FM809 Precision Reset Generator Circuit General Description Features The FM809 features comprehensive reset generation for microcontroller/microprocessor based systems. If the system VCC voltage level is determined to be in an out-of-tolerance state, the device automatically generates a low-going reset signal. The reset signal is held in the active state (low) for a specified duration (minimum 140 ms) after the VCC returns to an in-tolerance state. ■ Automatic reset generation on power-up ■ Minimum 140 ms reset pulse — compatible with other similar 809 class devices ■ Other reset pulse choices available: 32 - 256 ms ■ Choice of commercial and extended temperature ranges ■ Choice of Reset Thresholds: 4.63V, 4.38V, 4.00V, 3.08V, 2.93V, 2.63V The FM809 is fabricated using CMOS technology. The FM809 is available in the SOT-23 package. ■ Package available: SOT-23 Block Diagram VCC VCC Tolerance Detect & Reset Monitor Output Stage Reset_out (active low) Temp. Compensated Reference Connection Diagram 1 1 = GND 2 = RESET' 3 = VCC FM809 3 2 © 2000 Fairchild Semiconductor International FM809 Rev. A.1 1 www.fairchildsemi.com FM809 Precision Reset Generator Circuit August 2000 Reset Characteristics RESET THRESHOLD (V) Identifier(y) Fairchild Part Number 4.63 L FM809Lz 4.38 M FM809Mz 4.00 J FM809Jz 3.08 T FM809Tz 2.93 S FM809Sz 2.63 R FM809Rz RESET PULSE DURATION (mS) Identifier(z) Fairchild Part Number 32 E FM809yE* 64 F FM809yF* 128 H FM809yH* 256 Blank FM809y Note*: These choices are available upon special request only. Please work with Fairchild Marketing to determine availability. 2 FM809 Rev. A.1 www.fairchildsemi.com FM809 Precision Reset Generator Circuit Each FM809 device has the following Identifier (FM809yz) (Top Mark on devices will be 09yz) Absolute Maximum Ratings Ambient Storage Temperature Operating Conditions –65°C to +150°C All Input or Output Voltages with Respect to Ground Ambient Operating Temperature Commercial Industrial -0.3V to 6.5V Lead Temperature (Soldering, 10 seconds) ESD Rating 0°C to +70°C -40°C to +85°C +300°C 2000V min. Electrical Characteristics Parameter Symbol VCC Range Temp Conditions Com IND Supply Current ICC Com Reset Threshold VTH Com V 1.2 5.5 V 50 µA V 4.40 4.63 4.85 V 4.25 4.38 4.50 V 4.16 4.38 4.56 V ‘J’ Identifier 3.89 4.00 4.10 V 3.80 4.00 4.20 V ‘T’ Identifier 3.00 3.08 3.15 V 2.92 3.08 3.23 V 2.85 2.93 3.00 V 2.78 2.93 3.08 V 2.55 2.63 2.70 V 2.50 2.63 2.75 V Ind ‘S’ Identifier Ind ‘R’ Identifier Ind nRESET Output Voltage High 5.5V µA Ind Com 1.0 100 ‘M’ Identifier Com Units 4.75 Ind Com Max 4.63 Ind Com Typ 4.50 ‘L’ Identifier Com Min VOH All Isource = 150 mA nRESET Output Voltage Low VOL All Isink = 1.2mA Reset Timeout Period TRST All 0.8VCC V 0.4 175 V 240 375 ms Note: Production testing done at TA = +25°C, over temperature limits guaranteed by design only. General Description This is not a problem in most systems since most common devices are not functional in this range. If it is desired for the FM809 reset to be functional below the range above, it is suggested to use a 100KΩ pull-down resistor between RESET and VSS. The FM809 features a highly accurate voltage reference against which the Vcc is compared. Once the Vcc is below the specified threshold, it will drive the RESET line and continue to hold it low until the VCC returns above the threshold and the time for the RESET pulse duration has expired. The FM809 is immune to short negative going transients on the VCC line. The placement of a 0.1µF bypass capacitor as close as possible to the VCC pin provides additional transient immunity. Interfacing to Bidirectional reset pins FM809 can be used with microprocessors with bidirectional reset pins. In order to allow the microprocessor to drive the reset line, the output of the FM809 must be connected to the microprocessor through a 4.7kΩ resistor. This will ensure that the RESET line has correct level at both the FM809 as well as the device end. For a VCC value below 1.0V-1.3V, the FM809 does not sink current on the RESET pin. 3 FM809 Rev. A.1 www.fairchildsemi.com FM809 Precision Reset Generator Circuit Product Specifications FM809 Precision Reset Generator Circuit Typical Operating Characteristics Supply Current Vs. Temperature (FM809R/S/T) 8 7 Icc (uA) 6 V 5 V 4 3 2 1 0 -60 -40 -20 0 20 40 60 80 100 Temperature (C) Power up Reset Timeout Vs. Temperature FM809(R/S/T) 300 280 260 240 220 200 -60 -40 -20 0 20 40 60 80 100 60 80 100 Temperature (C) Normalized Reset Threshold Vs. Temperature FM809(R/S/T) 1.050 1.025 1.000 0.975 0.950 -60 -40 -20 0 20 40 Temperature (C) 4 FM809 Rev. A.1 www.fairchildsemi.com FM809 Precision Reset Generator Circuit 0.45~0.60 0.20 MIN Physical Dimensions inches (millimeters) unless otherwise noted 2.40 ±0.10 1.30 ±0.10 0.40 ±0.03 0.03~0.10 0.38 REF 0.40 ±0.03 +0.05 0.12 –0.023 0.96~1.14 2.90 ±0.10 0.97REF Dimensions in millimeters 0.95 ±0.03 0.95 ±0.03 1.90 ±0.03 0.508REF SOT-23 Package Dimensions FS Pkg Code AU Life Support Policy Fairchild's products are not authorized for use as critical components in life support devices or systems without the express written 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. Fairchild Semiconductor Americas Customer Response Center Tel. 1-888-522-5372 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 Europe Fax: +44 (0) 1793-856858 Deutsch Tel: +49 (0) 8141-6102-0 English Tel: +44 (0) 1793-856856 Français Tel: +33 (0) 1-6930-3696 Italiano Tel: +39 (0) 2-249111-1 Fairchild Semiconductor Hong Kong 8/F, Room 808, Empire Centre 68 Mody Road, Tsimshatsui East Kowloon. Hong Kong Tel; +852-2722-8338 Fax: +852-2722-8383 Fairchild Semiconductor Japan Ltd. 4F, Natsume Bldg. 2-18-6, Yushima, Bunkyo-ku Tokyo, 113-0034 Japan Tel: 81-3-3818-8840 Fax: 81-3-3818-8841 Fairchild does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and Fairchild reserves the right at any time without notice to change said circuitry and specifications. 5 FM809 Rev. A.1 www.fairchildsemi.com