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 50µA 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 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). BLOCK DIAGRAM January 1992 1/8 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 Value Unit VSDC DC Supply Voltage Parameter +26 V +40 V 7 V +40 mA -75 to 50 mA VSP Peak Transient Supply Voltage (t < 400ms) VCC Logic Supply Voltage IINDC Input DC Current IINP IOUT Input Pulse (tp = 0 to 2ms; f< 0.2Hz; n = 25000) Output Current (VO = 0 to 5.5V) internally limited VEN Enable Input Voltage VCC +0.3V;-0.3V V Ptot Total Power Dissipation (Tamb = 80°C) 875 420 mW mW max150 °C Tj DIP 20 SO 20 Junction Temperature Range PIN CONNECTION (top view) THERMAL DATA Symbol Description Rth j-amb Thermal Resistance Junction-ambient Rth j-amb Thermal Resistance Junction-ambient 2/8 DIP20 SO20L Unit °C/W 80 165 °C/W L9705 ELECTRICAL CHARACTERISTICS (VS = 5 to 25V, VCC = 4.75 to 5.25V, Vbat -0.5V < VS ,< Vbat -1V , Tj = –40 to 150°C unless otherwise specified.) Symbol Parameter Test Condition Min. Typ. VENL Enable Input Voltage LOW (device activated) VENH Enable Input Voltage HIGH 2.4 VENh Enable Input Threshold Hysteresis 200 420 -5 -1 4 0.05 IEN Enable Input Current -0.3 2.4V < VEN < VCC 0V < VEN < 0.8V VOUTH IOUT Output Voltage HIGH Output Current 0 < IOUT < 100µA OUT status = HIGH; VOUT = 0 VOUTL Output Voltage LOW IOUT = -1mA Max. Unit 0.8 V VCC V 800 mV 5 µA µA VCC - 0.1 0.5 VCC 2 V mA 0.2 0.4 V -5 -20 mA 0.5 µA VS - 0.4 V Output Current OUT status = LOW; VOUT = 5.5V IOUT TS Output Tristate Current 0 < VOUT < VCC VIN 1,4 Input Voltage (device active) EN = LOW; RIN = 1KΩ VIN 5,8 Input Voltage (device active) EN = LOW; RIN = 1KΩ 0.4 1.5 2 V VIN Input VoltageDuring Clamp (device disabled) VS +0.3 -2 VS +1 -1 VS +2 -0.3 V V 1.8 4 KΩ 1.8 4.8 KΩ IOUT VS - 2 VS - 1.5 RIL 1,4 Input Resistor LOW Threshold (note 1) EN = HIGH; IIN = 30mA IIN = -30mA 5V < VS <16V; ∆VGND≤ 0.1VS ∆VBAT≤ 0.1VBAT RIL 5,8 Input Resistor LOW Threshold (note 1) 5V < VS <16V; ∆VGND≤ 0.1VS ∆VBAT≤ 0.1VBAT RIH 1,4 Input Resistor HIGH Threshold (note 1) 5V < VS < 16V; ∆VGND≤ 0.1VS ∆VBAT≤ 0.1VBAT 5.3 20 KΩ RIH 5,8 Input Resistor HIGH Threshold (note 1) 5V < VS <16V; ∆VGND≤ 0.1VS ∆VBAT≤ 0.1VBAT 6.5 29 KΩ RIL Input Resistor Threshold Ratio (note 1) 5V < VS <16V; ∆VGND≤ 0.1VS ∆VBAT≤ 0.1VBAT 0.65 0.75 0.85 RIH Input Resistor Threshold Ratio (note 1) 5V < VS <16V; ∆VGND≤ 0.1VS ∆VBAT≤ 0.1VBAT 0.65 0.75 0.85 IQC Quiescent Current EN = HIGH (tENH >20µs) VS = 5 to 16V; Tj = -40 to 85°C 20 40 µA IQS Quiescent Current all contact open 10 µA IQS ΣIIN (2) Quiescent Current Quiescent Current all contact closed ∆VBAT≤ 0.1VBAT 35 25 µA µA IQC IQS Quiescent Current Quiescent Current EN = LOW EN = LOW 5 8 mA mA tdo Delay Time/Output (EN LOW to Output Data Ready) (note 3) COUT ≤ 50pF 15+ 3RIN*CIN µs tdTS Delay Time/Tristate (EN HIGH to Output Tristate) (note 3) COUT ≤ 50pF 10 µs tdIO Delay Time Input-Output (note 3) EN = LOW; COUT = 50pF 6 ms 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) ΣIIN 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 3/8 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. 4/8 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 = 1KΩ. 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) 1KΩ IIN = VBAT + ∆VBAT − 2V , for VBAT contacts, (2) 1KΩ 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 5.3KΩ (GND contacts) or 6.5KΩ (VBAT contacts) and goes LOW, when the input resistance decreases below 4KΩ (GND contacts) or 4.8KΩ (VBAT contacts); these values are typical values for the switching thresholds. The limit values of RI = 1.8KΩ (GND contacts) and RI = 1.8KΩ (VBAT contacts) for LOW and RI = 20KΩ (GND contacts) and 29KΩ (VBAT contacts) for HIGH implies that a contact with RCON = 100Ω ( at IIN = 10mA) will be recognized as ON = LOW and a contact with RCOFF = 19KΩ (GND contacts) or 28KΩ (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. 5/8 L9705 DIP20 PACKAGE MECHANICAL DATA mm DIM. MIN. a1 0.51 B 0.85 b b1 TYP. MAX. MIN. TYP. MAX. 0.020 1.40 0.033 0.50 0.38 0.055 0.020 0.50 D 0.015 0.020 24.80 0.976 E 8.80 0.346 e 2.54 0.100 e3 22.86 0.900 F 7.10 0.280 I 5.10 0.201 L Z 6/8 inch 3.30 0.130 1.27 0.050 L9705 SO20 PACKAGE MECHANICAL DATA mm DIM. MIN. TYP. A a1 inch MAX. MIN. TYP. 2.65 0.1 0.104 0.3 a2 MAX. 0.004 0.012 2.45 0.096 b 0.35 0.49 0.014 0.019 b1 0.23 0.32 0.009 0.013 C 0.5 0.020 c1 45 (typ.) D 12.6 13.0 0.496 0.512 E 10 10.65 0.394 0.419 e 1.27 0.050 e3 11.43 0.450 F 7.4 7.6 0.291 0.299 L 0.5 1.27 0.020 0.050 M S 0.75 0.030 8 (max.) 7/8 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. © 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. 8/8