LTC1696 Overvoltage Protection Controller FEATURES DESCRIPTION 2% Overvoltage Threshold Accuracy nn Low Profile (1mm) ThinSOTTM Package nn Gate Drive for SCR Crowbar or External N-Channel Disconnect MOSFET nn Monitors Two Output Voltages nn Senses Output Voltages from 0.8V to 24V nn Wide Supply Range: 2.7V to 27V nn Multifunction TIMER/RESET Pin The LTC(R)1696 is a standalone power supply overvoltage monitor and protection device designed to protect a power supply load in the event of an overvoltage fault. It monitors two adjustable output voltages. If an overvoltage condition is detected, the output drives either an external SCR crowbar or turns off external back-to-back N-channel MOSFETs, thereby, disconnecting the input voltage from the power supply. nn Pin 6 offers three functions. By connecting a capacitor to this pin, the internal glitch filter time delay can be programmed. Without the capacitor, the default time delay is determined by an internal capacitor. This pin also serves as a reset input to clear the internal latch after an overvoltage fault condition. By pulling it high, the OUT pin is activated if the FB1 and FB2 voltages remain below the trip threshold. APPLICATIONS Telecommunication Systems Computer Systems nn Industrial Control Systems nn Notebook Computers nn nn The LTC1696 is available in the low profile (1mm) ThinSOT package. 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. . TYPICAL APPLICATION SCR Crowbar Overvoltage Response VOUT2 5V VOUT1 3.3V POWER SUPPLY VCC 12V R2 137k 1% R1 44.2k 1% 1 LTC1696 2 3 SCR 2N6507 TIMER/ 6 RESET FB1 C2 0.1F GND VCC FB2 OUT FB1 0.5V/DIV R4 232k 1% C1 1nF Q1 2N7002 TIMER/RESET 2V/DIV RESET 5 IOUT 20mA/DIV R3 44.2k 1% 4 C1 = 1nF 100s/DIV 1696 TA02 1696 TA01 1696fb For more information www.linear.com/LTC1696 1 LTC1696 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Note 1) Supply Voltage (VCC).................................................28V Input Voltage FB1, FB2................................................ - 0.3V to 17V TIMER/RESET......................................... -0.3V to 17V Operating Junction Temperature Range (Note 2) LTC1696E............................................ -40C to 125C LTC1696I............................................ -40C to 125C LTC1696H........................................... -40C to 150C Storage Temperature Range.................... -65C to 150C Lead Temperature (Soldering, 10 sec)................... 300C TOP VIEW TIMER/ RESET 5 FB2 FB1 1 6 GND 2 VCC 3 4 OUT S6 PACKAGE 6-LEAD PLASTIC TSOT-23 TJMAX = 150C, JA = 192C/W ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE LTC1696ES6#PBF LTC1696ES6#TRPBF LTLT 6-Lead Plastic TSOT-23 -40C to 125C LTC1696IS6#PBF LTC1696IS6#TRPBF LTLT 6-Lead Plastic TSOT-23 -40C to 125C LTC1696HS6#PBF LTC1696HS6#TRPBF LTLT 6-Lead Plastic TSOT-23 -40C to 150C Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container. Consult LTC Marketing for information on nonstandard 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/ ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the specified operating junction temperature range, otherwise specifications are at TA = 25C. 2.7V VCC 27V (Notes 2, 3, 4) unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP UNITS Supply Voltage Range Operating Range IVCC Standby Supply Current FB1, FB2 < VFB Active Supply Current FB1, FB2 > VFB, COUT = 1000pF VFB FB1, FB2 Feedback Threshold Voltage Going Positive TA 0C and TA 85C TA 0C and TA 125C TA 0C and TA 150C TA < 0C 0.862 0.858 0.853 0.853 IFB FB1, FB2 Input Current -1 - 0.05 A VFBHST FB1, FB2 Feedback Hysteresis High-to-Low Transition 12 mV VLKO VCC Undervoltage Lockout Low-to-High Transition High-to-Low Transition FB1, FB2 > VFB VLKH VCC Undervoltage Lockout Hysteresis FB1, FB2 > VFB VRST TIMER/RESET Reset Low Threshold FB1, FB2 > VFB VTIM TIMER/RESET Timer High Threshold FB1, FB2 > VFB, 2 2.7 MAX VCC 27 V 540 A 1.1 3.5 mA 0.880 0.880 0.880 0.880 0.898 0.898 0.898 0.907 170 1.75 1.64 2.05 1.94 2.35 2.24 110 TA 85C TA 125C TA 150C V V V V V V mV 0.78 0.865 0.95 V 1.11 1.08 1.07 1.185 1.185 1.185 1.26 1.26 1.26 V V V 1696fb For more information www.linear.com/LTC1696 LTC1696 ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the specified operating junction temperature range, otherwise specifications are at TA = 25C. 2.7V VCC 27V (Notes 2, 3, 4) unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS 1.35 1.50 1.65 V 260 650 A VTRIG TIMER/RESET External Trigger High Threshold FB1, FB2 < VFB ITRIG TIMER/RESET External Trigger High Current FB1, FB2 < VFB, TIMER/RESET = VTRIG ITIM TIMER/RESET Timer Current FB1 = (VFB + 30mV), FB2 < VFB FB1 = (VFB + 200mV), FB2 < VFB FB2 = (VFB + 30mV), FB1 < VFB FB2 = (VFB + 200mV), FB1 < VFB FB1, FB2 = (VFB + 200mV) 4 5 4 5 8 10 12 10 12 18 22 26 22 26 40 A A A A A VOUTH OUT High Voltage 12V VCC 27V, FB1, FB2 > VFB, COUT = 1000pF VCC = 3.3V, FB1, FB2 > VFB, COUT = 1000pF 4.8 2.7 6.3 3.2 8.0 3.3 V V VOUTL OUT Low Voltage FB1, FB2 < VFB, ISINK = 1mA, VCC = 3.3V 0.45 V tOVPD1 OUT Propagation Delay for FB1 FB1 > VFB, FB2 < VFB, TIMER/RESET = Open, COUT = 1000pF 7 28 s tOVPD2 OUT Propagation Delay for FB2 FB2 > VFB, FB1 < VFB, TIMER/RESET = Open, COUT = 1000pF 7 28 s tOVPD1,2 OUT Propagation Delay for FB1, FB2 FB1, FB2 > VFB, TIMER/RESET = Open COUT = 1000pF 6 24 s tr OUT Rise Time FB1, FB2 > VFB, COUT = 1000pF 0.4 3 s IOUTSC OUT Short-Circuit Current 12V VCC 27V, FB1, FB2 > VFB, VOUT Shorted to GND 35 80 160 mA VCC = 2.7V, FB1, FB2 > VFB, VOUT Shorted to GND 2 9 18 mA Note 1: Absolute Maximum Ratings are those values beyond which the life of the device may be impaired. Note 2: The 1696E is guaranteed to meet performance specifications from 0C to 85C. Specifications over the -40C to 125C operating junction temperature range are assured by design, characterization and correlation with statistical process controls. The LTC1696I is guaranteed from -40C to 125C, and the LTC1696H is guaranteed over the -40C to 150C operating junction temperature range. High junction temperatures degrade operating lifetime; operating lifetime is derated for temperatures greater than 125C. The maximum ambient temperature consistent with these specifications is determined by specific operating conditions in conjunction with board layout, the package thermal impedance and other environmental factors. TJ is calculated from the ambient temperature, TA , and power dissipation, PD , according to the following formula: LTC1696S6: TJ = TA + (PD * 192C/W) Note 3: All currents into device pins are positive; all currents out of device pins are negative. All voltages are referenced to device ground unless otherwise specified. Note 4: All typical numbers are given for VCC = 12V and TA = 25C. 1696fb For more information www.linear.com/LTC1696 3 LTC1696 TYPICAL PERFORMANCE CHARACTERISTICS Standby Supply Current vs Supply Voltage 210 TA = 25C 180 200 SUPPLY CURRENT (A) SUPPLY CURRENT (A) 160 140 120 100 80 60 180 170 160 150 140 20 130 0 5 15 20 10 SUPPLY VOLTAGE (V) 25 0 1.1 1.05 1 25 50 75 100 125 150 TEMPERATURE (C) 0.8814 0.8811 0.8808 0.8805 0.8802 0.8799 0.8796 0 3 6 9 12 15 18 21 24 27 30 SUPPLY VOLTAGE (V) 1.185 1.180 1.175 1.170 1.165 1.160 0 5 10 20 15 SUPPLY VOLTAGE (V) 25 30 1696 G07 4 0.9 VCC = 12V 0.89 0.88 0.87 0.86 0.85 -50 -25 0 25 50 75 100 125 150 TEMPERATURE (C) 1696 G06 TIMER Current vs Supply Voltage 20 VCC = 12V 1.2 1.18 1.16 1.14 -50 -25 TA = 25C 18 1.22 TIMER CURRENT (A) TA = 25C TIMER THRESHOLD VOLTAGE (V) TIMER THRESHOLD VOLTAGE (V) 1.24 30 25 1696 G03 TIMER Threshold Voltage vs Temperature 1.190 20 15 10 SUPPLY VOLTAGE (V) 5 1696 G05 TIMER Threshold Voltage vs Supply Voltage 1.195 0 FB1, FB2 Feedback Threshold Voltage vs Temperature TA = 25C 1696 G04 1.200 0.4 0 FB1/FB2 FEEDBACK THRESHOLD VOLTAGE (V) FB1, FB2 FEEDBACK THRESHOLD VOLTAGE (V) SUPPLY CURRENT (mA) 1.15 0 0.6 FB1, FB2 Feedback Threshold Voltage vs Supply Voltage VCC = 12V COUT = 1000pF 0.95 -50 -25 0.8 1696 G02 Active Supply Current vs Temperature 1.2 1.0 25 50 75 100 125 150 TEMPERATURE (C) 1696 G01 1.25 TA = 25C COUT = 1000pF 0.2 120 -50 -25 30 Active Supply Current vs Supply Voltage 1.2 190 40 0 1.4 VCC = 12V SUPPLY CURRENT (mA) 200 Standby Supply Current vs Temperature FB1 AND FB2 OVERDRIVE = 200mV 16 14 FB1 OR FB2 OVERDRIVE = 200mV 12 10 0 25 50 75 100 125 150 TEMPERATURE (C) 1696 G08 8 0 5 10 15 20 SUPPLY VOLTAGE (V) 25 30 1696 G09 1696fb For more information www.linear.com/LTC1696 LTC1696 TYPICAL PERFORMANCE CHARACTERISTICS TIMER Current vs Feedback Overdrive 22 20 VCC = 12V 18 FB1 + FB2 OVERDRIVE 200mV 16 FB1 AND FB2 OVERDRIVE FB1 OR FB2 OVERDRIVE 200mV 12 FB1 OR FB2 OVERDRIVE 12 8 4 10 8 -50 -25 0 0 25 50 75 100 125 150 TEMPERATURE (C) 0 50 150 200 100 FEEDBACK OVERDRIVE (mV) FB1 OR FB2 OVERDRIVE FB1 AND FB2 OVERDRIVE 5 50 150 200 100 FEEDBACK OVERDRIVE (mV) 0 20 15 10 FB1 OR FB2 OVERDRIVE 5 FB1 AND FB2 OVERDRIVE 0 250 0 50 100 150 200 FEEDBACK OVERDRIVE (mV) 1.49 1.485 1.48 1.475 -50 -25 0 250 1.51 25 50 75 100 125 150 TEMPERATURE (C) 1696 G16 TA = 25C 1.50 1.49 1.48 1.47 1.46 1.45 1.44 0 20 15 10 SUPPLY VOLTAGE (V) 5 30 RESET Threshold Voltage vs Temperature 0.88 TA = 25C 0.866 0.875 0.864 0.87 0.862 0.860 0.858 0.856 0.854 0.852 25 1696 G15 RESET THRESHOLD (V) RESET THRESHOLD VOLTAGE (V) EXTERNAL TRIGGER THRESHOLD VOLTAGE (V) 0.868 VCC = 12V 250 1696 G12 RESET Threshold Voltage vs Supply Voltage 1.495 50 100 150 200 FEEDBACK OVERDRIVE (mV) 1696 G14 External Trigger Threshold Voltage vs Temperature 1.5 0 External Trigger Threshold Voltage vs Supply Voltage 1696 G13 1.505 8 4 250 VCC = 12V TA = 25C 25 GLITCH FILTER TIMER (s) GLITCH FILTER TIMER (s) 30 VCC = 3.3V TA = 25C 10 FB1 OR FB2 OVERDRIVE 10 Glitch Filter Timer vs Feedback Overdrive 15 0 12 1696 G11 Glitch Filter Timer vs Feedback Overdrive 20 FB1 AND FB2 OVERDRIVE 6 1696 G10 25 VCC = 3.3V TA = 25C 14 EXTERNAL TRIGGER TRESHOLD VOLTAGE (V) 14 16 VCC = 12V TA = 25C 16 TIMER CURRENT (A) TIMER CURRENT (A) 20 TIMER Current vs Feedback Overdrive TIMER CURRENT (A) TIMER Current vs Temperature VCC = 12V 0.865 0.86 0.855 0.85 0.845 0 5 10 20 15 SUPPLY VOLTAGE (V) 25 30 1696 G17 0.84 -50 -25 0 25 50 75 100 125 150 TEMPERATURE (C) 1696 G18 1696fb For more information www.linear.com/LTC1696 5 LTC1696 TYPICAL PERFORMANCE CHARACTERISTICS OUT Pin Active Output Voltage vs Supply Voltage 6.6 6 5 4 3 2 1 0 0 5 10 20 15 SUPPLY VOLTAGE (V) 25 6.5 6.4 6.3 6.2 6.1 6 5.9 5.8 5.7 -50 -25 30 0 80 VCC = 12V 60 8 -50 -25 VCC = 5V VCC = 2.7V 0 50 40 30 20 TA = 25C VOUT SHORTED TO GND 10 0 5 15 20 10 SUPPLY VOLTAGE (V) 30 25 1696 G21 OUT Pin Active Output Current vs Output Voltage 100 TA = 25C TA = 25C 90 25 20 VCC = 5V 15 10 VCC = 2.7V 5 80 70 60 50 VCC = 27V 40 30 VCC = 12V 20 10 25 50 75 100 125 150 TEMPERATURE (C) 1696 G10 6 30 ACTIVE OUTPUT CURRENT (mA) OUT PIN SHORT-CIRCUIT CURRENT (mA) VCC = 27V 20 70 60 OUT Pin Active Output Current vs Output Voltage VOUT SHORTED TO GND 40 80 1696 G20 OUT Pin Short-Circuit Current vs Temperature 100 90 0 25 50 75 100 125 150 TEMPERATURE (C) 1696 G19 120 100 VCC = 12V COUT = 1000pF ACTIVE OUTPUT CURRENT (mA) 7 OUT Pin Short-Circuit Current vs Supply Voltage OUT PIN SHORT-CIRCUIT CURRENT (mA) TA = 25C COUT = 1000pF OUT PIN ACTIVE OUTPUT VOLTAGE (V) OUT PIN ACTIVE OUTPUT VOLTAGE (V) 8 OUT Pin Active Output Voltage vs Temperature 0 0 0.5 1 1.5 2 2.5 3 3.5 4 OUTPUT VOLTAGE (V) 4.5 5 1696 G23 0 0 1 4 3 2 5 OUTPUT VOLTAGE (V) 6 7 1696 G24 1696fb For more information www.linear.com/LTC1696 LTC1696 PIN FUNCTIONS FB1 (Pin 1): First Feedback Input. FB1 monitors and senses the first supply output voltage through an external resistor divider. This voltage is then compared with an internal reference voltage of 0.88V, which sets the threshold for an overvoltage fault detection. If the sense voltage exceeds the threshold level, the output response time at the OUT pin is dependent on the feedback overdrive above the threshold level. The higher the feedback overdrive, the faster will be the response time. FB2 (Pin 5): S econd Feedback Input. FB2 monitors and senses the second supply output voltage through an external resistor divider. This voltage is then compared with an internal reference voltage of 0.88V, which sets the threshold for an overvoltage fault detection. If the sense voltage exceeds the threshold level, the output response time at the OUT pin is dependent on the feedback overdrive above the threshold level. The higher the feedback overdrive, the faster will be the response time. GND (Pin 2): Power Ground. Return path for all device currents. TIMER/RESET (Pin 6): Glitch Filter Timer Capacitor, Reset and External Trigger Input. The external capacitor connected to this pin programs the internal glitch filter time delay. The internal current source used to charge the timer capacitor is typically 10A with feedback overdrive of less than 20mV above the feedback trip threshold from one feedback input. The current source increases to 12A when the feedback overdrive increases to more than 100mV. It further increases to 18A if larger overdrive occurs from both feedback inputs. The default glitch filter time delay without an external timer capacitor is fixed by an internal capacitor of 5pF with the internal reference voltage of 1.185V. The delay reduces with increases in first and second feedback input overdrive. This pin also serves as a reset input to clear the internal latch during an overvoltage fault condition. If pulled low, it resets the active high state of the internal latch. The reset signal to this pin should be an open drain type. This pin can also be driven high externally to activate the OUT pin active high if the FB1 and FB2 voltages remain below the feedback trip threshold. VCC (Pin 3): Power Supply. The pin is connected separately from the power supply output that the chip is monitoring. Its input range is from 2.7V to 27V. The quiescent current is typically 100A in standby mode when the device is operating at 5V. The quiescent current increases to 170A when operating at 12V. OUT (Pin 4): Output Current Limit Driver. Capable of delivering continuous current, typically 80mA, at high supplies. The output current decreases with lower supply voltage. This pin directly drives the SCR crowbar at high supply voltage. It can also provide gate drive for an Nchannel MOSFET or the base of an NPN transistor, which drives the gate of an external SCR at low supply voltage. It is normally in the inactive low state in the standby mode. In the event of an overvoltage fault condition, the OUT pin is latched into the active high state. The latched active high state is reset by pulling the TIMER/RESET pin low through an N-channel MOSFET switch or if the supply voltage at the VCC pin goes below the undervoltage lockout threshold voltage of 1.94V. 1696fb For more information www.linear.com/LTC1696 7 LTC1696 BLOCK DIAGRAM VCC 3 R4 R3 INTERNAL 5V SUPPLY R2 + + - VREF 4 OUT - R1 2V UVLO - GND 2 1.185V INTERNAL 5V SUPPLY FB2 5 + - BANDGAP REFERENCE 0.88V 10A + FUNCTION OF FB1 AND FB2 OVERDRIVE + + + - FB1 1 GLITCH FILTER LOGIC + - 6 TIMER/ RESET 0.865V 1696 BD 8 1696fb For more information www.linear.com/LTC1696 LTC1696 APPLICATIONS INFORMATION Feedback Inputs VS The LTC1696 has two feedback inputs that allow monitoring of two output voltages. The trip point of the internal comparator is set by an internal reference of 0.88V with 2% accuracy. The output voltage, VS, is sensed through an external resistor divider network (Figure 1). The resistors R1 and R2 values are calculated with the typical trip point of 0.88V. R1 * V = 0.88 R1+ R2 S As an example, let's calculate values for R1 and R2 for a 3.3V supply in which an overvoltage indication is required at +10% (3.63V). First, a value for R1 is chosen based on the allowable resistor divider string current. This is determined by power dissipation requirements and possible sensitivity to noise coupling into the resistor divider. In this exercise, assume the resistor divider current is 20A. R1 is calculated from: VFB IDIVIDER = LTC1696 FB1 + R1 - + - VREF = 0.88V Figure 1 (V - 0.88) * R1 R2 = S 0.88 R1= R2 0.88V = 44k 20A The chosen values for R1 and R2 yield an overvoltage threshold of 3.608V (+ 9.3%). With worst-case tolerances applied, the minimum overvoltage threshold is 3.481V (+5.5%) and the maximum overvoltage threshold is 3.738V (+13.3%). Reset Function In the event of an overvoltage condition, the OUT pin of the LTC1696 is latched into an active high state. The internal latch is reset by pulling the TIMER/RESET pin low through an external N-channel MOSFET switch or pulling VCC voltage below the UVLO trip point of 1.94V. The nearest 1% value for R1 is 44.2k. Now, calculating for R2 yields: 44.2k * (3.63v - 0.88V) R2 = = 138.1k 0.88V Choosing the nearest 1% value yields 137k. 1696fb For more information www.linear.com/LTC1696 9 LTC1696 APPLICATIONS INFORMATION Glitch Filter Timer SCR Crowbar The LTC1696 has a programmable glitch filter to prevent the output from entering its active high latched condition if transients occur on the FB1 or FB2 pins. The filter time delay is programmed externally by an external capacitor C1 connected to the TIMER/RESET pin. The LTC1696 can deliver continuous output current typically 80mA at high supply voltage to trigger an external SCR crowbar in the event of an overvoltage condition as shown in the typical application on the front page of the data sheet. The output current decreases when the supply voltage reduces. It delivers 25mA at a supply voltage of 5V. At a low supply voltage of 3.3V, the output current reduces to 10mA and an external NPN emitter follower is needed to boost the current in order to drive the SCR crowbar as shown in Figure 2. The power dissipation due to the high output current at high supply voltage can potentially exceed the thermal limit of the package. This is avoided by resetting the device rapidly when the external SCR crowbar has been triggered, so that the device is not kept in the active high state for too long. The time delay is given by: tD = C1* VINT ICHG where VINT is the internal reference voltage of 1.185V and ICHG is the internal current source charging the external capacitor C1. The current source ICHG charging the external timer capacitor is 10A for small feedback transients and increases to 12A for large feedback transients (greater than 100mV) from one feedback input. The charging current increases to 18A for large feedback transients from both feedback inputs. R2 54.9k 1% 1 R1 44.2k 1% Q1 2N3904 R5 470 5% VOUT2 2.5V VOUT1 1.8 V POWER SUPPLY VCC 3.3V R6 22 5% TIMER/ 6 RESET FB1 LTC1696 2 GND FB2 VCC OUT R4 93.1k 1% C1 1nF 3 RESET 5 R3 44.2k 1% SCR 2N6507 C2 0.1F Q2 2N7002 4 1696 F02 Figure 2. External SCR with NPN Emitter Follower with Low Voltage Supplies 10 1696fb For more information www.linear.com/LTC1696 LTC1696 APPLICATIONS INFORMATION Back-to-Back N-Channel MOSFET by the power management controller when the LTC1696 OUT pin is in the low state. The LTC1696 drives the gate of Q1 high during an overvoltage fault condition. This pulls the drain of Q1 low and turns off the back-to-back N-channel MOSFETs. A power management circuit that uses the LTC1696 to control external back-to-back N-channel MOSFET at low supply voltage is shown in Figure 3. In standby mode, the drain of the external N-channel MOSFET, Q1, is pulled high 1.5V R2 38.3k 1% 1 R1 44.2k 1% VCC 3.3V TIMER/ 6 RESET FB1 LTC1696 2 3 C2 0.1F GND FB2 VCC OUT C1 1nF Q2 2N7002 5 4 R3 R4 44.2k 54.9k 1% 1% RESET 1.8V PRIMARY INPUT SUPPLY POWER MANAGEMENT CONTOLLER N-CHANNEL x2 Q1 2N7002 1696 F03 Figure 3. Back-to-Back N-Channel MOSFETs for Low Supply Application 1696fb For more information www.linear.com/LTC1696 11 LTC1696 PACKAGE DESCRIPTION S6 Package 6-Lead Plastic SOT-23 (LTC DWG # 05-08-1634) (LTC DWG # 05-08-1636) 2.80 - 3.10 (.110 - .118) (NOTE 3) SOT-23 (Original) SOT-23 (ThinSOT) A .90 - 1.45 (.035 - .057) 1.00 MAX (.039 MAX) A1 .00 - 0.15 (.00 - .006) .01 - .10 (.0004 - .004) A2 .90 - 1.30 (.035 - .051) .80 - .90 (.031 - .035) L .35 - .55 (.014 - .021) .30 - .50 REF (.012 - .019 REF) 2.60 - 3.00 (.102 - .118) 1.50 - 1.75 (.059 - .069) (NOTE 3) PIN ONE ID .95 (.037) REF .20 (.008) A DATUM `A' L NOTE: 1. CONTROLLING DIMENSION: MILLIMETERS MILLIMETERS 2. DIMENSIONS ARE IN (INCHES) .25 - .50 (.010 - .020) (6PLCS, NOTE 2) A2 .09 - .20 (.004 - .008) (NOTE 2) 1.90 (.074) REF A1 S6 SOT-23 0401 3. DRAWING NOT TO SCALE 4. DIMENSIONS ARE INCLUSIVE OF PLATING 5. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR 6. MOLD FLASH SHALL NOT EXCEED .254mm 7. PACKAGE EIAJ REFERENCE IS: SC-74A (EIAJ) FOR ORIGINAL JEDEC MO-193 FOR THIN 12 1696fb For more information www.linear.com/LTC1696 LTC1696 REVISION HISTORY REV DATE DESCRIPTION A 06/14 Added "I" and "H" Grade B 12/14 Changed Equation from PAGE NUMBER R1 * V = 0.88 R1+ R1 S 2-6 to R1 * V = 0.88 R1+ R2 S Changed Figure 2 schematic from Q1 to Q2 9 10 1696fb 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 representaof its circuits as described herein will not infringe on existing patent rights. tion that the interconnection For more information www.linear.com/LTC1696 13 LTC1696 TYPICAL APPLICATION External Triggering FB1 and FB2 pins are below the trip threshold of the internal comparator. The output is then reset by pulling the TIMER/RESET pin low. Figure 4 shows a circuit that uses the external triggering function of the LTC1696 The LTC1696 has a feature which allows the output to be latched into an active high state by pulling the TIMER/ RESET pin high even if both the feedback voltages at the 5V R5 6.8k 5% D1 1N4148 1.5V R2 38.3k 1% 1 R1 44.2k 1% VCC 3.3V C1 1nF TIMER/ 6 RESET FB1 LTC1696 2 3 C2 0.1F GND FB2 VCC OUT 5 Q2 2N7002 R4 54.9k 1% R3 44.2k 1% 4 RESET Q3 2N7002 TRIGGER 1.8V PRIMARY INPUT SUPPLY POWER MANAGEMENT CONTOLLER N-CHANNEL x2 Q1 2N7002 1696 F04 Figure 4. 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