package outline to-220 to-220f (7900a) (7900fa) absolute maximum ratings (ta=25) parameter symbol unit storage temperature range tstg tj topr power dissipation p d w thermal resistance ja jc parameter symbol min. typ. max. unit ml7905a / ml7905fa output voltage vo v in =-10v io=0.5a -4.8 -5.0 -5.2 v quiescent current i q v in =-10v io=0ma - 2.2 5.0 ma load regulation vo io v in =-10v - 50 100 mv line regulation vo vin v in =-7 to -25v io=0.5a - 12.5 100 mv ripple rejection rr v in =-10v io=0.5a e in=2vp-p f=120hz 54 60 -db output noise voltage v no v in =-10v io=0.5a - 125 - v average temperature cofficient of output voltage vo / t v in =-10v io=5ma - -0.4 - mv/ 1. out 2. in 3. common ml7900 series rev b the ml7900 series are 3-terminal negative voltage regulators. these negative regulators are intended as complements to the popular ml7800 series of positive voltage regulations, and they are available in the same voltage options from -5v to -24v. the ml7900 series employ internal current-limiting. safe-area protection , and thermal shutdown, making them virtually indestructible. 3-terminal negative voltage regulator /w (tj=25 ,c1=0.33 f,co=0.1 f) electrical characteristics measurement is to be conducted in pulse testing. thermal resistance junction-to-ambient temperature junction-to-case 60 5 operating temperature range operating ambient temperature -30 to +125 -30 to +75 input voltage -40 to +125 v -35 -35 -40 test conditions bw=10hz to 100khz io=0.005a to 1.5a maximum rating ml7905 to ml7909 ml7912 to ml7920 ml7924 operating junction temperature 15(tc Q 45 ) v in 3 2 1 page 1 of 10
parameter symbol min. typ. max. unit ml7906a / ml7906fa output voltage vo v in =-11v io=0.5a -5.75 -6.0 -6.25 v quiescent current i q v in =-11v io=0ma - 2.2 5.0 ma load regulation vo io v in =-11v - 50 120 mv line regulation vo vin v in =-8 to -25v io=0.5a - 12.5 120 mv ripple rejection rr v in =-11v io=0.5a e in=2vp-p f=120hz 54 60 -db output noise voltage v no v in =-11v io=0.5a - 150 - v average temperature cofficient of out p ut volta ge vo / t v in =-11v io=5ma - -0.4 - mv/ ml7908a / ml7908fa output voltage vo v in =-14v io=0.5a -7.7 -8.0 -8.3 v quiescent current i q v in =-14v io=0ma - 2.2 5.0 ma load regulation vo io v in =-14v - 60 160 mv line regulation vo vin v in =-10.5 to -25v io=0.5a - 12.5 160 mv ripple rejection rr v in =-14v io=0.5a e in=2vp-p f=120hz 54 60 -db output noise voltage v no v in =-14v io=0.5a - 200 - v average temperature cofficient of out p ut volta ge vo / t v in =-14v io=5ma - -0.7 - mv/ ml7909a / ml7909fa output voltage vo v in =-15v io=0.5a -8.65 -9.0 -9.35 v quiescent current i q v in =-15v io=0ma - 2.2 5.0 ma load regulation vo io v in =-15v - 60 180 mv line regulation vo vin v in =-11.5 to -25v io=0.5a - 8 180 mv ripple rejection rr v in =-15v io=0.5a e in=2vp-p f=120hz 54 60 -db output noise voltage v no v in =-15v io=0.5a - 250 - v average temperature cofficient of out p ut volta ge vo / t v in =-15v io=5ma - -0.8 - mv/ ml7912a / ml7912fa output voltage vo v in =-19v io=0.5a -11.5 -12.0 -12.5 v quiescent current i q v in =-19v io=0ma - 2.7 6.0 ma load regulation vo io v in =-19v - 60 240 mv line regulation vo vin v in =-14.5 to -30v io=0.5a - 5 240 mv ripple rejection rr v in =-19v io=0.5a e in=2vp-p f=120hz 54 60 -db output noise voltage v no v in =-19v io=0.5a - 300 - v average temperature cofficient of out p ut volta ge vo / t v in =-19v io=5ma - -0.8 - mv/ rev b io=0.005a to 1.5a bw=10hz to 100khz io=0.005a to 1.5a bw=10hz to 100khz io=0.005a to 1.5a bw=10hz to 100khz io=0.005a to 1.5a bw=10hz to 100khz electrical characteristics (tj=25 ,c1=0.33 f,co=0.1 f) measurement is to be conducted in pulse testing. test conditions page 2 of 10
parameter symbol min. typ. max. unit ml7915a / ml7915fa output voltage vo v in =-23v io=0.5a -14.4 -15.0 -15.6 v quiescent current i q v in =-23v io=0ma - 2.7 6.0 ma load regulation vo io v in =-23v - 60 300 mv line regulation vo vin v in =-17.5 to -30v io=0.5a - 5 300 mv ripple rejection rr v in =-23v io=0.5a e in=2vp-p f=120hz 54 60 -db output noise voltage v no v in =-23v io=0.5a - 375 - v average temperature cofficient of out p ut volta ge vo / t v in =-23v io=5ma - -1 - mv/ ml7918a / ml7918fa output voltage vo v in =-27v io=0.5a -17.3 -18.0 -18.7 v quiescent current i q v in =-27v io=0ma - 2.7 6.0 ma load regulation vo io v in =-27v - 60 360 mv line regulation vo vin v in =-21 to -33v io=0.5a - 5 360 mv ripple rejection rr v in =-27v io=0.5a e in=2vp-p f=120hz 54 60 -db output noise voltage v no v in =-27v io=0.5a - 450 - v average temperature cofficient of out p ut volta ge vo / t v in =-27v io=5ma - -1 - mv/ ml7924a / ml7924fa output voltage vo v in =-33v io=0.5a -23.0 -24.0 -25.0 v quiescent current i q v in =-33v io=0ma - 2.7 6.0 ma load regulation vo io v in =-33v - 85 480 mv line regulation vo vin v in =-28 to -38v io=0.5a - 5 480 mv ripple rejection rr v in =-33v io=0.5a e in=2vp-p f=120hz 54 60 -db output noise voltage v no v in =-33v io=0.5a - 600 - v average temperature cofficient of out p ut volta ge vo / t v in =-33v io=5ma - -1 - mv/ rev b io=0.005a to 1.5a bw=10hz to 100khz io=0.005a to 1.5a bw=10hz to 100khz io=0.005a to 1.5a bw=10hz to 100khz electrical characteristics (tj=25 ,c1=0.33 f,co=0.1 f) measurement is to be conducted in pulse testing. test conditions page 3 of 10
equivalent circuit power dissipation vs. ambient temperature test circuit 1. 2. rev b output voltage, line regulation, load regulation, quiescent current, average temperature coefficient of output voltage, output noise voltage. ripple rejection 25 50 75 0 5 10 15 20 p o w e r d i s s i p a t i o n p d ( w ) ambient temperature ta ( c) without heat sink hs = 20 c/w hs = 10 c/w hs = 5 c/w hs = 3 c/w heat sink hs = heat sink thermal resistance 2 1 3 2 3 1 page 4 of 10
typical characteristics rev b page 5 of 10
typical characteristics rev b page 6 of 10
1. application circuit positive/negative voltage supply note : 2. note in application circuit ( 1 ) ( 2 ) rev b * in case of negative voltage regulator, reverse the sbd and capacitor direction. in the following explain only the positive regulator unless otherwise specified. however they can apply to the negative voltage regulator by easy change. in the above positive and negative power supply application, d1 and d2 should be connected. if d1 and d2 are not connected, either of positive or negative power supply circuit may not turns on. if the higher voltage (above the rated value) or lower voltage (gnd-0.5v) is supplied to the input terminals, the ic may be destroyed. to avoid such a case, a zener diode or other parts of the surge supressor should be connected as shown below. if the higher voltage than the input terminal is supplied to the output terminal, the ic may be destroyed. to avoid input terminal short to the gnd or the stored voltage in the capacitor back to the output terminal, by the large value capacitor connecting to the output terminal application, the sbd should be required as shown below; com -vin +vin 0.33uf 0.33uf out com in 79 series out gnd in 78 series -vo +vo d2 d1 0.1uf 0.1uf vin vo in 1 gnd 2 out 3 capacitor + ze ner diode r vo vin capacitor + in 1 gnd 2 out 3 l diode vin vo capacitor + in 1 gnd 2 out 3 diode page 7 of 10
3. thermal design ( 1 ) heat producting (1-1) p loss-1 : heat producting by own operation p loss-1 = vin x i q (1-2) p loss-2 : heat producing by output current and the input-output differential voltage. internal power transistor produces the hest mentioned following equation. p loss-2 = (vin-vout) x iout (w) therefore, the total heat producing ploss is : p loss = p loss-1 + p loss-2 = vin x i q + (vin-vout) x iout (w) ( 2 ) thermal resistance (2-1) definition of thermal resistance : thermal resistance ( ) is a degree of heat radiation mentioned following equation. = (t1 - t2)/p ( /w) heat producing quantity : p (w) ambient temperature or case temperature :t2 ( ) heat source temperature :t1 ( ) (2-2) thermal resistance of to-220 jc : ja : rev b thermal resistance between ic chip (junction point) and ambience. input voltage (vin) and quiescent current (i q ) produce the heat mentioned below equation. there are two kinds of heat producting (p loss-1 , p loss-2 ) in three terminal regulator and the sum of them is total heat producting of ic (p loss ). there are two kinds of thermal resistance of to-220. one is " jc" for the application with the heat sink, the other is " ja" for the application without the heat sink. thermal resistance between ic chip (junction point) and the package back side contacting with the heat sink. input gnd in out output vin vout i q iout t1 t2 p(w) rp t1 > t2 page 8 of 10
( 3 ) heat radiation balance (3-1) to-220 with heat sink where jc : js : ch : hs : the relation between temperature and heat radiation quantity is shown below. rev b tj=p loss x ( jc+ ch + hs ) + ta ( ) thermal resistance between ic chip (junction point) and the package surface. thermal resistance between package backside and the heat sink including the condidtion of insulator, silicon grease and tighten torque. thermal resistance of the heat sink if the js is large enough compare with other thermal resistance, the js can be neglected and the heat radiation model can be mentioned as below. the heat produced in the ic is radiated to ambience through the package and the heat sink. the quantity of the heat radiation depends on the heat source temperature, ambient temperature and the thermal resistance of the package. heat radiation balance model of the to-220 with heat sink is shown as below. thermal resistance between ic chip (junction point) and the package backside connecting to the heatsink. tj ta loss p ambient temperature heat source (junction) temperature jc ? ch hs js heat sink ic package face side resin chip package back side js jc ch hs tj loss p jc ch ta hs page 9 of 10
( 4 ) thermal design the heat radiation balance model of the to-220 with the heat sink is shown as follows. heat radiation balance tj = p loss x ( jc + ch + hs ) + ta ( ) (4-1) p loss = vin x i q + (vin-vout) x iout (w) (4-2) substituting "eq.(4-2) into "eq.(4-1)" obtains tj = [vin x i q +(vin-vout) x iout] x ( jc + ch + hs )+ta ( ) (4-3) in eq.(4-3) vin, iout, ch , hs , ta depand on using condition. tj, i q ,vout, jc depend on ic depend on ic specification. when ch , i q and tj are assumed the following values, eq.(4-3) becomes eq.(4-4). ch =0.3 to 0.4 ( /w) i q = 5 to 6ma (max.) tj = 125 (max.) tj(max) = 125 = [5 x vin + (vin-vout) x iout] x (5+0.3+ hs ) +ta ( ) (4-4) when fix the vout, tj depends on the vin, iout, hs and ta. it means; rev b for more detail, please refer the heat resistance value mentioned in the specification of the heat sink supplier. insert the mica paper (0.1t) and thermal conduction silicon grease between the ic and heat sink and tighten them with the bolt by 4kg*cm-min. lower vin and / or iout are required to linit the temperature rise. smaller hs is required for the effective heat reduce (i.e. using the large heat sink). in the thermal design, when fix the vin, iout and ta, selectthe heat sink which hs is smaller that the result of eq.(4-4). page 10 of 10
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