MB4214 Fujitsu Microelectronics, Inc., MB4214 Datasheet - Page 4

• Manufacturer Part Number: MB4214
• Description: Timer
• Manufacturer: Fujitsu Microelectronics, Inc.

4
MB4214
The MB4214 contains reference voltage circuit, oscillator, divider and comparator as shown in Fig. 1. Oscillator frequency is
arbitrary controlled by external resistor R
Divider consists of 13 stages of divider circuit which is constructed by IIL (Intergrated Injection Logic) technique. It expands the
oscillator period up to 4096times. About 100hours period is achieved by a small capacitor.
Free Running Oscillation (Long period low frequency) is achieved when OSC/FR pin is connected to GND.
START RESISTOR R
R
RESET FUNCTION
Counter operation is interrupted by the instruction of reset pin (7pin). All counter is cleared when this pin is connected to GND.
Power on reset is available by connecting a external capacitor C
OSCILLATOR PERIOD
FREE RUNNING OSCILLATION
Free running oscillation is achieved when OSC/FR pin is connected to GND.
V
After the voltage is applied or reset is released, V
open, first divider data is output.
02
S
is a start resistor which controls zener diode current. Zener current is 20mA max and stability zener voltage 6.2V is generated.
Two kinds of oscillator period selecting ways are provided.
Divide internal reference voltage by external resistor, to be the V
R
Oscillator period is formulated:
Providing V
FUNCTIONAL DESCRIPTIONS
pin outputs 4096times as long as fundamental oscillator frequency.
T
pin voltage and reference voltage has the 2 : 3.5 ratio.
t
POR
t
Note:
Conversion value K = 1
OSC
t
OSC
= 3.5 ____
= K _______
=
S
___
3.5
voltage in other power supply source.
2
R
C
I
RS
T
RS
2
R
C
T
(s)
T
C
S
T
V
_______
R
S
1
(s)
R
+ R
2
2
(s)
T
, capacitor C
02
keeps 2048times as long as fundamental period. When OSC/FR pin is left
T
and V
S
input voltage.
RS
. Power on reset time t
S
voltage.
POR
is formulated: