SL74HC221

SL74HC221 Dual Monostable Multivibrator The SL74HC221 is identical in pinout to the LS/ALS221. The device inputs are compatible with standard CMOS outputs; with pullup resistors, they are compatible with LS/ALSTTL outputs. There are two trigger inputs, A INPUT (negative edge) and B INPUT (positive edge). These inputs are valid for rising/falling signals The device may also be triggered by using the CLR input (positiveedge) because of the Schmitt-trigger input; after triggering the output maintains the MONOSTABLE state for the time period determined by the external resistor RX and capacitor CX. Taking CLR low breaks this MONOSTABLE STATE. If the next trigger pulse occurs during the MONOSTABLE period it makes the MONOSTABLE period longer. • Outputs Directly Interface to CMOS, NMOS, and TTL • Operating Voltage Range: 3.0 to 6.0 V • Low Input Current: 1.0 µA • High Noise Immunity Characteristic of CMOS Devices ORDERING INFORMATION SL74HC221N Plastic SL74HC221D SOIC TA = -55° to 125° C for all packages PIN ASSIGNMENT LOGIC DIAGRAM PIN 16 =VCC PIN 8 = GND FUNCTION TABLE Inputs Outputs CLR H H H H H X L L H L* L * Note Note (1) CX, RX, DX are external components. (2) DX is a clamping diode. The external capacitor is charged to VCC in the stand-by state, i.e. no trigger. When the supply voltage is turned off CX is discharged mainly through an internal parasitic diode. If CX is sufficiently large and VCC decreases rapidy, there will be some possibility of damaging the I.C. with a surge current or latch-up. If the voltage supply filter capacitor is large enough and VCC decrease slowly, the surge current is automatically limited and damage the I.C. is avoided. The maximum forward current of the parasitic diode is approximately 20 mA. A B H Q Q Output Enable H* H * X H L L X L X Inhibit Inhibit Output Enable Output Enable Inhibit X = don’t care * - except for monostable period SLS System Logic Semiconductor SL74HC221 MAXIMUM RATINGS * Symbol VCC VIN VOUT IIN IOUT ICC PD T stg TL * Parameter DC Supply Voltage (Referenced to GND) DC Input Voltage (Referenced to GND) DC Output Voltage (Referenced to GND) DC Input Current, per Pin DC Output Current, per Pin DC Supply Current, VCC and GND Pins Power Dissipation in Still Air, Plastic DIP+ SOIC Package+ Storage Temperature Lead Temperature, 1 mm from Case for 10 Seconds (Plastic DIP or SOIC Package) A, B, CLR CX, RX Value -0.5 to +7.0 -1.5 to VCC +1.5 -0.5 to VCC +0.5 ±20 ±30 ±25 ±50 750 500 -65 to +150 260 Unit V V V mA mA mA mW °C °C Maximum Ratings are those values beyond which damage to the device may occur. Functional operation should be restricted to the Recommended Operating Conditions. +Derating - Plastic DIP: - 10 mW/°C from 65° to 125°C SOIC Package: : - 7 mW/°C from 65° to 125°C RECOMMENDED OPERATING CONDITIONS Symbol VCC VIN, VOUT TA tr, t f Parameter DC Supply Voltage (Referenced to GND) DC Input Voltage, Output Voltage (Referenced to GND) Operating Temperature, All Package Types Input Rise and Fall Time - CLR (Figure 2) A or B RX CX ** Min 3.0 0 -55 VCC =2.0 V VCC =4.5 V VCC =6.0 V 0 0 0 VCC