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CAT823, CAT824, CAT825
System Supervisory Voltage Reset with Watchdog and Manual Reset
FEATURES
Automatically restarts microprocessor after Power failure Monitors pushbutton for external override Accurate under voltage system monitoring Brownout detection system reset for use with 3.0, 3.3, and 5.0 volt systems Pin and function compatible with the MAX823/24/25 products Operating Range from -40C to +85C Available in TSOT-23 5-lead and SC-70 packages For Ordering Information details, see page 13.
DESCRIPTION
The CAT823, CAT824, and CAT825 provide basic reset and monitoring functions for the electronic systems. Each device monitors the system voltage and maintains a reset output until that voltage reaches the device's specified trip value and then maintains the reset output active condition until the device's internal timer, after a minimum timer of 140ms; to allow the systems power supply to stabilize. The CAT823 and CAT824 also have a watchdog input which can be used to monitor a system signal and cause a reset to be issued if the signal fails to change state prior to a timeout condition. The CAT823 and CAT825 also provide a manual reset input which can be used to initiate reset if pulled low. This input can be directly attached to a pushbutton or a processor signal.
APPLICATIONS
Microprocessor and Microcontroller based systems Intelligent Instruments Control Systems Critical P Monitors Portable Equipment
PIN CONFIGURATION
TSOT-23 5-Lead SC-70 5-Lead
RESET GND MR 1 2 3 5 VCC RESET GND 4 WDI RESET 1 2 3 5 VCC
PIN FUNCTIONS
Pin Name RESET GND Function CMOS Push-Pull Active Low Reset Output Ground Manual Reset input - Pulled high Internally by a 52k resistor designed to be driven low by a mechanical pushbutton, open drain output or CMOS output. CMOS Push-Pull Active High Reset Output Watchdog Timer Input - Designed to be driven by a processor output or can be disabled by tri-stating or leaving open. Power Supply
CAT823
CAT824
4 WDI
MR
RESET
RESET GND RESET 1 2 3 5 VCC
CAT825
4 MR
WDI VCC
(c) Catalyst Semiconductor, Inc. Characteristics subject to change without notice
1
Doc. No. MD-3027, Rev. A
CAT823, CAT824, CAT825
BLOCK DIAGRAM
VCC WDI* LEVEL SENSE & TIMER TIMEOUT COMPARATOR RESET
VCC
VCC TOLERANCE BIAS
+ -
DIGITAL DELAY VCC
VCC
VOLTAGE REFERENCE
RESET*
52k MR*
LEVEL SENSE & DEBOUNCE
* Functions Available by Device
Device CAT823 CAT824 CAT825
RESET x x x
RESET x x
MR x x
WDI x x
Doc. No. MD-3027, Rev. A
2
(c) Catalyst Semiconductor, Inc. Characteristics subject to change without notice
CAT823, CAT824, CAT825
ABSOLUTE MAXIMUM RATINGS (1) Parameters Supply Voltage All other pins Input Current, VCC Output Current RST, RST Continuous Power Dissipations (TA = +70C) SC-70 5-lead (derate 3.1mW/C above +70C) TSOT-23 5-lead (derate 7.1mW/C above +70C) Storage Temperature Operating Ambient Temperature Lead Soldering (10 seconds max) ESD Rating: Low Voltage Pins Human Body Model Machine Model RECOMMENDED OPERATING CONDITIONS Parameter VCC (TA = 0C to +70C) VCC (TA = -40C to +85C) All Other Pins Ambient Temperature Range 1.0 to 5.5 1.2 to 5.5 -0.1 to (VCC + 0.1) -40 to +85 Units V V V C 247 571 -65 to 150 -40 to +85 +300 2000 200 mW mW C C C V V Ratings 6 -0.3 to (VCC + 0.3) 20 20 Units V V mA mA
Notes: (1) Stresses above those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions outside of those listed in the operational sections of this specification is not implied. Exposure to any absolute maximum rating for extended periods may affect device performance and reliability.
(c) Catalyst Semiconductor, Inc. Characteristics subject to change without notice
3
Doc. No. MD-3027, Rev. A
CAT823, CAT824, CAT825
ELECTRICAL OPERATING CHARACTERISTICS DC Characteristics: VCC = 3.0V to 5.5V for L/M versions; VCC = 2.0V to 3.6V for the R/S/T/Y/Z version, -40C TA +85C unless otherwise noted. Typical Values at TA = 25C and VCC = 5V for L/M versions; VCC = 3.3V for the T/S versions; VCC = 3.0V for the R version; and VCC = 2.5V for the Y/Z versions. (1) Symbol Parameter Conditions CAT823 (L/M Versions) CAT824 (L/M Versions) ICC Supply Current CAT823 (R/S/T/Y/Z Versions) CAT824 (R/S/T/Y/Z Versions) CAT825 (L/M Versions) CAT825 (R/S/T/Y/Z Versions) CAT82_L at -40C TA +85C CAT82_M at -40C TA +85C CAT82_T at -40C TA +85C VRST Reset Threshold CAT82_S at -40C TA +85C CAT82_R at -40C TA +85C CAT82_Z at -40C TA +85C CAT82_Y at -40C TA +85C Reset Threshold Tempco Reset Threshold Hysteresis tRD tRP VCC to Reset Delay Reset Active Timeout Period RESET Output High Voltage CAT82_L/M, VCC = VRST max, ISOURCE = -120A CAT82_T/S/R/Z/Y, VCC = VRST max, ISOURCE = -30A CAT82_L/M, VCC = VRST min, ISINK = 3.2mA VOL RESET Output Low Voltage CAT82_T/S/R/Z/Y, VCC = VRST min, ISINK = 1.2mA TA = 0C to +70C, VCC = 1V, VCC falling, ISINK = 50A TA = TMIN to TMAX, VCC = 1.2V, VCC falling, ISINK = 100A ISOURCE VOH VOL Reset Output Voltage CAT82_L/M, Reset = 0V, VCC = 5.5V RESET Output Short-Circuit Current CAT82_L/M, Reset = 0V, VCC = 3.6V VCC > 1.8V, ISOURCE = -150A CAT824L/M & CAT825L/M, VCC = VRST max, ISINK = 3.2mA CAT824R/S/T/Y/Z & CAT825R/S/T/Y/Z, VCC = VRST max, ISINK = 1.2mA 0.8 x VCC 0.4 0.3 V
(2)
Min
Typ 6 4 3 2
Max 17 12 8 6 4.75 4.50 3.15 3.00 2.70 2.38 2.25
Units A A A A V V V V V V V ppm/C mV mV s
4.50 4.25 3.00 2.85 2.55 2.25 2.13
4.63 4.38 3.08 2.93 2.63 2.32 2.19 40
CAT82_L/M CAT82_R/S/T/Y/Z VCC = VTH to (VTH - 100mV) 140 VCC - 1.5V 0.8 x VCC
10 5 20 200 400
ms
VOH
0.4 V 0.3 0.3 0.3 1.5 0.8 mA
Notes: (1) Over-temperature limits are guaranteed by design and not production tested. (2) The RESET short-circuit current is the maximum pull-up current when reset is driven low by a bidirectional output. 4
(c) Catalyst Semiconductor, Inc. Characteristics subject to change without notice
Doc. No. MD-3027 Rev. A
CAT823, CAT824, CAT825
ELECTRICAL OPERATING CHARACTERISTICS (continued) DC Characteristics: VCC = 3.0V to 5.5V for L/M versions; VCC = 2.0V to 3.6V for the R/S/T/Y/Z version, -40C TA +85C unless otherwise noted. Typical Values at TA = 25C and VCC = 5V for L/M versions; VCC = 3.3V for the T/S versions; VCC = 3.0V for the R version; and VCC = 2.5V for the Y/Z versions. Symbol tWD tWDI VIL VIH Parameter Watchdog Timeout Period WDI Pulse Width WDI Input Voltage (3) WDI Input Current (4) WDI = VCC, Time Average WDI = 0V, Time Average -20 VIL = 0.4V, VIH = 0.8 x VCC Conditions Min 1.12 50 0.3 x VCC 0.7 x VCC 120 -15 0.3 x VCC 0.7 x VCC 1 5 Pulse Width with No Reset 35 100 52 75 160 Typ 1.60 Max 3.20 Units s ns V A
WATCHDOG INPUT (CAT823 & CAT824)
MANUAL RESET INPUT(CAT823 & CAT825) VIL VIH tPB tPDLY Input Voltage MR Pulse Width MR low to Reset Delay MR Noise Immunity MR Pullup Resistance (internal) MR V s s ns k
Notes: (3) WDI is internally serviced within the watchdog period if WDI is left open. (4) The WDI input current is specified as an average input current when the WDI input is driven high or low. The WDI input if connected to a three-stated output device can be disabled in the tristate mode as long as the leakage current is less than 10A and a maximum capacitance of less than 200pF. To clock the WDI input in the active mode the drive device must be able to source or sink at least 200A when active. 5
Doc. No. MD-3027, Rev. A
(c) Catalyst Semiconductor, Inc. Characteristics subject to change without notice
CAT823, CAT824, CAT825
TYPICAL ELECTRICAL OPERATING CHARACTERISTICS TABLES
VCC Supply Current vs. Temperature
8 SUPPLY CURRENT (A 7 6 5 4 3 2 1 -40 -20
NORMALIZED RESET THRESHOLD (V)
Normalized Reset Threshold Voltage vs. Temperature
1.06 1.04 1.02 1.00 0.98 0.96 0.94 -40 -20 0 20 40 60 80 100 TEM PERATURE (C) TEMPERATURE (C)
9
0
20
40
60
80 100 120
TEMPERATURE (C)
Doc. No. MD-3027 Rev. A
6
(c) Catalyst Semiconductor, Inc. Characteristics subject to change without notice
CAT823, CAT824, CAT825
FUNCTIONAL DESCRIPTION
PROCESSOR RESET The CAT823-825 detect supply voltage (VCC) conditions that are below the specified voltage trip value (VRST) and provide a reset output to maintain correct system operation. On power-up, RESET (and RESET if available) are kept active for a minimum delay tRP of 140ms after the supply voltage (VCC) rises above VRST to allow the power supply and processor to stabilize. When VCC drops below the voltage trip value (VRST), the reset output signals RESET (and RESET) are pulled active. RESET (and RESET if available) is specifically designed to provide the reset input signals for processors. This provides reliable and consistent operation as power is turned on, off or during brownout conditions by maintaining the processor operation in known conditions. MANUAL RESET The CAT823 and CAT825 each have a Manual Reset (MR ) input to allow for alternative control of the reset outputs. The input is designed for direct conMR nection to a pushbutton (see Figure 1). The input MR is internally pulled up by 52k resistor and must be pulled low to cause the reset outputs to go active. Internally, this input is debounced and timed such that RESET (and RESET) signals of at least 140ms minimum will be generated. The min 140ms tRP delay commences as the Manual Reset input is released from the low level. (see Figure 2)
Figure 1. Pushbutton RESET
MR Supply Voltage VCC RESET GND RESET
CAT825
Figure 2. Timing Diagram - Pushbutton RESET
MR tPDLY VIL tRP RESET VOH VOL tPB VIH
RESET
(c) Catalyst Semiconductor, Inc. Characteristics subject to change without notice
7
Doc. No. MD-3027, Rev. A
CAT823, CAT824, CAT825
WATCHDOG TIMER The CAT823 and CAT824 provide a Watchdog input (WDI). The watchdog timer function forces RESET (and RESET in the CAT824) signals active when the WDI input does not have a transition from low-to-high or high-to-low within 1.12 seconds. Timeout of the watchdog starts when RESET (RESET on the CAT824) becomes inactive. If a transition occurs on the WDI input pin prior to the watchdog time-out, the watchdog timer is reset and begins to time-out again. If the watchdog timer is allowed to time-out, then the reset output(s) will go active for tRP and once released will repeat the watchdog timeout process. Figure 3 below shows a typical implementation of a watchdog function. Any processor signal that repeats dependant on the normal operation of the processor or directed by the software operating on the processor can be used to strobe the watchdog input. The most reliable is a dedicated I/O output transitioned by a specific software instruction. The watchdog can be disabled by floating (or tristating) the WDI input (see Figure 4). If the watchdog is disabled the WDI pin will be pulled low for the first th 7/8 's of the watchdog period (tWD) and pulled high for the last 1/8th of the watchdog period. This pulling low of the WDI input and then high is used to detect an open or tri-state condition and will continue to repeat until the WDI input is driven high or low. For most efficient operation of devices with the watchdog function the WDI input should be held low the majority of the time and only strobed high as required to reset the watchdog timer.
Figure 3. Watchdog Timer
WDI Supply Voltage VCC
MR GND RESET PIC C
CAT823
ADDRESS
DECODER
MCLR
Figure 4. Watchdog Disable Circuit
VCC Tristate
VCC RESET GND MR WDI 110k
CAT823
150k
C
OUTPUT
Doc. No. MD-3027 Rev. A
8
(c) Catalyst Semiconductor, Inc. Characteristics subject to change without notice
CAT823, CAT824, CAT825
Figure 5. Timing Diagram - Strobe Input
INVALID STROBE WDI tWD MIN. MAX. VALID STROBE INDETERMINATE STROBE
RESET
Figure 6. Timing Diagram - Power Down
VCC VRST (MAX) VRST VRST (MIN)
tRD RESET
VOH
RESET Slews with VCC
RESET (CAT824 & CAT825)
VOL
Figure 7. Timing Diagram - Power Up
VRST (MAX) VRST VRST (MIN)
VCC
tRP RESET VOH
VOL RESET RESET (CAT824 & CAT825)
(c) Catalyst Semiconductor, Inc. Characteristics subject to change without notice
9
Doc. No. MD-3027, Rev. A
CAT823, CAT824, CAT825 APPLICATION NOTES
P's with Bidirectional Reset Pins The RESET output can be pulled low by processors like the 68HC11 allowing for a system reset issued by the processor. The maximum pullup current that can be sourced by the CAT82_L/M is 1.5mA (and by the CAT82_T/R/S/Z/Y is 800A) allowing the processor to pull the output low even when the CAT82x is pulling it high. Power Transients Generally short duration negative-going transients of less than 2s on the power supply at VRST minimum will not cause a reset condition. However the lower the voltage of the transient the shorter the required time to cause a reset output. These issues can usually be remedied by the proper location of bypass capacitance on the circuit board.
OUTPUT VALID CONDITIONS
The RESET output uses a push-pull output which can maintain a valid output down to a VCC of 1.0 volts. To sink current below 0.8V a resistor can be connected from RESET to Ground (see Figure 8.) This arrangement will maintain a valid value on the RESET output during both power up and down but will draw current when the RESET output is in the high state. A resistor value of about 100k should be adequate in most situations to maintain a low condition valid output down to VCC equal to 0V.
Figure 8. RESET Valid to 0 Volts VCC
WDI
MR
CAT823
VCC
GND RESET
100k
C
RESET
Doc. No. MD-3027 Rev. A
10
(c) Catalyst Semiconductor, Inc. Characteristics subject to change without notice
CAT823, CAT824, CAT825
PACKAGE OUTLINE DRAWING
TSOT-23 5-Lead (TD) (1)(2)
D e
SYMBO L A A1 A2 b c D
E1 E
MIN 0.01 0.80 0.30 0.12
NOM 0.05 0.87 0.15 2.90 BSC 2.80 BSC 1.60 BSC 0.95 TYP
MAX 1.00 0.10 0.90 0.45 0.20
E E1 e L L1 L2 0 0.30
0.40 0.60 REF 0.25 BSC
0.50
8
TOP VIEW
A2 A
b
A1 L1
L
c
L2
SIDE VIEW
END VIEW
For current Tape and Reel information, download the PDF file from: http://www.catsemi.com/documents/tapeandreel.pdf.
Notes: (1) All dimensions in millimeters. Angles in degrees. (2) Complies with JEDEC MO-193.
(c) Catalyst Semiconductor, Inc. Characteristics subject to change without notice
11
Doc. No. MD-3027, Rev. A
CAT823, CAT824, CAT825
SC-70 5-Lead (SD) (1)(2)
D e e
SYMBOL
MIN
NOM
MAX
A A1 A2 b c
E1 E
0.80 0.00 0.80 0.15 0.10 1.80 1.80 1.15 0.26 2.00 2.10 1.25 0.65 BSC 0.36 0.42 REF 0.15 BSC 0 4
1.10 0.10 1.00 0.30 0.18 2.20 2.40 1.35 0.46
D E E1 e L L1 L2 1
TOP VIEW
8 10
1
A2 A L L1
1
b
A1
c
L2
SIDE VIEW
END VIEW
For current Tape and Reel information, download the PDF file from: http://www.catsemi.com/documents/tapeandreel.pdf.
Notes: (1) All dimensions in millimeters. Angles in degrees. (2) Complies with JEDEC MO-203.
Doc. No. MD-3027 Rev. A
12
(c) Catalyst Semiconductor, Inc. Characteristics subject to change without notice
CAT823, CAT824, CAT825
EXAMPLE OF ORDERING INFORMATION (1)
Prefix CAT
Optional Company ID
Device # 823
Product Number
Suffix L TD
Package TD: TSOT-23 5-Lead SD: SC-70 5-Lead Reset Threshold Voltage L: 4.63V M: 4.38V T: 3.08V S: 2.93V R: 2.63V Z: 2.32V Y: 2.19V
I
-G
Lead Finish G:NiPdAu
T3
Tape & Reel T: Tape & Reel 3: 3000/Reel
823 824 825
Temperature Range I = Industrial (-40C to 85C)
TOP MARKING INFORMATION (For all Thresholds)
NiPdAu Finish (-G) Device # CAT823 CAT824 CAT825 Package TSOT-23 TSOT-23 TSOT-23 SC-70 SC-70 SC-70 Top Marking RG TB TD
ORDERING PART NUMBER
CAT823LTDI-G CAT823MTDI-G CAT823TTDI-G CAT823STDI-G CAT823RTDI-G CAT823ZTDI-G CAT823YTDI-G CAT823LSDI-G CAT823MSDI-G CAT823TSDI-G CAT823SSDI-G CAT823RSDI-G CAT823ZSDI-G CAT823YSDI-G CAT824LTDI-G(4) CAT824MTDI-G CAT824TTDI-G CAT824TSDI-G CAT824ZTDI-G
(4) (4) (4) (4)
CAT825LTDI-G CAT825MTDI-G CAT825TTDI-G CAT825STDI-G CAT825RTDI-G CAT825ZTDI-G CAT825YTDI-G CAT825LSDI-G CAT825MSDI-G CAT825TSDI-G CAT825SDI-G CAT825RSDI-G CAT825ZSDI-G CAT825YSDI-G
CAT824RTDI-G CAT824YTDI-G CAT824LSDI-G
(4) (4)
(4) (4)
CAT824MSDI-G CAT824SSDI-G CAT824ZSDI-G
CAT824TSDI-G(4)
(4) (4)
CAT824RSDI-G CAT824YSDI-G
(4) (4)
Notes: (1) All packages are RoHS-compliant (Lead-free, Halogen-free). (2) (3) (4) The standard lead finish is NiPdAu. This device used in the above example is a CAT823LTDI -GT3 (4.63V, TSOT-23 5-Lead, Industrial Temperature, NiPdAu, Tape & Reel) Contact factory for package availability. 13
Doc. No. MD-3027, Rev. A
(c) Catalyst Semiconductor, Inc. Characteristics subject to change without notice
REVISION HISTORY
Date 09/10/2007 Rev. A Reason Initial Release
Copyrights, Trademarks and Patents (c) Catalyst Semiconductor, Inc. Trademarks and registered trademarks of Catalyst Semiconductor include each of the following: Beyond MemoryTM, DPPTM, EZDimTM, LDDTM, MiniPotTM and Quad-ModeTM Catalyst Semiconductor has been issued U.S. and foreign patents and has patent applications pending that protect its products. CATALYST SEMICONDUCTOR MAKES NO WARRANTY, REPRESENTATION OR GUARANTEE, EXPRESS OR IMPLIED, REGARDING THE SUITABILITY OF ITS PRODUCTS FOR ANY PARTICULAR PURPOSE, NOR THAT THE USE OF ITS PRODUCTS WILL NOT INFRINGE ITS INTELLECTUAL PROPERTY RIGHTS OR THE RIGHTS OF THIRD PARTIES WITH RESPECT TO ANY PARTICULAR USE OR APPLICATION AND SPECIFICALLY DISCLAIMS ANY AND ALL LIABILITY ARISING OUT OF ANY SUCH USE OR APPLICATION, INCLUDING BUT NOT LIMITED TO, CONSEQUENTIAL OR INCIDENTAL DAMAGES. Catalyst Semiconductor products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other applications intended to support or sustain life, or for any other application in which the failure of the Catalyst Semiconductor product could create a situation where personal injury or death may occur. Catalyst Semiconductor reserves the right to make changes to or discontinue any product or service described herein without notice. Products with data sheets labeled "Advance Information" or "Preliminary" and other products described herein may not be in production or offered for sale. Catalyst Semiconductor advises customers to obtain the current version of the relevant product information before placing orders. Circuit diagrams illustrate typical semiconductor applications and may not be complete.
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Document No: MD-3027 Revision: A Issue date: 09/10/07

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