MB3771PF-G-BND-JNE1

MB3771 Power Supply Monitor Description The Cypress MB3771 is designed to monitor the voltage level of one or two power supplies (+5 V and an arbitrary voltage) in a microprocessor circuit, memory board in large-size computer, for example. If the circuit’s power supply deviates more than a specified amount, then the MB3771 generates a reset signal to the microprocessor. Thus, the computer data is protected from accidental erasure. Using the MB3771 requires few external components. To monitor only a +5 V supply, the MB3771 requires the connection of one external capacitor. The level of an arbitrary detection voltage is determined by two external resistors. The MB3771 is available in an 8-pin Dual In-Line, Single In-Line Package or space saving Flat Package. Features ■ Precision voltage detection (VSA = 4.2 V ± 2.5 %) ■ User selectable threshold level with hysteresis (VSB = 1.23 V ± 1.5 %) ■ Monitors the voltage of one or two power supplies (5 V and an arbitrary voltage, >1.23 V) ■ Usable as over voltage detector ■ Low voltage output for reset signal (VCC = 0.8 V Typ) ■ Minimal number of external components (one capacitor Min) ■ Low power dissipation (ICC = 0.35 mA Typ, VCC = 5 V) ■ Detection threshold voltage has hysteresis function ■ Reference voltage is connectable. ■ One type of package (SOP-8pin : 1 type) Application ■ Industrial Equipment ■ Arcade Amusement etc. Cypress Semiconductor Corporation Document Number: 002-08511 Rev. *D • 198 Champion Court • San Jose, CA 95134-1709 • 408-943-2600 Revised June 28, 2017 MB3771 Contents Description ............................................................................. 1 Features .................................................................................. 1 Application ............................................................................. 1 Contents ................................................................................. 2 1. Pin Assignment ................................................................. 3 2. Block Diagram ................................................................... 3 3. Functional Descriptions .................................................... 4 4. Function Explanation ........................................................ 4 5. Absolute Maximum Ratings ............................................. 5 6. Recommended Operating Conditions ............................. 5 7. Electrical Characteristics .................................................. 6 7.1 DC Characteristics ..................................................... 6 7.2 AC Characteristics ...................................................... 7 8. Application Circuit ............................................................. 8 8.1 5V Power Supply Monitor ........................................... 8 8.2 5V Power Supply Voltage Monitor (Externally Fine-Tuned Type) ........................................... 8 8.3 Arbitrary Voltage Supply Monitor ................................ 9 8.4 5 V and 12 V Power Supply Monitor (2 types of power supply monitor VCC1 = 5 V, VCC2 =12 V) ..................... 10 8.5 5 V and 12 V Power Supply Monitor (RESET signal is generated by 5 V, VCC1 = 5 V, VCC2 = 12 V) ............... 10 8.6 5 V Power Supply Monitor with forced RESET input Document Number: 002-08511 Rev. *D (VCC = 5 V) .................................................................... 11 8.7 5 V Power Supply Monitor with Non-inverted RESET ............................................................................ 11 8.8 Supply Voltage Monitoring with Delayed Trigger ..... 11 8.9 Dual (Positive/Negative) Power Supply Voltage Monitoring (VCC = 5 V, VEE = Negative Power Supply). 12 8.10 Reference Voltage Generation and Voltage Sagging Detection ........................................................................ 12 8.11 Low Voltage and Over Voltage Detection (VCC = 5 V) .................................................................... 14 8.12 Detection of Abnormal State of Power Supply System (VCC = 5 V) .................................................................... 14 8.13 Back-up Power Supply System (VCC = 5 V) ......... 15 9. Typical Characteristics ................................................... 17 10. Notes on Use .................................................................. 19 11. Ordering Information ..................................................... 19 12. RoHS Compliance Information ..................................... 19 13. Package Dimensions ..................................................... 20 Document History ................................................................ 21 Sales, Solutions, and Legal Information ........................... 22 Page 2 of 22 MB3771 1. Pin Assignment (TOP VIEW) CT 1 8 RESET VSC 2 7 VSA OUTC 3 6 VSB RESIN GND 4 5 VCC (SOE008) 2. Block Diagram VCC 5 ≅ 1.24 V ≅ 100 kΩ + + − Comp. A VSA 7 − ≅ 10 μA − + 2 VSC 4 GND + Comp. C + − ≅ 12 μA − ≅ 40 kΩ VSB / RESIN 6 ≅ 1.24 V REFERENCE VOLTAGE R Q Comp. B S 1 CT Document Number: 002-08511 Rev. *D 8 3 RESET OUTC Page 3 of 22 MB3771 3. Functional Descriptions Comparators Comp.A and Comp.B apply a hysteresis to the detected voltage, so that when the voltage at either the VSA or VSB pin falls below 1.23 V the RESET output signal goes to “low” level. Comp. B may be used to detect any given voltage(8.Application Circuit 8.3 : Arbitrary Voltage Supply Monitor), and can also be used as a forced reset pin (with reset hold time) with TTL input (8.Application Circuit 8.6 : 5V Power Supply Monitor with forced RESET input (VCC = 5 V) ). Note that if Comp.B is not used, the VSB pin should be connected to the VCC pin (8.Application Circuit 8.1 : 5V Power Supply Monitor). Instantaneous breaks or drops in the power supply can be detected as abnormal conditions by the MB3771 within a 2 µs interval. However because momentary breaks or drops of this duration do not cause problems in actual systems in some cases, a delayed trigger function can be created by connecting capacitors to the VSA or VSB pin (8.Application Circuit 8.8 : Supply Voltage Monitoring with Delayed Trigger). Because the RESET output has built-in pull-up resistance, there is no need to connect to external pull-up resistance when connected to a high impedance load such as a CMOS logic IC. Comparator Comp. C is an open-collector output comparator without hysteresis, in which the polarity of input/output characteristics is reversed. Thus Comp. C is useful for over-voltage detection (8.Application Circuit 8.11 : Low Voltage and Over Voltage Detection (VCC = 5 V) ) and positive logic RESET signal output (8.Application Circuit 8.7 : 5 V Power Supply Monitor with Non-inverted RESET), as well as for creating a reference voltage (8.Application Circuit 8.10 : Reference Voltage Generation and Voltage Sagging Detection). Note that if Comp. C is not used, the VSC pin should be connected to the GND pin (Application Circuit 1 : 5V Power Supply Monitor). 4. Function Explanation VHYS VS VCC 0.8 V VCC CT 1 2 3 4 8 7 6 5 t RESET TPO RESET TPO t (1) (2) (3) (4) (5) (6) (7) (8) 1. When VCC rises to about 0.8V, RESET goes low. 2. When VCC reaches VS +VHYS, CT then begins charging. RESET remains low during this time 3. RESET goes high when CT begins charging. TPO ≈ CT × 10 5 (Refer to “CT pin capacitance vs. reset hold time” in “9.Typical Characteristics”.) 4. When VCC level drops lower then VS, then RESET goes low and CT starts discharging. 5. When VCC level reaches VS + VHYS, then CT starts charging. In the case of voltage sagging, if the period from the time VCC goes lower than or equal to VS to the time VCC reaches VS +VHYS again, is longer than tPI, (as specified in the 7.2.AC Characteristics), CT is discharged and charged successively. 6. After TPO passes, and VCC level exceeds VS + VHYS, then RESET goes high. 7. Same as Point 4. 8. RESET remains low until VCC drops below 0.8V. Document Number: 002-08511 Rev. *D Page 4 of 22 MB3771 5. Absolute Maximum Ratings Parameter Rating Symbol Unit Min Max +20 V VCC + 0.3 ( < +20) V +20 V VSC −0.3 −0.3 −0.3 −0.3 +20 V Power dissipation PD – Storage temperature Tstg −55 Power supply voltage VCC Input voltage VSA VSB 200 (Ta ≤ 85°C) mW +125 °C WARNING: Semiconductor devices can be permanently damaged by application of stress (voltage, current, temperature, etc.) in excess of absolute maximum ratings. Do not exceed these ratings. 6. Recommended Operating Conditions Parameter Power supply voltage Output current Operating ambient temperature Symbol Value Unit Min Max VCC 3.5 18 V IRESET 0 20 mA IOUTC 0 6 mA Ta −40 +85 °C WARNING: The recommended operating conditions are required in order to ensure the normal operation of the semiconductor device. All of the device’s electrical characteristics are warranted when the device is operated within these ranges. Always use semiconductor devices within their recommended operating condition ranges. Operation outside these ranges may adversely affect reliability and could result in device failure. No warranty is made with respect to uses, operating conditions, or combinations not represented on the data sheet. Users considering application outside the listed conditions are advised to contact their Cypress representatives beforehand. Document Number: 002-08511 Rev. *D Page 5 of 22 MB3771 7. Electrical Characteristics 7.1 DC Characteristics (VCC = 5 V, Ta = + 25°C) Parameter Power supply current Detection voltage Symbol Conditions Value Min Typ Max Unit ICC1 VSB = 5 V, VSC = 0 V – 350 500 µA ICC2 VSB = 0 V, VSC = 0 V – 400 600 µA VSAL (DOWN) VCC 4.10 4.20 4.30 V Ta = −40°C to +85°C 4.05 4.20 4.35 V VCC 4.20 4.30 4.40 V Ta = −40°C to +85°C 4.15 4.30 4.45 V 50 100 150 mV VSB 1.212 1.230 1.248 V Ta = −40°C to +85°C 1.200 1.230 1.260 V VCC = 3.5 V to 18 V – 3 10 mV 14 28 42 mV VSAH (UP) Hysteresis width VHYSA Detection voltage VSB – Deviation of detection voltage ΔVSB Hysteresis width VHYSB Input current IIHB VSB = 5 V – 0 250 nA IILB VSB = 0 V – 20 250 nA VOHR IRESET = −5 μA, VSB = 5 V 4.5 4.9 – V VOLR IRESET = 3mA, VSB = 0 V – 0.28 0.4 V IRESET = 10mA, VSB = 0 V – 0.38 0.5 V Output voltage – Output sink current IRESET VOLR = 1.0 V, VSB = 0 V 20 40 – mA CT charge current ICT VSB = 5 V, VCT = 0.5 V 9 12 16 µA Input current IIHC VSC = 5 V – 0 500 nA IILC VSC = 0 V – 50 500 nA 1.225 1.245 1.265 V Ta = −40°C to +85°C 1.205 1.245 1.285 V Detection voltage – VSC Deviation of detection voltage ΔVSC VCC = 3.5 V to 18 V – 3 10 mV Output leakage current IOHC VOHC = 18 V – 0 1 µA Output voltage VOLC IOUTC = 4 mA, VSC = 5 V – 0.15 0.4 V Output sink current IOUTC VOLC = 1.0 V, VSC = 5 V 6 15 – mA Reset operation minimum supply voltage VCCL VOLR = 0.4 V, IRESET = 200 µA – 0.8 1.2 V Document Number: 002-08511 Rev. *D Page 6 of 22 MB3771 7.2 AC Characteristics Parameter Symbol Conditions (VCC = 5 V, Ta = + 25°C, CT = 0.01 µF) Value Unit Min Typ Max VSA, VSB input pulse width tPI – 5.0 – – µs Reset hold time tPO – 0.5 1.0 1.5 ms RESET rise time tr – 1.0 1.5 µs RESET fall time tf RL = 2.2 kΩ, CL = 100 pF – 0.1 0.5 µs Propagation delay time tPD*1 – – 2 10 µs tPHL*2 RL = 2.2 kΩ, CL = 100 pF – 0.5 – µs – 1.0 – µs tPLH*2 *1: In case of VSB termination. *2: In case of VSC termination. Document Number: 002-08511 Rev. *D Page 7 of 22 MB3771 8. Application Circuit 8.1 5V Power Supply Monitor Monitored by VSA. Detection threshold voltage is VSAL and VSAH VCC MB3771 CT 1 8 2 3 4 7 6 5 RESET Logic circuit 8.2 5V Power Supply Voltage Monitor (Externally Fine-Tuned Type) The VSA detection voltage can be adjusted externally. Resistance R1 and R2 are set sufficiently lower than the IC internal partial voltage resistance, so that the detection voltage can be set using the ratio between resistance R1 and R2. (Refer to the table below). ■ R1, R2 calculation formula (when R1