1 LTC1726 . Triple Supply Monitor and P Supervisor with Adjustable Reset and Watchdog Timer Features Description n Monitors Three Inputs Simultaneously The LTC 1726 is a Triple Supply Monitor and microproces- LTC1726 -5: 5V, and ADJ sor supervisory circuit with adjustable reset and watchdog : , and ADJ functions intended for systems with multiple Supply volt- n Threshold Accuracy Over Temperature ages. The part has a common open-drain reset output n Low Supply Current: 16 A Typ with an adjustable delay. The reset and watchdog time-out n Adjustable Reset Timeout periods are both adjustable using external capacitors. n Adjustable Watchdog Timeout n Active Low Open-Drain Reset Output Tight accuracy specifications and glitch immunity n Power Supply Glitch Immunity ensure reliable reset operation without false triggering.
2 N Guaranteed RESET for V. CC3 1V or VCC25/VCC5 1V The RST output is guaranteed to be in the correct state for n MS8 and SO-8 Packages VCC5/VCC25 or VCC3 down to 1V. The LTC1726 may also be configured to Monitor any one or two VCC inputs instead of three, depending on system requirements. Applications The low (16 A typical) Supply current makes the LTC1726 . n Desktop Computers ideal for power-conscious systems. n Notebook Computers L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and n Intelligent Instruments ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. n Portable Battery-Powered Equipment n Network Servers Typical Application A , 5V and Monitor A , and Monitor (VTRIP = ) (VTRIP = ).
3 R1 R1. F F 1% 1%. 5V R2 R2. 2 1 3 2 1 3. F CRT 100k F CRT 100k 47nF VCC5 VCC3 VCCA 1% 47nF VCC25 VCC3 VCCA 1%. 8 6 8 6. RT RST RESET RT RST RESET. CWT CWT. 47nF LTC1726 -5 P 47nF P. 7 5 7 5. WT WDI I/O WT WDI I/O. GND GND. tRT = 155ms 4 1726 TA01 tRT = 155ms 4 1726 TA02. tWT= 1s tWT= 1s 1726fd For more information 1. LTC1726 . Absolute Maximum Ratings (Notes 1, 2). Terminal Voltage Operating Temperature Range (Note 3). VCC3, VCC5/VCC25, to 7V LTC1726E, 40 C to 85 C. to 7V 40 C to 125 C. to 7V Storage Temperature 65 C to 150 C. RT, to 7V Lead Temperature (Soldering, 10 sec).. 300 C. Pin Configuration TOP VIEW. TOP VIEW. VCC3 1 8 RT. VCC3 1 8 RT. VCC25 /VCC5 2 7 WT VCC25/VCC5 2 7 WT. VCCA 3 6 RST VCCA 3 6 RST. GND 4 5 WDI.
4 GND 4 5 WDI. MS8 PACKAGE. 8-LEAD PLASTIC MSOP. S8 PACKAGE. TJMAX = 125 C, JA = 200 C/W 8-LEAD PLASTIC SO. TJMAX = 125 C, JA = 150 C/W. Order Information LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE. #PBF #TRPBF LTKZ 8-Lead Plastic MSOP 40 C to 85 C. LTC1726 EMS8-5#PBF LTC1726 EMS8-5#TRPBF LTLA 8-Lead Plastic MSOP 40 C to 85 C. LTC1726 HMS8-5#PBF LTC1726 HMS8-5#TRPBF LTLA 8-Lead Plastic MSOP 40 C to 125 C. #PBF #TRPBF 172625 8-Lead Plastic SO 40 C to 85 C. LTC1726ES8-5#PBF LTC1726ES8-5#TRPBF 17265 8-Lead Plastic SO 40 C to 85 C. #PBF #TRPBF 726I25 8-Lead Plastic SO 40 C to 85 C. LTC1726IS8-5#PBF LTC1726IS8-5#TRPBF 1726I5 8-Lead Plastic SO 40 C to 85 C. Consult LTC Marketing for parts specified with wider operating temperature ranges.
5 Consult LTC Marketing for information on non-standard lead based finish parts. For more information on lead free part marking, go to: For more information on tape and reel specifications, go to: 1726fd 2 For more information LTC1726 . Electrical Characteristics The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25 C. VCC3 = , VCC5 = 5V, VCC25 = , VCCA = VCC3 unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS. VRT3 Reset Threshold VCC3 VCC3 Input Threshold l V. H-Grade l V. VRT5 Reset Threshold VCC5 VCC5 Input Threshold (5V Version). l V. H-Grade l V. VRT25 Reset Threshold VCC25 VCC25 Input Threshold ( Version), l V. VRTA Reset Threshold VCCA VCCA Input Threshold l V.
6 H-Grade l V. VCC VCC3 or VCC5 Operating Voltage RST in Correct Logic State l 1 7 V. IVCC3 VCC3 Supply Current VCC5/VCC25 > VCC3 l 1 2 A. VCC5/VCC25 < VCC3, VCC3 = l 16 30 A. IVCC5 VCC5 Supply Current VCC5 = 5V l 16 30 A. IVCC25 VCC25 Supply Current VCC25 < VCC3, VCC25 = (Note 4) l 1 2 A. IVCCA VCCA Input Current VCCA = 1V l 15 0 15 nA. RT Charge Current Out VRT = 0V. l 2 A. H-Grade l 2 A. WT Charge Current Out VWT = 0V. l 2 A. H-Grade l 2 A. RT Discharge Current Out VRT = l 14 20 26 A. H-Grade l 13 20 28 A. WT Discharge Current Out VWT = l 14 20 26 A. H-Grade l 13 20 28 A. tRT Reset Time-Out Period Variation CRT = 1500pF Deviation from tRT = 5ms (Note 5). l 30 0 30 %. H-Grade l 45 0 45 %. tUV VCC Undervoltage Detect to RST VCC25/VCC5, VCC3 or VCCA Less Than Reset 130 s Threshold VRT by More Than 1%.
7 VOH RST Output Voltage High (Note 6) ISOURCE = 1 A l VCC3 1 V. VOL RST Output Voltage Low ISINK = , VCC5/VCC25 = 0V l V. ISINK = 100 A, VCC3 = 1V, VCC5/VCC25 = 0V l V. ISINK = 100 A, VCC3 = 0V, VCC5/VCC25 = 1V l V. ISINK = 100 A, VCC3 = 1V, VCC5/VCC25 = 1V l V. VIH WDI Input Threshold High l VCC3 V. VIL WDI Input Threshold Low l VCC3 V. tWP WDI Pulse Width l 40 ns tWT Watchdog Time-Out Period Variation CWT = 1500pF Deviation from tWT = 33ms (Note 5). l 30 0 30 %. H-Grade l 45 0 45 %. WDI Leakage Current l 1 A. LTC1726 -5 Only VOVR VCC5 Reset Override Voltage (Note 7) Override VCC5 Ability to Assert RST VCC3 V. 1726fd For more information 3. LTC1726 . Electrical Characteristics Note 1: Stresses beyond those listed under Absolute Maximum Ratings Note 4: Both VCC3 and VCC25/VCC5 can act as the Supply depending on may cause permanent damage to the device.
8 Exposure to any Absolute which pin has the greatest potential. Maximum Rating condition for extended periods may affect device Note 5: Timing measured with respect to RST passing through reliability and lifetime. Note 6: The output pin RST has a weak internal pull-up to VCC3 of typically Note 2: All voltage values are with respect to GND. 6 A. However, external pull-up resistors may be used when faster rise Note 3: The LTC1726E is guaranteed to meet performance specifications times are required or for VOH voltages greater than VCC3. from 0 C to 70 C. Specifications over the 40 C to 85 C operating Note 7: The VCC5 reset override voltage is valid for an operating range less temperature range are assured by design, characterization and correlation than approximately Above this point the override is turned off and with statistical process controls.
9 The VCC5 pin functions normally. Typical Performance Characteristics VCC5 Threshold Voltage VCC3 Threshold Voltage VCCA Threshold Voltage vs Temperature ( LTC1726 -5) vs Temperature vs Temperature VCCA THRESHOLD VOLTAGE, VRTA (V). VCC5 THRESHOLD VOLTAGE, VRT5 (V). VCC3 THRESHOLD VOLTAGE, VRT3 (V). 60 40 20 0 20 40 60 80 100 60 40 20 0 20 40 60 80 100 60 40 20 0 20 40 60 80 100. TEMPERATURE ( C) TEMPERATURE ( C) TEMPERATURE ( C). 1726 G01 1726 G02 1726 G03. VCC25 Threshold Voltage vs Temperature ( ) IVCC5 vs Temperature ( LTC1726 -5) IVCC3 vs Temperature ( LTC1726 -5). 20 VCC5 = 5V VCC5 = 5V. 19 VCC3 = VCC3 = VCC25 THRESHOLD VOLTAGE, VRT25 (V). 18 17 16 IVCC5 ( A). IVCC3 ( A). 15 14 13 12 11 10 60 40 20 0 20 40 60 80 100 60 40 20 0 20 40 60 80 100 60 40 20 0 20 40 60 80 100.
10 TEMPERATURE ( C) TEMPERATURE ( C) TEMPERATURE ( C). 1726 G04 1726 G05 1726 G06. 1726fd 4 For more information LTC1726 . Typical Performance Characteristics IVCC25 vs Temperature IVCC3 vs Temperature Typical Transient Duration ( ) ( ) vs Comparator Overdrive 20 700. VCC3 = VCC3 = TA = 25 C. VCC25 = 19 VCC25 = TYPICAL TRANSIENT DURATION ( s). 600. 18. 17 500. 16 RESET OCCURS. IVCC25 ( A). IVCC3 ( A). 400. ABOVE CURVE. 15. 300. 14. 13 200. 12. 100. 11. 10 0. 60 40 20 0 20 40 60 80 100 60 40 20 0 20 40 60 80 100 1 10 100. TEMPERATURE ( C) TEMPERATURE ( C) RESET COMPARATOR OVERDRIVE VOLTAGE (% OF VCC). 1726 G07 1726 G08. 1726 G09. VCCA Input Current Watchdog Time-Out Period Reset Pulse Width vs vs Input Voltage vs Temperature Temperature 40 TA = 25 C CWT = 1500pF CRT = 1500pF.