mic426/427/428 micrel 5 1997 5-9 mic426/427/428 dual 1.5a-peak low-side mosfet driver bipolar/cmos/dmos process 870 20 general description the mic426/427/428 are dual high speed drivers. a ttl/ cmos input voltage level is translated into an output voltage level swing equal to the supply. the dmos output will be within 25mv of ground or positive supply. bipolar designs are capable of swinging only within 1 volt of the supply. the low impedance high current driver outputs will swing a 1000pf load 18v in 30ns. the unique current and voltage drive qualities make the mic426/427/428 ideal power mosfet drivers, line drivers, and dc-to-dc converter building blocks. input logic signals may equal the power supply voltage. input current is a low 1 m a making direct interface to cmos/bipolar switch-mode power supply control integrated circuits possible as well as open-collector analog comparators. features ? high speed switching (c l = 1000pf) .................. 30ns ? high peak output current ..................................... 1.5a ? high output voltage swing ........................ v s C 25mv gnd + 25mv ? low input current (logic 0 or 1) ........................ 1 m a ? low equivalent input capacitance (typ) ................. 6pf ? ttl/cmos input compatible ? available in inverting & non-lnverting configurations ? wide operating supply voltage ................ 4.5v to 18v ? low power consumption (inputs low) ............................................. 0.4ma (inputs high) ................................................ 8ma ? single supply operation ? low output impedance (typ) ................................... 6 w ? pin out equivalent to ds0026 & mmh0026 functional diagram ina outa inverting noninverting 0.1ma 0.6ma 2k w inb outb inverting noninverting 0.1ma 0.6ma 2k w v s gnd pin configuration 1 2 3 4 8 7 6 5 nc ina gnd inb nc outa v s outb mic426 dual inverting a b 7 5 2 4 mic426 mic427 mic428 a b 7 5 2 4 a b 7 5 2 4 1 2 3 4 8 7 6 5 nc ina gnd inb nc outa v s outb mic427 dual noninverting 1 2 3 4 8 7 6 5 nc ina gnd inb nc outa v s outb mic428 inverting- noninverting ground unused inputs integrated component count: 4 resistors 4 capacitors 52 transistors
mic426/427/428 micrel 5-10 1997 ordering information part number temperature range package configuration mic426cm 0 c to +70 c 8-pin soic dual inverting mic426bm C40 c to +85 c mic426cn 0 c to +70 c 8-pin plastic dip dual inverting mic426bn C40 c to +85 c MIC426AJ C55 c to +125 c 8-pin cerdip dual inverting 5962-8850301pa 1 C55 c to +125 c 5962-8850302pa 2 C55 c to +125 c 8-pin cerdip dual noninverting 5962-8850303pa 3 C55 c to +125 c 8-pin cerdip noninverting + inverting 1 standard military drawing number for MIC426AJbq 2 standard military drawing number for mic427ajbq 3 standard military drawing number for mic428ajbq quiescent power supply current is 8ma maximum. the mic426 requires 1/5 the current of the pin compatible bipolar ds0026 device. this is important in dc-to-dc converter applications with power efficiency constraints and high frequency switch mode power supply applications. quiescent current is typically 6ma when driving a 1000pf load 18v at 100khz. the inverting mic426 driver is pin compatible with the bipolar ds0026 and mmh0026 devices. the mic427 is non-inverting; the mic428 contains an inverting and non-inverting driver. absolute maximum ratings (notes 1, 2, and 3) if military/aerospace specified devices are required, contact micrel for availability and specifications. supply voltage 20v input voltage any terminal v s + 0.3v to gnd C 0.3v maximum chip temperature 150 c storage temperature C65 c to 150 c lead temperature (10 sec) 300 c package thermal resistance cerdip r q j-a ( c/w) 100 cerdip r q j-c ( c/w) 50 pdip r q j-a ( c/w) 130 pdip r q j-c ( c/w) 42 soic r q j-a ( c/w) 120 soic r q j-c ( c/w) 75 operating temperature range c version 0 c to +70 c b version C40 c to +85 c a version C55 c to +125 c
mic426/427/428 micrel 5 1997 5-11 electrical characteristics: t a = 25 c with 4.5v v s 18v unless otherwise specified. no. symbol parameter conditions min typ max units input 1v ih logic 1 input voltage 2.4 1.4 v 2v il logic 0 input voltage 1.1 0.8 v 3i in input current 0 v in v s C1 1 m a output 4v oh high output voltage v s C0.025 v 5v ol low output voltage 0.025 v 6r o output resistance v in = 0.8v 6 15 w i out = 10ma, v s = 18v 7r o output resistance v in = 2.4v 6 10 w i out = 10ma, v s = 18v 8i pk peak output current 1.5 a switching time 9t r rise time test figures 1, 2 18 30 ns 10 t f fall time test figures 1, 2 15 20 ns 11 t d1 delay tlme test figures 1, 2 17 40 ns 12 t d2 delay time test figures 1, 2 23 75 ns power supply 13 i s power supply current v in = 3.0v (both inputs) 1.4 8.0 ma 14 i s power supply current v in = 0.0v (both inputs) 0.18 0.4 ma electrical characteristics: over operating temperature range with 4.5v v s 18v unless otherwise specified. no. symbol parameter conditions min typ max units input 1v ih logic 1 input voltage 2.4 1.5 v 2v il logic 0 input voltage 1.0 0.8 v 3i in input current 0 v in v s C10 10 m a
mic426/427/428 micrel 5-12 1997 electrical characteristics: over operating temperature range with 4.5v v s 18v unless otherwise specified (continued). no. symbol parameter conditions min typ max units output 4v oh high output voltage v s C0.025 v 5v ol low output voltage 0.025 v 6r o output resistance v in = 0.8v 8 20 w i out = 10ma, v s = 18v 7r o output resistance v in = 2.4v 10 15 w i out = 10ma, v s = 18v switching time 8t r rise time test figures 1, 2 20 60 ns 9t f fall time test figures 1, 2 29 40 ns 10 t d1 delay tlme test figures 1, 2 19 60 ns 11 t d2 delay time test figures 1, 2 27 120 ns power supply 12 i s power supply current v in = 3.0v (both inputs) 1.5 12.0 ma 13 i s power supply current v in = 0.0v (both inputs) 0.19 0.6 ma note 1: functional operation above the absolute maximum stress ratings is not implied. note 2: static sensitive device (above 2kv). unused devices must be stored in conductive material to protect devices from static discha rge and static fields. note 3: switching times guaranteed by design.
mic426/427/428 micrel 5 1997 5-13 switching time test circuits a b ina inb 2 4 mic426 5 7 outa 1000pf 6 v s = 18v 0.1? 4.7? outb 1000pf t d1 90% 10% t f 10% 0v 5v t d2 t r v s output input 90% 0v t pw 3 0.5? 2.5v t pw figure 1. inverting driver switching time a b ina inb 2 4 mic427 5 7 outa 1000pf 6 v s = 18v 0.1? 4.7? outb 1000pf 90% 10% t r 10% 0v 5v t f v s output input 90% 0v t pw 3 0.5? t d1 t d2 t pw 2.5v figure 2. noninverting driver switching time
mic426/427/428 micrel 5-14 1997 typical characteristic curves rise and fall time vs. supply voltage 05 20 10 15 t f supply voltage (v) 70 60 50 40 10 0 time (ns) 20 30 delay time vs. supply voltage 05 20 10 15 supply voltage (v) 35 30 25 20 5 0 time (ns) 10 15 40 30 10 time (ns) 20 -25 0 150 25 50 temperature (?) 75 100 125 delay time vs. temperature 35 30 25 20 5 0 time (ns) 10 15 -25 0 150 25 50 temperature (?) 75 100 125 t d1 supply current vs. capacitive load 80 70 60 50 20 0 supply current (ma) 30 40 10 400khz 200 khz 20khz 10 10000 100 capacitive load (pf) 1000 1k 100 10 1 time (ns) 10 10000 100 capacitive load (pf) 1000 rise and fall time vs. capacitive load t r t f supply current vs. frequency v = 18v s 10 v 5 v 20 0 supply current (ma) 30 10 1 1000 10 frequency (khz) 100 high output vs. current | v ?v | (v) s out current sourced (ma) low output vs. current 1.20 .96 .00 .48 .72 .24 010 current sunk (ma) 20 30 40 50 60 70 80 90 100 10 v 15 v output voltage (v) rise and fall time vs. temperature 1.20 .96 .00 .48 .72 .24 0 10 2030405060708090100 10 v 15 v -50 t r -50 -75 t r t f -75 t d2 t d1 t d2 c = 1000pf t = 25? l a c = 1000pf t = 25? l a c = 1000pf v = 18v l s c = 1000pf v = 18v l s t = 25? v = 18v a s t = 25? v = 18v a s t = 25? c = 1000pf l a t = 25? a v = 5v c t = 25? a v = 5v s
mic426/427/428 micrel 5 1997 5-15 typical characteristic curves (continued) supply bypassing charging and discharging large capacitive loads quickly requires large currents. for example, changing a 1000pf load 18 volts in 25ns requires a 0.8a current from the device power supply. to guarantee low supply impedance over a wide frequency range, a parallel capacitor combination is recommended for supply bypassing. low inductance ceramic disk capacitors with short lead lengths (< 0.5 inch) should be used. a 4.7 m f solid tantalum capacitor in parallel with one or two 0.1 m f ceramic disk capacitors normally provides adequate bypassing. grounding the mic426 and mic428 contain inverting drivers. ground potential drops developed in common ground impedances from input to output will appear as negative feedback and degrade switching speed characteristics. individual ground returns for the input and output circuits or a ground plane should be used. input stage the input voltage level changes the no load or quiescent supply current. the n channel mosfet input stage transistor drives a 2.5ma current source load. with a logic 1 input, the maximum quiescent supply current is 8ma. logic 0 input level signals reduce quiescent current to 400 m a maximum. minimum power dissipation occurs for logic 0 inputs for the mic426/427/428; unused driver inputs must be grounded or tied to the positive supply. the drivers are designed with 100mv of hysteresis. this provides clean transitions and minimizes output stage current spiking when changing states. input voltage thresholds are approximately 1.5v making the device ttl compatible over the 4.5v to 18v operating supply range. input current is less than 1 m a over this range. the mic426/427/428 may be directly driven by the tl494, sg1526/1527, sg1524, se5560 and similar switch-mode power supply integrated circuits. power dissipation the supply current vs. frequency and supply current vs. capacitive load characteristic curves will aid in performing power dissipation calculations. the mic426 cmos drivers have greatly reduced quiescent dc power consumption. maximum quiescent current is 8ma compared to the ds0026 40ma specification. for a 15v supply, power dissipation is typically 40mw. two other power dissipation components are: ? output stage ac and dc load power. ? transition state power. output stage power is: p o = p dc + p ac = v o (i dc ) + f c l v s where: v o = dc output voltage i dc = dc output load current f = switching frequency v s = supply voltage in power mosfet drive applications, the p dc term is negligible. mosfet power transistors are high impedance, capacitive input devices. in applications where resistive loads or relays are driven, the p dc component will normally dominate. the magnitude of p ac is readily estimated for several cases: a. 1. f = 200khz b. 1. f = 200khz 2. c l = 1000pf 2. c l = 1000pf 3. v s = 18v 3. v s = 15v 4. p ac = 65mw 4. p ac = 45mw d uring output level state changes, a current surge will flow through the series connected n- and p- channel output mosfets as one device is turning on while the other is 2 quiescent power supply current vs. supply voltage package power dissipation 25 50 150 75 100 ambient temperature (?) 1000 750 250 0 500 quiescent power supply current vs. supply voltage 0 0.5 2.5 1.0 1.5 supply current (ma) 20 15 5 0 supply voltage (v) 10 2.0 125 supply current (?) 15 10 05 0 50 100 150 200 300 400 20 supply voltage (v) maximum package power dissipation (mw) 1250 pdip cerdip no load both inputs logic "1" t = 25? a no load both inputs logic "0" t = 25? a soic
mic426/427/428 micrel 5-16 1997 870 25 turning off. the current spike flows only during output transitions. the input levels should not be maintained between the logic 0 and logic 1 levels. unused driver inputs must be tied to ground and not be allowed to float. average power dissipation will be reduced by minimizing input rise times. as shown in the characteristic curves, average supply current is frequency dependent. voltage doubler 0.1 m f 1/2 mic426 2 f in = 10khz +15v 4.7 m f + 47 m f + v out + 10 m f 3 7 30 29 28 27 26 25 24 23 21 22 0 5 10 20 30 40 50 60 70 80 90 100 v out (v) i out output voltage vs load current 6 1n4001 1n4001 (ma) voltage inverter 0.1 m f 1/2 mic426 2 f in = 10khz +15v 4.7 m f + 47 m f + v out + 10 m f 3 7 -5.0 -6.0 -7.0 -8.0 -9.0 -10.0 -11.0 -12.0 -14.0 -13.0 0 5 10 20 30 40 50 60 70 80 90 100 v out (v) i out (ma) 1n4001 1n4001 output voltage vs load current
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