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1 for more information www.linear.com/LTC2965 typical application features description 100v micropower single voltage monitor the lt c ? 2965 is a low current, high voltage single chan - nel voltage monitor. internal high value resistors sense the input monitor pin providing a compact and low power solution for voltage monitoring . t wo comparator reference inputs ( inh and inl) are included to allow configuration of a high and low threshold using an external resistive divider biased from the on-chip reference. a range selection pin is provided to set the internal resistive divider for 10x or 40x scaling. the thresholds are scaled according to the range selection settings. additionally, either inh or inl can be grounded to enable built-in hysteresis. polarity selection pin allows the output to be inverted. the output is 100v capable and includes a 500k pull-up resistor to an internal supply. applications n wide operating range: 3.5v to 100v n wide monitoring range: 3.5v to 98v n quiescent current: 7a n adjustable threshold range n internal high value resistive dividers n 1.4% (max) threshold accuracy over temperature n polarity selection n 100v rated outputs n selectable built-in hysteresis n 16-lead ms and 8-lead 3mm 3mm dfn packages n portable equipment n battery-powered equipment n telecom systems n automotive/industrial electronics l, lt , lt c , lt m , linear technology and the linear logo are registered trademarks of analog devices, inc. all other trademarks are the property of their respective owners. v in monitor range range selection 3.5v to 24.5v 10x 14v to 98v 40x undervoltage monitor ref 200k 91k threshold configuration polarity and range selection 100k 24v undervoltage 2965 ta01a 5v 909k inh inl LTC2965 gndrsps out 24v v in 5v sys rising threshold falling threshold hysteresis range 20.0v 18.2v 1.8v 10x v in (v) 0 0 i vin (a) 2 4 6 8 10 12 20 40 60 80 2965 ta01b 100 ?45c 25c 90c 125c range = 40x out = low i ref = 0a supply current vs v in lt c2965 2965fc
2 for more information www.linear.com/LTC2965 absolute maximum ratings input voltages v in ....................................................... C0. 3v to 140v ps , rs ..................................................... C 0. 3v to 6v inh , inl ................................................... C 0. 3v to 6v output voltages out ..................................................... C0. 3v to 140v average currents v in ................................................................... C20 ma out ................................................................... 5ma ref .................................................................... 5ma in h , in l ............................................................. C 1m a (notes 1, 2) order information lead free finish tube tape and reel part marking* package description temperature range LTC2965cdd#pbf LTC2965cdd#trpbf lgmk 8-lead (3mm 3mm) plastic dfn 0c to 70c LTC2965idd#pbf LTC2965idd#trpbf lgmk 8-lead (3mm 3mm) plastic dfn C40c to 85c LTC2965hdd#pbf LTC2965hdd#trpbf lgmk 8-lead (3mm 3mm) plastic dfn C40c to 125c LTC2965cms#pbf LTC2965cms#trpbf 2965 16-lead plastic msop 0c to 70c LTC2965ims#pbf LTC2965ims#trpbf 2965 16-lead plastic msop C40c to 85c LTC2965hms#pbf LTC2965hms#trpbf 2965 16-lead plastic msop C40c to 125c 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/. some packages are available in 500 unit reels through designated sales channels with #trmpbf suffix. operating ambient temperature range lt c296 5 c ................................................ 0 c to 70c lt c296 5 i ............................................. C 40 c to 85c lt c296 5 h .......................................... C 40 c to 125c storage temperature range .................. C 65 c to 150c lead temperature ( soldering , 10 sec ) ................... 30 0 c top view 9 gnd dd package 8-lead (3mm 3mm) plastic dfn 5 6 7 8 4 3 2 1v in ref inh inl out gnd rs ps t jmax = 150c, ja = 43c/w exposed pad (pin 9) pcb gnd connection optional 1 2 3 4 5 6 7 8 v in nc nc nc nc ref inh inl 16 15 14 13 12 11 10 9 out nc nc nc nc gnd rs ps top view ms package 16-lead plastic msop t jmax = 150c, ja = 120c/w pin configuration (http://www .linear.com/product/LTC2965#orderinfo) lt c2965 2965fc
3 for more information www.linear.com/LTC2965 electrical characteristics the l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at t a = 25c. v in = 12v, rs = gnd, ps = gnd, inh = 1.2v, inl = gnd (notes 1, 2). symbol parameter conditions min typ max units v in input supply operating range v in l 3.5 100 v v mon v in monitor range 3.5 98 v i vin v in input supply current v in = 100v, 40x l 3 7 15 a v uvlo undervoltage lockout v in rising l 3 v undervoltage lockout hysteresis v in falling 70 mv comparator reference input: inh, inl v cm comparator common mode voltage l 0.35 2.45 v v err v in error voltage at 96v inh = v ref , 40x 0.35v inh 2.4v, 40x l l 250 250 1360 400 mv mv v in error voltage at 24v inh = v ref , 10x 0.35v inh 2.4v, 10x l l 35 35 315 75 mv mv v os comparator offset voltage inh = 0.35v, 10x l 1.9 3 mv av err internal resistive divider range error inh = 2.4v, range = 10x, 40x l 0.4 % v hys comparator built-in hysteresis inh = gnd, inl rising, v in = 24v inl = gnd , inh falling, v in = 24v l l 14 C30 22 C22 30 C14 mv mv v hyth built-in hysteresis enable threshold l 100 175 mv t pd v in to out comparator propagation delay overdrive = 10%, out falling,10x inh = gnd, inl = 1.2v l 40 80 s i in(lkg) input leakage current (inh, inl) v = 1.2v, i-grade v = 1.2v, h-grade l l 0.1 0.1 1 10 na na reference: ref v ref reference output voltage i ref 100a, v in 3.5v l 2.378 2.402 2.426 v noise reference output noise 100hz to 100khz 140 v rms control inputs: rs, ps v th select input threshold l 0.4 1.4 v i lkg input leakage current v = 2.4v l 100 na status outputs: out v ol voltage output low v in = 1.25v, i = 10a v in = 3.5v, i = 500a l l 100 400 mv mv v oh voltage output high v in = 3.5v, i = C1a v in 4.5v, i = C1a l l 2 2.8 2 .375 3 2.75 4 v v i oh output current high v = gnd, v in = 3.5v l C15 C7.5 C5 a i o(lkg) leakage current, output high v = 100v, v in = 6v l 250 na 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. lt c2965 2965fc
4 for more information www.linear.com/LTC2965 typical performance characteristics v ref vs load current v ref vs v in % range error vs temperature comparator v os vs temperature supply current vs v in v ref vs temperature v in (v) 0 0 i vin (a) 2 4 6 8 10 12 20 40 60 80 2965 g01 100 ?45c 25c 90c 125c range = 40x out = low i ref = 0a load current (ma) 0 v ref (v) 2.400 2.425 1.6 2965 g03 2.375 2.350 0.4 0.8 1.2 2.0 2.450 ?45c 25c 90c 125c v in = 3.5v v in (v) 2.7 v ref (v) 2.400 2.425 3.7 2965 g04 2.375 2.350 3.0 3.2 3.5 4.0 2.450 1a 100a 1ma 25c temperature (c) ?50 ?1500 v os (v) ?1000 ?500 0 500 0 50 100 150 2965 g06 1000 1500 ?25 25 75 125 v inh(l) = 1.2v v in falling propagation delay vs % overdrive built-in hysteresis vs temperature % overdrive (%) 0.1 0 propagation delay, t pd (s) 75 100 125 v inl = 1.2v v inh = gnd v in = 12v 1 10 100 2965 g10 50 25 ?45c 25c 90c 125c temperature (c) ?50 16 |built-in hysteresis| v hys (mv) 18 20 22 24 28 0 50 2965 g08 100 150 26 v inh(l) = 1.2v temperature (c) ?50 v ref (v) 2.400 2.396 2.404 2.408 75 100 125 2965 g02 2.392 2.388 ?25 0 25 50 150 2.412 i = ?10a temperature (c) ?50 ?0.4 range error, av err (%) ?0.2 0 0.2 0.4 ?25 0 25 50 2965 g05 75 100 125 150 10x 40x lt c2965 2965fc
5 for more information www.linear.com/LTC2965 typical performance characteristics voltage output high vs pull-down current (out) voltage output low vs pull-up current (out) voltage output high vs input voltage pull-down current (a) 0 v oh (v) 2 3 ?12 2965 g09 1 0 ?3 ?6 ?9 4 v in = 12v ?45c 25c 90c 125c pull-up current (ma) 0 0 v ol (v) 0.25 0.50 0.75 1.00 1.25 1.50 1 2 3 4 2965 g10 5 ?45c 25c 90c 125c v in (v) 3 1.7 v oh (v) 2.0 2.3 2.6 2.9 3.2 3.5 4 5 6 7 2965 g11 8 i = ?1a pin functions exposed pad (dd8 only): exposed pad may be left floating or connected to device ground. gnd: device ground. inh: high comparator reference input. voltage on this pin is multiplied by the configured range setting to set the v in high or rising threshold. keep within valid voltage range, v cm , or tie to gnd to configure built-in hysteresis where high threshold for v in becomes inl + v hys scaled according to the rs pin configuration. inl: low comparator reference input. voltage on this pin is multiplied by the configured range setting to set the v in low or falling threshold. keep within valid voltage range, v cm , or tie to gnd to configure built-in hysteresis where low threshold becomes inh C v hys scaled according to the rs pin configuration . otherwise, inh-inl sets the hysteresis of the comparator. oscillation will occur if inl > inh unless built-in hysteresis is enabled. out: comparator output. out consists of a high voltage active pull-down and a gated, resistive (500k) pull-up to an internally generated supply between 3.5v and 5v depending on input supply voltage. blocking circuitry at the pin allows the pin to be resistively pulled up to volt - ages as high as 100v without back conducting onto the internal supply of the part . polarity with respect to the v in pin is configured using the polarity select pin, ps. out pulls low when the part is in uvlo. ps: polarity selection. connect to ref or a voltage >v th to configure comparator output to be inverting with re - spect to v in . otherwise connect pin to gnd to configure comparator output to be noninverting with respect to v in . ref: reference output. v ref with respect to gnd. use a maximum of 1nf to bypass unless damping resistor is used. rs: range select input. rs selects 10x or 40x range. connect to ref or gnd to configure pin. (see table 1) v in : voltage monitor and supply input. an internal high value resistive divider is connected to the pin. if v in falls below the uvlo threshold minus hysteresis , the output is pulled low. if v in < 1.2v, the logic state of the outputs cannot be guaranteed. lt c2965 2965fc
6 for more information www.linear.com/LTC2965 block diagrams 2965 bd 10x/40x v hyth inl inh v hyth v hys v hys + ? +? + ? +? ? + 500k v int out ps rs gnd ref v ref 1x v in 70m internal regulator v int lt c2965 2965fc
7 for more information www.linear.com/LTC2965 operation the LTC2965 is a micropower single channel voltage monitor with a 100v maximum operating voltage. its channel is comprised of an internal high value resistive divider and a comparator with a high voltage output. a reference voltage is provided to allow the thresholds to be set independently. this configuration has the advantage of being able to monitor very high voltages with very little current draw while threshold programming is done using low value resistors at low voltages. integration of a resis - tive divider for high voltage sensing makes the LTC2965 a compact and low power solution for generating voltage status signals to a monitoring system. a built-in buffered reference gives the monitor flexibil - ity to operate independently from a high voltage supply without the requirement of additional low voltage biasing . the reference provides an accurate voltage from which a resistive divider to ground configures the threshold voltage for the internal comparator. in addition, the ref pin can be used as a logic high voltage for the range and polarity select pins. the input voltage threshold at v in is determined by the voltage on the inh and inl pins which are scaled by the internal resistive divider. the LTC2965 offers two range settings to select from , 10x and 40x, using the rs pin. use table 1 to determine the correct configuration for a desired range setting. the polarity select pin , (ps), configures the out pin to be inverting or noninverting with respect to v in allowing the part to be configured for monitoring overvoltage and undervoltage conditions with either polarity output. table 1. v in monitor range range selection rs 3.5v to 24.5v 10x l 14v to 98v 40x h the inh pin determines the high or rising edge threshold for v in . if the monitored voltage connected to v in rises to the scaled inh voltage then the out pin is pulled high assuming ps is ground . likewise, the inl pin determines the low or falling edge threshold for v in in each channel. if v in falls to the scaled inl voltage then the out pin is pulled low assuming ps is ground. the amount of hys - teresis referred to v in is the difference in voltage between inh and inl scaled according to the rs pin configura - tion. inh and inl have an allowable voltage range, v cm . figure 1 shows the allowable monitor voltage at v in for each range as a function of comparator reference input voltage (inl/inh). typically, an external resistive divider biased from ref is used to generate the inh and inl pin voltages. a built-in hysteresis feature requiring only two resistors can be enabled on either the v in rising edge by grounding inh or on the falling edge by grounding inl. for example, it is appropriate to ground inh to activate rising edge hys - teresis if an accurate falling voltage threshold is required for undervoltage detection . conversely, it is appropriate to ground inl for falling edge built-in hysteresis if an ac - curate overvoltage threshold is required . do not ground both inh and inl. oscillation occurs if v inl > v inh unless inh built-in hysteresis is enabled. the high voltage out pins have the capability to be pulled up to a user defined voltage as high as 100v with an external resistor. the LTC2965 also includes an internal 500k pull-up resistor to an internal voltage between 3.5v and 5v depending on input voltage . (see v oh in electrical characteristics). if the v in pin falls below the uvlo threshold then the out pin is pulled low regardless of the ps pin state. figure 1. monitor threshold vs comparator reference inputs comparator reference input (inl, inh) (v) monitor threshold, v in (v) 2965 f01 100 10 1 0.5 2.5 21.5 1 40x 10x lt c2965 2965fc
8 for more information www.linear.com/LTC2965 applications information threshold configuration the LTC2965 channel monitors the voltage applied to the v in input. a comparator senses the v in pin on one of its inputs through the internal resistive divider. the other input is connected to inh/inl that is in turn biased with external resistive dividers off of the ref pin as shown in figure 2a and 2b. the v in rising and falling thresholds are determined by: v in(rise) = range ? v inh v in(fall) = range ? v inl where range is the configured range of the internal resistive divider. in order to set the threshold for the LTC2965, choose an appropriate range setting for the desired v in voltage threshold such that the inh and inl voltages are within the specified common mode range , v cm . for example, if a falling threshold of 18v is desired for monitoring a 24v power supply then a range greater than 10x is allowed. however, to maximize the accuracy of the v in threshold the smallest acceptable range is used, 10x in this case. to implement 2v of hysteresis referred to v in this means: v inh = 2v, v inl = 1.8v with 10x range the v in thresholds are: v in(rise) = 20v, v in(fall) = 18v one possible way to configure the thresholds is by us - ing three resistors to set the voltages on inh and inl. see figure 2a. the solution for r1, r2 and r3 provides three equations and three unknowns. maximum resistor size is governed by maximum input leakage current. the maximum input leakage current below 85c is 1na. for a maximum error of 1 % due to both input currents, the resistive divider current should be at least 100 times the sum of the leakage currents, or 0.2a. if in this example , a leakage current error of 0 .1% is desired then the total divider resistance is 1.2m which results in a current of 2a through this network. for r sum = 1.2m r sum = r1 + r2 + r3 r1 = v inl ?r sum ( ) v ref = 1.8v ?1.2m ? ( ) 2.402v = 899.5k ? the closest 1% value is 909k . r2 can be determined from: r2 = v inh ?r sum ( ) v ref Cr1 = 2v ?1.2m ? ( ) 2.402v C 909k ? = 90.2k ? the closest 1% value is 90.9k. r3 can be determined from r sum : r3 = r sum C r1 C r2 = 1.2m C 909k C 90.9k = 200.1k the closest 1% value is 200k. plugging the standard values back into the equations yields the design values for the v inh and v inl voltages: v inh = 2.002v, v inl = 1.819v the corresponding threshold voltages are: v in(rise) = 20.01v, v in(fall) = 18.19v another possible way to configure the thresholds is with independent dividers using two resistors per threshold to set the voltages on inh and inl. see figure 2b. care must be taken such that the thresholds are not set too close to each other, otherwise the mismatch of the resistors may cause the voltage at inl to be greater than the voltage at inh which may cause the comparator to oscillate. as in the previous example, if r sum = 1.2m is chosen and the target for v inl is 1.8v: r sum = r1 + r2 r1 = v inl ?r sum ( ) v ref = 1.8v ?1.2m ? ( ) 2.402v = 899.5k ? the closest 1% value is 909k. r2 can be determined by: r2 = v ref C v inl ( ) ? r1 v inl = 2.402v C 1.8v ( ) ? 909k ? ( ) 1.8v = 304k ? lt c2965 2965fc
9 for more information www.linear.com/LTC2965 applications information the closest 1% value is 301k. plugging the standard values back into the equation for v inl yields the design voltage for v inl : v inl = r1? v ref ( ) r1 + r2 ( ) = 909k ? ? 2.402v ( ) 301k ?+ 909k ? ( ) = 1.804v at this point in the independent divider example only the values required to set the voltage at inl have been found . repeat the process for the inh input by substituting the above equations with v inh for v inl , r3 for r1, r4 for r2 and v inh = 2.0v. using built-in hysteresis, the v ina thresholds are: v in(rise) = range ? (inl + v hys ) v in(fall) = range ? inl figure 3b introduces built-in hysteresis on the falling edge because inl is pulled to ground . similarly, a two-resistor network , r3 and r4, is used to set the voltage on inh using: r4 r3 = v ref v inh C 1 using built-in hysteresis the v in thresholds are: v in(rise) = range ? inh v in(fall) = range ? (inh C v hys ) consider v inh = 2v with built-in hysteresis activated on the falling edge. for 10x range, 1.1% falling hysteresis is obtained. if a larger percentage of hysteresis is desired then v inh is alternatively set to 0.5v and the range is selected to be 40x to obtain the same v in threshold but with 4.4% falling hysteresis. the amount of built-in hysteresis is scaled according to table 2 . if more hysteresis is needed then it is implemented in the external resistive divider as described in the threshold configuration section. figure 3a. rising edge built-in hysteresis figure 3b. falling edge built-in hysteresis using built-in hysteresis the LTC2965 has the capability of simplifying the threshold configuration such that only two resistors are required. the device pins can be configured to select a built-in hys - teresis voltage, v hys , which can be applied to either the rising or falling threshold depending on whether the inh or inl pin is grounded. note that the hysteresis voltage at each range setting remains at a fixed value. figure 3 introduces examples of each configuration. for example, if inh is biased from an external divider and the inl pin is grounded, then hysteresis is enabled on the low or falling threshold. the low threshold is then Cv hys relative to the high threshold determined by inh. figure 3a introduces built-in hysteresis on the rising edge because inh is pulled to ground. a two-resistor network , r1 and r2, is used to set the voltage on inl using: r2 r1 = v ref v inl C 1 figure 2a. three-resistor threshold configuration figure 2b.two-resistor threshold configuration table 2. built-in hysteresis voltage vs range range v in referred built-in hysteresis 10x 220mv 40x 880mv v in v in v in gnd LTC2965 ref ps rs inh inl r2 r1 v in gnd LTC2965 inh inl r4 r3 2965 f03ab ref out out ps rs v in v in gnd LTC2965 ref inl inh r4 r2 r3 r1 v in v in gnd LTC2965 ref rs out ps inl inh r3 r2 r1 2965 f02ab rs out ps lt c2965 2965fc
10 for more information www.linear.com/LTC2965 applications information error analysis v in thresholds are subject to the following errors: ? ref voltage v ariation (?v ref ) ? comparator offset (v os ) ? internal divider range error (a verr ) ? external resistive divider error (a xerr ) the effect these errors have on the v in threshold is expressed by: v err = range ? v os ? v ref ? v inh(l) v ref v inh(l) ? a xerr ? ? ? ? ? ? range ? a verr ? v inh(l) a xerr = 2 ? tolerance 100 ? 1C v inh(l) v ref ? ? ? ? ? ? external divider error is determined by the percentage toler - ance values of the resistors. if 1% tolerance resistors are used in the external divider then there is a 2 % worst-case voltage error associated with it . the effects of comparator offset and v ref voltage are uncorrelated with each other. therefore, a root-sum-square can be applied to the error voltage referred to v in . using the example from threshold configuration and assuming 1 % resistors implement the external resistive divider, the falling v in threshold of ap- proximately 18v has an error tolerance of: v err(ref) = range ( ) ? v ref ? v inl v ref ? ? ? ? ? ? = 10 ( ) ? 24mv ? 1.8v 2.402v ? ? ? ? ? ? = 180mv v err(ext) = range ( ) v inl ? 2 ? 0.01? 1C v inl v ref ? ? ? ? ? ? ? ? ? ? ? ? = 10 ( ) ? 1.8v ? 0.005 ( ) = 90mv v err(vos) = range ( ) ? v os ( ) = 10 ( ) ? 3mv ( ) = 30mv v err(rs) = range ( ) a verr ( ) v inl ( ) = 10 ( ) ? 0.004 ( ) ? 1.8v ( ) = 72mv v err = v err(ref) 2 + v err(ext) 2 + v err(vos) 2 + v err(rs) 2 = 180mv ( ) 2 + 90mv ( ) 2 + 30mv ( ) 2 + 72mv ( ) 2 = 216mv the actual v in falling threshold has an error tolerance of 216mv or 1.2%. improving threshold accuracy the biggest threshold error terms are: ? external resistive divider accuracy ? ref voltage v ariation even using 1 % tolerance resistors , external resistive divider accuracy still accounts for as much as 2% threshold error while ref voltage variation accounts for 1% threshold error. in order to minimize these threshold error terms, an external reference can be used to set the thresholds for inh/inl as shown in figure 4. an lt6656-2.048 has an initial accuracy of 0 .05% and provides bias via the 0.1% resistive divider network for inh and inl. it is biased off of the LTC2965 ref pin. the threshold error tolerance is calculated using the method described in the typical applications section with ?v ref = 1.024mv given the initial accuracy of the lt6656 2.048v output and using 0.1% tolerance resistors for the external divider. v err(ref) = range ( ) ? v ref ? v inl v ref ? ? ? ? ? ? = 10 ( ) ? 1.024mv ? 1.8v 2.048v ? ? ? ? ? ? = 9mv v err(ext) = range ( ) v inl ? 2 ? 0.001? 1C v inl v ref ? ? ? ? ? ? ? ? ? ? ? ? = 10 ( ) ? 1.8v ? 0.0005 ( ) = 9mv v err(vos) = range ( ) ? v os ( ) = 10 ( ) ? 3mv ( ) = 30mv v err(rs) = range ( ) a verr ( ) v inl ( ) = 10 ( ) ? 0.004 ( ) ? 1.8v ( ) = 72mv v err = v err(ref) 2 + v err(ext) 2 + v err(vos) 2 + v err(rs) 2 = 9mv ( ) 2 + 9mv ( ) 2 + 30mv ( ) 2 + 72mv ( ) 2 = 79mv the resulting v in threshold error is reduced to 0.44% from 1.2% in the previous error analysis example. lt c2965 2965fc
11 for more information www.linear.com/LTC2965 v in v in LTC2965 gnd ref 1f inh inl 2965 f04 lt6656-2.048 out r2 200k 0.1% r1 1.8m 0.1% r3 47.5k 0.1% r4 10k in gnd figure 4. reducing v in threshold error applications information output configuration with polarity selection the out pin may be used with a wide range of user-defined voltages up to 100v with an external resistor. select a resistor compatible with desired output rise time and load current specifications. when the status outputs are low, power is dissipated in the pull-up resistors. an internal pull-up is present if the out pins are left floating or if low power consumption is required. the internal pull-up resistor does not draw current if an external resistor pulls out up to a voltage greater than v oh . if ps is connected to ground, the comparator output is noninverting. this means that out pulls low when v in falls below the scaled inl voltages. out is released after v in rises above the scaled inh voltage. likewise, if ps is connected up to ref or a voltage > v th , the comparator output is inverting. this means that out pulls low when v in rises above the scaled inh voltage and is released when v in falls below the scaled inl voltage. if the v in pin falls below the uvlo threshold minus hysteresis, the output is pulled to ground. the output is guaranteed to stay low for v in 1.25v regardless of the output logic configuration. it is recommended that circuit board traces associated with the out pin be located on a different layer than those associated with the inh/inl and ref pins where possible to avoid capacitive coupling. hot swap events the LTC2965 can withstand high voltage transients up to 140v. however, when a supply voltage is abruptly connected to the input resonant ringing can occur as a result of series inductance . the peak voltage could rise to 2x the input supply, but in practice can reach 2.5x if a capacitor with a strong voltage coefficient is present. circuit board trace inductances of as little as 10nh can produce significant ringing. ringing beyond the absolute maximum specification can be destructive to the part and should be avoided whenever possible. one effective means to eliminate ringing seen at the v in pins and to protect the part is to include a 1k to 5k resistance between the monitored voltage and the v in pin as shown in figure 5. this provides damping for the resonant circuit . if there is a decoupling capacitor on the v in pins the time constant formed by the rc network should be considered. figure 5. hot swap protection high voltage pin creepage/clearance options appropriate spacing between component lead traces is critical to avoid flashover between conductors. there are multiple industry and safety standards that have different spacing requirements depending on factors such as operating voltage , presence of conformal coat , elevation, etc. the LTC2965 is available in a 16-lead msop package which offers landing clearance of at least 0. 79mm (0. 031in). the package incorporates unconnected pins between all adjacent high voltage and low voltage pins to maximize pc board trace clearance. for voltages >30v the msop should be used, otherwise the smaller or dfn is sufficient when clearance is not an issue. for more information, refer to the printed circuit board design standards described in ipc2221 and ul60950. gnd LTC2965 v ina /v inb r s 1k v in 2965 f05 lt c2965 2965fc
12 for more information www.linear.com/LTC2965 figure 6. using series resistance to dampen ref transient response figure 7. v ref load transient figure 8. v ref line transient 6a 6b 6c applications information voltage reference the ref pin is a buffered reference with a voltage of v ref referenced to gnd. a bypass capacitor up to 1000pf in value can be driven by the ref pin directly. larger capacitances require a series resistance to dampen the transient response as shown in figure 6a. if a resistive divider is already present then the bypass capacitor can be connected to the inh or inl pin as shown in figure 6b. figure 6c shows the resistor value required for different capacitor values to achieve critical damping. bypassing the reference can help prevent false tripping of the compara - tors by preventing glitches on the inh/inl pins. figure 7 shows the reference load transient response. figure 8 shows the reference line transient response . if there is a decoupling capacitor on the inh/inl pin the time constant formed by the rc network should be considered. use a capacitor with a compatible voltage rating. gnd LTC2965 ref inl inh r s c ref 2965 f06ab gnd LTC2965 ref inl inh r s c ref capacitance value (f) resistance value (k) 2965 f06c 100 10 1 0.1 0.001 0.1 1 0.01 100s/div 100a 2.4v 50mv/div 10a 2965 f07 1nf 10nf + 4.3k 0.1f + 1.5k 1f + 600 v ref load current 10s/div 1v/div 3.5v 8v 2.4v 10mv/div 2965 f08 1nf 1f + 600 v ref v in lt c2965 2965fc
13 for more information www.linear.com/LTC2965 typical applications negative voltage monitor with output level shift figure 9 illustrates an LTC2965 configured to monitor a C15v supply with a level-shifted output to a 5v supply. q1 buffers the digital input of the 5v system from the C15v supply and prevents uv from going below gnd. the out pin drives the base of q1 through a resistor network comprised of r3 and r4. keep r4/r3 0.4 to ensure there is proper base current to pull uv to ground . if an exposed pad is present it should be tied to the LTC2965 gnd pin or left open. current sink/source the LTC2965 can be used as a high voltage current source or a current sink as shown in figure 10. the current is determined by placing a resistive load, r set , on the ref pin. the total current is then v ref /r set + i va because the bias current of the part adds a small error term. part of the bias current is the internal resistive divider which is approximately 78m with the rs pin configured to 10x. figure 9. negative voltage monitor with output level shift to a 5v digital input figure 10. LTC2965 configured as high voltage current source v in rsps gnd LTC2965 ref inh out inl r2 976k ?15v 2965 f09 r3 1m uv 5v digital input q1 mmbt2907 fairchild r5 200k r4 510k r1 1.43m rising threshold falling threshold hysteresis range setting ?15v monitor with level shift ?14.5v ?14.2v ?0.3v 10x v in v in gnd ref i sink = 1ma i error = (v ref /r set ) ? i supply rs inh open inl r set 2.4k out ps LTC2965 load current sink i set = v ref /r set v in v in ref i src = 1ma 2965 f10 inh open inl r set 2.4k out load current source i set = v ref /r set LTC2965 gnd rs ps lt c2965 2965fc
14 for more information www.linear.com/LTC2965 configure the current to be no greater than 1ma to ensure that the ref voltage stays within 1% tolerance. current values larger than 1ma exceed the ref buffers load regulation capability and cause the ref voltage to drop out of regulation. shunt mode hysteretic regulator figure 11 shows the LTC2965 used as the controller for a shunt mode hysteretic regulator to manage a battery-based solar power system. when the battery voltage reaches a typical applications lower float limit of 13.7v q1 turns off and the solar panel current passes through to the battery and load . once the battery voltage rises to the upper charging limit of 14.7v, q1 turns on shorting the solar panel to ground with d1 isolating the battery from the shunt path . the upper and lower thresholds are generated from the on- chip reference as a separate external divider to set inh and inl and scaled by 10x. the charging thresholds are temperature compensated by an ntc thermistor over a 0c to 50c range. lt c2965 2965fc
15 for more information www.linear.com/LTC2965 package description 3.00 0.10 (4 sides) note: 1. drawing to be made a jedec package outline m0-229 variation of (weed-1) 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 top and bottom of package 0.40 0.10 bottom view?exposed pad 1.65 0.10 (2 sides) 0.75 0.05 r = 0.125 typ 2.38 0.10 1 4 8 5 pin 1 top mark (note 6) 0.200 ref 0.00 ? 0.05 (dd8) dfn 0509 rev c 0.25 0.05 2.38 0.05 recommended solder pad pitch and dimensions apply solder mask to areas that are not soldered 1.65 0.05 (2 sides) 2.10 0.05 0.50 bsc 0.70 0.05 3.5 0.05 package outline 0.25 0.05 0.50 bsc dd package 8-lead plastic dfn (3mm 3mm) (reference ltc dwg # 05-08-1698 rev c) please refer to http://www .linear.com/product/LTC2965#packaging for the most recent package drawings. lt c2965 2965fc
16 for more information www.linear.com/LTC2965 package description msop (ms16) 0213 rev a 0.53 0.152 (.021 .006) seating plane 0.18 (.007) 1.10 (.043) max 0.17 ?0.27 (.007 ? .011) typ 0.86 (.034) ref 0.50 (.0197) bsc 16151413121110 1 2 3 4 5 6 7 8 9 note: 1. dimensions in millimeter/(inch) 2. drawing not to scale 3. dimension does not include mold flash, protrusions or gate burrs. mold flash, protrusions or gate burrs shall not exceed 0.152mm (.006") per side 4. dimension does not include interlead flash or protrusions. interlead flash or protrusions shall not exceed 0.152mm (.006") per side 5. lead coplanarity (bottom of leads after forming) shall be 0.102mm (.004") max 0.254 (.010) 0 ? 6 typ detail ?a? detail ?a? gauge plane 5.10 (.201) min 3.20 ? 3.45 (.126 ? .136) 0.889 0.127 (.035 .005) recommended solder pad layout 0.305 0.038 (.0120 .0015) typ 0.50 (.0197) bsc 4.039 0.102 (.159 .004) (note 3) 0.1016 0.0508 (.004 .002) 3.00 0.102 (.118 .004) (note 4) 0.280 0.076 (.011 .003) ref 4.90 0.152 (.193 .006) ms package 16-lead plastic msop (reference ltc dwg # 05-08-1669 rev a) please refer to http://www .linear.com/product/LTC2965#packaging for the most recent package drawings. lt c2965 2965fc
17 for more information www.linear.com/LTC2965 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 representa- tion that the interconnection of its circuits as described herein will not infringe on existing patent rights . revision history rev date description page number a 09/15 fixed typos 3, 4, 10 C 12 b 03/16 added absolute maximum rating for inh and inl pins 2 c 08/17 corrected example error threshold calculations 10 lt c2965 2965fc
18 for more information www.linear.com/LTC2965 ? linear technology corporation 2015 lt 0817 rev c ? printed in usa www.linear.com/LTC2965 related parts typical application part number description comments ltc1326 micropower triple supply monitor for 5v/2.5v, 3.3v and adj 4.725v, 3.118v, 1v threshold (0.75%) and adj ltc1440/ltc1441/ ltc1442 ultralow power single/dual comparator with reference adjustable hysteresis, 3mm 3mm 0.75mm dfn package ltc1726/ltc1727/ ltc1728 micropower triple supply monitor adjustable reset and watchdog timeouts ltc1985 micropower triple supply monitor with push-pull reset output 5-lead sot-23 package ltc2900/ltc2901/ ltc2902 programmable quad supply monitor adjustable reset, watchdog timer and tolerance, 10-lead msop and dfn packages lt c2903 precision quad supply monitor 6-lead sot -23 and dfn packages 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/ltc2919 precision triple/dual input uv, ov and negative voltage monitor shunt regulated v cc pin, adjustable threshold and reset ltc2910 octal positive/negative voltage monitor separate v cc 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 v cc pin, adjustable reset timer ltc2915/ltc2916 ltc2917/ltc2918 single voltage supervisors with 27 pin-selectable thresholds manual reset and watchdog functions, 8- and 10-lead tsot-23, msop and dfn packages lt c2966 100v micropower dual v oltage monitor 1.75v to 98v monitoring range, 3.5v to 100v operating range, 7a quiescent current ltc2960 36v nano-current two input voltage monitor 36v, 850na quiescent current, 2mm 2mm 8-lead dfn and tsot-23 packages lt6700 micropower dual comparator with 400mv reference sot-23, 2mm 3mm dfn package figure 11. shunt mode hysteretic regulator 2965 f11 v in gnd rs ps ref out inh inl LTC2965 46.4k 6.81k 47nf 150k ntc**** *nxp **diodes inc ***panasonic ****murata ncp18wf104jo3rb 100k 95.3k 25v 100f fuse 2a lc-p127r2p*** (12v, 7.2ah) 100ma maximum 24 hour average load current 1m d1 b130** q1 buk7640-100a* 1a solar panel lt c2965 2965fc

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