LTC2935 ultra-low power voltage monitor provides system initialization

The Datasheet Archive - 100 Million Datasheets from 7500 Manufacturers.

LTC2935 ultra-low power voltage monitor provides system initialization

Datasheet Thumbnail

Top Searches for this datasheet

LTC2935 Ultra-Low Power Supervisor with Power-Fail Output, Selectable Thresholds FEATURES
LTC2935 ultra-low power voltage monitor provides system initialization, power-fail warning reset generation functions. quiescent current (500nA typical) makes LTC2935 ideal choice battery-operated applications. Three binary threshold-select inputs configure eight integrated reset thresholds, ranging from 1.6V 3.45V pre-determined increments. Early warning impending voltage condition provided powerfail output (PFO), whose threshold above configured reset threshold. Supervisory circuits monitor pull when drops below configured reset threshold. When rising from under-threshold condition, internal reset timer started after exceeding reset threshold 200ms reset timeout delays return output high state. pushbutton switch connected input typically used force manual reset. Outputs available with open-drain (LTC2935-1/LTC2935-3) active pull-up (LTC2935-2/LTC2935-4) circuits. Operating temperature range from -40°C 85°C.
500nA Quiescent Current ±1.5% (Max) Accuracy over Temperature Integrated Precision Attenuators Eight Pin-Selectable Reset Thresholds Eight Pin-Selectable Power-Fail Thresholds Early Warning Power-Fail Output 200ms Reset Timeout Manual Reset Input Compact 8-Lead, TSOT-23 (ThinSOTTM) Packages
APPLICATIONS
Portable Equipment Battery-Powered Equipment Security Systems Point-of-Sale Devices Wireless Systems
LTC, LTM, Linear Technology Linear logo registered trademarks Linear Technology Corporation. ThinSOT trademark Linear Technology Corporation. other trademarks property their respective owners.
TYPICAL APPLICATION
Falling Threshold Selection Table Configurable Power Voltage Monitor
0.1F
2935 TA01a
LTC2935-1/LTC2935-2
LTC2935-3/LTC2935-4
LTC2935-2 BATTERY POWERED SYSTEM LOGIC
RESET POWER-FAIL RESET POWER-FAIL THRESHOLD THRESHOLD THRESHOLD THRESHOLD 3.30 3.15 3.00 2.85 2.70 2.55 2.40 2.25 3.45 3.30 3.15 3.00 2.85 2.70 2.55 2.40 2.44 2.32 2.20 2.08 1.96 1.84 1.72 1.60 2.56 2.44 2.32 2.20 2.08 1.96 1.84 1.72
High High High High
High High High High
High High High High
2935fa
LTC2935 ABSOLUTE MAXIMUM RATINGS
(Notes
Input Voltages VCC. -0.3V .-0.3V (VCC 0.3V) Output Voltages (PFO, RST) LTC2935-1/LTC2935-3 -0.3V LTC2935-2/LTC2935-4 .-0.3V (VCC 0.3V) Currents PFO, .±5mA
Operating Ambient Temperature Range LTC2935C 70°C LTC2935I. -40°C 85°C Storage Temperature Range. -65°C 150°C Lead Temperature (Soldering, sec) TSOT-23 Package. 300°C
CONFIGURATION
VIEW VIEW
PACKAGE 8-LEAD (2mm 2mm) PLASTIC TJMAX 125°C, 102°C/W EXPOSED (PIN CONNECTION OPTIONAL
PACKAGE 8-LEAD PLASTIC TSOT-23 TJMAX 125°C, 195°C/W
ORDER INFORMATION
Lead Free Finish
TAPE REEL (MINI) LTC2935CTS8-1#TRMPBF LTC2935ITS8-1#TRMPBF LTC2935CTS8-2#TRMPBF LTC2935ITS8-2#TRMPBF LTC2935CTS8-3#TRMPBF LTC2935ITS8-3#TRMPBF LTC2935CTS8-4#TRMPBF LTC2935ITS8-4#TRMPBF LTC2935CDC-1#TRMPBF LTC2935IDC-1#TRMPBF LTC2935CDC-2#TRMPBF LTC2935IDC-2#TRMPBF LTC2935CDC-3#TRMPBF LTC2935IDC-3#TRMPBF LTC2935CDC-4#TRMPBF LTC2935IDC-4#TRMPBF TAPE REEL LTC2935CTS8-1#TRPBF LTC2935ITS8-1#TRPBF LTC2935CTS8-2#TRPBF LTC2935ITS8-2#TRPBF LTC2935CTS8-3#TRPBF LTC2935ITS8-3#TRPBF LTC2935CTS8-4#TRPBF LTC2935ITS8-4#TRPBF LTC2935CDC-1#TRPBF LTC2935IDC-1#TRPBF LTC2935CDC-2#TRPBF LTC2935IDC-2#TRPBF LTC2935CDC-3#TRPBF LTC2935IDC-3#TRPBF LTC2935CDC-4#TRPBF LTC2935IDC-4#TRPBF PART MARKING* LTDPW LTDPW LTDQB LTDQB LTFHV LTFHV LTFHX LTFHX LDPX LDPX LDQC LDQC LFHW LFHW LFHY LFHY PACKAGE DESCRIPTION 8-Lead Plastic TSOT-23 8-Lead Plastic TSOT-23 8-Lead Plastic TSOT-23 8-Lead Plastic TSOT-23 8-Lead Plastic TSOT-23 8-Lead Plastic TSOT-23 8-Lead Plastic TSOT-23 8-Lead Plastic TSOT-23 8-Lead (2mm 2mm) Plastic 8-Lead (2mm 2mm) Plastic 8-Lead (2mm 2mm) Plastic 8-Lead (2mm 2mm) Plastic 8-Lead (2mm 2mm) Plastic 8-Lead (2mm 2mm) Plastic 8-Lead (2mm 2mm) Plastic TEMPERATURE RANGE 70°C -40°C 85°C 70°C -40°C 85°C 70°C -40°C 85°C 70°C -40°C 85°C 70°C -40°C 85°C 70°C -40°C 85°C 70°C -40°C 85°C 70°C -40°C 85°C
8-Lead (2mm 2mm) Plastic pieces. *Temperature grades identified label shipping container. Consult Marketing parts specified with wider operating temperature ranges. Consult Marketing information lead based finish parts. more information lead free part marking, http://www.linear.com/leadfree/ more information tape reel specifications,
2935fa
LTC2935 ELECTRICAL CHARACTERISTICS
SYMBOL VRTF1 VRTF2 VRTF3 VRTF4 VRTF5 VRTF6 VRTF7 VRTF8 VRTF VRT(HYST) tUVR VRTF1 VRTF2 VRTF3 VRTF4 VRTF5 VRTF6 VRTF7 VRTF8 VRTF VRT(HYST) tUVR VPFT PARAMETER Input Supply Voltage Input Supply Current Reset Threshold (VCC Falling) Reset Threshold (VCC Falling) Reset Threshold (VCC Falling) Reset Threshold (VCC Falling) Reset Threshold (VCC Falling) Reset Threshold (VCC Falling) Reset Threshold (VCC Falling) Reset Threshold (VCC Falling) Reset Threshold Differential VRTF(N+1) VRTF(N) Reset Threshold Hysteresis (VCC Rising) Undervoltage Detect Falling Reset Threshold (VCC Falling) Reset Threshold (VCC Falling) Reset Threshold (VCC Falling) Reset Threshold (VCC Falling) Reset Threshold (VCC Falling) Reset Threshold (VCC Falling) Reset Threshold (VCC Falling) Reset Threshold (VCC Falling) Reset Threshold Differential VRTF(N+1) VRTF(N) Reset Threshold Hysteresis (VCC Rising) Undervoltage Detect Falling Power-Fail Threshold Differential VPFT(N) VRTF(N) High High High High High High High High High High High High (Note Relative Selected Reset Threshold Below Threshold (Note High High High High High High High High High High High High (Note Relative Selected Reset Threshold Below Threshold (Note Selected Reset Threshold (VCC Falling) Relative Selected Power-Fail Threshold (VCC Rising) Below Threshold (Note Selected Reset Threshold (VCC Falling) Relative Selected Power-Fail Threshold (VCC Rising) Below Threshold (Note Manual Reset Falling
denotes specifications which apply over full operating temperature range, otherwise specifications 25°C, 3.6V, unless otherwise noted. (Note
CONDITIONS
3.251 3.103 2.955 2.808 2.660 2.512 2.364 2.217
3.300 3.150 3.000 2.850 2.700 2.550 2.400 2.250
1000 3.349 3.197 3.045 2.892 2.740 2.588 2.436 2.283
UNITS
Reset Thresholds (LTC2935-1/LTC2935-2)
Reset Thresholds (LTC2935-3/LTC2935-4) 2.404 2.286 2.167 2.049 1.931 1.813 1.695 1.576 2.440 2.320 2.200 2.080 1.960 1.840 1.720 1.600 1200 2.476 2.354 2.233 2.111 1.989 1.867 1.745 1.624
2935fa
Power-Fail Thresholds (LTC2935-1/LTC2935-2) VPFT(HYST) Power-Fail Threshold Hysteresis tUVP VPFT Undervoltage Detect Falling Power-Fail Threshold Differential VPFT(N) VRTF(N)
Power-Fail Thresholds (LTC2935-3/LTC2935-4) VPFT(HYST) Power-Fail Threshold Hysteresis tUVP VIN(TH) Undervoltage Detect Falling Control Input Threshold Input Pulse Width Propagation Delay Falling Internal Pull-Up Resistance Input Leakage Current
Control Inputs:
LTC2935 ELECTRICAL CHARACTERISTICS
SYMBOL PARAMETER Voltage Output Reset Power-Fail Outputs: RST, 200A Pull-Up Current Pull-Up Current -200A Pull-Down Current VRST, VPFO 3.6V
denotes specifications which apply over full operating temperature range, otherwise specifications 25°C, 3.6V, unless otherwise noted. (Note
CONDITIONS UNITS
tRST
Voltage Output High (LTC2935-2) Current Output High, Leakage (LTC2935-1) Reset Timeout Period
Note Stresses beyond those listed under Absolute Maximum Ratings cause permanent damage device. Exposure Absolute Maximum Rating condition extended periods affect device reliability lifetime.
Note currents into pins positive, voltages referenced unless otherwise noted. Note Guaranteed design. Characterized, production tested.
TYPICAL PERFORMANCE CHARACTERISTICS
Supply Current Supply Voltage
1000 NORMALIZED THRESHOLD 85°C 1.015 1.010 1.005 1.000 0.995 0.990 0.985
25°C, unless otherwise noted. Comparator Undervoltage Glitch Immunity
3.6V
Normalized Reset Power-Fail Thresholds Temperature
GLITCH DURATION, (ms)
(nA)
25°C -40°C
COMPARATORS PULL DOWN ABOVE CURVE
2935
TEMPERATURE (°C)
2935
COMPARATOR OVERDRIVE
2935
Reset Timeout Period Temperature
tRST (ms) (mV) 3.6V
Voltage Output Pull-Up Current (RST, PFO)
85°C 25°C (mV) -40°C
Voltage Output High Pull-Down Current (RST, PFO)
LTC2935-2 3.6V
-40°C 25°C
85°C
TEMPERATURE (°C)
2935
PULL-UP CURRENT (mA)
2935
-0.4 -0.6 -0.8 -0.2 PULL-DOWN CURRENT (mA)
2935
2935fa
LTC2935 TYPICAL PERFORMANCE CHARACTERISTICS
Supply Current Input Voltage
3.6V
25°C, unless otherwise noted.
Supply Current Input Voltage
3.6V
2935
INPUT VOLTAGE
2935
INPUT VOLTAGE
FUNCTIONS
Exposed (DFN Only): Exposed left floating connected device ground. GND: Device ground. Manual Reset Input. Attach pushbutton switch between this input ground. logic this input pulls low. When input returns logic high, returns high after 200ms. unused. PFO: Power-Fail Output. pulls when falls below power-fail threshold. power-fail threshold above configured falling reset threshold pre-determined margin. released when rises above power-fail threshold 2.5%. available with open-drain (LTC2935-1/LTC2935-3) active pull-up (LTC2935-2/LTC2935-4) outputs. Leave open unused. RST: Reset Output. pulls when falls below reset threshold. released 200ms after exceeds reset threshold plus hysteresis. available with open-drain (LTC2935-1/LTC2935-3) active pull-up (LTC2935-2/LTC2935-4) outputs. Leave open unused. Threshold Selection Inputs. required reset threshold. Falling Threshold Selection Table page settings. VCC: Power Supply Monitored Voltage Input. Bypass with 0.1F capacitor GND.
2935fa
LTC2935 BLOCK DIAGRAM
900k LTC2935-2/LTC2935-4
RESET DELAY
0.4V
TIMING DIAGRAM
VPFT VRTF
2935
LTC2935-2/LTC2935-4
2935
2935fa
LTC2935 APPLICATIONS INFORMATION
VOLTAGE MONITORING Unmanaged power cause various system problems. power-up, voltage fluctuation around critical thresholds cause improper system processor initialization. LTC2935 provides power management capabilities system power-up phase. supervisory device issues system reset after monitored voltage stabilized. Built-in hysteresis filtering ensures that fluctuations load transients supply noise cause chattering status outputs. Comparator undervoltage glitch immunity shown Typical Performance Characteristics section. curve demonstrates transient amplitude width required switch comparators. Because many batteries exhibit large series resistance, load currents cause significant voltage drops. current draw LTC2935 input voltage) does loading problem. When voltage initially applied VCC, pull once there enough voltage turn pull-down devices maximum). monitored supply voltage falls power-fail threshold, built-in power-fail comparator pulls low. this point, there remains voltage margin before output pulls low. remains until rises above power-fail threshold plus 2.5% hysteresis. typically used signal preparation controlled shutdown. example, output connected processor nonmaskable interrupt. Upon interrupt, processor begin shutdown procedures. Shutdown events include supply sequencing and/or storage/ erasure system state nonvolatile memory. monitored voltage drops below reset threshold, pulls until rises above reset threshold plus hysteresis. This occur through battery charging replacement. internal reset timer delays return output high state provide settling initialization time. output typically connected processor reset input. Few, external components necessary reliable operation. However, decoupling capacitor between ground recommended (0.01F minimum). Threshold Configuration LTC2935 monitors compares voltage against internal thresholds during operation. higher threshold (power-fail) level used early warning voltage condition, reported output. lower threshold (reset) level which output pulls low. system requirements choose appropriate reset threshold from Table
Table Falling Threshold Selection
LTC2935-1/LTC2935-2 LTC2935-3/LTC2935-4 RESET POWER-FAIL RESET POWER-FAIL THRESHOLD THRESHOLD THRESHOLD THRESHOLD 3.30 3.15 3.00 2.85 2.70 2.55 2.40 2.25 3.45 3.30 3.15 3.00 2.85 2.70 2.55 2.40 2.44 2.32 2.20 2.08 1.96 1.84 1.72 1.60 2.56 2.44 2.32 2.20 2.08 1.96 1.84 1.72
High High High High High High High High High High High High
LTC2935-1/LTC2935-2 power-fail threshold always 150mV higher than configured reset threshold. LTC2935-3/LTC2935-4 power-fail threshold always 120mV higher than configured reset threshold. threshold selection inputs (S2, accordingly.
2935fa
LTC2935 APPLICATIONS INFORMATION
Selecting Output Logic Style LTC2935 status outputs available options: open-drain (LTC2935-1/LTC2935-3) active pull-up (LTC2935-2/LTC2935-4). open-drain options (LTC2935-1/LTC2935-3) allow outputs pulled user defined voltage with resistor. open-drain pull-up voltage greater than (5.5V maximum), which always possible with inferior battery supervisors, internal clamps. When status outputs low, power dissipated pull-up resistors. Recommended resistor values range between 470k. Figure demonstrates typical LTC2935-1/LTC2935-3 output behavior. active pull-up options (LTC2935-2/LTC2935-4) eliminate need external pull-up resistors status outputs. Integrated pull-up devices pull outputs VCC. Actively pulled outputs driven above VCC. Some applications require and/or outputs valid with down ground. Active pull-up handles this requirement with addition external resistor from output ground. resistor provides path leakage currents, preventing output from floating
LTC2935-1
2935
undetermined voltages when connected high impedance (such CMOS logic inputs). resistor value should small enough provide effective pull-down without excessively loading pull-up circuitry. 100k resistor from output ground satisfactory most applications. When status outputs high, power dissipated pull-down resistors. Figure demonstrates typical LTC2935-2/LTC2935-4 output behavior. Manual Reset Input When above reset threshold, manual reset input (MR) pulled low, output forced low. remains 200ms after manual reset input released pulled high. manual reset input pulled internally through 900k VCC. external leakage currents have ability pull down manual reset input below logic threshold, lower value pull-up resistor, placed between will problem. Input often pulled down through pushbutton switch requiring human contact. extended tolerance required, series resistance between switch input recommended. most applications, resistor provides sufficient current limiting.
LTC2935-2
2935
Figure with Pull-Up
Figure
2935fa
LTC2935 TYPICAL APPLICATIONS
Battery Monitor with Interface Voltage Logic
SHDN LT3009 1.18M 590k 100k 100k LTC2935-1 1.8V
Li-Ion
0.1F
RESD* MANUAL RESET PUSHBUTTON
2935 TA02
POWER FAIL FALLING THRESHOLD 3.15V RESET FALLING THRESHOLD 3.00V
*OPTIONAL RESISTOR ADDED PROTECTION
Alkaline Cell Stack Voltage Monitor
LTC2935-2 BATTERY
1.5V
0.1F
1.5V 1.5V
2935 TA03
SYSTEM RESET
POWER FAIL FAIL THRESHOLD 2.55V RESET THRESHOLD 2.40V
Coin Cell Voltage Monitor
LTC2935-2
2935 TA04
CR2032
0.1F
BATTERY
SYSTEM RESET
POWER FAIL FAIL THRESHOLD 2.70V RESET THRESHOLD 2.55V
2935fa
LTC2935 PACKAGE Package 8-Lead Plastic (2mm 2mm)
(Reference 05-08-1719
0.70 ±0.05 2.55 ±0.05 1.15 ±0.05 0.64 ±0.05 SIDES) PACKAGE OUTLINE
0.25 0.05 0.45 1.37 ±0.05 SIDES) RECOMMENDED SOLDER PITCH DIMENSIONS APPLY SOLDER MASK AREAS THAT SOLDERED
0.05 2.00 ±0.10 SIDES)
0.115
0.40 0.10 NOTCH 0.20 0.25 CHAMFER
(DC8) 0106
MARK (SEE NOTE
0.64 0.10 SIDES)
0.200 0.75 ±0.05 1.37 ±0.10 SIDES) 0.00 0.05
0.23 0.05 0.45
BOTTOM VIEW-EXPOSED
NOTE: DRAWING JEDEC PACKAGE OUTLINE DRAWING SCALE DIMENSIONS MILLIMETERS DIMENSIONS EXPOSED BOTTOM PACKAGE INCLUDE MOLD FLASH. MOLD FLASH, PRESENT, SHALL EXCEED 0.15mm SIDE EXPOSED SHALL SOLDER PLATED SHADED AREA ONLY REFERENCE LOCATION BOTTOM PACKAGE
2935fa
LTC2935 PACKAGE Package 8-Lead Plastic TSOT-23
(Reference 05-08-1637)
0.52 0.65 2.90 (NOTE
1.22
3.85 2.62
2.80
1.50 1.75 (NOTE
RECOMMENDED SOLDER LAYOUT CALCULATOR
0.65
0.22 0.36 PLCS (NOTE
0.80 0.90 0.20 1.00 DATUM 0.01 0.10
0.30 0.50
NOTE: DIMENSIONS MILLIMETERS DRAWING SCALE DIMENSIONS INCLUSIVE PLATING DIMENSIONS EXCLUSIVE MOLD FLASH METAL BURR MOLD FLASH SHALL EXCEED 0.254mm JEDEC PACKAGE REFERENCE MO-193
0.09 0.20 (NOTE
1.95
TSOT-23 0802
2935fa
Information furnished Linear Technology Corporation believed accurate reliable. However, responsibility assumed use. Linear Technology Corporation makes representation that interconnection circuits described herein will infringe existing patent rights.
LTC2935 TYPICAL APPLICATION
Portable Device Battery Monitor
1.8V Li-Ion 0.1F LTC2935-1 590k 100k SHDN LT3009 1.18M 100k
POWER FAIL FALLING THRESHOLD 3.15V RESET FALLING THRESHOLD 3.00V
2935 TA05
BATTERY EARLY WARNING
RELATED PARTS
PART NUMBER LTC690 LTC694-3.3 LTC1232 LTC1326 LTC1726 LTC1727 LTC1728 LTC1985 LTC2900 LTC2901 LTC2902 LTC2903 LTC2904/LTC2905/ LTC2906/LTC2907 LTC2908 LTC2909 LTC2910 LTC2912/LTC2913/ LTC2914 LTC2915/LTC2916/ LTC2917/LTC2918 LTC2934 DESCRIPTION Supply Monitor, Watchdog Timer Battery Backup 3.3V Supply Monitor, Watchdog Timer Battery Backup Supply Monitor, Watchdog Timer Pushbutton Reset Micropower Triple Supply Monitor 5V/2.5V, 3.3V Micropower Triple Supply Monitor 2.5V/5V, 3.3V Micropower Triple Supply Monitor with Open-Drain Reset Micropower Triple Supply Monitor with Open-Drain Reset Micropower Triple Supply Monitor with Push-Pull Reset Output Programmable Quad Supply Monitor Programmable Quad Supply Monitor Programmable Quad Supply Monitor Precision Quad Supply Monitor Three-State Programmable Precision Dual Supply Monitor Precision Six-Supply Monitor (Four Fixed Adjustable) Precision Triple/Dual Input Negative Voltage Monitor Octal Positive/Negative Voltage Monitor Single/Dual/Quad Voltage Monitors Single Voltage Supervisors with Pin-Selectable Thresholds Ultralow Power Supervisor with Power-Fail Output COMMENTS 4.65V Threshold 2.9V Threshold 4.37V/4.62V Threshold 4.725V, 3.118V, Threshold (±0.75%) Adjustable Reset Watchdog Timeouts Individual Monitor Outputs MSOP 5-Lead SOT-23 Package 5-Lead SOT-23 Package Adjustable Reset, 10-Lead MSOP Packages Adjustable Reset Watchdog Timer Adjustable Reset Tolerance 6-Lead SOT-23 Package 8-Lead SOT-23 Packages 8-Lead TSOT-23 Packages Shunt Regulated Pin, Adjustable Threshold Reset, 8-Lead SOT-23 Packages Separate Pin, Eight Inputs, Negative Monitors Adjustable Reset Timer, 16-Lead SSOP Packages Separate Pin, Adjustable Reset Timer Manual Reset Watchdog Functions 500nA Quiescent Current, 8-Lead TSOT-23 Packages, Adjustable External Resistors
2935fa
Linear Technology Corporation
(408) 432-1900 FAX: (408) 434-0507
0609 PRINTED
1630 McCarthy Blvd., Milpitas, 95035-7417
www.linear.com
LINEAR TECHNOLOGY CORPORATION 2008

LTC2935 ultra-low power voltage monitor provides system initialization

Top Searches for this datasheet

Other recent searches