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1
Standard ICs
CR timer
BA225 / BA225F / BA235 / BA226 / BA226F / BA236
The BA225, BA225F, BA235, BA226, BA226F, and BA236 are monolithic ICs having independent monostable multivibrator circuits which consume very low current (0.75mA typ.). Using external resistors and capacitors, the timing
control time can be set within a range from 0.01ms to 100ms.
As the BA225, BA225F, and BA235 are triggered at the rising edge of the signal, they have no trigger input differentiating circuit and can be used in measuring instruments, control devices, digital data systems and other equipment as
sub-compact attachments. The BA226, BA226F, and BA236 are available as falling edge trigger types.
•
Block diagram
OUT1
CR1
TRIGGER1
4
GND
3
2
1
5
6
7
8
V
CC
OUT2
CR2
TRIGGER2
O
T
CR
O
T
CR
1
VCC
OT
CR
V
CC
VCC
GND
2
OUT1
3
CR1
4
TRIGGER1
5
GND
6
TRIGGER2
7
CR2
8
OUT2
9
VCC
OT
CR
BA225 / BA225F
BA226 / BA226F
BA235 / BA236
•
Applications
Delay timers
Monostable multivibrator (ideal for VCR system controllers)
Pulse generators
•
Features
1) As these are edge trigger types (BA225 / BA235: ris-
ing edge trigger types, BA226 / BA236: falling edge
trigger types), there is no need for an input differentiating circuit.
2) The dual type design enables delay timer configura-
tion.
3) Fewer attachments are required.
4) Current dissipation is as low as 0.75mA for each cir-
cuit.
5) Uniformity in the supply current between high and
low output states simplifies the design of the power
supply section.
6) Wide operating power supply voltage range of 4.0V
to 16V.
7) The BA235 and BA236 pin assignments are symmetrical, allowing reverse insertion.
8) Hysteresis in the input results in a high level of noise
withstand resistance.
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Standard ICs BA225 / BA225F / BA235 / BA226 / BA226F / BA236
•
Absolute maximum ratings (Ta = 25°C)
Parameter Symbol Limits Unit
Power supply voltage V
CC 16 V
Power
dissipation
BA225 / BA226
BA235 / BA236
BA225F / BA226F
Pd
800
∗
1
950
∗
2
450
∗
3
mW
mW
mW
Operating temperature Topr °C– 20 ~ + 75
Storage temperature Tstg °C– 55 ~ + 125
∗
1 Reduced by 8mW for each increase in Ta of 1°C over 25°C.
∗
2 Reduced by 9.5mW for each increase in Ta of 1°C over 25°C.
∗
3 Reduced by 4.5mW for each increase in Ta of 1°C over 25°C.
•
Electrical characteristics (unless otherwise noted, Ta = 25°C, VCC = 5V)
BA236
Parameter Symbol Min. Typ. Max. Unit Conditions
Measurement
circuit
Operating power supply voltage 4.0 5.0 16.0 V — Fig.7
Quiescent current I
Q — 1.5 3.0 mA — Fig.7
Timing accuracy T
ERR — 10 % Fig.7
Timing change with power supply T
DS — 0.5 3.0 % 5V➝16V Fig.7
Timing change with temperature T
OT — 200 — — Fig.7
Trigger voltage V
T
1.0 2.0 3.0
V
∗
2
Fig.7
0.7 1.6 2.5
Trigger current I
T — 70 200 µA Fig.7
Output low level voltage V
OL — 0.5 1.0 V Fig.7
Output high level voltage V
OH 3.0 4.0 — V Fig.7
V
CC
1
R = 100kΩ, C = 0.1µF
∗
1
VT = 3.0V (BA225 / BA235)
V
T = 2.5V (BA226 / BA226F / BA236)
ppm / °C
∗
1 One-shot cycle T = 0.5 CR
∗
2 With input hysteresis (hysteresis width ⱌ 200 to 600mV)
ISINK = 5mA
I
SOURCE = 5mA
•
Electrical characteristic curves
4
3
"H" output
"L" output
2
1
0
QUIESCENT CURRENT: IO (mA)
POWER SUPPLY VOLTAGE: VCC (V)
04 1282016
Fig. 1 Quiescent current vs. power
supply voltage
2.0
1.0
0
SATURATION VOLTAGE: VOL (V)
SINK CURRENT: ISINK (mA)
04 1282016
VCC = 5V
Fig. 3 Output voltage (logic 0
side) characteristics
3.2
2.4
V
CC = 5V
1.6
0.8
2.8
2.0
1.2
0.4
0
SATURATION VOLTAGE: VCC—VOH (V)
SOURCE CURRENT: ISOURCE (mA)
04 1282016
Fig. 2 Output voltage (logic 1
side) characteristics
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Standard ICs BA225 / BA225F / BA235 / BA226 / BA226F / BA236
1.010
1.000
C = 0.01µF
R = 100kΩ
0.990
0.980
1.005
0.995
0.985
0
DELAY TIME NORMALIZED: td
POWER SUPPLY VOLTAGE: VCC (V)
04 1282016
Fig. 4 Power supply voltage vs.
delay time
10
0.001
CAPACITANCE: C (µF)
1.0
0.1
0.01
TIMING PERIOD: T (ms)
0.01 0.1 101100
10k
Ω
100k
Ω
1M
Ω
Fig. 6 One-shot time
characteristics
AMBIENT TEMPERATURE: Ta (°C)
– 25 0 5025 75
VCC = 5V
C = 0.01µF
R = 100kΩ
1.010
1.015
1.020
1.000
0.990
0.980
1.005
0.995
0.985
DELAY TIME NORMALIZED: td
Fig. 5 Temperature vs.
delay time
•
Measurement circuit
VCC
CR
mA
PG
BA225
BA225F
BA235
GND
S3
5mA5mA
D.V
µA
D.V
Counter
OUTIN
S
1
S0
OFF
ON
V
CC
S2
0.1µF
100kΩ
Fig. 7
•
Attached components
(1) Timing capacitors (Pins 2 and 6)
Connected between these pins and the ground (GND),
this capacitor determines the one-shot period. We recommend using a capacitor with a value greater than
1000pF. The one-shot cycle is determined by T = 1 / 2
C • R.
(2) Timing resistor (Pins 2 and 6)
Connected to the power supply line, these resistors
determine the one-shot period. The timing capacitor is
charged through this resistor. The recommended range
for the timing resistor is 10kΩ to 1MΩ.
(3) Power supply capacitor (Pin 8)
Connect a 0.02µF capacitor between the power supply
pin and the ground (GND) so as to prevent malfunction
resulting from a rise in the impedance of the power
supply line.
(4) Load (Pins 1 and 7)
A load of up to 5mA can be accommodated for both the
inflow current and the outflow current.
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Standard ICs BA225 / BA225F / BA235 / BA226 / BA226F / BA236
•
Operation notes
(1) Usage range for voltage
The recommended voltage range is 4.0V to 16V. Use
of these ICs at 3.0V or lower voltage may cause the
same mode as the input trigger signal to be output at
around 2.6V.
(2) Input trigger
The input trigger level is 2.0V. The LOW level is 1.0V
or lower and the HIGH level is 3.0 V or higher. Trigger
signals of 10ms / V or lower should be used for both
the rising and falling edges.
(3) Time constant determining C • R
The recommended value for the timing capacitor is
1000pF or more and that for the timing resistor is from
10kΩ to 1MΩ.
The voltage, which is determined by comparison of discharge resistance and the timing resistance in the IC,
remains on the CR pins. If timing resistance is set at
5kΩ or less, this voltage will reach threshold level (0.4
× V
CC), and operation will come to a halt. Also, when
timing resistance is set to a low value, voltage remains
on the CR pins, which shortens the time constant. If
timing resistance is set to 2MΩ or higher, the IC's internal comparator cannot be driven, which may bring
operation to a halt.
(4) Note that pin connections and pin arrangements on
the BA225 / BA226 (BA235F / BA226F) differ from
those on the BA235 / BA236.
•
Application example
Figure 8 shows an example of the circuit including
these ICs, while Figure 9 shows the basic operation
timing chart. Figure 10 shows the basic operation timing chart of the falling edge trigger type IC. When no
trigger signal is applied, the output is in the LOW state
and the timing capacitor is in the discharged state.
When a trigger signal is applied, its rising edge causes
the output to become HIGH and the timing capacitor to
be charged.
The charging time of this timing capacitor is determined
by the time constants of the external timing resistor and
the timing capacitor. When the charged voltage reaches 0.4 × V
CC, the flip-flop in the IC is reset and the out-
put state changes from HIGH to LOW. At the same
time, the timing capacitor is discharged to be ready for
the next operation.
CR
M. M2
0T
CR
GND
BA225
BA226
BA225F
BA226F
VCC
VCC
1234
0.1µF
C
V
CC = 5V
R
100kΩ
C
8765
0.02µF
V
CC
OUT2
OUT1
100kΩ
R
M. M1
0T
Fig. 8
0.1µF
Page 5
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Standard ICs BA225 / BA225F / BA235 / BA226 / BA226F / BA236
•
Application examples
Rising edge trigger
Trigger input
CR pin
Output
T
One-shot cycle: T ⱌ 0.5 CR
0.4V
CC
Fig. 9 Basic operation timing chart
(Rising edge trigger)
Falling edge trigger
Trigger input
CR pin
Output
T
One-shot cycle: T ⱌ 0.5 CR
0.4V
CC
Fig. 10 Basic operation timing chart
(Falling edge trigger)
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Standard ICs BA225 / BA225F / BA235 / BA226 / BA226F / BA236
•
External dimensions (Units: mm)
DIP8 SIP9
SOP8
BA225 / BA226 BA235 / BA236
BA225F / BA226F
2.54
10.5 ± 0.5
3.5 ± 0.5
1
1.2
5.8 ± 0.2
0.6
9
0.3 ± 0.1
0.8
1.3
21.8 ± 0.2 2.8 ± 0.2
0.4 ± 0.11.27
0.15
0.3Min.
0.15 ± 0.1
0.11
6.2 ± 0.3
4.4 ± 0.2
5.0 ± 0.2
85
41
1.5 ± 0.1
0.5 ± 0.1
3.2 ± 0.2 3.4 ± 0.3
85
14
9.3
± 0.3
6.5 ± 0.3
0.3
±
0.1
0.51Min.
2.54
0° ~ 15°
7.62
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