L9700 HEX PRECISION LIMITER . .. . .. HIGH PERFORMANCE CLAMPING AT GROUND AND POSITIVE REFERENCE VOLTAGE FAST ACTIVE CLAMPING OPERATING RANGE 4.75 - 5.25 V SINGLE VOLTAGEFOR SUPPLY AND POSITIVE REFERENCE LOW QUIESCENT CURRENT LOW INPUT LEAKAGE CURRENT DESCRIPTION The L9700 is a monolithic circuit which is suited for input protection and voltage clamping purpose. The limiting function is referred to ground and the positive supply voltage. One single element contains six independentchannels. Very fast speed is achieved by internal feedback and the application of a new vertical PNP-transistor with isolated collector. Min idip ORDERING NUMBER : L9700 BLOCK DIAGRAM November 1990 This is advanced information on a new product now in development or undergoing evaluation. Details are subject to change without notice. 1/5 L9700 ABSOLUTE MAXIMUM RATINGS Symbol VCC IIN Tj, Tstg Ptot Parameter Value Un it Supply Voltage 20 V Input Current per Channel 30 mA Junction and Storage Temperature Total Power Dissipation (Tamb = 85°C) –55 to 150 °C 650 mW Note: The circuit is ESD protected according to MIL-STD-883C THERMAL DATA Symbol R th j-amb Parameter Thermal Resistance Junction to Ambient Max. Value Un it 100 °C/W PIN CONNECTION ELECTRICAL CHARACTERISTICS (VCC = 5V, T J = –40 to 125°C unless otherwise specified) Symbol Parameter Test co ndition VCC Supply Voltage ICC Supply Current Vcis Static Input Clamping Voltage Negative IIN = –10mA Positive I IN = +10mA IIN Input Current (static) Dynamic Input Clamping Voltage Vcld (*) tS (*) Setting Time RIN (*) Dynamic Input Resistance Crtk (*) Crosstalk between any two inputs Min. Typ . 4.75 Max. Un it 5.25 V 3 mA 0 VCC +250 mV VIN = 0 VIN = VCC VIN = 50mV VIN = VCC –50mV 15 15 5 5 µA µA µA µA IIN = ± 10mA, tR = 5ns Positive Overshoot Negative Overshoot 400 400 mV mV See fig. 2 20 ns 1.5 –250 VCC 5 0 ≤ VIN ≤ VCC, fIN < 1kHz 70 Ω dB (*) Design limits are guaranteed by statistical control on production samples over the indicated temperature and supply voltage ranges. These limits are not used to calculate outgoing quality levels. 2/7 L9700 Figure 1 : DC INPUT CHARACTERISTIC Limit Points of the Characteristic Approximation. Figure 2 : Dynamical Input Characteristics. 2a 3/7 L9700 Figure 2 : Dynamical Input Characteristics (continued) . 2b APPLICATION INFORMATION Most integrated circuits, both HNMOS and bipolar, are very sensitive to positive and negative overvoltages on the supply and at the inputs. These transients occur in large numbers and with different magnitudes in the automotive environment, making adequate protection for devices aimed at it indispensible. Overvoltages on the supply line are faced through high voltage integration technologies or through external protection (transil, varistor). Signal inputsare generally protected using clampdiodes to the supply and ground, and a current limi-ter resistor. However, such solutions do not always completely satisfy the protection specifications in terms of intervention speed, negative clamping and current leakage high enough to change analog signals. The L9700 device combines a high intervention speed with a high precision positive and negative 4/7 clamp and a low current leakage providing the optimal solution to the problems of the automotive environment. The high intervention speed, due to the pre-bias of the limiter stage and internal feedback, limits the voltage overshoot and avoid the use of external capacitors for the limitation of the transient rise times. Figure 3 illustrates a typical automotive application scheme. The resistor RS limits the input current of the device and is therefore dimensioned considering the characteristics of the transients to be eliminated. Consequently : RS = Vtransient Peak IIN MAX The CIN capacitors must be used only on analog inputs because they present a low impedance during the sampling period. L9700 Figure 3 : Typical Application. The minimum value for CIN is determined by the accuracy required, the time taken to sample the input and the input impedance during that time, while the maximum value is determined by the required frequency response and the value of RS. Thus for a resistive input A/D connector where : TS = Sample time (Seconds) RD = Device input resistance (Ohms) VIN = Input voltage (Volts) k = Required accuracy (%) Q1 = Charge on capacitor before sampling Q2 = Charge on capacitor after sampling ID = Device input current (Amps) Thus : k ⋅ Q1 Q1– Q2 = 100 but Q1 = CIN VIN and Q1– Q2 = ID – TS so that ID TS = and CIN so CIN k ⋅ CIN – VIN 100 ID ⋅ TS (min) = Farad VIN ⋅ k 100 ⋅ TS (min) = Farad k ⋅ RD The calculationfor a sample and hold type convertor is even simpler : k = Required accuracy (%) CH = Hold capacitor (Farad) CIN (min) = 100 ⋅ CH Farad k 5/7 L9700 MINIDIP PACKAGE MECHANICAL DATA mm DIM. MIN. A TYP. MAX. MIN. 3.32 TYP. MAX. 0.131 a1 0.51 0.020 B 1.15 1.65 0.045 0.065 b 0.356 0.55 0.014 0.022 b1 0.204 0.304 0.008 0.012 D E 10.92 7.95 9.75 0.430 0.313 0.384 e 2.54 0.100 e3 7.62 0.300 e4 7.62 0.300 F 6.6 0.260 I 5.08 0.200 L Z 6/7 inch 3.18 3.81 1.52 0.125 0.150 0.060 L9700 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-THO MSON 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. 7/7