11/91 rev 1.3 9/02 l infinity microelectronics inc. copyright ? 1997 11861 western avenue garden grove, ca 92841 1 (714) 898-8121 fax: (714) 893-2570 sg1548/sg2548/sg3548 quad power fault monitor description the sg1548 is an integrated circuit capable of monitoring up to four positive dc supply voltages simultaneously for overvoltage and undervoltage fault conditions. an on-chip inverting op amp also allows monitoring one negative dc voltage. the fault tolerance window is accurately programmable from 5% to 40% using a simple divider network on the 2.5v reference. a single external capacitor sets the fault indication delay, eliminating false outputs due to switching noise, logic transition current spikes, and short-term ac line interrup- tions. an additional comparator referenced to 2.5v allows the ac line to be monitored for undervoltage conditions or for generation of a line clock. the comparator can also be used for programmable undervoltage lockout in a switching power supply. uncommitted collector and emitter outputs permit both inverting and non-inverting operation. external availability of the precision 2.5v reference and open-collector logic outputs permit expansion to monitor additional voltage using available open-collector quad comparators. features monitors four dc voltages and the ac line precision 2.5v 1% low-drift reference fault tolerance adjustable from 5% to 40% 3% trip threshold tolerance over temperature separate 10ma, 40v overvoltage, undervoltage and ac line fault outputs fault delay programmable with a single capacitor 30mv comparator hysteresis to prevent oscilla- tions on-chip inverting op amp for negative voltage open-collector output logic or expandability operation from 4.5v to 40v supply high reliability features - sg1548 available to mil-std-883 lmi level "s" processing available block diagram
11/91 rev 1.3 9/02 l infinity microelectronics inc. copyright ? 1997 11861 western avenue garden grove, ca 92841 2 (714) 898-8121 fax: (714) 893-2570 absolute maximum ratings (note 1) sg1548/sg2548/sg3548 inverting op amp output current .................................... operating junction temperature hermetic (j, l packages) ............................................. plastic (n, dw packages) ............................................ storage temperature range ............................ lead temperature ........................................................... supply voltage (+v in ) .......................................................... fault output collector voltage ............................................ sense input voltage range ................................. fault output sink current ................................................ line sense input current ................................................. inverting op amp input current ........................................ 40v 40v -0.3v to 6.0v 20ma 1ma -5ma 25ma 150 c 150 c -65 c to 150 c 300 c note 1. values beyond which damage may occur. thermal data j package: thermal resistance- junction to case , q jc ................... 30c/w thermal resistance- junction to ambient , q ja .............. 80c/w n package: thermal resistance- junction to case , q jc .................. 40c/w thermal resistance- junction to ambient , q ja ............. 65c/w dw package: thermal resistance- junction to case , q jc .................. 40c/w thermal resistance- junction to ambient , q ja ............. 95c/w l package: thermal resistance- junction to case , q jc .................. 35c/w thermal resistance- junction to ambient , q ja ........... 120c/w note a. junction temperature calculation: t j = t a + (p d x q ja ). note b. the above numbers for q jc are maximums for the limiting thermal resistance of the package in a standard mount- ing configuration. the q ja numbers are meant to be guidelines for the thermal performance of the device/pc- board system. all of the above assume no ambient airflow. 2.625 3.500 2.375 1.500 0.6 100 dc sense inputs section v pin 1 = 0.95 x v ref v pin 1 = 0.60 x v ref v pin 1 = 0.95 x v ref v pin 1 = 0.60 x v ref v sense = 1.5v to 3.5v +v in = 4.5v to 35v overvoltage threshold undervoltage threshold input bias current threshold supply rejection 4.5v to 35v 5.0v to 35v 1.5v to 2.45v 5% to 40% 0 to 10ma supply voltage range 25% maximum fault window (note 3) .............. 40% maximum fault window ........................... lower threshold input range ............................. fault tolerance window range .......................... fault output sink current range ............................. line sense output current range ........................... voltage reference output current ........................... operating ambient temperature range sg1548 ......................................................... sg2548 ........................................................... sg3548 ............................................................... 0 to 10ma 0 to 10ma -55 c to 125 c -25 c to 85 c 0 c to 70 c note 2. range over which the device is functional. note 3. limited by inverter amplifier positive swing at -55 c. recommended operating conditions (note 2) electrical characteristics (unless otherwise specified, these specifications apply over the operating ambient temperatures for sg1548 with -55 c t a 125 c, sg2548 with -25 c t a 85 c, sg3548 with 0 c t a 70 c, and +v in = 15v. low duty cycle pulse testing techniques are used which maintains junction and case temperatures equal to the ambient temperature.) reference section (note 4) t j = 25 c over temperature +v in = 4.5v to 35v i l = 0 to 10ma v ref = 0v output voltage line regulation load regulation short circuit current 4.8 +v in = 40v supply current ma 10 min. typ. max. sg3548 sg1548/2548 test conditions parameter units supply section -0.4 v pin 1 = 1.5v to 2.45v input bias current m a fault window generator section min. typ. max. 10 4.8 2.475 2.450 10 2.500 1 3 25 2.525 2.550 5 10 50 2.475 2.450 10 2.500 1 3 25 2.525 2.550 5 10 50 v v mv mv ma -2.0 -0.4 -2.0 2.547 3.396 2.304 1.455 60 2.704 3.606 2.447 1.545 2.0 2.547 3.396 2.304 1.455 60 2.625 3.500 2.375 1.500 0.6 100 2.704 3.606 2.447 1.545 2.0 v v v v m a db note 4. i l = 0ma
11/91 rev 1.3 9/02 l infinity microelectronics inc. copyright ? 1997 11861 western avenue garden grove, ca 92841 3 (714) 898-8121 fax: (714) 893-2570 fault logic outputs (each output) v c = 40v i c = 10ma collector leakage current collector saturation voltage 2.500 25 1 1 0.2 13 ac line sense section v pin 5 = low to high v pin 5 = 2.5v v ce = 40v i c = 10ma i e = 10ma i pin 5 = 1ma i pin 5 = -1ma comparator threshold comparator hysteresis input bias current collector leakage current collector saturation voltage emitter output voltage diode clamp voltage 2.440 12 6.0 -0.3 2.560 2 10 0.5 7.5 -1.0 2.440 12 6.0 -0.3 2.500 25 1 1 0.2 13 2 -0.3 3.5 1.0 100 15 100 3.2 72 5 72 inverting op amp section (note 5) i source = 5ma i sink = 5ma r l = 10k +v in = 4.5v to 35v input offset voltage input bias current output high voltage output low voltage large signal voltage gain output source current power supply rejection ratio mv m a v v db ma db 1.250 25 50 0.1 +3.2 1.200 32.5 v pin 8 = 0v i pin 8 = 0ma i pin 8 = 0ma comparator threshold comparator hysteresis delay charging current on saturation voltage off clamp voltage sg1548/sg2548/sg3548 min. typ. max. sg3548 sg1548/2548 test conditions parameter units electrical characteristics (continued) min. typ. max. application information note 5. +v in = 4.5v. fault delay section 1.300 67.5 0.2 +3.6 1.200 32.5 1.250 25 50 0.1 +3.2 1.300 67.5 0.2 +3.6 v mv m a v v 15 -1.0 1.9 25 3.2 72 5 72 2 -0.3 3.5 1.0 100 15 100 15 -1.0 1.9 25 2.560 2 10 0.5 7.5 -1.0 v mv m a m a v v v v m a v 10 0.5 1 0.2 10 0.5 1 0.2 setting the fault tolerance window the fault tolerance window is set by applying a voltage less than the +2.50vreference to the lower threshold input (pin 1). the voltage is obtained by a resistor divider from the reference (pin 3) to ground. if 5% tolerance is desired, then 95% of the reference (+2.375v) is applied to pin 1. if 40% is wanted, then 60% of the reference (+1.50v) is applied. in the example on the back page, the tolerance is 5%. the nominal overvoltage and undervoltage thresholds are centered about the reference at +2.625v and +2.375v (+2.500v 0.125v). scaling the monitored supply voltages each positive voltage to be monitored is divided down to +2.50v with a resistor network and connected to one of the sense inputs. unused sense inputs should be connected to the reference. this will not increase the bias current. a variation of the monitored voltages out of the programmed tolerance range will cause the appropriate overvoltage or undervoltage fault output to switch low. the effective tolerance on any input may be broadened with an additional resistor to the voltage reference. the example on the back page shows a 10% tolerance on the +5vsupply although the sg1548 is programmed for a 5% tolerance. the procedure for calculating the resistor value is found in the sg1548 application note. monitoring a negative voltage a negative voltage can be converted to a positive one and simultaneously scaled to +2.50v by using the internal operational amplifier as an inverter. only an input resistor and feedback resistor are required. setting the fault delay a single capacitor at the delay pin sets the time an out-of- tolerance fault must persist before a fault is actually declared. this feature allows switching noise on the supplies to be rejected. the delay time is given by: delay = 25ms/ m f . ac line monitoring the ac line voltage can be monitored for single-cycle dropouts with the few components shown in the example. a half-wave rectifier charges the capacitor on positive line cycles. after the positive peak and during the negative line cycle the capacitor discharges from a fixed voltage controlled by the internal zener diode. if a positive cycle is missing, the capacitor discharges to below the +2.5v trip point of the comparator, causing the output transistor to turn on.
11/91 rev 1.3 9 /02 l infinity microelectronics inc. copyright ? 1997 11861 western avenue garden grove, ca 92841 4 (714) 898-8121 fax: (714) 893-2570 sg1548/sg2548/sg3548 application example in this example, the sg1548 simultaneously monitors four dc voltages: +5v, +24v, and 15v. three different fault tolerances ar e programmed: 5% on the two 15v supplies, 10% on the +5v supply, and 20% on the +24v supply. the 5 m f delay capacitor provides 125 milliseconds of fault delay. connection diagrams & ordering information (see notes below) ambient temperature range part no. package connection diagram 16-pin ceramic dip j - package sg1548j/883b -55 c to 125 c sg1548j -55 c to 125 c sg2548j -25 c to 85 c sg3548j 0 c to 70 c sg2548n -25 c to 85 c sg3548n 0 c to 70 c 16-pin plastic dip n - package 2 3 4 5 6 7 8 1 15 16 14 13 10 9 12 11 2 3 4 5 6 7 8 16-pin wide body plastic s.o.i.c. dw - package sg2548dw -25 c to 85 c SG3548DW 0 c to 70 c inv. output inv. input sense 4 sense 3 sense 2 sense 1 u.v. fault o.v. fault delay v ref ground lower threshold collector output emitter output +v in line sense 15 16 14 13 10 9 12 11 1 delay v ref ground lower threshold +v in line sense collector output emitter output inv. output inv. input sense 4 sense 3 sense 2 sense 1 u.v. fault o.v. fault 20-pin ceramic (lcc) leadless chip carrier l- package sg1548l/883b -55 c to 125 c sg1548l -55 c to 125 c note 1. contact factory for jan and desc product availability. 2. all parts are viewed from the top. 11. n.c. 12. o.v. fault 13. u.v. fault 14. sense 1 15. sense 2 16. n.c. 17. sense 3 18. sense 4 19. inv. input 20. inv. output 1. n.c. 2. lower threshold 3. ground 4. v ref 5. +v in 6. n.c. 7. line sense 8. emitter output 9. collector output 4 5 6 7 8 321 9 111213 10 14 15 16 17 18 20 19 10.delay
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