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L9704
OCTAL SUPPLY CONTACT MONITORING CIRCUIT
.OPERATI .SUPPLYOVERVOLTAGEPULSEUPTO40V .VERY .I .I .NOMI .CONTACT .HI
DESCRIPTION BLOCK DIAGRAM
NG DC SUPPLY VOLTAGE RANGE 5V TO 25V LOW STANDBY QUIESCENT CURRENT 0.2mA NTERNAL CLAMPING DIODES AT CONTACT INPUTS TO VS AND GND NPUT PULSE CURRENT CAPABILITY UP TO + 50mA, - 75mA NAL CONTACT CURRENTS OF 10mA DEFINED BY EXTERNAL CONTACT SERIES RESISTORS RIN1-8 STATUS MONITORING BY COMPARING THE RESISTANCE AT CONTACT SENSEINPUTS WITH THE INTERNAL REFERENCE RESISTOR VALUE GH IMMUNITY DUE TO RESISTANCE COMPARISON WITH HYSTERESIS
DIP-20
SO-20L ORDERING NUMBERS: L9704 (DIP-20) L9704D (SO-20L)
The L9704 is a bipolar monolithic integrated circuit for monitoring the status of up to eight contactsconnected to the power supply (battery).
It contains eight contact sense inputs and eight microcomputer compatible three-state outputs.
March 1992
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L9704
ABSOLUTE MAXIMUM RATINGS
Symbol VS VCC IIN DC IINP IO VEN PO Logic Supply Voltage Input DC Current Input DC Pulse (test pulse specification: 0 < tP < 2ms, f 0.2Hz, n = 25000) Output Current Enable Input Voltage Power Dissipation at Tamb = 80C DIP20 SO20 Storage and Junction Temperature Range Parameter Transient Supply Voltage (t 1s) Test Conditions +40 7 40 50 -75 Internally Limited VCC +0.3 -0.3 875 420 -55 to 150 V V mW mW C Unit V V mA mA mA
Tstg,TJ
THERMAL DATA
Symbol Rth j-amb Parameter Thermal Resistance Junction to Ambient MAX. DIP20 80 SO20 165 Unit C/W
PIN CONNECTION (top view)
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L9704
ELECTRICAL CHARACTERISTICS (5V VS 25V; -40C Tj 125C; 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 VENL VENH IEN VOUTH VOUTL IOUT TS VIN VIN Parameter Enable Input Voltage LOW (device activated) Enable Input Voltage HIGH Enable Input Current Output Voltage HIGH Output Voltage LOW Output TRISTATE Current Input Voltage (device active) Input Voltage During Clamping (device disabled) Output Current Output Current Input Resistor (note 1) LOW Threshold Input Resistor (note 1) HIGH Threshold Input Resistor Threshold Ratio (note1) Quiescent Current EN = HIGH (tENH 80s) 5V < VS < 16V -40C Tj 100C All Inputs Open All Inputs Closed VBAT VD1 EN = LOW C OUT 50pF C OUT 50pF 0.65 2.4V < VEN < VCC 0V < VEN < 0.8V 0 < IOUT < 100A IOUT = -1mA 0 < VOUT < VCC EN = LOW R IN = 1k EN = HIGH IIN = 30mA IIN = -30mA OUT = HIGH VOUT = 0 OUT = LOW VOUT = 5.5V 5V < VS < 16V VGND 0.1VS 1.1 4.8 6.5 0.75 0.12 29 0.85 0.16 mA 0.4 1.5 -5 4.0 0.05 -1 VCC -0.1 0.2 VCC 0.4 0.5 2 2.4 200 300 800 5 Test Conditions Min. Typ. Max. 0.8 Unit V V mV A A V V A V
VEN hyst Enable Input Hysteresis
VS + 0.3 -2
VS + 1 -1
VS + 2 -0.3 2 -20
V V mA mA K K
IOUT IOUT RIL RIH RIL RIH IQC
IQS SIIN 2) IQC IQS tdo tdTS Input Leakage Current Quiescent Current Delay Time/Output (EN LOW to output data ready) Delay Time/Tristate (EN HIGH to output TRISTAT E)
0.04 0.24 13 2 15 +3RIN CIN 10
mA mA mA mA s s
Notes : 1. The input resi stor threshold value is a resistor value from the IN-pin to battery at which the corresponding output changes its status (see fig. 3) 2: SIIN is the sum of the input curr ents SIIN =
8
IIN1 .
i=1
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L9704
APPLICATION CIRCUIT DIAGRAM Figure 1 : Typical application diagram for the L9704 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.
FUNCTIONAL DESCRIPTION The L9704 circuit monitors the status of the contacts connectedto battery and through the series external resistors RIN to the contact sense input pins. The contacts equivalent circuit is supposed to be as shown in fig. 2. The L9704 circuit compares the input current with the current through the internal reference resistor. The device is designed to work with an externalinput series resistor of RIN1-8 =1k. With thisinput resistor the contact current, when the contact is closed and the device activated (EN = LOW) is VBAT + VBAT - 2V IIN = 1K (1) For this calculation the limit value of the VIN (saturation voltage of 2V) was consideredso that thelowest limit value of I IN is calculated in (1). The function of the circuit can be demonstratedwith the transfer characteristics, showing the output
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status as a function of the input resistor RI, shown in figure 3. The input resistor is a sum of the RIN and the contactresistance RCON or RCOFF, for the closed contact : (2) RI = RIN + RCON, and for the open contact : RI = RIN + RCOFF. (3) The output goes HIGH when the input resistance increases above 6.5k (typical value) and goesLOW, when the input resistance decreases below 4.8K (typical value). The limit values of RI = 1.1K for LOW and RI = 29k for HIGH implies that a contact with RCON = 100 (at IIN = 10mA) will be recognized as ON = LOW and a contact with RCOFF = 28k 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 and the variation of the reverse battery protection diode D1 voltage from 0.5V to 1V.
L9704
The internal clamping diodes at the contact monitoring inputs, together with the external contact series resistors RIN, allows the device to withstand transients at the contact connection.The contact series resistor RIN limits the input current at the transient. The dynamic behaviour of the circuit is defined by the times tdo and t dTS. When the contact becomes open, the input capacitor CIN must be charged through the resistor RIN. In this case the total delay time may also be influenced by the time constant RIN CIN. The delay time tdTS, when disabling the device is defined only by the internal circuitry. In bothcases, an externaloutput capacitanceless than 50pF is assumed, the internal output capacitances of the three-state buffers are less than 5pF.
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.
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L9704
SO20 PACKAGE MECHANICAL DATA
DIM. MIN. A a1 a2 b b1 C c1 D E e e3 F L M S 7.4 0.5 12.6 10 1.27 11.43 7.6 1.27 0.75 8 (max.) 0.291 0.020 13.0 10.65 0.35 0.23 0.5 45 (typ.) 0.496 0.394 0.050 0.450 0.299 0.050 0.030 0.512 0.419 0.1 mm TYP. MAX. 2.65 0.3 2.45 0.49 0.32 0.014 0.009 0.020 0.004 MIN. inch TYP. MAX. 0.104 0.012 0.096 0.019 0.013
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L9704
DIP20 PACKAGE MECHANICAL DATA
DIM. MIN. a1 B b b1 D E e e3 F I L Z 3.3 1.34 8.5 2.54 22.86 7.1 3.93 0.130 0.053 0.254 1.39 0.45 0.25 25.4 0.335 0.100 0.900 0.280 0.155 1.65 mm TYP. MAX. MIN. 0.010 0.055 0.018 0.010 1.000 0.065 inch TYP. MAX.
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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. Specifications mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously 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. (c) 1994 SGS-THOMSON Microelectronics - All Rights Reserved SGS-THOMSON Microelectronics GROUP OF COMPANIES Australia - Brazil - France - Germany - Hong Kong - Italy - Japan - Korea - Malaysia - Malta - Morocco - The Netherlands - Singapore Spain - Sweden - Switzerland - Taiwan - Thaliand - United Kingdom - U.S.A.
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