TDA0161
April 1993
PROXIMITY DETECTORS
.
OUTPUT CURRENT : 10mA
.
OSCILLATOR FREQUENCY : 10 MHz
.
SUPPLY VOLTAGE : + 4 TO + 35 V
Minidip
ORDERING NUMBER : TDA0161DP
SO8
ORDERING NUMBER : TDA0161FP
DESCRIPTION
These monolithic integrated circuits are designed
for metallic body detection by detecting the vari-
ations in high frequency Eddy current losses. With
an external tuned circuit they act as oscillators.
Output signal level is altered by an approaching
metallic object.
Output signal is determined by supply current
changes. Independent of supply voltage, this cur-
rent is high or low according to the presence or the
absence of a close metallic object.
PIN CONNECTION (top view)
SCHEMATIC DIAGRAM
1/6
ELECTRICAL CHARACTERISTICS
TDA0161DP
-40
o
C < T
amb
< +100
o
C
TDA0161FP
-40
o
C < T
amb
< +100
o
C
Ptot < 150mW, unless otherwise specified
Symbol
Parameter
Min.
Typ.
Max.
Unit
V
CC
Supply Voltage
4
35
V
Reverse Voltage Limitation (I
CC
= -100 mA)
TDA0161
1
V
I
CC
Supply Current, Close Target (T
amb
= +25
o
C)
+4V < V
CC
< +35V
TDA0161
8
10
12
mA
I
CC
Supply Current, Remote Target
+4V < V
CC
< +35V
TDA0161
1
mA
Supply Current Transition Time
C3 = 0
C3
0
1
(100 x C3 (nF))
s
f
osc
Oscillator Tuning Frequency
10
MHz
f
O
Output Frequency (C3 = 0)
0
10
kHz
I
CC
Output Current Ripple - C3 = 0, C2 (pF) > 150/f
osc
(MHz)
20
A
R
n
Negative Resistance on Terminals A and E
4k
< R1 < 50k
, f
osc
< 3 MHz
0.9 R1
R1
1.1 R1
H
yst
Hysteresis at Detection Point C2 (Pf) > 150/f
osc
(MHz)
0.5
5
%
* If the circuit is used at a frequency higher than 3MHz, it is recommended to connect a capacitor of 100pF between terminals E and D.
ABSOLUTE MAXIMUM RATINGS
Symbol
Parameter
Value
Unit
V
CC
Supply Voltage
35
V
T
j
Junction Temperature
+150
o
C
T
stg
Storage Temperature Range
55 to +150
o
C
OPERATING MODE
Between terminals A and E, the integrated circuit
acts like a negative resistance equal to the external
resistor R1 connected between terminals B and H.
The oscillation stops when loss resistance Rp of
tuned circuit becomes smaller than R1. Then, the
supply current will be I
CC
= 10mA (pins G and D).
The oscillation sustains when loss resistance Rp of
tuned circuit becomes higher than R1. Then, the
supply current will be I
CC
1mA (pins G and D).
Eddy currents induced by coil L1 in a metallic body,
determine loss resistance Rp.
TDA0161
2/6
TYPICAL APPLICATIONS
Detection Range (*)
L1 (
H)
C1 (pF)
f
osc
(kHz)
R1
(k
)
C2
pF
2mm
30
(1)
120
2650
6.8
47
5mm
300
(2)
470
425
27
470
10mm
2160
(3)
4700
50
27
3300
(*) Ingot steel target
COIL CHARACTERISTICS
Core
Coil Former
Wire**
Number of Turns
1
Cofelec
432 FP 9 x 5 SE
1/2
CAR 091 - 2
THOMSON Fils et Cbles
Thomrex 14
(14/100mm)
40
2
Cofelec
432 FP 14 x 8 SE
1/2
CAR 142 - 2
THOMSON Fils et Cbles
Thomrex 14
(14/100mm)
100
3
Cofelec
432 FP 26 x 16 SE
1/2
CAR 262 - 2
THOMSON Fils et Cbles
Thomrex 14
(14/100mm)
200
** The above results are obtained with single wire coil. When using Litz wire instead of single wire, the parallel resistance of the coil
be-
comes higher and the value of R1 may be increased, resulting in better sensitivity.
TDA0161
3/6
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