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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
FEATURES * Separate reset inputs * Triggering from leading or trailing edge * Output capability: standard * ICC category: MSI * Power-on reset on-chip GENERAL DESCRIPTION The 74HC/HCT4538 are high-speed Si-gate CMOS devices and are pin compatible with "4538" of the "4000B" series. They are specified in compliance with JEDEC standard no. 7A. The 74HC/HCT4538 are dual retriggerable-resettable monostable multivibrators. Each multivibrator has an active LOW trigger/retrigger input (nA0), an active HIGH QUICK REFERENCE DATA GND = 0 V; Tamb = 25 C; tr = tf = 6 ns
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%. The "4538" may be triggered by either the positive or the negative edges of the input pulse. 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 0.7 x Rt x Ct. The linear design techniques guarantee precise control of the output pulse width. A LOW level at nRD terminates the output pulse immediately. Schmitt-trigger action in the trigger inputs makes the circuit highly tolerant to slower rise and fall times.
TYPICAL SYMBOL tPHL/ tPLH CI CPD Notes 1. CPD is used to determine the dynamic power dissipation (PD in W): PD = CPD x VCC2 x fi + (CL x VCC2 x fo) + + 0.48 x CEXT x VCC2 x fo + D x 0.8 x VCC where: fi = input frequency in MHz fo = output frequency in MHz (CL x VCC2 x fo) = sum of outputs CL = output load capacitance in pF VCC = supply voltage in V D = duty factor in % CEXT = timing capacitance in pF 2. For HC the condition is VI = GND to VCC For HCT the condition is VI = GND to VCC - 1.5 V ORDERING INFORMATION See "74HC/HCT/HCU/HCMOS Logic Package Information". PARAMETER propagation delay nA0, nA1 to nQ, nQ input capacitance power dissipation capacitance per multivibrator notes 1 and 2 CONDITIONS HC CL = 15 pF; VCC = 5 V 27 3.5 136 HCT 30 3.5 138 ns pF pF UNIT
September 1993
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Philips Semiconductors
Product specification
Dual retriggerable precision monostable multivibrator
PIN DESCRIPTION PIN NO. 1, 15 2, 14 3, 13 4, 12 5, 11 6, 10 7, 9 8 16 SYMBOL 1CTC, 2CTC 1RCTC, 2RCTC 1RD, 2RD 1A1, 2A1 1A0, 2A0 1Q, 2Q 1Q, 2Q GND VCC NAME AND FUNCTION external capacitor connections external resistor/capacitor connections direct reset inputs (active LOW) trigger inputs (LOW-to-HIGH, edge-triggered) trigger inputs (HIGH-to-LOW, edge-triggered) pulse outputs complementary pulse outputs ground (0 V) positive supply voltage
74HC/HCT4538
Fig.1 Pin configuration.
Fig.2 Logic symbol.
Fig.3 IEC logic symbol.
September 1993
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Philips Semiconductors
Product specification
Dual retriggerable precision monostable multivibrator
FUNCTION TABLE INPUTS nA0 H X Notes 1. H L X nA1 L X nRD H H L
74HC/HCT4538
OUTPUTS nQ nQ
L
H
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.5
Connection of the external timing components Rt and Ct.
(1) Positive edge triggering. (2) Positive edge retriggering (pulse lengthening). (3) (4) (5) (6) Negative edge triggering. Reset (pulse shortening). Vref1 and Vref2 are internal reference voltages. T = 0.7 x Rt x Ct (see also Fig.5).
Fig.6 Timing diagram.
September 1993
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Philips Semiconductors
Product specification
Dual retriggerable precision monostable multivibrator
74HC/HCT4538
nA1 nA0
power - on reset VCC nRC TC
VCC
Vref1 nC TC GND
enable nQ
nQ nR D V ref2 enable
MBA338
Fig.7 Logic diagram (Vref1 and Vref2 are internal reference voltages).
September 1993
handbook, full pagewidth
5
Philips Semiconductors
Product specification
Dual retriggerable precision monostable multivibrator
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) 74HC SYMBOL PARAMETER min. tPLH propagation delay nA0, nA1 to nQ propagation delay nA0, nA1 to nQ propagation delay nRD to nQ propagation delay nRD to nQ output transition time nA0 pulse width LOW nA1 pulse width HIGH nRD pulse width LOW nQ, nQ pulse width HIGH or LOW removal time RD to nA0, nA1 80 16 14 80 16 14 80 16 14 +25 typ. 85 31 25 83 30 24 80 29 23 83 30 24 19 7 6 17 6 5 17 6 5 19 7 6 0.77 max. 265 53 45 265 53 45 265 53 45 265 53 45 75 15 13 100 20 17 100 20 17 100 20 17 -40 to +85 min. max. 330 66 56 330 66 56 330 66 56 340 68 58 95 19 16 120 24 20 120 24 20 120 24 20 -40 to +125 min. max. 400 80 68 400 80 68 400 80 68 400 80 68 110 22 19 ns
74HC/HCT4538
TEST CONDITIONS UNIT V CC (V) 2.0 4.5 6.0 2.0 4.5 6.0 2.0 4.5 6.0 2.0 4.5 6.0 2.0 4.5 6.0 2.0 4.5 6.0 2.0 4.5 6.0 2.0 4.5 6.0 5.0
OTHER
Fig.8
tPHL
ns
Fig.8
tPHL
ns
Fig.8
tPLH
ns
Fig.8
tTHL/ tTLH
ns
Fig.8
tW
ns
Fig.8
tW
ns
Fig.8
tW
ns
Fig.8
tW
0.63 0.70
0.602 0.798 0.595 0.805
ms
Fig.8; Rt = 10 k; Ct = 0.1 F Fig.8
trem
35 7 6
6 2 2
45 9 8
55 11 9
ns
2.0 4.5 6.0
September 1993
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Philips Semiconductors
Product specification
Dual retriggerable precision monostable multivibrator
Tamb (C) 74HC SYMBOL PARAMETER min. trt retrigger time nA0, nA1 external timing resistor external timing capacitor - - - 10 2 +25 typ. 455+X 80+X 55+X 1000 1000 no limits max. - - - -40 to +85 min. max. -40 to +125 min. - - - max. ns
74HC/HCT4538
TEST CONDITIONS UNIT V CC (V) 2.0 4.5 6.0 2.0 5.0 5.0
OTHER
Fig.8 X = CEXT / (4.5 x VCC)
REXT CEXT
k pF
NON-STANDARD DC CHARACTERISTICS FOR 74HC Voltages are referenced to GND (ground = 0 V) Tamb (C) 74HC SYMBOL PARAMETER +25 -40 to +85 -40 to +125 UNIT VCC (V) 6.0 VI (V) OTHER TEST CONDITIONS
min. typ max. min. max. min. max. II input leakage current nRCEXT 0.5 5.0 10.0 A 2.0 VCC or GND; or note 1 GND
Note 1. This measurement can only be carried out after a trigger pulse is applied.
September 1993
7
Philips Semiconductors
Product specification
Dual retriggerable precision monostable multivibrator
DC CHARACTERISTICS FOR 74HCT For the DC characteristics see "74HC/HCT/HCU/HCMOS Logic Family Specifications". Output capability: standard ICC category: MSI
74HC/HCT4538
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. INPUT nA0, nA1 nRD UNIT LOAD COEFFICIENT 0.50 0.65
AC CHARACTERISTICS FOR 74HCT GND = 0 V; tr = tf = 6 ns; CL = 50 pF Tamb (C) 74HCT SYMBOL PARAMETER min. tPLH tPHL tPHL tPLH tTHL/ tTLH tW tW tW tW trem trt propagation delay nA0, nA1 to nQ propagation delay nA0, nA1 to nQ propagation delay nRD to nQ propagation delay nRD to nQ output transition time nA0 pulse width LOW nA1 pulse width HIGH nRD pulse width LOW nQ, nQ pulse width HIGH or LOW removal time RD to nA0, nA1 retrigger time nA0, nA1 external timing resistor external timing capacitor 20 16 20 +25 typ. 35 35 35 35 7 11 5 11 0.77 max. 60 60 60 60 15 25 20 25 -40 to +85 min. max. 75 75 75 75 19 30 24 30 -40 to +125 min. max. 90 90 90 90 21 ns ns ns ns ns ns ns ns 4.5 4.5 4.5 4.5 4.5 4.5 4.5 4.5 5.0 4.5 4.5 Fig.8 Fig.8 Fig.8 Fig.8 Fig.8 Fig.8 Fig.8 Fig.8 Fig.8; Rt = 10 k; Ct = 0.1 F Fig.8 Fig.8 X = CEXT / (4.5 x VCC) UNIT V OTHER CC (V) TEST CONDITIONS
0.63 0.70 7 - 2 80+X
0.602 0.798 0.595 0.805 ms 9 - 11 - ns ns
REXT CEXT
2
1000
k pF
5.0 5.0
no limits 8
September 1993
Philips Semiconductors
Product specification
Dual retriggerable precision monostable multivibrator
NON-STANDARD DC CHARACTERISTICS FOR 74HCT Voltages are referenced to GND (ground = 0 V) Tamb (C) 74HCT SYMBOL PARAMETER +25 -40 to +85 -40 to +125
74HC/HCT4538
TEST CONDITIONS UNIT V CC (V) A 5.5 VI (V) OTHER
min. typ max. min. max. min. max. II input leakage current nRCEXT 0.5 5.0 10.0 2.0 VCC or GND; or note 1 GND
Note 1. This measurement can only be carried out after a trigger pulse is applied. AC WAVEFORMS
(1) HC : VM = 50%; VI = GND to VCC. HCT: VM = 1.3 V; VI = GND to 3 V.
Fig.8
Waveforms showing the input (nA1, nA0, nRD) to output (nQ, nQ) propagation delays, the output transition times, the input and output pulse widths, the removal time from direct reset (nRD) to input (nA1, nA0), and the input retrigger time.
September 1993
9
Philips Semiconductors
Product specification
Dual retriggerable precision monostable multivibrator
APPLICATION INFORMATION
74HC/HCT4538
(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.
September 1993
10
Philips Semiconductors
Product specification
Dual retriggerable precision monostable multivibrator
Power-down considerations
74HC/HCT4538
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. To avoid this possibility, use a damping diode (DX) preferably a germanium or Schottky type diode able to withstand large current surges and connect as shown in Fig.11. Fig.11 Power-down protection circuit.
Fig.12 Typical pulse width accuracy versus external capacitance; VCC = 4.5 V; Tamb = 25 C.
Fig.13 Typical pulse width accuracy versus external resistance; VCC = 4.5 V; Tamb = 25 C.
September 1993
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Philips Semiconductors
Product specification
Dual retriggerable precision monostable multivibrator
74HC/HCT4538
Fig.14 Typical pulse width accuracy versus external capacitance; REXT = 10 k; 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.
September 1993
12
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 F; VCC = 4.5 V.
PACKAGE OUTLINES See "74HC/HCT/HCU/HCMOS Logic Package Outlines".
September 1993
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