FMFFM1233AC FAIRCHILD | Alldatasheet

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Precision monitoring of 3.3V and lower voltage microprocessor systems V TH values of 3.08V, 2.88V and 2.72V Automatic restart of microprocessor after power failure Reset Timeout Period Choice: – Options AC and AD: 140ms (min)/256ms (typ) – Option ABA: 17ms (min)/32ms (typ) – Available on request: 64ms (typ) and 128ms (typ) Internal 5k Ω pull-up resistor Operating Temperature -40°C to +105°C Monitors external pushbutton override Internal switch debounce circuitry SOT23-3 package Typical Operating Circuit Connection Diagram FM1233A Controller VCC GND RESET GND VCC RESET FM1233A

FM1233A 3-Pin µC Supervisor Circuit www.fairchildsemi.com FM1233A Rev. E Absolute Maximum Ratings Voltage on any pin relative to GND V CC -0.3V to +6.0V RESET -0.3V to (V CC + 0.3V) Input Current 20mA Output Current (RESET ) 20mA Continuous Power Dissipation (T A = 70°C) SOT23 (derate 4mW above 70°C) 300mW Operating Temperature Range -40°C to +105°C Storage Temperature Range -65°C to +150°C Lead Temperature (soldering, 10s) +300°C These are stress ratings only, and functional operation is not implied for these levels or beyond. Exposure to Absolute Maximum Rating conditions for extended periods may affect device reliability. Electrical Characteristics (V CC = 3.3V; T A = -40°C to +105°C unless otherwise noted) (Note 1) Note 1: Testing at production is done at 25°C only. Limits over temperature are guaranteed by design. Note 2: C = 100pF , V CC = 3.3V. It is recommended to connect 100pF capacitor between the Reset pin and Ground pin if pushbutton reset is implemented. Parameter Symbol Conditions Min Typ Max Units Operating Voltage V CC 1.2 3.3 5.5 V Supply Current I CC V CC < 3.3V 3 6 µA Reset Threshold V TH FM1233AC 2.70 2.88 2.97 V Reset Threshold V TH FM1233AD 2.58 2.72 2.86 V Reset Threshold V TH FM1233ABA 2.97 3.08 3.19 V Reset Output Voltage V OL I SINK = 1.2mA V CC = V TH (min) 0.4 V Reset Timeout Period t RST FM1233AC, FM1233AD 140 256 560 ms Reset Timeout Period t RST FM1233ABA 17 32 64 ms Pushbutton Detect PBV DET V CC = 3.3V 0.8 2.0 V Pushbutton Release PBV REL Note 2 0.3 1.5 V

FM1233A 3-Pin µC Supervisor Circuit www.fairchildsemi.com FM1233A Rev. E Typical Operating Characteristics Supply Current Vs. Temperature Power up Reset Timeout Vs. Temperature +110C+25C-55C Temperature (C) ICC (µA) VCC = 3.3V 100 200 300 400 500 600 100 200 300 400 500 600 +105C+25C-40C Temperature (C) Power up Reset timeout (ms)

FM1233A 3-Pin µC Supervisor Circuit www.fairchildsemi.com FM1233A Rev. E Pin Descriptions Circuit Timing (Ex: FM1233A) When operating properly with 3V V CC (for example), RESET will also be about 3V. When V CC starts to fall, RESET will follow it down as shown. When V CC drops below V TH , RESET drops to ground (“issues a RESET”) and stays there unless V CC also falls below its minimum operating voltage, approx. 1V. At this point, the supervisor loses control, and its output may rise, only to again follow V CC down to the ground. When V CC begins to rise, RESET follows it until 1.0V or so is reached, whereupon the device regains control, RESET is pulled to ground, etc. When V CC rises above V TH , RESET comes out of RESET after the minimum Reset Timeout period. If it is required that a lower value than GND + 1.0V is needed on RESET signal during V CC 1V, a 100K resistor may be used on the device output to GND. Pin Number Name Function

1 GND GROUND

2 RESET RESET remains LOW while V

, and for at least the minimum Reset Timeout period after V CC rises above V TH CC 3.3V VTH GND 3.3V VTH GND VCC RESET 140ms (min)

FM1233A 3-Pin µC Supervisor Circuit www.fairchildsemi.com FM1233A Rev. E General Description The FM1233A features a highly accurate voltage reference to which V CC is compared. Once V CC is below the specified thresh- old, it will drive the RESET line and continue to hold it low until V CC returns above the threshold and the time for the RESET pulse duration has expired. The FM1233A is immune to short negative going transients on the V CC line. The placement of a 0.1µF bypass capacitor as close as possible to the V CC pin pro- vides additional transient immunity. For a V CC value below 1.0V, the FM1233A does not sink very much current on the RESET pin. This is not a problem in most systems since common devices are not functional in this range. If it is desired for the FM1233A reset to be functional below this range, use a 100K Ω pull-down resistor between RESET and V SS Bi-Directional Reset The FM1233A permits a pushbutton (or a signal) to initiate a reset externally. Once this external reset is detected on the reset pin, FM1233 also actively asserts the reset signal to main- tain the Reset Timeout period when the external reset is not present . FM1233 internally debounces glitches seen during a typical push button closure. For proper operation, the external switch should be paralleled by an external capacitor of 100pF to 0.01µF . Connecting an External Reset to the FM1233A FM1233 Controller VCC GND 100pF PUSH BUTTON RESET

FM1233A 3-Pin µC Supervisor Circuit www.fairchildsemi.com FM1233A Rev. E

Ordering Information

Note 3: FM1233AC and FM1233AD feature 256ms (typ) Reset timeout while FM1233ABA features 32ms (typ) Reset Timeout. Consult Fairchild Sales for other reset pulse width options. Part Number Top Marking RESET Threshold (V) Output Type Package Type Packing Method FM1233ACS3X 33AC 2.88 Open-Drain, active LOW 3-Pin, SOT23 3000 units in T&R FM1233ADS3X 33AD 2.72 Open-Drain, active LOW 3-Pin, SOT23 3000 units in T&R FM1233ABAS3X 3ABA 3.08 Open-Drain, active LOW 3-PIN, SOT23 3000 units in T&R

www.fairchildsemi.com FM1233A Rev. E FM1233A 3-Pin µC Supervisor Circuit Life Support Policy Fairchild's products are not authorized for use as critical components in life support devices or systems without the express w ritten approval of the President of Fairchild Semiconductor Corporation. As used herein: 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and whose failure to perform, when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury to the user. 2. A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. Fairchild Semiconductor Fairchild Semiconductor Fairchild Semiconductor Fairchild Semiconductor Americas Europe Hong Kong Japan Ltd. Customer Response Center Fax: +44 (0) 1793-856858 8/F , Room 808, Empire Centre 4F , Natsume Bldg. Tel. 1-888-522-5372 Deutsch Tel: +49 (0) 8141-6102-0 68 Mody Road, Tsimshatsui East 2-18-6, Yushima, Bunkyo-ku English Tel: +44 (0) 1793-856856 Kowloon. Hong Kong Tokyo, 113-0034 Japan Français Tel: +33 (0) 1-6930-3696 Tel; +852-2722-8338 Tel: 81-3-3818-8840 Italiano Tel: +39 (0) 2-249111-1 Fax: +852-2722-8383 Fax: 81-3-3818-8841 Physical Dimensions inches (millimeters) unless otherwise noted FS Pkg Code AU 0.120 0.105 0.079 0.071 0.004 0.001 0.040 0.031 0.021 0.015 0.055 0.047 0.098 0.083 0.010 0.005 0.0059 0.0035 0-8° PKG CL 0.76 0.76 0.95 2.29 LAND PATTERN RECOMMENDATION