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L9705
DOUBLE QUAD CONTACT INTERFACE CIRCUIT
ADVANCE DATA
OPERATING DC SUPPLY VOLTAGE RANGE 5V TO 25V SUPPLY OVERVOLTAGE PULSE UP TO 40V VERY LOW STAND-BY QUIESCENT CURRENT, MAX 50A INTERNAL CLAMPING DIODES AT CONTACT INPUTS TO Vs AND gnd WITH PULSE CURRENT CAPABILITY UP TO +50mA, -75mA CHIP ENABLE FUNCTION AND TRISTATE OUTPUTS FOR PARALLEL BUS CONNECTION NOMINAL CONTACT CURRENTS OF 10mA DEFINED WITH EXTERNAL CONTACT SERIES RESISTORS RIN1-8 CONTACT STATUS MONITORING BY MEANS OF COMPARING THE RESISTANCE AT CONTACT SENSE INPUTS WITH THE INTERNAL REFERENCE RESISTOR VALUE RESISTANCE COMPARING WITH HYSTERESIS FOR HIGH NOISE IMMUNITY AND IMMUNITY TO GROUND AND BATTERY POTENTIAL DIFFERENCES BLOCK DIAGRAM
DIP 20
SO20L
ORDERING NUMBERS : L9705
DESCRIPTION The L9705 is a bipolar monolithic integrated circuit for monitoring the status of up to four contacts connected to GND and up to four contacts connected to the battery. The contact sense input supply the contact current and perform the contact resistance comparison function. At the output the contact status is translated into a logical LOW level (contact closed) or logical HIGh level (contact open).
January 1992
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This is advanced information on a new product now in development or undergoing evaluation. Details are subject to change without notice.
L9705
ABSOLUTE MAXIMUM RATINGS
Symbol VSDC VSP VCC IINDC IINP IOUT VEN Ptot Tj DC Supply Voltage Peak Transient Supply Voltage (t < 400ms) Logic Supply Voltage Input DC Current Input Pulse (tp = 0 to 2ms; f< 0.2Hz; n = 25000) Output Current (VO = 0 to 5.5V) Enable Input Voltage Total Power Dissipation (Tamb = 80C) Junction Temperature Range DIP 20 SO 20 Parameter Value +26 +40 7 +40 -75 to 50 internally limited VCC +0.3V;-0.3V 875 420 max150 V mW mW C Unit V V V mA mA
PIN CONNECTION (top view)
THERMAL DATA
Symbol Rth j-amb Rth j-amb Description Thermal Resistance Junction-ambient Thermal Resistance Junction-ambient DIP20 80 165 SO20L Unit C/W C/W
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L9705
ELECTRICAL CHARACTERISTICS (VS = 5 to 25V, VCC = 4.75 to 5.25V, Vbat -0.5V < VS ,< Vbat -1V , Tj = -40 to 150C unless otherwise specified.)
Symbol VENL VENH VENh IEN VOUTH IOUT VOUTL IOUT IOUT TS VIN 1,4 VIN 5,8 VIN RIL 1,4 RIL 5,8 RIH 1,4 RIH 5,8 RIL RIH IQC IQS IQS IIN (2) IQC IQS tdo tdTS tdIO
NOTES: 1) The input resistor threshold value is a resistor value from the IN-pin to ground at which the corresponding output changes its status (fig.4) 2) IIN is the sum of the IN5 to IN8 input currents. 3) The delay times are defined from the crossing point of 50% initiating signal amplitude to the crossing point of 50% output signal amplitude
Parameter Enable Input Voltage LOW (device activated) Enable Input Voltage HIGH Enable Input Threshold Hysteresis Enable Input Current Output Voltage HIGH Output Current Output Voltage LOW Output Current Output Tristate Current Input Voltage (device active) Input Voltage (device active) Input VoltageDuring Clamp (device disabled) Input Resistor LOW Threshold (note 1) Input Resistor LOW Threshold (note 1) Input Resistor HIGH Threshold (note 1) Input Resistor HIGH Threshold (note 1) Input Resistor Threshold Ratio (note 1) Input Resistor Threshold Ratio (note 1) Quiescent Current Quiescent Current Quiescent Current Quiescent Current Quiescent Current Quiescent Current Delay Time/Output (EN LOW to Output Data Ready) (note 3) Delay Time/Tristate (EN HIGH to Output Tristate) (note 3) Delay Time Input-Output (note 3)
Test Condition
Min. -0.3 2.4 200
Typ.
Max. 0.8 VCC
Unit V V mV A A V mA V mA A V V V V K K
420
800 5
2.4V < VEN < VCC 0V < VEN < 0.8V 0 < IOUT < 100A OUT status = HIGH; VOUT = 0 IOUT = -1mA OUT status = LOW; VOUT = 5.5V 0 < VOUT < VCC EN = LOW; RIN = 1K EN = LOW; RIN = 1K EN = HIGH; IIN = 30mA IIN = -30mA 5V < VS <16V; VGND 0.1VS VBAT 0.1VBAT 5V < VS <16V; VGND 0.1VS VBAT 0.1VBAT 5V < VS < 16V; VGND 0.1VS VBAT 0.1VBAT 5V < VS <16V; VGND 0.1VS VBAT 0.1VBAT 5V < VS <16V; VGND 0.1VS VBAT 0.1VBAT 5V < VS <16V; VGND 0.1VS VBAT 0.1VBAT EN = HIGH (tENH >20s) VS = 5 to 16V; Tj = -40 to 85C all contact open all contact closed VBAT 0.1VBAT EN = LOW EN = LOW COUT 50pF COUT 50pF EN = LOW; COUT = 50pF
-5 4 0.05
-1 VCC - 0.1 0.5 0.2 -5 VCC 2 0.4 -20 0.5 VS - 0.4 2 VS +2 -0.3
VS - 2 0.4 VS +0.3 -2 1.8 1.8
VS - 1.5 1.5 VS +1 -1 4 4.8 5.3 6.5
20 29 0.85 0.85 40 10 35 25 5 8 15+ 3RIN*CIN 10 6
K K
0.65 0.65
0.75 0.75 20
A A A A mA mA s s ms
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L9705
Figure 1: Typical application diagram for the L9705 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 L9705 circuit monitors the status of the contacts which are connected 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 for GND connected contacts (IN 1 to 4) and as shown in fig. 3 for VBAT connected contacts (IN 5 to 8).
Figure 2: The contact sense input connection with the contact equivalent circuit for GND connected contacts.
Figure 3: The contact sense input connection with the contact equivalent circuit for VBAT connected contacts.
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L9705
The L9705 circuit compares the input current with the current through the internal reference resistor. The device is designed to work with an external input series resistor of RIN1-8 = 1K. With this input resistor the contact current, when the contact is closed and the device activated (EN =LOW) is: IIN = VS - 2V ,for GND contacts, (1) 1K IIN = VBAT + VBAT - 2V , for VBAT contacts, (2) 1K
For this calculation the limit value of the VS to VIN and VIN saturation voltage of 2V was considered so that the lowest limit value of IIN is calculated in (1) and (2)
Figure 4: The output voltage as a function of the input resistance at the corresponding sense input.
The function of the circuit can be demonstrated with the transfer characteristics, showing the output status as a function of the input resistor RI, shown in figure 4. The input resistor is a sum of the RIN and the contact resistance RCON or RCOFF, for the closed contact: RI = RIN + RCON, (3) and for the open contact: RI = RIN + RCOFF, (4) The output goes HIGH when the input resistance increases above 5.3K (GND contacts) or 6.5K (VBAT contacts) and goes LOW, when the input resistance decreases below 4K (GND contacts) or 4.8K (VBAT contacts); these values are typical values for the switching thresholds. The limit values of RI = 1.8K (GND contacts) and RI = 1.8K (VBAT contacts) for LOW and RI = 20K (GND contacts) and 29K (VBAT contacts) for HIGH implies that a contact with RCON = 100 ( at IIN = 10mA) will be recognized as ON = LOW and a contact with RCOFF = 19K (GND contacts) or 28K (VBAT contact) will be recognized as OFF = HIGH.
These limits are valid within the supply voltage range 6V < VS < 16V, the ground potential difference of VGND = 0.1VS, 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. The internal clamping diodes at the contact monitoring inputs together with the external contacts series resistors RIN allows to withstand the 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 with the times tdo and tdTS. When the contact is open, the input capacitor CIN must be charged through the resistor RIN. In this case the total delay time tdo may be influenced also with the time constant RINCIN. The delay time tdTS, when disabling the device, is defined only with the internal circuitry. In both cases, output external capacitance less than 50pF is assumed, the internal output capacitance of the tristate buffers are less than 5pF.
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L9705
DIP20 PACKAGE MECHANICAL DATA
DIM. MIN. a1 B b b1 D E e e3 F I L Z 3.30 1.27 8.80 2.54 22.86 7.10 5.10 0.130 0.050 0.38 0.51 0.85 0.50 0.50 24.80 0.346 0.100 0.900 0.280 0.201 0.015 1.40 mm TYP. MAX. MIN. 0.020 0.033 0.020 0.020 0.976 0.055 inch TYP. MAX.
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L9705
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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L9705
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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