M62050 Ver la hoja de datos (PDF) - Renesas Electronics

Número de pieza

componentes Descripción

Fabricante

M62050

3 V Supply System Reset with Watchdog Timer

Renesas Electronics 

M62050P/FP

Operating Description

Timing Chart 1 (When the delay capacitor is not connected with Ct1 pin)

VCC

VTH1

VTH2(H)

VTH1(H)

0V

VTH3(H)

TC VTH3(L)

0V

VTH2(L)

VTH1(L)

WD

0V

RST1

Power ON

reset timer

0V

RST2

0V

tRST(1)

tWD

tRST(2)

(1)(2)(3)

(4) (5)

(6)

(7) (8)

(9) (10) (11)

(1): The VCC rises up to 0.8 V, then RST1 and RST2 generates low output, and rising up to 2.2 V(VTH1(H)), charge

of C1 begins.

(2): The VCC rises up to 2.5 V(VTH2(H)), then RST2 generates high.

(3), (4): The voltage at TC pin is 1.2 V(VTH3(L) = 2/5 VCC), then RST2 generates high, when 2.4 V(VTH3(H) = 4/5 VCC),

C1 is discharged and RST1 generates low.

(5): The voltage at TC pin falls to 1.2 V, then RST1 generates high unless normal clock signal is entered to WD

pin, RST1 repeats this operation.

(6), (7): Before the voltage at TC pin reaches 4 V, if normal clock signal is entered to WD pin, low RST1 is canceled.

(8), (9): In the case of entrance of abnormal signal input, as the waveform of TC pin repeats charge and discharge of

RST1 alternatively, the RST1 repeats high and low output operation.

(10): The VCC falls to 2.5 V(VTH2(L)), then RST2 generates low, this detective voltage has a 50 mV hysteresis.

(11): When VCC goes down to 2.2 V(VTH1(L)), the status of TC pin is switched to discharge. When the potentional at

TC pin is detected being VTH3(H) or VTH3(L), the status of RST1 becomes "low".

(This detective voltage has a 50 mV hysteresis.)

Terminology

tRST(1) : Time required for TC pin potential to rise from 0 V VTH3(L) when VCC is being applied.

tWD : Time required for TC pin potential to rise from VTH3(L) to VTH3(H).

tRST(2) : Time required for TC pin potential to go down from VTH3(H) to VTH3(L).

tdRST(1) : Time required for delay of charge with TC pin when VCC is impressed by connecting capacitor with Ct1 pin between GND.

Figure 1 Timing Chart 1

REJ03D0786-0200 Rev.2.00 Jun 15, 2007

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