L9703D [STMICROELECTRONICS]
OCTAL GROUND CONTACT MONITORING CIRCUIT; 八路接触地面监控电路
| 型号： | L9703D |
| 厂家： | 
ST |
| 描述： | OCTAL GROUND CONTACT MONITORING CIRCUIT |
| 文件： | 总9页 (文件大小：171K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
L9703
OCTAL GROUND CONTACT MONITORING CIRCUIT
.
OPERATING DC SUPPLY VOLTAGE RANGE
5V TO 25V
.
.
SUPPLY OVERVOLTAGEPULSE UP TO 40V
VERY LOW STANDBY QUIESCENT CUR-
RENT 0.2mA
INTERNAL CLAMPING DIODES AT CONTACT
INPUTS TO VS AND GND
INPUT PULSE CURRENT CAPABILITY UP TO
+ 50mA ; – 75mA
NOMINAL CONTACT CURRENT OF 10mA DE-
FINED BY EXTERNAL CONTACT SERIES RE-
SISTORS RI N1–8
CONTACT STATUS MONITORING BY COM-
PARING THE RESISTANCE AT CONTACT
SENSEINPUTSWITHTHE INTERNAL REFER-
ENCE RESISTOR VALUE
HIGHIMMUNITY DUE TO RESISTANCE COM-
PARISONWITH HYSTERESIS
.
.
.
DIP-20
.
.
SO-20L
ORDERING NUMBERS : L9703 (DIP-20)
L9703D (SO-20L)
DESCRIPTION
The L9703isa bipolarmonolithicintegratedcir-
cuit for monitoring the status of up to eight con-
tacts connected to GND.
It containseight contact senseinputs and eight
microcomputercompatiblethree-state outputs.
BLOCK DIAGRAM
March 1992
1/9
L9703
PIN CONNECTION (top view)
ABSOLUTE MAXIMUM RATINGS
Symbol
Parameter
Transient Supply Voltage (t ≤ 1s)
Test Conditions
Unit
V
VS
VCC
IIN DC
IINP
+40
7
Logic Supply Voltage
Input DC Current
V
±40
mA
Input DC Pulse
(test pulse specification: 0 < tP < 2ms, f ≤ 0.2Hz, n = 25000)
50
-75
mA
mA
IO
Output Current
Internally Limited
VEN
Enable Input Voltage
VCC +0.3
-0.3
V
V
PO
Power Dissipation at Tamb = 80°C
DIP20
SO20
875
420
mW
mW
Tstg,TJ
Storage and Junction Temperature Range
-55 to 150
°C
THERMAL DATA
Symbol
Parameter
Thermal Resistance Junction to Ambient
DIP20
80
SO20
Unit
°C/W
Rth j-amb
MAX.
165
2/9
L9703
ELECTRICAL CHARACTERISTICS (5V ≤ VS ≤ 25V; -40°C ≤ Tj ≤ 125°C; 4.75V ≤ VCC ≤ 5.25V unless oth-
erwise specified;the currentsflowing in the arrowdirection are assumed positive as marked in the application
circuit diagram, fig. 1).
Symbol
Parameter
Test Conditions
Min.
Typ.
Max.
Unit
VENL
Enable Input Voltage LOW
(device activated)
0.8
V
VENH
Enable Input Voltage HIGH
2.4
V
mV
µA
µA
V
VEN hyst Enable Input Hysteresis
200
420
800
5
IEN
Enable Input Current
2.4V < VEN < VCC
0V < VEN < 0.8V
0 < IOUT < 100µA
IOUT = -1mA
-5
-1
VCC -0.1
0.2
VOUTH
VOUTL
Output Voltage HIGH
Output Voltage LOW
4.0
VCC
0.4
0.5
0.05
V
IOUT TS Output TRISTATE Current
0 < VOUT < VCC
µA
VIN
Input Voltage (device active)
EN = LOW
RIN = 1kΩ
VS - 2
VS - 1.5 VS - 0.4
V
VIN
Input Clamped Voltage
(device disabled)
EN = HIGH
IIN = 30mA
IIN = -30mA
VS + 0.3 VS + 1
VS + 2
-0.3
V
V
-2
-1
IOUT
IOUT
RIL
Output Current
Output Current
OUT = HIGH
VOUT = 0
2
mA
mA
KΩ
KΩ
OUT = LOW
VOUT = 5.5V
-20
Input Resistor (note 1)
LOW Threshold
5V < VS < 16V
∆ VGND ≤ 0.1VS
1.8
4
RIH
Input Resistor (note 1)
HIGH Threshold
5.3
20
RIL
RIH
Input Resistor
0.65
0.75
0.12
0.85
0.16
Threshold Ratio (note1)
IQC
Quiescent Current
EN = HIGH (tENH ≥ 80µs)
5V < VS < 16V
-40°C ≤ Tj ≤ 100°C
mA
IQS
Quiescent Current
Quiescent Current
All Inputs Open
All Inputs Closed
EN = LOW
0.04
0.24
mA
mA
IQC
IQS
6
6
mA
mA
tdo
Delay Time/Output
COUT ≤ 50pF
COUT ≤ 50pF
15
+3RIN C
µs
(EN LOW to output data ready)
IN
tdTS
Delay Time/Tristate
(EN HIGH to output TRISTATE)
10
µs
Note : 1. The input resistor threshold value is the resistor value from the IN-pin to ground at which the corresponding output changes
its status (see fig. 3).
3/9
L9703
APPLICATION CIRCUIT
Figure 1 : Typical Application Diagram for the L9703 Circuit. The current flowing in the arrow direction is
assumed positive. The external capacitors CIN and COUT represent the total wiring capacitance
at the corresponding pins.
4/9
L9703
FUNCTIONAL DESCRIPTION
The L9703circuit monitorsthe statusof thecontacts
connected to ground and throughthis series exter-
nalresistorsRIN to thecontactsense input pins. The
contacts equivalent circuit is supposed to be as
shown in fig. 2.
The outputgoes HIGH when theinput resistance in-
creases above5.3kΩ (typicalvalue) andgoesLOW,
when the input resistance decreases below 4kΩ
(typical value). The limit values of RI = 1.8KΩ for
LOW and RI =20kΩ for HIGH implies that a contact
withRCON =100Ω (at IIN =10mA) will be recognized
as ON = LOW and a contactwith RCOFF = 19kΩ will
be recognized as OFF = HIGH. These limits are
valid within the supplyvoltage range 6V ≤ VS ≤ 16V
and the ground potential difference of
∆VGND = 0,1V.
The internal clamping diodes at the contact moni-
toring inputs, togetherwith the externalcontactsse-
ries resistors RIN, allows the device to withstand
transientsatthe contactconnection.The contactse-
ries resistor RIN limits the input current at the tran-
sient.
The L9703 circuit compares the input current with
the current through the internal reference resistor.
The deviceisdesignedtoworkwith anexternalinput
seriesresistorofRIN1-8 =1kΩ. With thisinputresistor
the contact current, when the contact is closed and
the device activated (EN = LOW) is
VS - 2V
IIN
=
1kΩ
(1)
For this calculation the limit value of the VS to IN
saturation voltage of 2V was considered so that the
lowest limit value of IIN is calculated in (1).
The dynamic behaviour of the circuit is defined by
the times tdo and tdTs. When the contactis open,the
input capacitor CIN must be charged throughthe re-
sistor RIN. In this case the total delay time may also
be influenced by the time constant RINCIN.
Thedelaytime tdTs, when disablingthe device, isde-
fined only by the internal circuitry. In both cases, an
external output capacitance less than 50pF is as-
sumed, the internal output capacitances of the
three-statebuffers are less than 5pF.
The functionof the circuit can be demonstratedwith
the transfer characteristics, showing the output
status as a function of the input resistor RI, shown
in figure 3. The input resistor is a sum of the RIN and
thecontactresistanceRCON orRCOFF, fortheclosed
contact :
RI = RIN + RCON,
and for the open contact :
RI = RIN + RCOFF
(2)
.
(3)
Figure 2 : The Contact Sense Input Connection with the Contact Equivalent Circuit.
5/9
L9703
Figure 3 : The Output Voltage as a Function of the Input Resistance at the Corresponding Contact Sense
Input.
6/9
L9703
SO20 PACKAGE MECHANICAL DATA
mm
inch
TYP.
DIM.
MIN.
TYP.
MAX.
2.65
0.3
MIN.
MAX.
A
a1
a2
b
0.104
0.012
0.096
0.019
0.013
0.1
0.004
2.45
0.49
0.32
0.35
0.23
0.014
0.009
b1
C
0.5
0.020
c1
D
45 (typ.)
12.6
10
13.0
0.496
0.394
0.512
0.419
E
10.65
e
1.27
0.050
0.450
e3
F
11.43
7.4
0.5
7.6
0.291
0.020
0.299
0.050
0.030
L
1.27
0.75
M
S
8 (max.)
7/9
L9703
DIP20 PACKAGE MECHANICAL DATA
mm
inch
TYP.
DIM.
MIN.
0.254
1.39
TYP.
MAX.
MIN.
0.010
0.055
MAX.
a1
B
b
1.65
0.065
0.45
0.25
0.018
0.010
b1
D
E
e
25.4
1.000
8.5
2.54
22.86
0.335
0.100
0.900
e3
F
7.1
0.280
0.155
I
3.93
L
3.3
0.130
Z
1.34
0.053
8/9
L9703
Information furnished is believed to be accurate and reliable. However, SGS-THOMSON Microelectronics assumes no responsibility for
the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its
use. No license is granted by implication or otherwise under any patent or patent rights of SGS-THOMSON Microelectronics. Specifica-
tions mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information pre-
viously supplied. SGS-THOMSON Microelectronics products are not authorized for use as critical components in life support devices or
systems without express written approval of SGS-THOMSON Microelectronics.
1994 SGS-THOMSON Microelectronics - All Rights Reserved
SGS-THOMSON Microelectronics GROUP OF COMPANIES
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