HA16113FPJ Datasheet, PDF (9/18 Pages) Hitachi Semiconductor – Dual Watchdog Timers

HA16113FPJ
External Circuit Constant Calculations
Equations for the various functions are given below. C_R1 and Cf1 are for RES1. C_R2 and Cf2 are for RES2. (Values
given in equations are for reference.)
Item
Equation
Regulated
output voltage
Vout
=
0.388 ×
Re2
Re1
+
2.63
Remarks
If the desired Vout is 5 V
± 2.5%, recommended
values are Re1 = 1.5 kΩ
and Re2 = 9.1 kΩ
Vout
HA16113FPJ
Short-circuit
detection
voltage
V_CS < Iout × R_CS
When this function
operates, V_CONT stops
drawing current from the
base of the external
transistor, so Vout output
stops
Re1 Re2
Iout
R CS
V_CC C _S V _C Vout
Re1 Re2 GND
Maximum Vout Max < 7.0 V
output voltage
t_RH, t_RL (for
both RES1
and RES2)
t_RH = 3.2 × C_R × R’
t_RL = 1.1 × C_R × R’
R’ = ¹
1 ₊₁
Rf R_R
Prevents microprocessor damage that would result if
the output voltage were raised too high by mistake.
The maximum output voltage is fixed.
Determines the
frequency and duty cycle
of the reset pulse
RES
t_RL
t_RH
t_ON (for both
RES1 and
RES2)
t_ON = 2.2 × C_R × Rf
Sets the time from the _Vout
rise of Vout to the
clearing of RES output
t_ON
RES
t_OFF (for both
RES1 and
RES2)
tr, t_RES (for
both RES1
and RES2)
t_OFF = 6.1 ×C _R × R’
R’ =
1
1
+1
Rf R_R
t_r = 0.75 × C_RES × Rf
t_RES = 0.625 × C_RES × Rf
Sets the time from when _P-RUN
P-RUN pulses stop until
the reset pulse is output
RES
t_OFF
tr sets the time from the rise of NMI to the rise of
RES, when Vout drops by more than the STBY trigger
voltage, then recovers. t_RES is the time from the fall of
NMI to the fall of RES.
Vout
4.65 V (typ)
4.6 V (typ)
NMI
RES
t_r
t_RES
9