LTC2935 Ultra-Low Power Supervisor with Power-Fail Output, Selectable Thresholds FEATURES DESCRIPTION n The LTC®2935 ultra-low power voltage monitor provides system initialization, power-fail warning and reset generation functions. Low quiescent current (500nA typical) makes the LTC2935 an ideal choice for battery-operated applications. n n n n n n n n 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, 2mm × 2mm DFN and TSOT-23 (ThinSOT™) Packages APPLICATIONS n n n n n Portable Equipment Battery-Powered Equipment Security Systems Point-of-Sale Devices Wireless Systems L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. Three binary threshold-select inputs configure one of eight integrated reset thresholds, ranging from 1.6V to 3.45V in pre-determined increments. Early warning of an impending low voltage condition is provided at the powerfail output (PFO), whose threshold is above the configured reset threshold. Supervisory circuits monitor VCC and pull RST low when VCC drops below the configured reset threshold. When VCC is rising from an under-threshold condition, an internal reset timer is started after exceeding the reset threshold by 5%. A 200ms reset timeout delays the return of the RST output to a high state. A pushbutton switch connected to the MR input is typically used to force a manual reset. Outputs RST and PFO are available with open-drain (LTC2935-1/LTC2935-3) or active pull-up (LTC2935-2/LTC2935-4) circuits. Operating temperature range is from –40°C to 85°C. TYPICAL APPLICATION Falling Threshold Selection Table Configurable Low Power Voltage Monitor VIN 0.1μF S1 PFO S0 BATTERY POWERED SYSTEM LOGIC LTC2935-2 RST MR LTC2935-3/LTC2935-4 RESET POWER-FAIL RESET POWER-FAIL THRESHOLD THRESHOLD THRESHOLD THRESHOLD (V) (V) (V) (V) VCC S2 LTC2935-1/LTC2935-2 GND S2 S1 S0 3.30 3.45 2.44 2.56 Low Low Low 3.15 3.30 2.32 2.44 Low Low High 3.00 3.15 2.20 2.32 Low High High 2.85 3.00 2.08 2.20 Low High Low 2.70 2.85 1.96 2.08 High High Low 2.55 2.70 1.84 1.96 High Low Low 2.40 2.55 1.72 1.84 High Low High 2.25 2.40 1.60 1.72 High High High 2935 TA01a 2935fa 1 LTC2935 ABSOLUTE MAXIMUM RATINGS (Notes 1, 2) Input Voltages VCC........................................................... –0.3V to 6V S2, S1, S0, MR .........................–0.3V to (VCC + 0.3V) Output Voltages (PFO, RST) LTC2935-1/LTC2935-3 ............................. –0.3V to 6V LTC2935-2/LTC2935-4 ..............–0.3V to (VCC + 0.3V) RMS Currents PFO, RST ..........................................................±5mA Operating Ambient Temperature Range LTC2935C ................................................ 0°C to 70°C LTC2935I.............................................. –40°C to 85°C Storage Temperature Range................... –65°C to 150°C Lead Temperature (Soldering, 10 sec) TSOT-23 Package.............................................. 300°C PIN CONFIGURATION TOP VIEW MR 2 RST 3 PFO 4 TOP VIEW 8 S2 VCC 1 9 S2 1 S1 2 S0 3 GND 4 7 S1 6 S0 5 GND DC PACKAGE 8-LEAD (2mm s 2mm) PLASTIC DFN TJMAX = 125°C, θJA = 102°C/W EXPOSED PAD (PIN 9), PCB GND CONNECTION OPTIONAL 8 VCC 7 MR 6 RST 5 PFO TS8 PACKAGE 8-LEAD PLASTIC TSOT-23 TJMAX = 125°C, θJA = 195°C/W ORDER INFORMATION Lead Free Finish TAPE AND REEL (MINI) TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LTC2935CTS8-1#TRMPBF LTC2935CTS8-1#TRPBF LTDPW 8-Lead Plastic TSOT-23 0°C to 70°C LTC2935ITS8-1#TRMPBF LTC2935ITS8-1#TRPBF LTDPW 8-Lead Plastic TSOT-23 –40°C to 85°C LTC2935CTS8-2#TRMPBF LTC2935CTS8-2#TRPBF LTDQB 8-Lead Plastic TSOT-23 0°C to 70°C LTC2935ITS8-2#TRMPBF LTC2935ITS8-2#TRPBF LTDQB 8-Lead Plastic TSOT-23 –40°C to 85°C LTC2935CTS8-3#TRMPBF LTC2935CTS8-3#TRPBF LTFHV 8-Lead Plastic TSOT-23 0°C to 70°C LTC2935ITS8-3#TRMPBF LTC2935ITS8-3#TRPBF LTFHV 8-Lead Plastic TSOT-23 –40°C to 85°C LTC2935CTS8-4#TRMPBF LTC2935CTS8-4#TRPBF LTFHX 8-Lead Plastic TSOT-23 0°C to 70°C LTC2935ITS8-4#TRMPBF LTC2935ITS8-4#TRPBF LTFHX 8-Lead Plastic TSOT-23 –40°C to 85°C LTC2935CDC-1#TRMPBF LTC2935CDC-1#TRPBF LDPX 8-Lead (2mm × 2mm) Plastic DFN 0°C to 70°C LTC2935IDC-1#TRMPBF LTC2935IDC-1#TRPBF LDPX 8-Lead (2mm × 2mm) Plastic DFN –40°C to 85°C LTC2935CDC-2#TRMPBF LTC2935CDC-2#TRPBF LDQC 8-Lead (2mm × 2mm) Plastic DFN 0°C to 70°C LTC2935IDC-2#TRMPBF LTC2935IDC-2#TRPBF LDQC 8-Lead (2mm × 2mm) Plastic DFN –40°C to 85°C LTC2935CDC-3#TRMPBF LTC2935CDC-3#TRPBF LFHW 8-Lead (2mm × 2mm) Plastic DFN 0°C to 70°C LTC2935IDC-3#TRMPBF LTC2935IDC-3#TRPBF LFHW 8-Lead (2mm × 2mm) Plastic DFN –40°C to 85°C LFHY 8-Lead (2mm × 2mm) Plastic DFN LTC2935CDC-4#TRMPBF LTC2935CDC-4#TRPBF 8-Lead (2mm × 2mm) Plastic DFN TRM = 500 pieces. *Temperature grades are identified by a label on the shipping container. Consult LTC Marketing for parts specified with wider operating temperature ranges. Consult LTC Marketing for information on lead based finish parts. For more information on lead free part marking, go to: http://www.linear.com/leadfree/ For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/ LTC2935IDC-4#TRMPBF LTC2935IDC-4#TRPBF LFHY 0°C to 70°C –40°C to 85°C 2935fa 2 LTC2935 ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C, VCC = 3.6V, unless otherwise noted. (Note 2) SYMBOL PARAMETER VCC VCC Input Supply Voltage CONDITIONS l MIN ICC VCC Input Supply Current l 225 S2 = Low : S1 = Low : S0 = Low l TYP MAX UNITS 5.5 V 500 1000 nA 3.251 3.300 3.349 V Reset Thresholds (LTC2935-1/LTC2935-2) VRTF1 Reset Threshold 1 (VCC Falling) VRTF2 Reset Threshold 2 (VCC Falling) S2 = Low : S1 = Low : S0 = High l 3.103 3.150 3.197 V VRTF3 Reset Threshold 3 (VCC Falling) S2 = Low : S1 = High : S0 = High l 2.955 3.000 3.045 V VRTF4 Reset Threshold 4 (VCC Falling) S2 = Low : S1 = High : S0 = Low l 2.808 2.850 2.892 V VRTF5 Reset Threshold 5 (VCC Falling) S2 = High : S1 = High : S0 = Low l 2.660 2.700 2.740 V VRTF6 Reset Threshold 6 (VCC Falling) S2 = High : S1 = Low : S0 = Low l 2.512 2.550 2.588 V VRTF7 Reset Threshold 7 (VCC Falling) S2 = High : S1 = Low : S0 = High l 2.364 2.400 2.436 V VRTF8 Reset Threshold 8 (VCC Falling) S2 = High : S1 = High : S0 = High l 2.217 2.250 2.283 ΔVRTF Reset Threshold Differential VRTF(N+1) – VRTF(N) (Note 3) l 142 150 158 mV VRT(HYST) Reset Threshold Hysteresis (VCC Rising) Relative to Any Selected Reset Threshold l 4.5 5 6 % tUVR Undervoltage Detect to RST Falling VCC Below Threshold by 1% (Note 3) 1 V ms Reset Thresholds (LTC2935-3/LTC2935-4) VRTF1 Reset Threshold 1 (VCC Falling) S2 = Low : S1 = Low : S0 = Low l 2.404 2.440 2.476 V VRTF2 Reset Threshold 2 (VCC Falling) S2 = Low : S1 = Low : S0 = High l 2.286 2.320 2.354 V VRTF3 Reset Threshold 3 (VCC Falling) S2 = Low : S1 = High : S0 = High l 2.167 2.200 2.233 V VRTF4 Reset Threshold 4 (VCC Falling) S2 = Low : S1 = High : S0 = Low l 2.049 2.080 2.111 V VRTF5 Reset Threshold 5 (VCC Falling) S2 = High : S1 = High : S0 = Low l 1.931 1.960 1.989 V VRTF6 Reset Threshold 6 (VCC Falling) S2 = High : S1 = Low : S0 = Low l 1.813 1.840 1.867 V VRTF7 Reset Threshold 7 (VCC Falling) S2 = High : S1 = Low : S0 = High l 1.695 1.720 1.745 V VRTF8 Reset Threshold 8 (VCC Falling) S2 = High : S1 = High : S0 = High l 1.576 1.600 1.624 ΔVRTF Reset Threshold Differential VRTF(N+1) – VRTF(N) (Note 3) l 112 120 128 mV VRT(HYST) Reset Threshold Hysteresis (VCC Rising) Relative to Any Selected Reset Threshold l 4.5 5 6 % tUVR Undervoltage Detect to RST Falling VCC Below Threshold by 1% (Note 3) 1 V ms Power-Fail Thresholds (LTC2935-1/LTC2935-2) ΔVPFT Power-Fail Threshold Differential VPFT(N) – VRTF(N) VPFT(HYST) Power-Fail Threshold Hysteresis tUVP Undervoltage Detect to PFO Falling Any Selected Reset Threshold (VCC Falling) l 100 150 200 mV Relative to Any Selected Power-Fail Threshold (VCC Rising) l 2 2.5 3.5 % VCC Below Threshold by 1% (Note 3) 1 ms Power-Fail Thresholds (LTC2935-3/LTC2935-4) ΔVPFT Power-Fail Threshold Differential VPFT(N) – VRTF(N) VPFT(HYST) Power-Fail Threshold Hysteresis tUVP Undervoltage Detect to PFO Falling Any Selected Reset Threshold (VCC Falling) l 70 120 170 mV Relative to Any Selected Power-Fail Threshold (VCC Rising) l 2 2.5 3 % VCC Below Threshold by 1% (Note 3) 1 ms Control Inputs: MR, S2, S1, S0 VIN(TH) Control Input Threshold S2, S1, S0 MR l 0.3 • VCC l 0.4 tPW Input Pulse Width MR l 20 tPD Propagation Delay to RST Falling Manual Reset Falling l 2 5 20 μs RPU Internal Pull-Up Resistance MR l 600 900 1200 kΩ ILK Input Leakage Current S2, S1, S0 = VCC or GND l ±1 ±10 nA 0.7 • VCC 1.4 V V μs 2935fa 3 LTC2935 ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C, VCC = 3.6V, unless otherwise noted. (Note 2) SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS 25 50 100 150 mV mV ±1 ±10 nA 200 260 ms Reset and Power-Fail Outputs: RST, PFO VOL Voltage Output Low VCC = 1V, 200μA Pull-Up Current VCC = 3V, 3mA Pull-Up Current S2, S1, S0 = Low l l VOH Voltage Output High (LTC2935-2) –200μA Pull-Down Current l 0.7 • VCC IOH Current Output High, Leakage (LTC2935-1) VRST, VPFO = 3.6V l tRST Reset Timeout Period l Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime. Note 2. All currents into pins are positive, all voltages are referenced to GND unless otherwise noted. Note 3. Guaranteed by design. Characterized, but not production tested. TYPICAL PERFORMANCE CHARACTERISTICS 800 85°C 600 25°C 400 –40°C 200 0 1 2 3 VCC (V) 4 5 6 1.015 3.0 1.010 2.5 1.005 1.000 0.995 0.990 0.985 –50 –25 0 25 50 TEMPERATURE (°C) 75 2935 G01 COMPARATORS PULL DOWN ABOVE CURVE 1.5 1.0 0 0.1 100 1 10 COMPARATOR OVERDRIVE (%) 100 2935 G03 Voltage Output Low vs Pull-Up Current (RST, PFO) Voltage Output High vs Pull-Down Current (RST, PFO) 3.6 100 VCC = 3.6V 240 VCC = 3V LTC2935-2 VCC = 3.6V 85°C 80 3.5 25°C VOL (mV) 220 tRST (ms) 2.0 2935 G02 Reset Timeout Period vs Temperature 260 VCC = 3.6V 0.5 200 60 VOH (mV) 0 Comparator Undervoltage Glitch Immunity GLITCH DURATION, t UV (ms) S0 = S1 = S2 = GND NORMALIZED THRESHOLD (V/ V) ICC (nA) 1000 TA = 25°C, unless otherwise noted. Normalized Reset and Power-Fail Thresholds vs Temperature Supply Current vs Supply Voltage 140 V –40°C 40 –40°C 3.4 25°C 180 3.3 20 160 140 –50 –25 0 25 50 TEMPERATURE (°C) 75 100 2935 G04 0 85°C 3.2 0 1 2 3 4 PULL-UP CURRENT (mA) 5 2935 G05 0 –0.4 –0.6 –0.8 –0.2 PULL-DOWN CURRENT (mA) –1 2935 G06 2935fa 4 LTC2935 TYPICAL PERFORMANCE CHARACTERISTICS Supply Current vs S0, S1, S2 Input Voltage Supply Current vs MR Input Voltage 5 VCC = 3.6V 200 4 150 3 ICC (μA) ICC (μA) 250 TA = 25°C, unless otherwise noted. 100 50 VCC = 3.6V 2 1 0 0 0 0.5 1 1.5 2 2.5 3 S0, S1, S2 INPUT VOLTAGE (V) 3.5 4 2935 G07 0 0.5 1 1.5 2 2.5 3 MR INPUT VOLTAGE (V) 3.5 4 2935 G08 PIN FUNCTIONS Exposed Pad (DFN Only): Exposed Pad may be left floating or connected to device ground. GND: Device ground. MR: Manual Reset Input. Attach a pushbutton switch between this input and ground. A logic low on this input pulls RST low. When the MR input returns to logic high, RST returns high after 200ms. Tie to VCC if unused. PFO: Power-Fail Output. PFO pulls low when VCC falls below the power-fail threshold. The power-fail threshold is above the configured falling reset threshold by a pre-determined margin. PFO is released when VCC rises above the power-fail threshold by 2.5%. PFO is available with open-drain (LTC2935-1/LTC2935-3) or active pull-up (LTC2935-2/LTC2935-4) outputs. Leave open if unused. RST: Reset Output. RST pulls low when VCC falls below the reset threshold. RST is released 200ms after VCC exceeds the reset threshold plus 5% hysteresis. RST is available with open-drain (LTC2935-1/LTC2935-3) or active pull-up (LTC2935-2/LTC2935-4) outputs. Leave open if unused. S2, S1, S0: Threshold Selection Inputs. Tie to GND or VCC for required reset threshold. See the Falling Threshold Selection Table on page 1 for settings. VCC: Power Supply and Monitored Voltage Input. Bypass VCC with a 0.1μF capacitor to GND. 2935fa 5 LTC2935 BLOCK DIAGRAM LTC2935-2/LTC2935-4 MR VCC 900k VCC – RST RC RESET DELAY + S0 LTC2935-2/LTC2935-4 S1 VCC S2 0.4V + PFO PC – GND 2935 BD TIMING DIAGRAM VPFT VRTF VCC PFO t RST t RST RST MR 2935 TD t PD 2935fa 6 LTC2935 APPLICATIONS INFORMATION VOLTAGE MONITORING Unmanaged power can cause various system problems. At power-up, voltage fluctuation around critical thresholds can cause improper system or processor initialization. The LTC2935 provides power management capabilities for the system power-up phase. The supervisory device issues a system reset after the monitored voltage has stabilized. Built-in hysteresis and filtering ensures that fluctuations due to load transients or supply noise do not cause chattering of the status outputs. Comparator undervoltage glitch immunity is shown in the Typical Performance Characteristics section. The curve demonstrates the transient amplitude and width required to switch the comparators. Because many batteries exhibit large series resistance, load currents can cause significant voltage drops. The low DC current draw of the LTC2935 (at any input voltage) does not add to the loading problem. When voltage is initially applied to VCC, RST and PFO pull low once there is enough voltage to turn on the pull-down devices (1V maximum). If the monitored supply voltage falls to the power-fail threshold, the built-in power-fail comparator pulls PFO low. At this point, there remains a voltage margin before the RST output pulls low. PFO remains low until VCC rises above the power-fail threshold plus 2.5% hysteresis. PFO is typically used in signal preparation for controlled shutdown. For example, the PFO output may be connected to a processor nonmaskable interrupt. Upon interrupt, the processor may begin shutdown procedures. Shutdown events may include supply sequencing and/or storage/ erasure of system state in nonvolatile memory. If the monitored voltage drops below the reset threshold, RST pulls low until VCC rises above the reset threshold plus 5% hysteresis. This may occur through battery charging or replacement. An internal reset timer delays the return of the RST output to a high state to provide settling and initialization time. The RST output is typically connected to a processor reset input. Few, if any external components are necessary for reliable operation. However, a decoupling capacitor between VCC and ground is recommended (0.01μF minimum). Threshold Configuration The LTC2935 monitors and compares the VCC voltage against two internal thresholds during operation. The higher threshold (power-fail) is the level used for early warning of a low voltage condition, reported on the PFO output. The lower threshold (reset) is the level at which the RST output pulls low. Use system requirements to choose the appropriate reset threshold from Table 1. Table 1. Falling Threshold Selection LTC2935-1/LTC2935-2 LTC2935-3/LTC2935-4 RESET POWER-FAIL RESET POWER-FAIL THRESHOLD THRESHOLD THRESHOLD THRESHOLD (V) (V) (V) (V) S2 S1 S0 3.30 3.45 2.44 2.56 Low Low Low 3.15 3.30 2.32 2.44 Low Low High 3.00 3.15 2.20 2.32 Low High High 2.85 3.00 2.08 2.20 Low High Low 2.70 2.85 1.96 2.08 High High Low 2.55 2.70 1.84 1.96 High Low Low 2.40 2.55 1.72 1.84 High Low High 2.25 2.40 1.60 1.72 High High High In the LTC2935-1/LTC2935-2 the power-fail threshold is always 150mV higher than the configured reset threshold. In the LTC2935-3/LTC2935-4 the power-fail threshold is always 120mV higher than the configured reset threshold. Set the threshold selection inputs (S2, S1, S0) accordingly. 2935fa 7 LTC2935 APPLICATIONS INFORMATION Selecting Output Logic Style The LTC2935 status outputs are available in two options: open-drain (LTC2935-1/LTC2935-3) or active pull-up (LTC2935-2/LTC2935-4). The open-drain options (LTC2935-1/LTC2935-3) allow the outputs to be pulled up to a user defined voltage with a resistor. The open-drain pull-up voltage may be greater than VCC (5.5V maximum), which is not always possible with inferior battery supervisors, due to internal clamps. When the status outputs are low, power is dissipated in the pull-up resistors. Recommended resistor values lie in the range between 10k and 470k. Figure 1 demonstrates typical LTC2935-1/LTC2935-3 RST output behavior. undetermined voltages when connected to high impedance (such as CMOS logic inputs). The resistor value should be small enough to provide effective pull-down without excessively loading the pull-up circuitry. A 100k resistor from output to ground is satisfactory for most applications. When the status outputs are high, power is dissipated in the pull-down resistors. Figure 2 demonstrates typical LTC2935-2/LTC2935-4 RST output behavior. Manual Reset Input The active pull-up options (LTC2935-2/LTC2935-4) eliminate the need for external pull-up resistors on the status outputs. Integrated pull-up devices pull the outputs up to VCC. Actively pulled up outputs may not be driven above VCC. When VCC is above its reset threshold, and the manual reset input (MR) is pulled low, the RST output is forced low. RST remains low for 200ms after the manual reset input is released and pulled high. The manual reset input is pulled up internally through 900k to VCC. If external leakage currents have the ability to pull down the manual reset input below its logic threshold, a lower value pull-up resistor, placed between VCC and MR will fix the problem. Some applications require the RST and/or PFO outputs to be valid with VCC down to ground. Active pull-up handles this requirement with the addition of an external resistor from the output to ground. The resistor provides a path for leakage currents, preventing the output from floating to Input MR is often pulled down through a pushbutton switch requiring human contact. If extended ESD tolerance is required, series resistance between the switch and the input is recommended. For most applications, a 10k resistor provides sufficient current limiting. 3.5 LTC2935-1 S2 = GND 3.0 S1 = S0 = V CC LTC2935-2 S2 = GND 3.0 S1 = S0 = V CC 2.5 2.5 RST (V) RST (V) 3.5 2.0 1.5 2.0 1.5 1.0 1.0 0.5 0.5 0 0 0.5 1 1.5 2 VCC (V) 2.5 3 3.5 2935 F01 Figure 1. RST vs VCC with 10k Pull-Up 0 0 0.5 1 1.5 2 2.5 VCC (V) 3 3.5 2935 F02 Figure 2. RST vs VCC 2935fa 8 LTC2935 TYPICAL APPLICATIONS Battery Monitor with Interface to Low Voltage Logic 3μA LDO IN SHDN LT3009 OUT GND ADJ 1.8V 1.18M 1μF 590k 100k 100k VCC + Li-Ion 0.1μF S1 S2 RESD* 10k VDD PFO S0 NMI LTC2935-1 μP RST MR RST GND MANUAL PB1 RESET PUSHBUTTON POWER FAIL FALLING THRESHOLD = 3.15V RESET FALLING THRESHOLD = 3.00V 2935 TA02 *OPTIONAL RESISTOR FOR ADDED ESD PROTECTION Alkaline Cell Stack Voltage Monitor VCC + 1.5V 0.1μF S0 S2 + + S1 MR PFO LOW BATTERY RST SYSTEM RESET LTC2935-2 1.5V GND 1.5V 2935 TA03 POWER FAIL FAIL THRESHOLD = 2.55V RESET THRESHOLD = 2.40V Coin Cell Voltage Monitor VCC + CR2032 0.1μF S2 S1 MR PFO LOW BATTERY RST SYSTEM RESET LTC2935-2 S0 GND 2935 TA04 POWER FAIL FAIL THRESHOLD = 2.70V RESET THRESHOLD = 2.55V 2935fa 9 LTC2935 PACKAGE DESCRIPTION DC Package 8-Lead Plastic DFN (2mm × 2mm) (Reference LTC DWG # 05-08-1719 Rev Ø) 0.70 ±0.05 2.55 ±0.05 1.15 ±0.05 0.64 ±0.05 (2 SIDES) PACKAGE OUTLINE 0.25 ± 0.05 0.45 BSC 1.37 ±0.05 (2 SIDES) RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED R = 0.05 TYP 2.00 ±0.10 (4 SIDES) PIN 1 BAR TOP MARK (SEE NOTE 6) R = 0.115 TYP 5 8 0.40 ± 0.10 0.64 ± 0.10 (2 SIDES) PIN 1 NOTCH R = 0.20 OR 0.25 × 45° CHAMFER (DC8) DFN 0106 REVØ 4 0.200 REF 1 0.23 ± 0.05 0.45 BSC 0.75 ±0.05 1.37 ±0.10 (2 SIDES) 0.00 – 0.05 BOTTOM VIEW—EXPOSED PAD NOTE: 1. DRAWING IS NOT A JEDEC PACKAGE OUTLINE 2. DRAWING NOT TO SCALE 3. ALL DIMENSIONS ARE IN MILLIMETERS 4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE 5. EXPOSED PAD SHALL BE SOLDER PLATED 6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE TOP AND BOTTOM OF PACKAGE 2935fa 10 LTC2935 PACKAGE DESCRIPTION TS8 Package 8-Lead Plastic TSOT-23 (Reference LTC DWG # 05-08-1637) 0.52 MAX 2.90 BSC (NOTE 4) 0.65 REF 1.22 REF 1.4 MIN 3.85 MAX 2.62 REF 2.80 BSC 1.50 – 1.75 (NOTE 4) PIN ONE ID RECOMMENDED SOLDER PAD LAYOUT PER IPC CALCULATOR 0.22 – 0.36 8 PLCS (NOTE 3) 0.65 BSC 0.80 – 0.90 0.20 BSC 0.01 – 0.10 1.00 MAX DATUM ‘A’ 0.30 – 0.50 REF 0.09 – 0.20 (NOTE 3) 1.95 BSC TS8 TSOT-23 0802 NOTE: 1. DIMENSIONS ARE IN MILLIMETERS 2. DRAWING NOT TO SCALE 3. DIMENSIONS ARE INCLUSIVE OF PLATING 4. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR 5. MOLD FLASH SHALL NOT EXCEED 0.254mm 6. JEDEC PACKAGE REFERENCE IS MO-193 2935fa Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. 11 LTC2935 TYPICAL APPLICATION Portable Device Battery Monitor 3μA LDO 1.8V IN + VCC Li-Ion 0.1μF MR 100k LT3009 OUT GND ADJ SHDN 1.18M S0 S1 S2 LTC2935-1 GND 1μF RST 590k 100k LOW BATTERY EARLY WARNING PFO POWER FAIL FALLING THRESHOLD = 3.15V RESET FALLING THRESHOLD = 3.00V 2935 TA05 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LTC690 5V Supply Monitor, Watchdog Timer and Battery Backup 4.65V Threshold LTC694-3.3 3.3V Supply Monitor, Watchdog Timer and Battery Backup 2.9V Threshold LTC1232 5V Supply Monitor, Watchdog Timer and Pushbutton Reset 4.37V/4.62V Threshold LTC1326 Micropower Triple Supply Monitor for 5V/2.5V, 3.3V and ADJ 4.725V, 3.118V, 1V Threshold (±0.75%) and ADJ LTC1726 Micropower Triple Supply Monitor for 2.5V/5V, 3.3V and ADJ Adjustable Reset and Watchdog Timeouts LTC1727 Micropower Triple Supply Monitor with Open-Drain Reset Individual Monitor Outputs in MSOP LTC1728 Micropower Triple Supply Monitor with Open-Drain Reset 5-Lead SOT-23 Package LTC1985 Micropower Triple Supply Monitor with Push-Pull Reset Output 5-Lead SOT-23 Package LTC2900 Programmable Quad Supply Monitor Adjustable Reset, 10-Lead MSOP and DFN Packages LTC2901 Programmable Quad Supply Monitor Adjustable Reset and Watchdog Timer LTC2902 Programmable Quad Supply Monitor Adjustable Reset and Tolerance LTC2903 Precision Quad Supply Monitor 6-Lead SOT-23 Package LTC2904/LTC2905/ LTC2906/LTC2907 Three-State Programmable Precision Dual Supply Monitor 8-Lead SOT-23 and DFN Packages LTC2908 Precision Six-Supply Monitor (Four Fixed and Two Adjustable) 8-Lead TSOT-23 and DFN Packages LTC2909 Precision Triple/Dual Input UV, OV and Negative Voltage Monitor Shunt Regulated VCC Pin, Adjustable Threshold and Reset, 8-Lead SOT-23 and DFN Packages LTC2910 Octal Positive/Negative Voltage Monitor Separate VCC Pin, Eight Inputs, Up to Two Negative Monitors Adjustable Reset Timer, 16-Lead SSOP and DFN Packages LTC2912/LTC2913/ LTC2914 Single/Dual/Quad UV and OV Voltage Monitors Separate VCC Pin, Adjustable Reset Timer LTC2915/LTC2916/ LTC2917/LTC2918 Single Voltage Supervisors with 27 Pin-Selectable Thresholds Manual Reset and Watchdog Functions LTC2934 Ultralow Power Supervisor with Power-Fail Output 500nA Quiescent Current, 2mm × 2mm 8-Lead DFN and TSOT-23 Packages, Adjustable via External Resistors 2935fa 12 Linear Technology Corporation LT 0609 REV A • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com © LINEAR TECHNOLOGY CORPORATION 2008