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INTEGRATED CIRCUITS DATA SHEET For a complete data sheet, please also download: · The IC04 LOCMOS HE4000B Logic Family Specifications HEF, HEC · The IC04 LOCMOS HE4000B Logic Package Outlines/Information HEF, HEC HEF4938B Dual precision monostable multivibrator Preliminary specification File under Integrated Circuits, IC04 January 1995 Philips Semiconductors Preliminary specification Dual precision monostable multivibrator FEATURES · Separate reset inputs · Triggering from leading or trailing edge · ICC category: MSI DESCRIPTION The HEF4938B is a dual retriggerable-resettable monostable multivibrator. Each multivibrator has an active LOW trigger/retrigger input (I0), an active HIGH trigger/retrigger input (I1), an overriding active LOW direct reset input (CD), an output (O) and its complement (O), and two pins (CTC and RCTC) for connecting the external timing components Ct and Rt. Typical pulse width variation over temperature range is ±0.2%. The HEF4938B may be triggered by either the positive or the negative edges of the input pulse and will produce an accurate output pulse with a pulse width range of 10 µs to infinity. The duration and accuracy of the output pulse are determined by the external timing components Ct and Rt. The output pulse width (T) is equal to Rt Ч Ct. The linear design techniques in LOCMOS guarantee precise control of the output pulse width. A LOW level at CD terminates the output pulse immediately. Schmitt-trigger action in the inputs makes the circuit highly tolerant for slower rise and fall times. FUNCTION TABLE INPUTS I0 H X Notes 1. H = HIGH voltage level 2. L = LOW voltage level January 1995 I1 L X CD H H L L H 3. X = state is immaterial 4. = positive-going transition 5. = negative-going transition 6. 7. = positive output pulse = negative output pulse 2 OUTPUTS O O TYPE NUMBER PINS HEF4938B PIN DESCRIPTION PIN NO. 1, 15 2, 14 3, 13 4, 12 5, 11 6, 10 7, 9 8 16 SYMBOL CTC A, CTC B RCTC A, RCTC B CDA, CDB I1A, I1B I0A, I0B OA, OB OA, OB VSS VDD 16 PIN POSITION DIL ORDERING AND PACKAGE INFORMATION PACKAGES HEF4938B MATERIAL plastic CODE SOT38Z NAME AND FUNCTION external capacitor connections external capacitor/resistor connections direct reset input (active LOW) input (LOW-to-HIGH triggered) input (HIGH-to-LOW triggered) output complementary output (active LOW) ground (0 V) positive supply voltage Fig.1 Pin configuration. Fig.2 Functional diagram. This text is here in white to force landscape pages to be rotated correctly when browsing through the pdf in the Acrobat reader.This text is here in _white to force landscape pages to be rotated correctly when browsing through the pdf in the Acrobat reader.This text is here inThis text is here in white to force landscape pages to be rotated correctly when browsing through the pdf in the Acrobat reader. white to force landscape pages to be ... January 1995 3 Fig.3 Logic diagram. Philips Semiconductors Dual precision monostable multivibrator HEF4938B Preliminary s