
OUT2
Z 5
Z 3
Current Monitor
IC
U4793B
Rev. 4557AAUTO11/02
2
U4793B
4557AAUTO11/02
Pin Configuration
Figure 2. Pinning DIP8/SO8
GND
VS
OUT2
IN1
Input switch
VRef
IN2
OUT1
1
2
3
4
8
7
6
5
Pin Description
Pin
Symbol
Function
1
GND
Reference point, ground
2
VS
Supply voltage
3
OUT2
Output 2
4
IN1
Input 1
5
OUT1
Output 1
6
IN2
Input 2
7
VRef
Reference voltage
8
Input switch
Input switch
Absolute Maximum Ratings
Parameters
Symbol
Value
Unit
Supply voltage
Pin 2, 7
V
S
16.5
V
Current consumption
t = 2 ms, measured at Pin 1 (GND) Pin 1
I
1
1.5
A
Output current
Pin 3, 5
I
3,5
20
mA
Input voltage reference point Pin 7 Pin 4, 6
-V
4,6
6
V
Power dissipation
T
amb
= 125
C,DIP8
SO8
P
tot
220
150
mW
mW
T
amb
= 95
C, DIP8
SO8
P
tot
420
360
mW
mW
T
amb
= 60
C, DIP8
SO8
P
tot
690
560
mW
mW
Ambient temperature range
T
amb
-40 to +125
C
Storage temperature range
T
stg
-55 to +125
C
Junction temperature
T
j
150
C
Thermal Resistance
Parameters
Symbol
Value
Unit
Junction ambient
DIP8
SO8
R
thJA
R
thJA
110
160
K/W
K/W
3
U4793B
4557AAUTO11/02
Electrical Characteristics
V
S
= 9 V to 15 V, T
amb
= -40
C to +125
C, unless otherwise specified (see Figure 1)
No.
Parameters
Test Conditions
Pin
Symbol
Min.
Typ.
Max.
Unit
Type*
1
Supply
1.1
Supply voltage
2, 7
V
S
9
15
V
A
1.2
Internal Z-diode Z
2
2
V
Z
20
V
A
1.3
Current consumption
V
S
= 12 V measured
T
amb
= -40
C
1
I
1
3.5
4.8
6.0
mA
C
1.4
V
S
= 12 V measured
T
amb
= 25
C
1
I
1
2.8
3.4
6.0
mA
A
1.5
V
S
= 12 V measured
T
amb
= 125
C
1
I
1
2.0
2.6
3.2
mA
C
2
Output
2.1
Output saturation
voltage
V
S
= 9 V,
I
3,5
= 10 mA
T
amb
= 25
C
3, 5
V
sat
0.5
V
A
2.2
Output Z-diodes Z
3
,
Z
5
3, 5
V
Z
21
V
A
3
Control Signal
3.1
Control signal
threshold
I
3,5
= 1 mA, figure 3
T
amb
= -40
C
4, 6
-V
T
42
44
46
mV
C
3.2
I
3,5
= 1 mA, figure 3
T
amb
= 25
C
4, 6
-V
T
43
44.5
46
mV
A
3.3
I
3,5
= 1 mA, figure 3
T
amb
= 125
C
4, 6
-V
T
44.5
46
47.5
mV
C
3.4
Temperature
coefficient of control
signal threshold
TC
15
V/K
C
3.5
Input currents
Pins connected
to 12 V
T
amb
= -40
C
4, 6
I
I
100
190
nA
C
3.6
T
amb
= 25
C
I
I
60
100
150
nA
A
3.7
T
amb
= 125
C
I
I
30
110
nA
C
3.8
Input currents
Pins connected
to 12 V
T
amb
= -40
C
8
I
I
5.5
7.0
A
C
3.9
T
amb
= 25
C
I
I
4.0
5.0
5.5
A
A
3.10
T
amb
= 125
C
I
I
3.0
4.5
A
C
4
Threshold
4.1
Threshold voltage
Switch identification
T
amb
= -40
C
8
V
8
0.47
V
S
0.69
V
S
V
C
4.2
Switch identification
T
amb
= 25
C
V
8
0.47
V
S
0.6 V
S
0.69
V
S
V
A
4.3
Switch identification
T
amb
= 125
C
V
8
0.47
V
S
0.69
V
S
V
C
*) Type means: A = 100% tested, B = 100% correlation tested, C = Characterized on samples, D = Design parameter
4
U4793B
4557AAUTO11/02
Figure 3. Timing Diagram
Figure 4. Threshold Voltage = f (V
Batt
and Temperature)
5
Switch Delay (R
L
= 10 k
W
connected from Pin 3 or Pin 5 to V
Batt
)
5.1
Delay time
Switch-on
High to low
T
amb
= -40
C
3, 5
t
d(on)
3
4
6
s
C
5.2
T
amb
= 25
C
t
d(on)
4
6
8
s
C
5.3
T
amb
= 125
C
t
d(on)
5
7
9
s
C
5.4
Delay time
Switch-off
Low to high
T
amb
= -40
C
t
d(off)
16
24
32
s
C
5.5
T
amb
= 25
C
t
d(off)
18
30
50
s
A
5.6
T
amb
= 125
C
t
d(off)
30
50
70
s
C
Electrical Characteristics (Continued)
V
S
= 9 V to 15 V, T
amb
= -40
C to +125
C, unless otherwise specified (see Figure 1)
No.
Parameters
Test Conditions
Pin
Symbol
Min.
Typ.
Max.
Unit
Type*
*) Type means: A = 100% tested, B = 100% correlation tested, C = Characterized on samples, D = Design parameter
12.00
11.90
12
V
4,6
V
0
t
d(off)
t
d(on)
10
20
30
40
50
60
0
t
(V)
(V)
6
(
m
s)
40
41
42
43
44
45
46
47
48
6.0
7.0
8.0
9.0
10.0
11.0
12.0
13.0
14.0
15.0
16.0
T
amb
= 125C
-40C
25C
95C
-V
T
( mV
)
V
Batt
( V )
5
U4793B
4557AAUTO11/02
Package Information
Ordering Information
Extended Type Number
Package
Remarks
U4793B
DIP8
U4793B-FP
SO8
9.8
9.5
Package DIP8
Dimensions in mm
1.64
1.44
4.8 max
0.5 min 3.3
0.58
0.48
7.62
2.54
6.4 max
0.36 max
9.8
8.2
7.77
7.47
8
5
1
4
technical drawings
according to DIN
specifications
technical drawings
according to DIN
specifications
Package SO8
Dimensions in mm
5.00
4.85
0.4
1.27
3.81
1.4
0.25
0.10
5.2
4.8
3.7
3.8
6.15
5.85
0.2
8
5
1
4
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