L9703 OCTAL GROUND CONTACT MONITORING CIRCUIT . .. . . . . . OPERATING DC SUPPLY VOLTAGE RANGE 5V TO 25V SUPPLY OVERVOLTAGE PULSE UP TO 40V VERY LOW STANDBY QUIESCENT CURRENT 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 DEFINED BY EXTERNAL CONTACT SERIES RESISTORS RI N1–8 CONTACT STATUS MONITORING BY COMPARING THE RESISTANCE AT CONTACT SENSE INPUTS WITH THE INTERNAL REFERENCE RESISTOR VALUE HIGH IMMUNITY DUE TO RESISTANCE COMPARISON WITH HYSTERESIS DESCRIPTION The L9703 is a bipolar monolithic integrated circuit for monitoring the status of up to eight contacts connected to GND. DIP-20 SO-20L ORDERING NUMBERS : L9703 (DIP-20) L9703D (SO-20L) It contains eight contact sense inputs and eight microcomputer compatible three-state outputs. BLOCK DIAGRAM March 1992 1/9 L9703 PIN CONNECTION (top view) ABSOLUTE MAXIMUM RATINGS Symbol Parameter VS Transient Supply Voltage (t ≤ 1s) VCC Logic Supply Voltage IIN DC IINP IO Unit +40 V 7 V Input DC Current ±40 mA Input DC Pulse (test pulse specification: 0 < tP < 2ms, f ≤ 0.2Hz, n = 25000) 50 -75 mA mA Output Current Internally Limited VEN Enable Input Voltage PO Power Dissipation at Tamb = 80°C DIP20 SO20 Tstg,TJ Test Conditions Storage and Junction Temperature Range VCC +0.3 -0.3 V V 875 420 mW mW -55 to 150 °C THERMAL DATA Symbol Rth j-amb 2/9 Parameter Thermal Resistance Junction to Ambient MAX. DIP20 SO20 Unit 80 165 °C/W L9703 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 VENL Enable Input Voltage LOW (device activated) VENH Enable Input Voltage HIGH VEN hyst IEN Test Conditions Typ. Max. Unit 0.8 V 2.4 Enable Input Hysteresis Enable Input Current Min. 200 V 420 2.4V < VEN < VCC 0V < VEN < 0.8V 800 5 -5 -1 mV µA µA VOUTH Output Voltage HIGH 0 < IOUT < 100µA 4.0 VCC -0.1 VCC VOUTL Output Voltage LOW IOUT = -1mA 0.05 0.2 0.4 V IOUT TS Output TRISTATE Current 0 < VOUT < VCC 0.5 µA VIN Input Voltage (device active) EN = LOW R IN = 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 -2 VS + 1 -1 VS + 2 -0.3 V V IOUT Output Current OUT = HIGH VOUT = 0 2 mA IOUT Output Current OUT = LOW VOUT = 5.5V -20 mA RIL Input Resistor (note 1) LOW Threshold 5V < VS < 16V ∆ VGND ≤ 0.1VS RIH Input Resistor (note 1) HIGH Threshold R IL RIH Input Resistor Threshold Ratio (note1) IQC Quiescent Current IQS Quiescent Current 1.8 0.65 EN = HIGH (tENH ≥ 80µs) 5V < VS < 16V -40°C ≤ Tj ≤ 100°C 4 V KΩ 5.3 20 0.75 0.85 0.12 0.16 KΩ mA All Inputs Open 0.04 mA All Inputs Closed 0.24 mA 6 6 mA mA IQC IQS Quiescent Current EN = LOW tdo Delay Time/Output (EN LOW to output data ready) C OUT ≤ 50pF 15 +3RIN CIN µs tdTS Delay Time/Tristate (EN HIGH to output TRISTATE) C OUT ≤ 50pF 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 L9703 circuit monitors the status of the contacts connected to ground and through this series external resistors RIN to the contact sense input pins. The contacts equivalent circuit is supposed to be as shown in fig. 2. The L9703 circuit compares the input current with the current through the internal reference resistor. The device is designed to work with anexternal 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 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 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 3. The input resistor is a sum of the RIN and the contact resistance RCON orRCOFF, 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 above5.3kΩ (typical value) and goes LOW, 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 with RCON = 100Ω (at IIN = 10mA) will be recognized as ON = LOW and a contact with RCOFF = 19kΩ will be recognized as OFF = HIGH. These limits are valid within the supply voltage range 6V ≤ VS ≤ 16V and the ground potential difference of ∆VGND = 0,1V. The internal clamping diodes at the contact monitoring inputs, togetherwith the external contacts series resistors RIN, allows the device to withstand transientsat the contactconnection.The contactseries resistor RIN limits the input current at the transient. The dynamic behaviour of the circuit is defined by 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 may also be influenced by the time constant RINCIN. The delay time tdTs, when disabling the device, is defined only by the internal circuitry. In both cases, an external output capacitance less 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. 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 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.) 7/9 L9703 DIP20 PACKAGE MECHANICAL DATA mm DIM. MIN. a1 0.254 B 1.39 TYP. MAX. MIN. TYP. MAX. 0.010 1.65 0.055 0.065 b 0.45 0.018 b1 0.25 0.010 D 25.4 1.000 E 8.5 0.335 e 2.54 0.100 e3 22.86 0.900 F 7.1 0.280 I 3.93 0.155 L Z 8/9 inch 3.3 0.130 1.34 0.053 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. 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. 9/9