Instruction/ maintenance manual of the product 3773 Fujitsu
Go to page of 29
DS04-27401-7E FUJITSU SEMICONDUCT OR DA T A S H E E T ASSP P o wer Suppl y Monitor with W atc h-Dog Timer MB3773 ■ DESCRIPTION MB3773 generates the reset signal to protect an arbitrary system when the power-supply v oltage momentarily is intercepted or decreased.
MB3773 2 ■ ■ ■ ■ PIN ASSIGNMENT C T RESET CK GND RESET V S V REF V CC 1 2 3 4 8 7 6 5 C T RESET CK GND RESET V S V REF V CC 1 2 3 4 8 7 6 5 (TOP VIEW) (SIP-8P-M03) (DIP-8P-M01) (FPT-8P-M01) (F.
MB3773 3 ■ ■ ■ ■ BLOCK DIA GRAM C T + _ + _ 8 2 7 3 1 4 5 GND RESET V S V CC R S Q : = 1.24 V : = 40 k Ω : = 1.24 V : = 10 µ A : = 1.2 µ A : = 100 k Ω Watch Dog Timer P.G + _ Reference Voltage Generator + _ Reference AMP. V REF 6 COMP.O RESET : = 10 µ A Inhibit CK COMP.
MB3773 4 ■ ■ ■ ■ FUNCTIONAL DESCRIPTIONS Comp .S is comparator including hysteresis . it compare the reference v oltage and the voltage of Vs, so that when the v oltage of Vs ter minal f alls below appro ximately 1.23 V , reset signal outputs.
MB3773 5 RESET V CC V SH V SL 0.8 V CK C T T CK T PR T WD T WR T PR (1) (2) (3) (4)(5) (5) (6) (7) (8) (9) (10) (11) (12) • • • • MB3773 Basic Operation V CC RESET RESET CK Logic Circuit T PR (ms) : = 1000 · C T ( µ F) T WD (ms) : = 100 · C T ( µ F) T WR (ms) : = 20 · C T ( µ F) Example : C T = 0.
MB3773 6 ■ ■ ■ ■ OPERA TION SEQUENCE (1) When Vcc rises to about 0.8 V , RESET goes “Low” and RESET goes “High”. The pull-up current of appro ximately 1 µ A (Vcc = 0.8 V) is output from RESET . (2) When Vcc rises to V SH ( : = 4.3V) , the charge with C T star ts.
MB3773 7 ■ ■ ■ ■ ABSOLUTE MAXIMUM RA TINGS W ARNING: Semiconductor de vices can be per manently damaged by application of stress (v oltage, current, temperature , etc.
MB3773 8 ■ ■ ■ ■ ELECT ORICAL CHARA CTERISTICS (1) DC Characteristics ( V CC = 5 V, Ta = + 25 ° C) P arameter Symbol Condition Va l u e Unit Min T yp Max Supply current I CC Watch dog timer operating 600 900 µ A Detection voltage V SL V CC 4.
MB3773 9 (2)A C Characteristics ( V CC = 5 V, Ta = + 25 ° C) * : Output rising/falling time are measured at 10 % to 90 % of v oltage. P arameter Symbol Condition Va l u e Unit Min T yp Max V CC input pulse width T PI V CC 8.0 µ s CK input pulse width T CKW CK 3.
MB3773 10 ■ ■ ■ ■ TYPICAL CHAR A C TERISTIC CU R V ES (Conti n ued) 6.0 5.0 4.0 3.0 2.0 1.0 0 1. 0 2. 0 3. 0 4. 0 5. 0 6. 0 7.0 Ta = + 85 ° C Ta = + 25 ° C Ta = − 40 ° C 4.50 4.44 4.30 4.20 4.10 4.00 − 4 0 − 2 0 0 2 0 4 0 6 0 8 0 100 V SH V SL 400 300 200 0 2.
MB3773 11 (Conti n ued) Ta = + 25 ° C Ta = + 85 ° C Ta = − 40 ° C C T = 0.1 µ F 5.0 4.5 4.0 0 − 5 − 1 0 − 15 5.0 4.5 4.0 0 − 5 − 1 0 − 15 C T = 0.1 µ F Ta = + 25 ° C Ta = + 85 ° C Ta = − 40 ° C 1.246 1.244 1.242 1.240 1.238 1.236 1.
MB3773 12 (Conti n u ed) 3 2 1 0 − 4 0 − 2 0 20 0 4 0 6 0 8 0 100 C T = 0.1 µ F V CC = 5 V − 4 0 − 2 0 20 0 4 06 08 0 1 0 0 16 14 12 10 8 6 4 0 C T = 0.
MB3773 13 ■ ■ ■ ■ APPLICA TION CIRCUIT EXAMPLE 1: Monitoring 5V Supply Voltage and Watchdog Timer VCC (5V) MB3773 RESET RESET CK GND Logic circuit Notes : • Supply voltage is monitored using V S .
MB3773 14 EXAMPLE 3: With Forced Reset (with reset hold) V CC 1 2 3 4 8 7 6 5 MB3773 RESET RESET CK GND Logic circuit Note : Grounding pin 7 at the time of SW ON sets RESET (pin 8) to Low and RESET (pin 2) to High.
MB3773 15 EXAMPLE 4: Monitoring Two Supply Voltages (with hysteresis, reset output and NMI ) V CC1 (5 V) 1 2 3 4 8 7 6 5 MB3773 RESET RESET CK GND Comp. 2 Example : Comp. 1, Comp. 2 : MB4204, MB47393 NMI or port R 6 + _ + _ V CC2 (12 V) 180 k Ω R 4 30 k Ω R 3 5.
MB3773 16 EXAMPLE 5: Monitoring Two Supply Voltages (with hysteresis and reset output) V CC 1 (5 V) 1 2 3 4 8 7 6 5 MB3773 RESET RESET CK GND Comp. 2 Example : Comp. 1, Comp. 2 : MB4204, MB47393 20 k Ω R 6 + _ + _ V CC2 (12 V) 180 k Ω R 4 30 k Ω R 3 5.
MB3773 17 EXAMPLE 6: Monitoring Low voltage and Overvoltage Monitoring (with hysteresis) V CC (5 V) 1 2 3 4 8 7 6 5 MB3773 RESET RESET CK GND Comp. 2 Example : Comp. 1, Comp. 2 : MB4204, MB47393 20 k Ω R 6 _ + 180 k Ω R 4 30 k Ω R 3 5.6 k Ω R 6 1.
MB3773 18 EXAMPLE 7: Monitoring Supply Voltage Using Delayed Trigger V CC 1 2 3 4 8 7 6 5 MB3773 RESET RESET CK GND Logic circuit Note : Adding voltage such as shown in the figure to V CC increases the minimum input pulse width by 50 µ s (C 1 = 1000 pF).
MB3773 19 (Continued) EXAMPLE 8: Stopping Watch-dog Timer (Monitoring only supply voltage) (a) Using NPN transistor These are example application circuits in which the MB3773 monitors supply voltage alone without resetting the microprocessor even if the latter, used in standby mode, stops sending the clock pulse to the MB3773.
MB3773 20 (Continued) (c) Using NPN transistor V CC (5 V) 1 2 3 4 8 7 6 5 C T MB3773 RESET RESET CK GND Logic circuit R 2 =1 k Ω HALT R 1 =1 M Ω (d) Using PNP transistor V CC (5 V) 1 2 3 4 8 7 6 5.
MB3773 21 EXAMPLE 9: Reducing Reset Hold Time V CC ( = 5 V) 1 2 3 4 8 7 6 5 C T MB3773 RESET RESET CK GND Logic circuit (a) T PR reduction method V CC ( = 5 V) 1 2 3 4 8 7 6 5 C T MB3773 RESET RESET CK GND Logic circuit Notes : • RESET is the only output that can be used.
MB3773 22 EXAMPLE 10: Circuit for Monitoring Multiple Microprocessor V CC ( = 5 V) 1 2 3 4 8 7 6 5 C T MB3773 RESET RESET CK GND Notes : • connects from FF1 and FF2 outputs Q 1 and Q 2 to the NOR input. • Depending on timing, these connections may not be necessary.
MB3773 23 Description of Application Circuits Using one MB3773, this application circuit monitors multiple microprocessor in one system. Signals from each microprocessor are sent to FF1, FF2 and FF3 clock inputs . Figure 2 shows these timings . Each flip-flop operates using signals sent from microprocessor as its clock pulse .
MB3773 24 CR T 1 0.01 µ F1 0 k Ω 30 µ s 0.1 µ F1 0 k Ω 300 µ s EXAMPLE 11: Circuit for Limiting Upper Clock Input Frequency Notes : • This is an example application to limit upper frequency f H of clock pulses sent from the microprocessor. If the CK cycle sent from the microprocessor exceeds f H , the circuit generates a reset signal.
MB3773 25 ■ ■ ■ ■ NO TES ON USE • T ak e account of common impedance when designing the ear th line on a pr inted wir ing board. • T ak e measures against static electr icity . - F or semiconductors, use antistatic or conductiv e containers.
MB3773 26 ■ ■ ■ ■ P A CKA GE DIMENSIONS (Continued) 8-pin plastic DIP (DIP-8P-M01) Dimensions in mm (inches) . Note : The values in parentheses are reference values. C 1994 FUJITSU LIMITED D08006S-2C-3 0.89 +0.35 –0.30 –0.30 +0.40 9.40 –0 0.
MB3773 27 (Continued) 8-pin plastic FPT (FPT-8P-M01) Note 1 : *1 : These dimensions include resin protrusion. Note 2 : *2 : These dimensions do not include resin protrusion. Note 3 : Pins width and pins thickness include plating thickness. Note 4 : Pins width do not include tie bar cutting remainder.
MB3773 28 (Continued) 8-pin plastic SIP (SIP-8P-M03) Dimensions in mm (inches) . Note : The values in parentheses are reference values. C 1994 FUJITSU LIMITED S08010S-3C-2 1.52 +0.30 –0 INDEX-1 INDEX-2 –0.35 +0.15 19.65 –0 +0.30 0.99 +.006 –.014 .
MB3773 FUJITSU LIMITED All Rights Reserved. The contents of this document are subject to change without notice. Customers are advised to consult with FUJITSU sales representatives before ordering.
An important point after buying a device Fujitsu 3773 (or even before the purchase) is to read its user manual. We should do this for several simple reasons:
If you have not bought Fujitsu 3773 yet, this is a good time to familiarize yourself with the basic data on the product. First of all view first pages of the manual, you can find above. You should find there the most important technical data Fujitsu 3773 - thus you can check whether the hardware meets your expectations. When delving into next pages of the user manual, Fujitsu 3773 you will learn all the available features of the product, as well as information on its operation. The information that you get Fujitsu 3773 will certainly help you make a decision on the purchase.
If you already are a holder of Fujitsu 3773, but have not read the manual yet, you should do it for the reasons described above. You will learn then if you properly used the available features, and whether you have not made any mistakes, which can shorten the lifetime Fujitsu 3773.
However, one of the most important roles played by the user manual is to help in solving problems with Fujitsu 3773. Almost always you will find there Troubleshooting, which are the most frequently occurring failures and malfunctions of the device Fujitsu 3773 along with tips on how to solve them. Even if you fail to solve the problem, the manual will show you a further procedure – contact to the customer service center or the nearest service center
