74HCT5555 [NXP]
Programmable delay timer with oscillator; 与振荡器的可编程延迟计时器
| 型号： | 74HCT5555 |
| 厂家： | 
NXP |
| 描述： | Programmable delay timer with oscillator |
| 文件： | 总23页 (文件大小：146K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
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/HCT5555
Programmable delay timer with
oscillator
September 1993
Product specification
File under Integrated Circuits, IC06
Philips Semiconductors
Product specification
Programmable delay timer with oscillator
74HC/HCT5555
• retriggerable/non-retriggerable
FEATURES
GENERAL DESCRIPTION
monostable
• Positive and negative edge
triggered
The 74HC/HCT5555 are high-speed
Si-gate CMOS devices and are pin
compatible with low power Schottky
TTL (LSTTL). They are specified in
compliance with JEDEC standard
no. 7A.
• automatic power-ON reset
• output control logic
• Retriggerable or non-retriggerable
• Programmable delay
• oscillator control logic
• overriding asynchronous master
reset (MR).
minimum: 100 ns
maximum: depends on input
frequency and division ratio
• Divide-by range of 2 to 224
The 74HC/HCT5555 are precision
programmable delay timers which
consist of:
• Direct reset terminates output
• 24-stage binary counter
pulse
• integrated oscillator (using external
• Very low power consumption in
timing components)
triggered start mode
• 3 oscillator operating modes:
– RC oscillator
QUICK REFERENCE DATA
GND = 0 V; Tamb = 25 °C; tr = tf = 6 ns.
– Crystal oscillator
SYMBOL
PHL/tPLH
PARAMETER
CONDITIONS
TYP.
UNIT
– External oscillator
t
propagation delay
A, B to Q/Q
CL = 15 pF;
VCC = 5 V
• Device is unaffected by variations
in temperature and VCC when using
an external oscillator
24
19
26
24
ns
MR to Q/Q
20
28
ns
ns
• Automatic power-ON reset
RS to Q/Q
• Schmitt trigger action on both
trigger inputs
CI
input capacitance
3.5 3.5 pF
23 36 pF
CPD
power dissipation
capacitance per buffer
notes 1 and 2
• Direct drive for a power transistor
• Low power consumption in active
mode with respect to TTL type
timers
Notes
1. CPD is used to determine the dynamic power dissipation (PD in µW):
PD = CPD x VCC2 x fi + Σ(CL x VCC2 x fo) where:
fi = input frequency in MHz
• High precision due to digital timing
• Output capability: 20 mA
• ICC category: MSI.
fo = output frequency in MHz
Σ(CL x VCC2 x fo) = sum of outputs.
CL = output load capacitance in pF
APPLICATIONS
VCC = supply voltage in V
• Motor control
2. For HC the condition is VI = GND to VCC
• Attic fan timers
For HCT the condition is VI = GND to VCC − 1.5 V.
• Delay circuits
• Automotive applications
• Precision timing
• Domestic appliances.
ORDERING INFORMATION
PACKAGE
EXTENDED TYPE
NUMBER
PINS PIN POSITION MATERIAL
CODE
74HC/HCT5555N
74HC/HCT5555D
16
16
DIL
plastic
plastic
SOT38Z
SO16
SOT109A
September 1993
2
Philips Semiconductors
Product specification
Programmable delay timer with oscillator
74HC/HCT5555
PINNING
SYMBOL
RS
PIN
1
DESCRIPTION
clock input/oscillator pin
external resistor connection
external capacitor connection
RTC
CTC
A
2
3
handbook, halfpage
V
RS
TC
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
CC
4
trigger input (positive-edge
triggered)
R
C
MR
OSC
CON
B
5
6
trigger input (negative-edge
triggered)
TC
A
S
3
RTR/RTR
retriggerable/non-retriggerable
input (active HIGH/active LOW)
5555
B
S
2
RTR/
RTR
S
1
Q
7
8
9
pulse output (active LOW)
ground (0 V)
S
0
GND
Q
Q
pulse output (active HIGH)
GND
Q
S0 − S3
10, 11, programmable input
12, 13
MGA642
OSC CON
MR
14
15
oscillator control
master reset input (active
HIGH)
Fig.1 Pin configuration.
VCC
16
positive supply voltage
handbook, halfpage
X / Y
CTRDIVm
[T]
Y = 0
10
1
2
4
8
0
11
12
13
15 Y = 15
! G
2
3
RX
CX
+
14
1
16G17
17
6
4
5
&
CT = 0
CT = m
1
R
9
7
S
R
V16
I = 0
15
R
MGA643
Fig.2 IEC logic diagram.
September 1993
3
Philips Semiconductors
Product specification
Programmable delay timer with oscillator
74HC/HCT5555
2
3
10
11
12
13
R
C
S
0
S
1
S
2
S
3
TC
TC
CP
24 - STAGE COUNTER
1
RS
OSC
CON
CD
14
POWER-ON
RESET
15 MR
4
A
B
9
7
Q
Q
MONOSTABLE
CIRCUITRY
OUTPUT
STAGE
5
6
RTR/RTR
MGA644
Fig.3 Functional diagram.
• Trigger pulse applied input B for
negative-edge triggering
An internal power-on reset is used to
reset all flip-flop stages.
FUNCTIONAL DESCRIPTION
The oscillator configuration allows the
design of RC or crystal oscillator
circuits. The device can operate from
an external clock signal applied to the
RS input (RTC and CTC must not be
connected). The oscillator frequency
is determined by the external timing
components (RT and CT), within the
frequency range 1 Hz to 4 MHz
(32 kHz to 20 MHz with crystal
oscillator).
• Trigger pulse applied to inputs A
and B (tied together) for both
positive-edge and negative
triggering.
The output pulse can be terminated
by the asynchronous overriding
master reset (MR), this results in all
flip-flop stages being reset. The
output signal is capable of driving a
power transistor. The output time
delay is calculated using the following
formula (minimum time delay is
100 ns):
The Schmitt trigger action in the
trigger inputs, transforms slowly
changing input signals into sharply
defined jitter-free output signals and
provides the circuit with excellent
noise immunity.
1
fi
× division ratio (s).
--
In the HCT version the MR input is
TTL compatible but the RS input has
CMOS input switching levels. The RS
input can be driven by TTL input
levels if RS is tied to VCC via a pull-up
resistor.
The OSC CON input is used to select
the oscillator mode, either
continuously running (OSC CON =
HIGH) or triggered start mode (OSC
CON = LOW). The continuously
running mode is selected where a
start-up delay is an undesirable
feature and the triggered start mode
is selected where very low power
consumption is the primary concern.
Once triggered, the output width may
be extended by retriggering the
gated, active HIGH-going input A or
the active LOW-going input B. By
repeating this process, the output
pulse period (Q = HIGH, Q = LOW)
can be made as long as desired. This
mode is selected by RTR/RTR =
HIGH. A LOW on RTR/RTR makes,
once triggered, the outputs (Q, Q)
independent of further transitions of
inputs A and B.
The counter divides the frequency to
obtain a long pulse duration. The
24-stage is digitally programmed via
the select inputs (S0 to S3). Pin S3 can
also be used to select the test mode,
which is a convenient way of
The start of the programmed time
delay occurs when output Q goes
HIGH (in the triggered start mode, the
previously disabled oscillator will
start-up). After the programmed time
delay, the flip-flop stages are reset
and the output returns to its original
state.
functionally testing the counter.
The “5555” is triggered on either the
positive-edge, negative-edge or both.
• Trigger pulse applied to input A for
positive-edge triggering
September 1993
4
Philips Semiconductors
Product specification
Programmable delay timer with oscillator
74HC/HCT5555
GM6A5
n
September 1993
5
Philips Semiconductors
Product specification
Programmable delay timer with oscillator
74HC/HCT5555
TEST MODE
Set S3 to a logic LOW level, this will divide the 24 stage counter into three, parallel clocking, 8-stage counters. Set S0,
S1 and S2 to a logic HIGH level, this programs the counter to divide-by 28 (256). Apply a trigger pulse and clock in 255
pulses, this sets all flip-flop stages to a logic HIGH level. Set S3 to a logic HIGH level, this causes the counter to divide-by
224. Clock one more pulse into the RS input, this causes a logic 0 to ripple through the counter and output Q/Q goes from
HIGH-to-LOW level. This method of testing the delay counter is faster than clocking in 224 (16 777 216) clock pulses.
FUNCTION TABLE
INPUTS
A
OUTPUTS
MR
B
Q
Q
H
L
X
X
X
L
H
↑
one HIGH level
output pulse
one LOW level
output pulse
L
X
↓
one HIGH level
output pulse
one LOW level
output pulse
Notes
1. H = HIGH voltage level
L = LOW voltage level
X = don't care
↑ = LOW-to-HIGH transition
↓ = HIGH-to-LOW transition.
September 1993
6
Philips Semiconductors
Product specification
Programmable delay timer with oscillator
74HC/HCT5555
DELAY TIME SELECTION
SELECT INPUTS
OUTPUT Q/Q (FREQUENCY DIVIDING)
BINARY DECIMAL
S3
S2
S1
S0
L
L
L
L
L
L
L
H
L
21
22
23
24
25
26
27
28
2
4
L
L
H
H
L
8
L
L
H
L
16
L
H
H
H
H
.
32
L
L
H
L
64
L
H
H
.
128
L
H
.
256
.
.
.
H
H
H
H
H
H
H
H
L
L
L
217
218
219
220
221
222
223
224
131 072
262 144
524 288
L
L
H
L
L
H
H
L
L
H
L
1 048 576
2 097 152
4 194 304
8 388 608
16 777 216
H
H
H
H
L
H
L
H
H
H
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15 16
RS
MR
A
Q
MGA649
Timing example shown for S3, S2, S1, S0 = 0011 (binary 24, decimal 16).
Fig.5 Timing diagram.
September 1993
7
Philips Semiconductors
Product specification
Programmable delay timer with oscillator
74HC/HCT5555
DC CHARACTERISTICS FOR 74HC
For the DC characteristics see “74HC/HCT/HCU/HCMOS Logic Family Specifications”.
Output capability: parallel outputs, bus driver; serial output, standard ICC category: MSI.
DC CHARACTERISTICS FOR 74HC
Tamb (°C)
TEST CONDITION
SYM-
BOL
PARAMETER
+25
−40 to +85 −40 to +125 UNIT
VCC
(V)
VI
OTHER
MIN TYP MAX MIN MAX MIN MAX
VOH
HIGH level
output voltage 4.4 4.5
Q and Q
outputs
1.9
2
−
−
−
1.9
4.4
5.9
−
−
−
1.9
4.4
5.9
−
−
−
V
V
V
2.0
4.5
6.0
Io = −20 µA
5.9 6.0
VOH
VOH
VOL
VOL
VOL
HIGH level
output voltage 5.48 5.81
Q and Q
3.98 4.32
−
−
3.84
5.34
−
−
3.7
5.2
−
−
V
V
4.5
6.0
Io = −6.0 mA
Io = −7.8 mA
outputs
HIGH level
output voltage 4.8
Q and Q
3.3
−
−
−
−
3
4.5
−
−
2.7
4.2
−
−
V
V
4.5
6.0
Io = −20 mA
Io = −20 mA
outputs
LOW level
output voltage
Q and Q
−
−
−
0
0
0
0.1
0.1
0.1
−
−
−
0.1
0.1
0.1
−
−
−
0.1
0.1
0.1
V
V
V
2.0
4.5
6.0
Io = 20 µA
outputs
LOW level
output voltage
Q and Q
−
−
0.15 0.26
0.15 0.26
−
−
0.33
0.33
−
−
0.40
0.40
V
V
4.5
6.0
Io = 6.0 mA
Io = 7.8 mA
outputs
LOW level
output voltage
Q and Q
−
−
−
−
0.9
0.9
−
−
1.14
1.14
−
−
1.34
1.34
V
V
4.5
6.0
Io = 20 mA
Io = 25 mA
outputs
VIH
VIL
HIGH level
input voltage
RS input
1.7
3.6
4.8
−
−
−
−
−
−
1.7
3.6
4.8
−
−
−
1.7
3.6
4.8
−
−
−
V
V
V
2
4.5
6.0
LOW level
input voltage
RS input
−
−
−
−
−
−
0.3
0.9
1.2
−
−
−
0.3
0.9
1.2
−
−
−
0.3
0.9
1.2
V
V
V
2.0
4.5
6.0
September 1993
8
Philips Semiconductors
Product specification
Programmable delay timer with oscillator
74HC/HCT5555
Tamb (°C)
TEST CONDITION
SYM-
BOL
PARAMETER
+25
−40 to +85 −40 to +125 UNIT
VCC
(V)
VI
OTHER
MIN TYP MAX MIN MAX MIN MAX
VOH
HIGH level
output voltage 5.48
RTC output
3.98
−
−
−
−
3.84
5.34
−
−
3.7
5.2
−
−
V
V
4.5 RS = GND; Io = −2.6 mA
6.0 OSC CON Io = −3.3 mA
= VCC
3.98
5.48
−
−
−
−
3.84
5.34
−
−
3.7
5.2
−
−
V
V
4.5 RS = VCC
6.0 OSC CON Io = −0.85 mA
= GND;
;
Io = −0.65 mA
untriggered
1.9 2.0
4.4 4.5
−
−
−
1.9
4.4
5.9
−
−
−
1.9
4.4
5.9
−
−
−
V
V
V
2.0 RS = VCC
4.5 OSC CON
6.0 = VCC
;
Io = −20 µA
Io = −20 µA
5.9
6
1.9 2.0
4.4 4.5
5.9 6.0
−
−
−
1.9
4.4
5.9
−
−
−
1.9
4.4
5.9
−
−
−
V
V
V
2
RS = VCC;
4.5 OSC CON
6.0 = GND;
untriggered
VOH
HIGH level
output voltage 5.48
TC output
3.98
−
−
−
−
3.84
5.34
−
−
3.7
5.2
−
−
V
V
4.5 RS = VIH;
6.0 OSC CON Io = −4.2 mA
Io = −3.2 mA
C
= VIH
VOL
LOW level
output voltage
RTC output
−
−
−
−
0.26
0.26
−
−
0.33
0.33
−
−
0.4
0.4
V
V
4.5 RS = VCC
;
Io = 2.6 mA Io
6
OSC CON = 3.3 mA
= VCC
−
−
−
0
0
0
0.1
0.1
0.1
−
−
−
0.1
0.1
0.1
−
−
−
0.1
0.1
0.1
V
V
V
2.0 RS = VCC
4.5 OSC CON
= VCC
4.5 RS = VIL;
6.0 OSC CON = 4.2 mA
= VIL;
;
Io = 20 µA
6
VOL
LOW level
−
−
−
−
0.26
0.26
−
−
0.33
0.33
−
−
0.4
0.4
V
V
Io = 3.2 mA Io
output voltage
C
TC output
untriggered
September 1993
9
Philips Semiconductors
Product specification
Programmable delay timer with oscillator
74HC/HCT5555
AC CHARACTERISTICS FOR 74HC
GND = 0 V; tr = tf = 6 ns; CL = 50 pF.
Tamb (°C)
TEST CONDITION
SYMBOL PARAMETER
+25
−40 to +85
−40 to +125 UNIT
VCC
WAVEFORMS
(V)
MIN TYP MAX MIN MAX MIN MAX
t
PLH/tPHL
propagation
delay A, B to
Q, Q
−
−
−
77
28
22
240
48
41
−
−
−
300
60
51
−
−
−
360
72
61
ns
ns
ns
2.0
4.5
6.0
Fig.6
tPLH/tPHL
propagation
delay MR to Q,
Q
−
−
−
61
22
18
185
37
31
−
−
−
230
46
39
−
−
−
280
56
48
ns
ns
ns
2.0
4.5
6.0
Fig.7
t
t
PLH/tPHL
propagation
delay RS to Q,
Q
−
−
−
83
30
24
250
50
43
−
−
−
315
63
54
−
−
−
375
75
64
ns
ns
ns
2.0
4.5
6.0
Fig.8; note 1
Fig.6
THL/tTLH
output
transition time
−
−
−
19
7
6
75
15
13
−
−
−
95
19
16
−
−
−
110
22
19
ns
ns
ns
2.0
4.5
6.0
tW
trigger pulse
width
A = HIGH
70
14
12
17
6
5
−
−
−
90
18
15
−
−
−
105
21
18
−
−
−
ns
ns
ns
2.0
4.5
6.0
Fig.6
B = LOW
tW
tW
tW
master reset
pulse width
HIGH
70
14
12
19
7
6
−
−
−
90
18
15
−
105
21
18
−
−
−
ns
ns
ns
2.0
4.5
6.0
Fig.7
clock pulse
width RS;
HIGH or LOW
80
16
14
25
9
7
−
−
−
100
20
17
−
−
−
120
24
20
−
−
−
ns
ns
ns
2.0
4.5
6.0
Fig.8
minimum
output pulse
width
−
−
−
275
100
80
−
−
−
−
−
−
−
−
−
−
−
−
−
−
−
ns
ns
ns
2.0
4.5
6.0
Fig.6; note 1
Q = HIGH,
Q = LOW
trt
retrigger time
A, B
−
−
−
0
0
0
−
−
−
−
−
−
−
−
−
−
−
−
−
−
−
ns
ns
ns
2.0
4.5
6.0
Fig.10; note 2
Fig.13
REXT
external timing
resistor
5
1
−
−
1000
1000
−
−
−
−
−
−
−
−
−
−
kΩ
kΩ
2.0
5.0
CEXT
trem
external timing
capacitor
50
50
pF
pF
2.0
5.0
Fig.13
Fig.7
no limits
removal time
MR to A, B
120
24
20
39
14
11
−
−
−
150
−
−
−
180
36
31
−
−
−
ns
ns
ns
2.0
4.5
6.0
30
26
September 1993
10
Philips Semiconductors
Product specification
Programmable delay timer with oscillator
74HC/HCT5555
Tamb (°C)
TEST CONDITION
SYMBOL PARAMETER
+25
−40 to +85
−40 to +125 UNIT
VCC
WAVEFORMS
(V)
MIN TYP MAX MIN MAX MIN MAX
fmax
maximum
clock pulse
frequency
2
10
12
5.9
18
21
−
−
−
1.8
8
10
−
−
−
1.3
6.6
8
−
−
−
MHz 2.0
MHz 4.5
MHz 6.0
Fig.8; note 3
fmax
maximum
clock pulse
frequency
6
30
35
24.8
75
89
−
−
−
4.8
24
28
−
−
−
4
20
24
−
−
−
MHz 2.0
MHz 4.5
MHz 6.0
Fig.9; note 4
Notes
1. One stage selected.
2. It is possible to retrigger directly after the trigger pulse, however the pulse will only be extended, if the time period
exceeds the clock input cycle time divided by 2.
3. One stage selected. The termination of the output pulse remains synchronized with respect to the falling edge of the
RS clock input.
4. One stage selected. The termination of the output pulse is no longer synchronized with respect to the falling edge of
the RS clock input.
September 1993
11
Philips Semiconductors
Product specification
Programmable delay timer with oscillator
74HC/HCT5555
DC CHARACTERISTICS FOR 74HCT
For the DC characteristics see “74HC/HCT/HCU/HCMOS Logic Family Specifications”.
Output capability: non-standard; bus driver with extended specification on VOH and VOL
ICC category: MSI.
Tamb (°C)
TEST CONDITION
SYMBOL PARAMETER
+25
−40 to +85 −0 to +125 UNIT
VCC
(V)
VI
OTHER
MIN TYP MAX MIN MAX MIN MAX
VOH
VOH
VOH
VOL
VOL
VOL
HIGH level
output voltage
Q and Q
4.4 4.5
−
4.4
3.84
3
−
4.4
3.7
2.7
−
−
V
V
V
V
V
V
4.5
4.5
4.5
4.5
4.5
4.5
Io = −20 µA
outputs
HIGH level
output voltage
Q and Q
3.98 4.32
−
−
−
Io = −6 mA
Io = −20 mA
Io = 20 µA
Io = 6 mA
outputs
HIGH level
output voltage
Q and Q
3.3
−
−
−
−
−
outputs
LOW level
output voltage
Q and Q
0
0.1
−
0.1
0.33
1.14
0.1
0.40
1.34
outputs
LOW level
output voltage
Q and Q
−
0.15 0.26
−
−
outputs
LOW level
output voltage
Q and Q
−
−
0.9
−
−
−
Io = 20 mA
outputs
September 1993
12
Philips Semiconductors
Product specification
Programmable delay timer with oscillator
74HC/HCT5555
Tamb (°C)
TEST CONDITION
SYMBOL PARAMETER
+25
−40 to +85 −0 to +125 UNIT
VCC
(V)
VI
OTHER
MIN TYP MAX MIN MAX MIN MAX
VOH
HIGH level
output
voltage RTC
output
3.98
3.98
−
−
−
−
3.84
3.84
−
−
3.7
3.7
−
−
V
V
4.5
RS = GND; Io = −2.6 mA
OSC CON
= VCC
4.5
RS = VCC
OSC CON
= GND;
;
Io =
−0.65 mA
untriggered
4.4 4.5
4.4 4.5
−
−
4.4
4.4
−
−
4.4
4.4
−
−
V
V
4.5
4.5
RS = VCC
OSC CON
= VCC
;
Io = −20 µA
Io = −20 µA
RS = VCC
;
OSC CON
= GND;
untriggered
HIGH level
output
voltage CTC
output
RS = VIH;
OSC CON Io = −3.2 mA
= VIH
VOH
3.98
−
−
3.84
−
3.7
−
V
4.5
RS = VCC
;
−
−
−
0.26
0.1
−
−
0.33
0.1
−
−
0.4
0.1
V
V
4.5
4.5
OSC CON Io = 2.6 mA
= VCC
LOW level
output
voltage RTC
output
VOL
RS = VCC
;
0
OSC CON Io = 20 µA
= VCC
LOW level
output
voltage CTC
output
RS = VIL;
OSC CON
Io = 3.2 mA
= VIL;
VOL
−
−
0.26
−
0.33
−
0.4
V
4.5
untriggered
Notes
1. The RS input has CMOS input switching levels.
2. 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 following table.
UNIT LOAD COEFFICIENT
INPUT
UNIT LOAD COEFFICIENT
MR
A
0.35
0.69
0.50
0.35
1.20
0.65
0.40
B
RTR/RTR
OSC CON
S0 - S2
S3
September 1993
13
Philips Semiconductors
Product specification
Programmable delay timer with oscillator
74HC/HCT5555
AC CHARACTERISTICS FOR 74HCT
GND = 0 V; tr = tf = 6 ns; CL = 50 pF.
Tamb (°C)
TEST CONDITION
SYMBOL PARAMETER
+25
−40 to +85
−40 to +125 UNIT
VCC
WAVEFORMS
(V)
MIN TYP MAX MIN MAX MIN MAX
t
PLH/tPHL
propagation
delay A, B to
Q, Q
−
−
−
28
24
32
48
41
54
−
−
−
60
51
68
−
−
−
72
62
81
ns
ns
ns
4.5
4.5
4.5
Fig.6
tPHL/tPLH
propagation
delay MR to Q,
Q
Fig.7
t
t
PHL/tPLH
propagation
delay RS to Q,
Q
Fig.8; note 1
THL/tTLH
output
transition time
−
7
15
−
19
−
22
ns
ns
4.5
4.5
Fig.6
Fig.6
tW
trigger pulse
width
21
12
−
26
−
32
−
A = HIGH
B = LOW
tW
tW
tW
master reset
pulse width
HIGH
14
16
−
5
−
−
−
18
20
−
−
−
−
21
24
−
−
−
−
ns
ns
ns
4.5
4.5
4.5
Fig.7
Fig.8
Fig.6
clock pulse
width RS;
HIGH or LOW
9
minimum
output pulse
width
100
Q = HIGH,
Q = LOW
trt
retrigger time
A, B
−
0
−
−
−
−
−
−
−
−
ns
kΩ
pF
ns
4.5
4.5
4.5
4.5
Fig.10; note 2
Fig.13
REXT
CEXT
trem
fmax
external timing
resistor
1
−
1000
−
external timing
capacitor
50
24
10
no limits
Fig.13
removal time
MR to A, B
14
18
−
−
30
8
−
−
36
−
−
Fig.7
maximum
clock pulse
frequency
6.6
MHz 4.5
MHz 4.5
Fig.8; note 3
fmax
maximum
clock pulse
frequency
30
75
−
24
−
20
−
Fig.9; note 4
September 1993
14
Philips Semiconductors
Product specification
Programmable delay timer with oscillator
74HC/HCT5555
Notes
1. One stage selected.
2. It is possible to retrigger directly after the trigger pulse, however the pulse will only be extended, if the time period
exceeds the clock input cycle time divided by 2.
3. One stage selected. The termination of the output pulse remains synchronized with respect to the falling edge of the
RS clock input.
4. One stage selected. The termination of the output pulse is no longer synchronized with respect to the falling edge of
the RS clock input.
September 1993
15
Philips Semiconductors
Product specification
Programmable delay timer with oscillator
74HC/HCT5555
AC WAVEFORMS
t
W
90%
10%
(1)
B INPUT
A INPUT
V
M
90%
10%
(1)
V
M
GND
t
W
t
t
TLH
THL
90%
(1)
V
V
Q OUTPUT
Q OUTPUT
M
10%
t
t
PHL
PLH
t
W
90%
10%
(1)
M
t
t
TLH
THL
MGA653
(1) HC : VM = 50%; VI = GND to VCC
.
HCT: VM = 1.3 V; VI = GND to 3 V.
Fig.6 Waveforms showing the triggering of the delay timer by input A or B, the minimum pulse widths of the
trigger inputs A and B, the output pulse width and output transition times.
September 1993
16
Philips Semiconductors
Product specification
Programmable delay timer with oscillator
74HC/HCT5555
(1)
V
MR INPUT
A INPUT
B INPUT
M
t
W
t
t
rem
rem
(1)
(1)
V
V
M
M
t
t
PLH
PHL
(1)
(1)
V
Q OUTPUT
Q OUTPUT
M
M
V
MGA652-1
(1) HC : VM = 50%; VI = GND to VCC
.
HCT: VM = 1.3 V; VI = GND to 3 V.
Fig.7 Waveforms showing the master reset (MR) pulse width, the master reset to outputs (Q and Q) propagation
delays and the master reset to trigger inputs (A and B) removal time.
September 1993
17
Philips Semiconductors
Product specification
Programmable delay timer with oscillator
74HC/HCT5555
1/f max
1
RS INPUT
2V
CC
t
W
t
PHL
(1)
(1)
V
V
Q OUTPUT
Q OUTPUT
M
M
t
PLH
MGA651
(1) HC : VM = 50%; VI = GND to VCC
.
HCT: VM = 1.3 V; VI = GND to 3 V.
Fig.8 Waveforms showing the clock (RS) to outputs (Q and Q) propagation delays, the clock pulse width and
the maximum clock frequency.
1/f max
(1)
RS INPUT
V
M
t
PHL
(1)
V
M
Q OUTPUT
Q OUTPUT
t
PLH
(1)
V
M
MGA654
(1) HC : VM = 50%; VI = GND to VCC
.
HCT: VM = 1.3 V; VI = GND to 3 V.
Fig.9 Waveforms showing the clock (RS) to outputs (Q and Q) propagation delays, the clock pulse width and
the maximum clock frequency (Output waveforms are not synchronized with respect to the RS waveform).
September 1993
18
Philips Semiconductors
Product specification
Programmable delay timer with oscillator
74HC/HCT5555
A INPUT
t
W
B INPUT
t
r t
t
W
Q OUTPUT
t
t
W
W
MGA650
t
W
(1) HC : VM = 50%; VI = GND to VCC
.
HCT: VM = 1.3 V; VI = GND to 3 V.
Fig.10 Output pulse control using retrigger pulse (RTR/RTR = HIGH).
September 1993
19
Philips Semiconductors
Product specification
Programmable delay timer with oscillator
74HC/HCT5555
APPLICATION INFORMATION
MBA333
14
handbook, halfpage
g
max.
fs
(mA/V)
12
R
= 560 kΩ
bias
typ.
handbook, halfpage
10
8
V
CC
min.
0.47 µF
100 F
µ
output
input
6
v
i
i
A
o
(f = 1 kHz)
4
GND
MGA645
2
0
1
2
3
4
5
6
V
(V)
CC
Fig.12 Typical forward transconductance gfs as a
function of the supply voltage at VCC at
Fig.11 Test set-up for measuring forward
transconductance gfs = dio/dvi at vo is
constant (see Fig.12) and MR = LOW.
T
amb = 25 °C.
MGA647
5
10
handbook, halfpage
f
osc
(Hz)
handbook, halfpage
R
MR (from logic)
t
4
10
C
t
1
RS
3
R
2
C
3
10
TC
TC
R
C
t
C2
R2
2
t
10
MGA646
10
10
3
4
5
6
10
10
10
10
R
(
)
10
10
Ω
t
– 4
– 3
– 2
– 1
10
C ( µF)
Typical formula for oscillator frequency:
t
1
fosc
=
-------------------------------
2.5 × Rt × Ct
Ct curve at Rt = 100 kΩ; R2 = 200 kΩ.
Rt curve at Ct = 1 nF; R2 = 2 x Rt.
RC oscillator frequency as a function of Rt and Ct
at VCC = 2 to 6 V; Tamb = 25 °C.
Fig.13 Application information.
Fig.14 Example of an RC oscillator.
September 1993
20
Philips Semiconductors
Product specification
Programmable delay timer with oscillator
74HC/HCT5555
Timing Component Limitations
Start-up Using External Clock
Termination of the Timing Pulse
The oscillator frequency is mainly
determined by RtCt, provided R2 ≈
2Rt and R2C2 << RtCt. The function
of R2 is to minimize the influence of
the forward voltage across the input
protection diodes on the frequency.
The stray capacitance C2 should be
kept as small as possible. In
consideration of accuracy, Ct must be
larger than the inherent stray
capacitance. Rt must be larger than
the “ON” resistance in series with it,
which typically is 280 Ω at
The start of the timing pulse is
initiated directly by the trigger pulse
(asynchronously with respect to the
oscillator clock). Triggering on a clock
HIGH or clock LOW results in the
following:
The end of the timing pulse is
synchronized with the falling edge of
the oscillator clock. The timing pulse
may lose synchronization under the
following conditions:
• high clock frequency and large
number of stages are selected.
This depends on the dynamic
relationship that exists between the
clock frequency and the ripple
through delay of the subsequent
stages.
• clock = HIGH; the timing pulse may
be lengthened by a maximum of
tW/2 (tW = clock pulse width)
• clock = LOW; the timing pulse may
be shortened by a maximum of tW/2
(tW = clock pulse width).
V
CC = 2 V, 130 Ω at VCC = 4.5 V and
This effect can be minimized by
selecting more delay stages. When
using only one or two delay stages, it
is recommended to use an external
time base that is synchronized with
the negative-edge of the clock.
Synchronization
100 Ω at VCC = 6 V. The
When frequencies higher than those
specified in the Table
recommended values for these
components to maintain agreement
with the typical oscillation formula are:
'Synchronization limits' are used, the
termination of timing pulse will lose
synchronization with the falling edge
of the oscillator. The unsynchronized
timing pulse introduces errors, which
can be minimized by increasing the
number of stages used e.g. a 20 MHz
clock frequency using all 24 stages
will result in a frequency division of
16 777 225 instead of 16 777 216, an
error of 0.0005%.
Ct > 50 pF, up to any practical value,
10 kΩ < Rt < 1 MΩ.
Start-up Using RC Oscillator
In order to avoid start-up problems,
Rt >> 1 kΩ.
The first clock cycle is ≈35% of a time
period too long. This effect can also
be minimized by selecting more delay
stages.
Typical Crystal Oscillator
In Fig.15, R2 is the power limiting
resistor. For starting and maintaining
oscillation a minimum
Start-up Using Crystal Oscillator
A crystal oscillator requires at least
two clock cycles to start-up plus an
unspecified period (ms) before the
amplitude of the clock signal
increases to its expected level.
Although this device also operates at
lower clock amplitudes, it is
recommended to select the
continuously running mode
The amount of error increases at high
clock frequencies as the number of
stages decrease. A clock frequency
of 40 MHz and 4 stages selected
results in a division of 18 instead of
16, a 12.5% error. Application
example:
transconductance is necessary, so
R2 should not be too large. A practical
value for R2 is 2.2 kΩ. Above 14 MHz
it is recommended replacement of R2
by a capacitor with a typical value of
35 pF.
Accuracy
• If a 400 ns timing pulse was
required it would be more accurate
to utilize a 5 MHz clock frequency
using 1 stage or a 10 MHz clock
frequency using 2 stages (due to
synchronization with falling edge of
the oscillator) than a 40 MHz clock
frequency and 4 stages
Device accuracy is very precise for
long time delays and has an accuracy
of better than 1% for short time delays
(1% applies to values ≥ 400 ns).
Tolerances are dependent on the
external components used, either RC
network or crystal oscillator.
(OSC CON = HIGH) to prevent
start-up delays.
(synchronization is lost).
September 1993
21
Philips Semiconductors
Product specification
Programmable delay timer with oscillator
74HC/HCT5555
RS to Q propagation delay is some
graph shows that the minimum
Minimum Output Pulse Width
what longer, resulting in inaccurate
outputs for extremely short pulses.
The propagation delays are listed in
the section 'AC Characteristics'. With
these numbers it is possible to
calculate the maximum deviation (an
example is shown in Fig.16).
Figure 16 is valid for an external clock
where the trigger is synchronized to
the falling edge of the clock only. The
programmed pulse width of 100 ns is:
The minimum output pulse width is
determined by the minimum clock
pulse width, plus the maximum
propagation delay of A, B to Q. The
rising edge of Q is dominated by the
A, B to Q propagation delay, while the
falling edge of Q is dominated by RS
to Q propagation delay. These
• minimum of 4% too long
• typically 7% too long
• maximum of 10% too long.
propagation delays are not equal. The
SYNCHRONIZATION LIMITS
NUMBER OF STAGES SELECTED
CLOCK FREQUENCY (TYPICAL)
1
18 MHz
14 MHz
11 MHz
9.6 MHz
8.3 MHz
7.3 MHz
6.6 MHz
6 MHz
2
3
4
5
6
7
8
.
.
17
18
19
20
21
22
23
24
3.2 MHz
3.0 MHz
2.9 MHz
2.8 MHz
2.7 MHz
2.6 MHz
2.5 MHz
2.4 MHz
September 1993
22
Philips Semiconductors
Product specification
Programmable delay timer with oscillator
74HC/HCT5555
handbook, halfpage
MR (from logic)
1
RS
R
2
TC
R
bias
100 kΩ to 1 MΩ
R2
2.2 kΩ
22 to
37 pF
C3
C2
100 pF
MLB336
Fig.15 External components configuration for a crystal oscillator.
MGA648
40
36
32
28
24
20
16
12
8
max. expected
typ. expected
min. expected
4
0
0
100
200
300
400
500
600
programmed time (ns)
Fig.16 Graphic representation of short time delay accuracy; one stage selected; VCC = 4.5 V.
PACKAGE OUTLINES
See “74HC/HCT/HCU/HCMOS Logic Package Outlines”.
September 1993
23
相关型号：
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