INTEGRATED CIRCUITS DATA SHEET For a complete data sheet, please also download: • The IC06 74HC/HCT/HCU/HCMOS Logic Family Specifications • The IC06 74HC/HCT/HCU/HCMOS Logic Package Information • The IC06 74HC/HCT/HCU/HCMOS Logic Package Outlines 74HC/HCT4538 Dual retriggerable precision monostable multivibrator Product specification File under Integrated Circuits, IC06 September 1993
Philips Semiconductors Product specification Dual retriggerable precision monostable multivibrator 74HC/HCT4538 trigger/retrigger input (nA1) , an overriding active LOW direct reset input (nRD), an output (nQ) and its complement (nQ), and two pins (nCTC and nRCTC) for connecting the external timing components Ct and Rt. Typical pulse width variation over temperature range is ± 0.2%.
Philips Semiconductors Product specification Dual retriggerable precision monostable multivibrator 74HC/HCT4538 PIN DESCRIPTION PIN NO.
Philips Semiconductors Product specification Dual retriggerable precision monostable multivibrator 74HC/HCT4538 FUNCTION TABLE INPUTS OUTPUTS nA0 nA1 nRD ↓ L H H ↑ H X X L nQ nQ L H Notes 1. H L X ↑ ↓ Fig.4 Functional diagram. = HIGH voltage level = LOW voltage level = don’t care = LOW-to-HIGH transition = HIGH-to-LOW transition = one HIGH level output pulse = one LOW level output pulse (1) Connect CTC (pins 1 and 15) to GND (pin 8). Fig.
Philips Semiconductors Product specification Dual retriggerable precision monostable multivibrator 74HC/HCT4538 nA1 nA0 VCC power - on reset VCC nRC TC Vref1 enable nQ nC TC GND nQ nR D V ref2 enable handbook, full pagewidth MBA338 Fig.7 Logic diagram (Vref1 and Vref2 are internal reference voltages).
Philips Semiconductors Product specification Dual retriggerable precision monostable multivibrator 74HC/HCT4538 DC CHARACTERISTICS FOR 74HC For the DC characteristics see “74HC/HCT/HCU/HCMOS Logic Family Specifications”. Output capability: standard ICC category: MSI AC CHARACTERISTICS FOR 74HC GND = 0 V; tr = tf = 6 ns; CL = 50 pF Tamb (°C) TEST CONDITIONS 74HC SYMBOL PARAMETER +25 min. typ. −40 to +85 max. min. max. −40 to +125 min. UNIT V CC (V) OTHER max.
Philips Semiconductors Product specification Dual retriggerable precision monostable multivibrator 74HC/HCT4538 Tamb (°C) TEST CONDITIONS 74HC SYMBOL PARAMETER +25 min. trt retrigger time nA0, nA1 − − − REXT external timing resistor 10 2 CEXT external timing capacitor typ. −40 to +85 max. min. − − − 455+X 80+X 55+X max. −40 to +125 min. UNIT V CC (V) OTHER max. − − − 1000 1000 no limits ns 2.0 4.5 6.0 kΩ 2.0 5.0 pF 5.0 Fig.8 X = CEXT / (4.
Philips Semiconductors Product specification Dual retriggerable precision monostable multivibrator 74HC/HCT4538 DC CHARACTERISTICS FOR 74HCT For the DC characteristics see “74HC/HCT/HCU/HCMOS Logic Family Specifications”. Output capability: standard ICC category: MSI Note to HCT types The value of additional quiescent supply current (∆ICC) for a unit load of 1 is given in the family specifications. To determine ∆ICC per input, multiply this value by the unit load coefficient shown in the table below.
Philips Semiconductors Product specification Dual retriggerable precision monostable multivibrator 74HC/HCT4538 NON-STANDARD DC CHARACTERISTICS FOR 74HCT Voltages are referenced to GND (ground = 0 V) Tamb (°C) TEST CONDITIONS 74HCT SYMBOL PARAMETER +25 −40 to +85 −40 to +125 UNIT V CC (V) VI (V) OTHER min. typ max. min. max. min. max. ±II input leakage current nRCEXT 0.5 5.0 10.0 µA 5.5 2.0 VCC or GND; or note 1 GND Note 1.
Philips Semiconductors Product specification Dual retriggerable precision monostable multivibrator 74HC/HCT4538 APPLICATION INFORMATION (a) (b) Fig.9 Retriggerable monostable circuitry. (a) rising-edge triggered; (b) falling-edge triggered. (a) (b) Fig.10 Non-retriggerable monostable circuitry. (a) rising-edge triggered; (b) falling-edge triggered.
Philips Semiconductors Product specification Dual retriggerable precision monostable multivibrator 74HC/HCT4538 Power-down considerations A large capacitor (CX) may cause problems when powering-down the monostable due to the energy stored in this capacitor. When a system containing this device is powered-down or a rapid decrease of VCC to zero occurs, the monostable may sustain damage, due to the capacitor discharging through the input protection diodes.
Philips Semiconductors Product specification Dual retriggerable precision monostable multivibrator 74HC/HCT4538 Fig.14 Typical pulse width accuracy versus external capacitance; REXT = 10 kΩ; VCC = 4.5 V; Tamb = 25 °C. Fig.15 Typical pulse width accuracy versus power supply; CEXT = 1 nF; Tamb = 25 °C. Fig.16 Typical pulse width accuracy versus power supply; CEXT = 100 nF; Tamb = 25 °C.
Philips Semiconductors Product specification Dual retriggerable precision monostable multivibrator 74HC/HCT4538 Fig.17 Typical pulse width accuracy versus temperature; CEXT = 1 nF; VCC = 4.5 V. Fig.18 Typical pulse width accuracy versus temperature; CEXT = 1 µF; VCC = 4.5 V. PACKAGE OUTLINES See “74HC/HCT/HCU/HCMOS Logic Package Outlines”.
