CS209A
CS209A
Proximity Detector
Description
The CS209A is a bipolar monolithic
integrated circuit for use in metal detec-
tion/proximity sensing applications.
The IC (see block diagram) contains two
on-chip current regulators, oscillator
and low-level feedback circuitry, peak
detection/demodulation circuit, a com-
parator and two complementary output
stages.
The oscillator, along with an external
LC network, provides controlled oscilla-
tions where amplitude is highly depen-
dent on the Q of the LC tank. During
low Q conditions, a variable low-level
feedback circuit provides drive to main-
tain oscillation. The peak demodulator
senses the negative portion of the oscil-
lator envelop and provides a demodu-
lated waveform as input to the com-
parator. The comparator sets the states
of the complementary outputs by com-
paring the input from the demodulator
to an internal reference. External loads
are required for the output pins.
A transient suppression circuit is
included to absorb negative transients
at the tank circuit terminal.
Features
s
Separate Current
Regulator for Oscillator
s
Negative Transient
Suppression
s
Variable Low-Level
Feedback
s
Improved Performance
over Temperature
s
6mA Supply Current
Consumption at
V
CC
= 12V
s
Output Current Sink
Capability
20mA at 4V
CC
100mA at 24V
CC
Absolute Maximum Ratings
Supply Voltage ................................................................................................24V
Power Dissipation (T
A
= 125¡C).............................................................200mW
Storage Temperature Range ....................................................Ð55¡C to +165¡C
Junction Temperature...............................................................Ð40¡C to +150¡C
Electrostatic Discharge (except TANK pin) ................................................2kV
Lead Temperature Soldering
Wave Solder(through hole styles only) ...........10 sec. max, 260¡C peak
Reflow (SMD styles only) ...........60 sec. max above 183¡C, 230¡C peak
Package Options
14L SO
OSC
1
TANK
2
Gnd
3
14
13
12
11
10
9
8
N.C.
RF
V
CC
N.C.
DEMOD
N.C.
N.C.
Block Diagram
OUT
1
4
N.C.
5
DVBE/R
Current
Regulator
300mA
Oscillator
VBE/R Current
Regulator
OUT
2
6
V
CC
N.C.
7
OSC
4.8kW
OSC
Feedback
23.6kW
8L PDIP & SO
OUT
1
V
CC
RF
OSC
1
TANK
+
2
8
7
6
5
RF
V
CC
DEMOD
OUT
2
Neg Transient
Suppression
OUT
2
COMP
DEMOD
-
Gnd
3
OUT
1
4
TANK
GND
DEMOD
Cherry Semiconductor Corporation
2000 South County Trail, East Greenwich, RI 02818
Tel: (401)885-3600 Fax: (401)885-5786
Email: info@cherry-semi.com
Web Site: www.cherry-semi.com
Rev. 3/11/99
1
A
¨
Company
CHERRY [ CHERRY SEMICONDUCTOR CORPORATION ]
