L9704 OCTAL SUPPLY 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 CURRENTS OF 10mA DEFINED BY EXTERNAL CONTACT SERIES RESISTORS RIN1-8 CONTACT STATUS MONITORING BY COMPARING THE RESISTANCE AT CONTACT SENSEINPUTS WITH THE INTERNAL REFERENCE RESISTOR VALUE HIGH IMMUNITY DUE TO RESISTANCE COMPARISON WITH HYSTERESIS DESCRIPTION The L9704 is a bipolar monolithic integrated circuit for monitoring the status of up to eight contactsconnected to the power supply (battery). DIP–20 SO–20L ORDERING NUMBERS: L9704 (DIP–20) L9704D (SO–20L) It contains eight contact sense inputs and eight microcomputer compatible three-state outputs. BLOCK DIAGRAM March 1992 1/8 L9704 ABSOLUTE MAXIMUM RATINGS Symbol Parameter Test Conditions Unit VS Transient Supply Voltage (t ≤ 1s) VCC Logic Supply Voltage IIN DC Input DC Current ±40 mA Input DC Pulse (test pulse specification: 0 < tP < 2ms, f ≤ 0.2Hz, n = 25000) 50 -75 mA mA IINP IO Output Current V 7 V Internally Limited VEN Enable Input Voltage PO Power Dissipation at Tamb = 80°C DIP20 SO20 Tstg,TJ +40 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 Parameter Thermal Resistance Junction to Ambient PIN CONNECTION (top view) 2/8 MAX. DIP20 SO20 Unit 80 165 °C/W 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 VENL Enable Input Voltage LOW (device activated) VENH Enable Input Voltage HIGH Test Conditions Typ. Max. Unit 0.8 V 800 mV 5 µA 2.4 VEN hyst Enable Input Hysteresis IEN Min. Enable Input Current V 200 300 -5 -1 2.4V < VEN < VCC 0V < VEN < 0.8V µA VOUTH Output Voltage HIGH 0 < IOUT < 100µA 4.0 VCC -0.1 VCC V 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 VIN Input Voltage During Clamping (device disabled) EN = HIGH IIN = 30mA IIN = -30mA IOUT Output Current IOUT 0.4 1.5 2 V VS + 0.3 -2 VS + 1 -1 VS + 2 -0.3 V V OUT = HIGH VOUT = 0 2 mA 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 RIL RIH IQC Input Resistor Threshold Ratio (note1) 1.1 0.65 4.8 KΩ 6.5 29 KΩ 0.75 0.85 0.12 0.16 mA 0.04 mA 0.24 mA 13 2 mA mA Quiescent Current EN = HIGH (tENH ≥ 80µs) 5V < VS < 16V -40°C ≤ Tj ≤ 100°C All Inputs Open Input Leakage Current All Inputs Closed VBAT ≤ VD1 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 TRISTAT E) C OUT ≤ 50pF 10 µs IQS SIIN 2) 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) 8 2: SIIN is the sum of the input curr ents 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 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 =1kΩ. With thisinput resistor the contact current, when the contact is closed and the device activated (EN = LOW) is VBAT + ∆VBAT – 2V IIN = 1KΩ (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 4/8 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 6.5kΩ (typical value) and goesLOW, when the input resistance decreases below 4.8KΩ (typical value). The limit values of RI = 1.1KΩ for LOW and RI = 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 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. 5/8 L9704 SO20 PACKAGE MECHANICAL DATA mm DIM. MIN. TYP. A a1 inch MAX. TYP. 2.65 0.1 MAX. 0.104 0.3 a2 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 6/8 MIN. 0.75 0.030 8 (max.) L9704 DIP20 PACKAGE MECHANICAL DATA mm DIM. MIN. a1 0.254 B 1.39 TYP. inch 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 3.3 0.130 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. 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