L9704 [STMICROELECTRONICS]
OCTAL SUPPLY CONTACT MONITORING CIRCUIT; 八路供应联系电话监控电路
| 型号： | L9704 |
| 厂家： | 
ST |
| 描述： | OCTAL SUPPLY CONTACT MONITORING CIRCUIT |
| 文件： | 总8页 (文件大小：173K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
L9704
OCTAL SUPPLY CONTACT MONITORING CIRCUIT
.
OPERATING DC SUPPLY VOLTAGE RANGE
5V TO 25V
SUPPLY OVERVOLTAGE PULSE UP TO 40V
VERY LOW STANDBY QUIESCENT CUR-
RENT 0.2mA
INTERNAL CLAMPING DIODES AT CONTACT
INPUTS TO VS AND GND
INPUT PULSE CURRENT CAPABILITYUP TO
+ 50mA, – 75mA
NOMINAL CONTACT CURRENTS OF 10mA
DEFINED BY EXTERNAL CONTACT SERIES
RESISTORS RIN1-8
CONTACT STATUS MONITORING BY COM-
PARING THE RESISTANCE AT CONTACT
SENSEINPUTS WITH THEINTERNAL REFER-
ENCE RESISTOR VALUE
HIGH IMMUNITY DUE TO RESISTANCE COM-
PARISON WITH HYSTERESIS
.
.
.
.
.
.
.
DIP–20
SO–20L
ORDERING NUMBERS: L9704 (DIP–20)
L9704D (SO–20L)
DESCRIPTION
The L9704 is a bipolar monolithic integrated circuit
for monitoring the statusof up to eightcontactscon-
nected to the power supply (battery).
It containseight contact sense inputs and eight mi-
crocomputer compatible three-state outputs.
BLOCK DIAGRAM
March 1992
1/8
L9704
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
875
420
mW
mW
DIP20
SO20
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
PIN CONNECTION (top view)
2/8
L9704
ELECTRICAL CHARACTERISTICS (5V ≤ VS ≤ 25V; -40°C ≤ Tj ≤ 125°C; 4.75V ≤ VCC ≤ 5.25V unless
otherwise specified; the currents flowing in the arrow direction 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
VEN hyst Enable Input Hysteresis
2.4
V
mV
µA
µA
V
200
300
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 Output Voltage HIGH
VOUTL Output Voltage LOW
IOUT TS Output TRISTATE Current
4.0
VCC
0.4
0.5
2
0.05
V
0 < VOUT < VCC
µA
V
VIN
Input Voltage (device active)
EN = LOW
0.4
1.5
RIN = 1kΩ
VIN
Input Voltage During Clamping
(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
1.1
4.8
6.5
RIH
Input Resistor (note 1)
HIGH Threshold
29
RIL
RIH
IQC
Input Resistor
Threshold Ratio (note1)
0.65
0.75
0.12
0.85
0.16
Quiescent Current
EN = HIGH (tENH ≥ 80µs)
5V < VS < 16V
mA
-40°C ≤ Tj ≤ 100°C
All Inputs Open
IQS
0.04
0.24
mA
mA
SIIN 2) Input Leakage Current
All Inputs Closed VBAT ≤ VD1
IQC
IQS
Quiescent Current
EN = LOW
13
2
mA
mA
tdo
Delay Time/Output
(EN LOW to output data ready)
COUT ≤ 50pF
COUT ≤ 50pF
15
+3RIN C
µs
IN
tdTS
Delay Time/Tristate
10
µs
(EN HIGH to output TRISTATE)
Notes :
1. The input resistor threshold value is a resistor value from the IN–pin to battery at which the corresponding output changes
its status (see fig. 3)
8
2: SIIN is the sum of the input currents SIIN
=
IIN1.
∑
i = 1
3/8
L9704
APPLICATION CIRCUIT DIAGRAM
Figure 1 : Typical application diagram for the L9704 circuit. The current flowing in the arrow direction is as-
sumed positive. The external capacitors CIN and COUT represent the total wiring capacitance at
the corresponding pins.
FUNCTIONAL DESCRIPTION
status as a function of the input resistor RI, shown
in figure3. The inputresistor is a sum of theRIN and
the contactresistanceRCON orRCOFF, fortheclosed
contact :
TheL9704circuit monitors thestatusof thecontacts
connectedto batteryandthroughtheseriesexternal
resistors RIN to the contact sense input pins. The
contacts equivalent circuit is supposed to be as
shown in fig. 2.
RI = RIN + RCON
and for the open contact :
RI = RIN + RCOFF
,
(2)
The L9704 circuit compares the input current with
the current through the internal reference resistor.
Thedevice isdesignedto workwith anexternalinput
series resistorof RIN1-8 =1kΩ. With thisinputresistor
the contact current, when the contact is closed and
the device activated (EN = LOW) is
.
(3)
The outputgoesHIGH when the input resistance in-
creases above6.5kΩ (typicalvalue)andgoesLOW,
when the input resistance decreases below 4.8KΩ
(typical value). The limit values of RI = 1.1KΩ for
LOW andRI = 29kΩ for HIGH implies that a contact
with RCON = 100Ω (at IIN = 10mA) will be recognized
as ON = LOW and a contact with RCOFF = 28kΩ will
be recognized as OFF = HIGH. These limits are
valid within the supply voltage range 5V≤ Vs ≤ 16V,
the battery voltage potential difference of
∆VBAT ≤ 0.1VBAT andthevariation ofthereverse
batteryprotection diode D1 voltage from 0.5V to 1V.
VBAT + ∆VBAT – 2V
IIN
=
1KΩ
(1)
For this calculation the limit value of the VIN (satura-
tion voltageof 2V)wasconsideredso that thelowest
limit value of IIN is calculated in (1).
The function of the circuit can be demonstratedwith
the transfer characteristics, showing the output
4/8
L9704
The internalclamping diodesat thecontactmonitor-
ing inputs, together with the external contact series
resistors RIN, allows the device to withstand tran-
sients at the contact connection.The contact series
resistor RIN limits the input current at the transient.
throughthe resistor RIN. In this case the total delay
timemay alsobe influencedbythetime constantR
IN
CIN. The delay time tdTS, when disabling the device
isdefinedonly bytheinternalcircuitry. Inbothcases,
an externaloutputcapacitanceless than 50pFis as-
sumed, the internal output capacitances of the
three-statebuffers are less than 5pF.
The dynamic behaviour of the circuit is defined by
the times tdo and tdTS. When the contact becomes
open, the input capacitor CIN must be charged
Figure 2 : The Contact Sense Input Connection with the Contact Equivalent Circuit.
Figure 3 : The Output Voltage as a Function of the Input Resistance at the Corresponding Contact Sense
Input.
5/8
L9704
SO20 PACKAGE MECHANICAL DATA
mm
inch
TYP.
DIM.
MIN.
TYP.
MAX.
2.65
0.3
MIN.
MAX.
0.104
0.012
0.096
0.019
0.013
A
a1
a2
b
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.)
6/8
L9704
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
1.000
0.45
0.25
0.018
0.010
b1
D
E
e
25.4
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
7/8
L9704
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
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