M5295AFP データシートの表示（PDF） - Renesas Electronics

部品番号

コンポーネント説明

メーカー

M5295AFP

Watchdog Timer

Renesas Electronics 

M5295AL/AP/AFP

Application Example

M5295A

12345678

Clock

RST1

(RESET)

MCU/MPU

RST2

(HOLD)

VDD

Figure 8 Application Example

Notice for Use

1. When malfunction occurs due to noise or order related trouble, connect capacitance of approximately 1000 pF

between pin (5) and GND as well as pin (8) and GND to stabilize operation.

2. To adjust detection voltage, add resistance of 15 kΩ or less to both VCC and GND via adjusting pins. (Set detection

voltage to no less than 3 V.)

3. Set tWD and tRST(2) as shown below:

110 µs ≤ tWD ≤ 1.1 s

8.3 µs ≤ tRST(2) ≤ 83 ms

10 kΩ ≤ R1 ≤ 30 kΩ

4. Input clock pulses to pin (1) via capacitor. To determine capacitance, refer to “Relationship between input pulse

width and input capacitance Cin”.

Backup power supply

M5295A

10kΩ 3.5V

R4

12345678

R3

VCC

RESET output

To System

Backup switching voltage VTH2(L) Switching voltage calculation formula

VTH2(L) =

R03 + R04

R04

× 1.24 (V)

R03 = R3 // 51.2kΩ

R04 = R4 // 18.8kΩ

Note: Set backup switching voltage to be more than or equal to backup supply voltage.

Figure 9 Example of Backup Circuit with M5295AL

REJ03D0780-0200 Rev.2.00 Jun 15, 2007

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