FM811 FAIRCHILD | Alldatasheet

Document overview

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Technical content

Features

  • Feature
  • Precision V oltage Monitor for 3V , 3.3V or 5V Power Supplies
  • 6µA Supply Current
  • 140ms Minimum Reset Pulse Width
  • RESET Remains Valid with V CC as Low as 1.4V
  • Active Low Manual Reset Input
  • No External Components
  • 4-Pin SOT-143 Package

Applications

  • Critical Microprocessor Power Monitoring
  • Portable Equipment
  • Intelligent Instruments
  • Computers & Printers
  • Controllers

Description

The FM811/FM812 is a low cost microprocessor supervisory circuit that asserts a reset if the power supply drops below a designated threshold or the manual reset pin is forced low. Several different reset thresholds are available to accommodate systems operating at 3V, 3.3V or 5V. The FM811 has an active low RESET output, while the FM812 offers an active high RESET output. The reset output is guaranteed to remain asserted for a minimum of 140ms after V CC has risen above the designated reset threshold. The FM811/FM812 is available in a 4-pin SOT-143. Typical Applications FM811 FM812 µP VCC VCC RESET RESET INPUTMR (RESET) ( ) = FM812 VCC FM811/812 Microprocessor Reset Circuits

REV. 1.5.1 7/15/02 Preliminary Information Pin Assignments Pin Definitions Internal Block Diagram Pin Name Pin Number DescriptionFM811 FM812 GND 1 1 Ground Pin RESET 2 N/A RESET goes low if V CC falls below the reset threshold and remains asserted for one reset time-out period (140ms min.) after V CC exceeds the reset threshold. RESET N/A 2 RESET goes high if V CC falls below the reset threshold and remains asserted for one reset time-out period (140ms min.) after V CC exceeds the reset threshold. MR 3 3 Manual reset input. Shorting this pin to GND forces a reset. The reset will remain asserted as long as MR is held low and for one reset time-out period (140ms min.) after MR goes high. This input cannot be driven by a CMOS or TTL logic. Push-button switch is recommended to be used with this pin. Float if unused. V CC 4 4 Power supply input, 3V, 3.3V, or 5V FM811 VCC Top View RESET MR2 FM812 VCC RESET MR GND 1GND 1 4 Reset Generator 2 Reset Threshold (V) VCC MR RESET (FM811) RESET (FM812) GND

REV. 1.5.1 7/15/02 Preliminary Information Absolute Maximum Ratings Stresses above those listed under ABSOLUTE MAXIMUM RATINGS may cause permanent device failure. Functionality at or above these limits is not implied. Exposure to absolute maximum ratings for extended periods may affect device reliability. Operating ranges define those limits between which the functionality of the device is guaranteed.

Electrical Characteristics

V CC = 5V for FM81_L/M/J, V CC = 3.3V for FM81_S/T, V CC = 3V for FM81_R, T A = Operating Temperature Range, unless otherwise noted. Parameter Symbol Ratings Units Terminal Voltage V CC -0.3 to 6.0 V MR -0.3 to (V CC + 0.3) V Input Current V CC , MR 20 mA Output Current RESET, RESET 20 mA Rate of Rise V CC

100 V/µs

Operating Temperature Range T A -40 to +85 ˚C Storage Temperature Range -65 to +150 ˚C Lead Temperature Range 300 ˚C Power Dissipation (T A = +70˚C) 320 mW Parameter Conditions Min. Typ. Max. Units Operating Voltage Range T A = 0˚C to 70˚C T A = -40˚C to 85˚C 1.4 1.6 5.5 5.5 V Supply Current, I CC FM811L/M/J, FM812L/M/J V CC < 3.6V, FM811R/S/T, FM812R/S/T µA Reset Voltage Threshold, V TH FM811L, FM812L FM811M, FM812M FM811J, FM812J FM811T, FM812T FM811S, FM812S FM811R, FM812R 4.40 4.18 3.90 2.97 2.79 2.49 4.63 4.38 4.00 3.08 2.93 2.63 4.86 4.52 4.18 3.19 3.00 2.70 V Reset Time-out Period, t R 140 240 560 ms RESET Output Voltage, V OH I SOURCE = 800µA, FM811L/M/J I SOURCE = 500µA, FM811R/S/T V CC - 1.5 0.8 x V CC V RESET Output Voltage, V OL V CC = V TH Min., I SINK = 3.2mA, FM811L/M/J V CC = V TH Min., I SINK = 1.2mA, FM811R/S/T V CC > 1.4V, I SINK = 50µA, T A = 0˚C to 70˚C V CC > 1.6V, I SINK = 50µA, T A = -40˚C to 85˚C 0.4 0.3 0.3 0.3 V RESET Output Voltage, V OH 1.8V < V CC < V TH Min., I SOURCE = 150µA 0.8 x V CC V RESET Output Voltage, V OL I SINK = 3.2mA, FM810L/M/J I SINK = 1.2mA, FM810R/S/T 0.4 0.35 V MR Minimum Pulse Width 10 µs MR to Reset Delay 0.5 µs MR Input Threshold, V IH V CC > V TH Max., FM81_L/M/J FM81_R/S/T 2.3 0.7 x V CC V MR Input Threshold, V IL V CC > V TH Max., FM81_L/M/J FM81_R/S/T 0.8 0.25xV CC MR Pull-Up Resistance 10 20 30 k Ω MR Glitch Immunity 100 ns

REV. 1.5.1 7/15/02 Preliminary Information Circuit Description Microprocessor Reset The RESET pin is asserted whenever V CC falls below the reset threshold voltage or if MR (manual reset) is forced low. The reset pin remains asserted for a period of 40ms after V CC has risen above the reset threshold voltage or MR has returned high. The reset function ensures the microprocessor is properly reset and powers up into a known condition after a power failure. RESET will remain valid with V CC as low as 1.4V . V CC Transients The FM811/ FM812 are relatively immune to negative-going V CC glitches below the reset threshold. Typically, a negative- going transient 125mV below the reset threshold with a duration of 50ms (25ms for FM81_R/S/T) or less will not cause an unwanted reset. Manual Reset Function Momentarily connecting the Manual Reset input pin (MR) to GND forces a reset. Typically a Push-button switch is used in most of the applications to force a manual reset. See Typical Applications diagram. The reset will remain asserted as long as MR is held low and for one reset time-out period (140ms min.) after MR goes high. Note that this input cannot be driven by a CMOS or TTL logic. This pin should be left floating if manual reset feature is unused. Interfacing to Bidirectional Reset Pins The FM811/ FM812 can interface with µPs with bidirectional reset pins by connecting a 4.7k Ω resistor in series with the FM811/ FM812 output and the µP reset pin. RESET Valid to 0V A resistor can be added from the RESET pin to ground to ensure the RESET output remains low with V CC down to 0V . A 100k Ω resistor connected from RESET to ground is recommended. The size of the resistor should be large enough to not load the RESET output and small enough to pull-down any stray leakage currents. VTH VCC tR MR RESET tR FM811 µP 100k VCC VCC RESET RESET VCC

REV. 1.5.1 7/15/02 Preliminary Information Packaging Information 4-Pin SOT-143 Tape and Reel Information 0.120 0.105 0.004 0.001 0.040 0.031 0.079 0.071 0.055 0.047 0.098 0.083 0.010 0.005 0.0059 0.0035 0.037 0.030 0.021 0.015 0.080 0.070 Dimensions are in inches O1.5 ± 0.1 3.5 ± 0.05 8.0 ± 0.3 1.75 ± 0.1 4.0 ± 0.1 2.0 ± 0.05 4.0 ± 0.1 O1.1 ± 0.1 3.1 ± 0.1 1.2 ± 0.1 2.7 ± 0.1 Dimensions are in millimeters

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 (c) 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 of the user. 2. A critical component in 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. www.fairchildsemi.com 7/15/02 0.0m 004 Stock#DS30000811

2002 Fairchild Semiconductor Corporation

FAIRCHILD SEMICONDUCTOR RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY PRODUCTS HEREIN TO IMPROVE RELIABILITY, FUNCTION OR DESIGN. FAIRCHILD DOES NOT ASSUME ANY LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCT OR CIRCUIT DESCRIBED HEREIN; NEITHER DOES IT CONVEY ANY LICENSE UNDER ITS PATENT RIGHTS, NOR THE RIGHTS OF OTHERS. Preliminary Information

Ordering Information

  • YY = Lot Code Part Number Top Marking* RESET Threshold (V) Output Type Package Packing Method FM811LUX KL YY 4.63 Push-Pull, active LOW 4-Pin, SOT143 3000 units in T&R FM811MUX KMYY 4.38 Push-Pull, active LOW 4-Pin, SOT143 3000 units in T&R FM811JUX KJYY 4.00 Push-Pull, active LOW 4-Pin, SOT143 3000 units in T&R FM811TUX KTYY 3.08 Push-Pull, active LOW 4-Pin, SOT143 3000 units in T&R FM811SUX KSYY 2.93 Push-Pull, active LOW 4-Pin, SOT143 3000 units in T&R FM811RUX KRYY 2.63 Push-Pull, active LOW 4-Pin, SOT143 3000 units in T&R FM812LUX LL YY 4.63 Push-Pull, active HIGH 4-Pin, SOT143 3000 units in T&R FM812MUX LMYY 4.38 Push-Pull, active HIGH 4-Pin, SOT143 3000 units in T&R FM812JUX LJYY 4.00 Push-Pull, active HIGH 4-Pin, SOT143 3000 units in T&R FM812TUX LTYY 3.08 Push-Pull, active HIGH 4-Pin, SOT143 3000 units in T&R FM812SUX LSYY 2.93 Push-Pull, active HIGH 4-Pin, SOT143 3000 units in T&R FM812RUX LRYY 2.63 Push-Pull, active HIGH 4-Pin, SOT143 3000 units in T&R