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Fujitsu MB3773 - page 1
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. It is IC f or the power-supply v oltage watch and “P ower on reset” is generated ...
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Fujitsu MB3773 - page 2
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) (FRONT VIEW) ...
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Fujitsu MB3773 - page 3
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.S ...
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Fujitsu MB3773 - page 4
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. Instantaneous breaks or drops in the pow er can be detected as abnor mal conditions by the MB3773 ...
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Fujitsu MB3773 - page 5
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 = 0.1 µ F T RR (ms) : = 100 (ms) T WD (ms ...
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Fujitsu MB3773 - page 6
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. At this time, the output is being reset. (3) When C T begins charging ...
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Fujitsu MB3773 - page 7
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.) in e xcess of absolute maximum ratings. Do not e xceed these ratings. ■ ■ ■ ■ RECOMMENDED OPERA TING CONDITIONS W ARNING: The recommended operating conditions are re ...
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Fujitsu MB3773 - page 8
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 4.10 4.20 4.30 V Ta = − 40 ° C to + 85 ° C 4.05 4.20 4.35 V SH V CC 4.20 4.30 4.40 Ta = − ...
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Fujitsu MB3773 - page 9
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 3.0 µ s CK input frequency T CK 20 µ s Watch dog timer watchi ...
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Fujitsu MB3773 - page 10
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 2.0 10.0 12.0 14.0 16.0 4.0 6.0 8.0 18.0 100 Ta = − 40 ° C Ta = + 25 ° ...
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Fujitsu MB3773 - page 11
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 1.234 0 3. 0 5. 0 7. 0 9. 0 13.0 11. 0 17. 0 19. 0 21.0 15.0 Ta = − 40 ° C Ta = + 25 ° C Ta ...
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Fujitsu MB3773 - page 12
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 = 0.1 µ F V C C = 5 V 10 6 10 5 10 4 10 3 10 2 10 1 10 0 10 − 1 10 − 2 10 − 3 10 − 3 10 − 2 10 − 1 10 0 10 1 10 2 Ta = − 40 ° C Ta = + 25 ° C + 85 ° C 10 − 3 10 − 2 10 − ...
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Fujitsu MB3773 - page 13
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 . • Detection voltage are V SH and V SL . C T 1 2 3 4 8 7 6 5 EXAMPLE 2: 5V Supply Voltage Monitoring (external fine-tuning type) V CC (5V) 1 2 ...
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Fujitsu MB3773 - page 14
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. SW V CC 1 2 3 4 8 7 6 5 MB3773 RESET RESET CK GND Logic circuit Note : Feeding the signal to terminal RESIN and turning on Tr sets the ...
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Fujitsu MB3773 - page 15
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 5.1 k Ω R 2 1.2 k Ω R 1 4.7 k Ω R 5 Comp. 1 Notes : • The 5 V supply voltage i ...
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Fujitsu MB3773 - page 16
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 5.1 k Ω R 2 1.2 k Ω R 1 4.7 k Ω R 5 Comp. 1 Notes : • When either 5 V or 12 V supply v ...
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Fujitsu MB3773 - page 17
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 1.2 k Ω R 1 4.7 k Ω R 5 Comp. 1 Notes : • Comp. 1 and Comp. 2 are used to monitor for overv ...
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Fujitsu MB3773 - page 18
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). C 1 V CC 5V 4V C T ...
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Fujitsu MB3773 - page 19
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. • The watch-dog tim ...
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Fujitsu MB3773 - page 20
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 C T MB3773 RESET RESET CK GND Logic circuit R 2 =1 k Ω HALT R 1 =51 k Ω ...
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Fujitsu MB3773 - page 21
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. • Standard T PR , T WD and T WR value can be found using the following fo ...
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Fujitsu MB3773 - page 22
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. • Example : R 1 = R 2 = 2.2 k Ω C T = 0.1 µ F RESET RESET CK GND RESET RESE ...
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Fujitsu MB3773 - page 23
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 . When ev en one signal ...
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Fujitsu MB3773 - page 24
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. (Th ...
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Fujitsu MB3773 - page 25
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. - When storing or carr ying a printed circuit board after chip mounting, put it in a conductive ...
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Fujitsu MB3773 - page 26
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 0.99 1.52 +0.30 –0 +.014 –.012 .035 .370 –.012 +.016 .060 –0 +.012 +.012 –0 .039 4.36(. ...
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Fujitsu MB3773 - page 27
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. Dimensions in mm (inches) . Note : The values in ...
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Fujitsu MB3773 - page 28
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 .774 .039 –0 +.012 +.012 –0 .060 2.54(.100) TYP 0.50±0.08 (.020±.003) 4.00±0.30 (.157±.0 ...
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Fujitsu MB3773 - page 29
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. The information, such as descriptions of function and application circuit examples, in this document are presented solely for the purpose of reference to ...
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