FAN A, 1.2V Low Dropout Linear Regulator for VRM8.5. Features. Description. Applications. Typical Application.

Transcription

1 2.7A, 1.2V Low Dropout Linar Rgulator for VRM8.5 Faturs Fast transint rspons Low dropout voltag at up to 2.7A Load rgulation: 0.05% typical Trimmd currnt limit On-chip thrmal limiting Standard TO-220, TO-263, TO-263 cntr cut and TO-252 (DPAK) packags Applications A GTL+ bus supply for VRM 8.5 Low voltag logic supply Post rgulator for switching supply Dscription Th is a low dropout thr-trminal rgulator with 2.7A output currnt capability. This dvic has bn optimizd for VTT bus trmination, whr transint rspons and minimum input voltag ar critical. Th offrs fixd 1.2V with 2.7A currnt capability for a GTL+ bus VTT trmination. Currnt limit is trimmd to nsur spcifid output currnt and controlld short-circuit currnt. On-chip thrmal limiting provids protction against any combination of ovrload and ambint tmpratur that would crat xcssiv junction tmpraturs. Th is availabl in th industry-standard TO-220, TO-263, TO-263 cntr cut and TO-252 (DPAK) powr packags. Typical Application V IN = 3.3V V IN V OUT 1.2V at 2.7A + GND + 10µF 22µF REV /10/03

2 PRODUCT SPECIFICATION Pin Assignmnts T FRONT VIEW M FRONT VIEW Tab is OUT Tab is OUT GND OUT IN GND OUT IN 3-Lad Plastic TO-263 θjc = 3 C/W* 3-Lad Plastic TO-220 θjc = 3 C/W MC FRONT VIEW Tab is OUT D FRONT VIEW Tab is OUT GND IN GND OUT IN 3-Lad Plastic TO-263 Cntr Cut θjc = 3 C/W* 3-Lad Plastic TO-252 θjc = 3 C/W* *With packag soldrd to 0.5 squar inch coppr ara ovr backsid ground plan or intrnal powr plan, ΘJA can vary from 30 C/W to mor than 40 C/W. Othr mounting tchniqus can provid a thrmal rsistanc lowr than 30 C/W. Absolut Maximum Ratings Paramtr Min. Max. Unit VIN 7 V Oprating Junction Tmpratur Rang C Storag Tmpratur Rang C Lad Tmpratur (Soldring, 10 sc.) 300 C 2 REV /10/03

3 PRODUCT SPECIFICATION Elctrical Charactristics Tj = 25 C unlss othrwis spcifid. Th dnots spcifications which apply ovr th spcifid oprating tmpratur rang. Paramtr Conditions Min. Typ. Max Units Output Voltag 3.3V VIN 7V 10mA IOUT 2.7A Lin Rgulation 1, 2 (VOUT + 1.5V) VIN 7V, IOUT = 10mA V % Load Rgulation 1, 2 (VIN VOUT) = 3V % 10mA IOUT 2.7A Dropout Voltag VREF = 1%, IOUT = 2.7A V Currnt Limit (VIN VOUT) = 2V A Minimum Load Currnt 1.5V (VIN VOUT) 5.75V 10 ma Quiscnt Currnt VIN = 5V 4 13 ma Rippl Rjction f = 120Hz, COUT = 22µF Tantalum, (VIN VOUT) = 3V, IOUT = 2.7A db Thrmal Rgulation TA = 25 C, 30ms puls %/W Tmpratur Stability 0.5 % Long-Trm Stability TA = 125 C, 1000 hrs % RMS Output Nois TA = 25 C, 10Hz f 10kHz % (% of VOUT) Thrmal Rsistanc, TO C/W Junction to Cas TO-263, TO C/W Thrmal Shutdown 150 C Nots: 1. S thrmal rgulation spcifications for changs in output voltag du to hating ffcts. Load and lin rgulation ar masurd at a constant junction tmpratur by low duty cycl puls tsting. 2. Lin and load rgulation ar guarantd up to th maximum powr dissipation (18W). Powr dissipation is dtrmind by input/output diffrntial and th output currrnt. Guarantd maximum output powr will not b availabl ovr th full input/ output voltag rang. REV /10/03 3

4 PRODUCT SPECIFICATION Typical Prformanc Charactristics DROPOUT VOLTAGE (V) T=0 C T=25 C T=125 C OUTPUT VOLTAGE DEVIATION (%) I = 2.7A OUTPUT CURRENT (A) JUNCTION TEMPERATURE ( C) Figur 1. Dropout Voltag vs. Output Currnt Figur 2. Load Rgulation vs. Tmpratur 1.30 V OUT SET WITH 1% RESISTORS 5 REFERENCE VOLTAGE (V) MINIMUM LOAD CURRENT (ma) JUNCTION TEMPERATURE ( C) JUNCTION TEMPERATURE ( C) Figur 3. Output Voltag vs. Tmpratur Figur 4. Minimum Load Currnt vs. Tmpratur SHORT-CIRCUIT CURRENT (A) RIPPLE REJECTIONS (db) (V IN VOUT) 3V 0.5V V RIPPLE 2V I OUT = 2.7A JUNCTION TEMPERATURE ( C) Figur 5. Short-Circuit Currnt vs. Tmpratur K 10K 100K FREQUENCY (Hz) Figur 6. Rippl Rjction vs. Frquncy 4 REV /10/03

5 PRODUCT SPECIFICATION Typical Prformanc Charactristics (continud) POWER (W) CASE TEMPERATURE ( C) Figur 7. Maximum Powr Dissipation OUTPUT CAPACITANCE ESR, (Ω) Ara of Instability Stabl Ara LOAD CURRENT (ma) Figur 9. Stability Rgion REV /10/03 5

6 Applications Information Gnral Th is a thr-trminal rgulator optimizd for a GTL+ VTT trmination applications. It is short-circuit protctd, and offrs thrmal shutdown to turn off th rgulator whn th junction tmpratur xcds about 150 C. Th provids low dropout voltag and fast transint rspons. Frquncy compnsation uss capacitors with low ESR whil still maintaining stability. This is critical in addrssing th nds of low voltag high spd microprocssor buss lik a GTL+. Stability Th rquirs an output capacitor as a part of th frquncy compnsation. It is rcommndd to us a 22µF solid tantalum or a 100µF aluminum lctrolytic on th output to nsur stability. Th frquncy compnsation of ths dvics optimizs th frquncy rspons with low ESR capacitors. In gnral, it is suggstd to us capacitors with an ESR of <1Ω. Protction Diods In normal opration, th dos not rquir any protction diods. A protction diod btwn th input and output pins is usually not ndd. An intrnal diod btwn th input and output pins on th can handl microscond surg currnts of 50A to 100A. Evn with larg valu output capacitors it is difficult to obtain thos valus of surg currnts in normal opration. Only with larg valus of output capacitanc, such as 1000µF to 5000µF, and with th input pin instantanously shortd to ground can damag occur. A crowbar circuit at th input can gnrat thos lvls of currnt; a diod from output to input is thn rcommndd, as shown in Figur 9. Usually, normal powr supply cycling or systm hot plugging and unplugging will not gnrat currnt larg nough to do any damag. As with any IC rgulator, xcding th maximum input-tooutput voltag diffrntial causs th intrnal transistors to brak down and non of th protction circuitry is thn functional. V IN C1 10µF D1 1N4002 (OPTIONAL) IN OUT + + GND C2 22µF V OUT Load Rgulation PRODUCT SPECIFICATION It is not possibl to provid tru rmot load snsing bcaus th is a thr-trminal dvic. Load rgulation is limitd by th rsistanc of th wir conncting th rgulators to th load. Load rgulation pr th data sht spcification is masurd at th bottom of th packag. For fixd voltag dvics, ngativ sid snsing is a tru Klvin connction with th ground pin of th dvic rturnd to th ngativ sid of th load. This is illustratd in Figur 10. V IN Figur 9. Connction for Bst Load Rgulation Thrmal Considrations Th protcts itslf undr ovrload conditions with intrnal powr and thrmal limiting circuitry. Howvr, for normal continuous load conditions, do not xcd maximum junction tmpratur ratings. It is important to considr all sourcs of thrmal rsistanc from junction-to-ambint. Ths sourcs includ th junction-to-cas rsistanc, th cas-to-hat sink intrfac rsistanc, and th hat sink rsistanc. Thrmal rsistanc spcifications hav bn dvlopd to mor accuratly rflct dvic tmpratur and nsur saf oprating tmpraturs. For xampl, look at using an to gnrat 1.2V ± 2% from a 3.3V sourc (3.2V to 3.6V). Assumptions: IN GND OUT VIN = 3.6V worst cas VOUT = 1.176V worst cas IOUT = 2.7A continuous TA = 70 C θcas-to-ambint = 3 C/W (assuming both a hatsink and a thrmally conductiv matrial) Th powr dissipation in this application is: PD = (VIN VOUT) * (IOUT) = ( ) * (2.7) = 6.53W From th spcification tabl: R P PARASITIC LINE RESISTANCE TJ = TA + (PD) * (θcas-to-ambint + θjc) = 70 + (6.53) * (3 + 3) = 109 C Th junction tmpratur is blow th maximum rating. R L Figur 8. Optional Protction 6 REV /10/03

7 PRODUCT SPECIFICATION Junction-to-cas thrmal rsistanc is spcifid from th IC junction to th bottom of th cas dirctly blow th di. This is th lowst rsistanc path for hat flow. Propr mounting nsurs th bst thrmal flow from this ara of th packag to th hat sink. Us of a thrmally conductiv matrial at th cas-to-hat sink intrfac is rcommndd. Us a thrmally conductiv spacr if th cas of th dvic must b lctrically isolatd and includ its contribution to th total thrmal rsistanc. Th cas of th is dirctly connctd to th output of th dvic. V IN 3.3V C1 10µF + V IN U1 GND V OUT C3 100µF Figur 10. Application Circuit () + V OUT 1.2V Tabl 1. Bill of Matrials for Application Circuit for th Itm Quantity Manufacturr Part Numbr Dscription C1 1 Xicon L10V10 10µF, 10V Aluminum C3 1 Xicon L10V µF, 10V Aluminum U1 1 Fairchild T 2.7A Rgulator REV /10/03 7

8 PRODUCT SPECIFICATION Mchanical Dimnsions 3-Lad TO-263 Packag Symbol Inchs Millimtrs Min. Max. Min. Max. A b b c D E BSC 2.54 BSC L L L R α Nots Nots: 1. Dimnsions ar xclusiv of mold flash and mtal burrs. 2. Standoff-hight is masurd from lad tip with rf. to Datum -B-. 3. Foot lngth is masurd with rf. to Datum -A- with lad surfac (at innr R). 4. Dimnsiuon xclusiv of dambar protrusion or intrusion. 5. Formd lads to b planar with rspct to on anothr at sating plac L2 c2 L D E-PIN b2 R (2 PLCS) L1 b -A- -B- -C- A 8 REV /10/03

9 PRODUCT SPECIFICATION Mchanical Dimnsions (continud) 3-Lad TO-263 Cntr Cut Packag Symbol Inchs Millimtrs Min. Max. Min. Max. A b b c D E BSC 2.54 BSC L L L L R α Nots Nots: 1. Dimnsions ar xclusiv of mold flash and mtal burrs. 2. Standoff-hight is masurd from lad tip with rf. to Datum -B-. 3. Foot lngth is masurd with rf. to Datum -A- with lad surfac (at innr R). 4. Dimnsiuon xclusiv of dambar protrusion or intrusion. 5. Formd lads to b planar with rspct to on anothr at sating plac L2 c2 L D E-PIN b2 R (2 PLCS) b L3 L1 -A- -B- -C- A REV /10/03 9

10 PRODUCT SPECIFICATION Mchanical Dimnsions (continud) 3-Lad TO-220 Packag Symbol Inchs Millimtrs Min. Max. Min. Max. A b b c øp D E F H J L L1.250 BSC 6.35 BSC Q α Nots Nots: 1. Dimnsion c1 apply for lad finish. H1 L Q 3 b1 1 E b L1 E-PIN øp c1 α (5X) J1 A D F 10 REV /10/03

11 PRODUCT SPECIFICATION Mchanical Dimnsions (continud) 3-Lad TO-252 Packag Symbol Inchs Millimtrs Min. Max. Min. Max. A Nots b b b c c D E BSC 2.29 BSC H L L1.108 REF 2.74 REF L L Nots: 1. Dimnsions ar xclusiv of mold flash, mtal burrs or intrlad protrusion Stand off-hight is masurd from lad tip with rf. to Datum -B-. Foot lngth is masurd with rf. to Datum -A- with lad surfac. Thrmal pad contour optional within dimnsion b3 and L3. Formd lads to b planar with rspct to on anothr at sating plac -C-. Dimnsions and tolrancs pr ASME b3 L3 c2 H D E-PIN b2 L4 L1 L b -B- -C- α = A- A REV /10/03 11

12 PRODUCT SPECIFICATION Ordring Information Product Numbr MX MCX T DX Packag TO-263 in tap and rl TO-263 cntr cut in tap and rl TO-220 TO-252 in tap and rl DISCLAIMER FAIRCHILD SEMICONDUCTOR RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY PRODUCTS HEREIN TO IMPROVE RELIABILITY, FUNCTION OR DESIGN. FAIRCHILD DOES NOT ASSUME ANY LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCT OR CIRCUIT DESCRIBED HEREIN; NEITHER DOES IT CONVEY ANY LICENSE UNDER ITS PATENT RIGHTS, NOR THE RIGHTS OF OTHERS. LIFE SUPPORT POLICY FAIRCHILD S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD SEMICONDUCTOR CORPORATION. As usd hrin: 1. Lif support dvics or systms ar dvics or systms which, (a) ar intndd for surgical implant into th body, or (b) support or sustain lif, and (c) whos failur to prform whn proprly usd in accordanc with instructions for us providd in th labling, can b rasonably xpctd to rsult in a significant injury of th usr. 2. A critical componnt in any componnt of a lif support dvic or systm whos failur to prform can b rasonably xpctd to caus th failur of th lif support dvic or systm, or to affct its safty or ffctivnss. 11/10/03 0.0m 004 Stock#DS Fairchild Smiconductor Corporation