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low power, precision reference and op amp adr821/adr827 rev. 0 information furnished by analog devices is believed to be accurate and reliable. however, no responsibility is assumed by analog devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. specifications subject to change without notice. no license is granted by implication or otherwise under any patent or patent rights of analog devices. trademarks and registered trademarks are the property of their respective owners. one technology way, p.o. box 9106, norwood, ma 02062-9106, u.s.a. tel: 781.329.4700 www.analog.com fax: 781.461.3113 ?2007 analog devices, inc. all rights reserved. features 10-lead msop 400 a supply current ?40c to +125c temperature range on-board precision resistors reference adr821: 2.8 v to 15 v operation adr827: 2.7 v to 15 v operation 0.2% initial accuracy 15 ppm/c temperature drift maximum +5 ma/?3 ma output drive amplifier adr821 2.8 v to 15 v operation 2.8 v to 15 v single-supply operation adr827 2.7 v to 15 v operation 2.7 v to 15 v single-supply operation rail-to-rail input and output 500 v offset voltage maximum 50 na bias current maximum unity gain stable no phase reversal applications battery-powered instrumentation portable medical instrumentation data acquisition systems industrial process controls automotive applications functional block diagram v+ r 1 g nd nc v? amp_out r 2 +in ?in nc = no connect 06665-001 1 2 3 4 5 10 9 8 7 6 ref r 1 r 2 ref_out adr821/adr827 figure 1. table 1. selection table part no. reference v out reference accuracy reference temperature coefficient adr827armz 1.25 v 0.4% 30 ppm/c adr827brmz 1.25 v 0.2% 15 ppm/c adr821armz 2.50 v 0.4% 30 ppm/c adr821brmz 2.50 v 0.2% 15 ppm/c general description the adr821/adr827 combines a precision voltage reference and an op amp in a 10-lead mini small outline package (msop). the reference and the op amp can be operated independently, offering the user a range of flexibility when arranging the combination. featuring a combined operating current of less than 400 a and 15 ppm/c temperature drift on the reference, the adr821/adr827 are ideally suited for applications requir- ing precision and low power. available with the reference at 1.25 v and at 2.5 v, the adr821/adr827 also come in two grades. the reference on the a grade offers 30 ppm/c temperature drift performance and 0.4% initial accuracy. the b grade provides a tighter temperature drift performance of 15 ppm/c and only 0.2% initial accuracy. all versions operate from ?40c to +125c.
adr821/adr827 rev. 0 | page 2 of 20 table of contents features .............................................................................................. 1 applications....................................................................................... 1 functional block diagram .............................................................. 1 general description ......................................................................... 1 revision history ............................................................................... 2 specifications..................................................................................... 3 adr821 electrical characteristicsreference ....................... 3 adr821 electrical characteristicsamplifier (v s = 2.8 v)................................................................................. 4 adr821 electrical characteristicsamplifier (v s = 15 v).................................................................................. 5 adr827 electrical characteristicsreference ....................... 6 adr827 electrical characteristicsamplifier (v s = 2.7 v)................................................................................. 7 adr827 electrical characteristicsamplifier (v s = 15 v).................................................................................. 8 absolute maximum ratings ............................................................9 thermal resistance .......................................................................9 esd caution...................................................................................9 pin configuration and function descriptions........................... 10 typical performance characteristics ........................................... 11 reference ..................................................................................... 11 amplifier (ad821/ad827)....................................................... 15 applications information .............................................................. 18 +2.5 v and ?2.5 v outputs (adr821) ................................... 18 2.5 v and 5.0 v outputs (adr821)......................................... 18 multiple 2.5 v outputs (adr821)........................................... 18 outline dimensions ....................................................................... 19 ordering guide .......................................................................... 19 revision history 10/07revision 0: initial ver sion
adr821/adr827 rev. 0 | page 3 of 20 specifications adr821 electrical characteristicsreference v in = 2.8 v to 15 v, t a = 25c, c in = c out = 0.1 f, unless otherwise noted. table 2. parameter symbol conditions min typ max unit output voltage v out a grade 2.490 2.500 2.510 v b grade 2.495 2.500 2.505 v initial accuracy v oerr a grade 10 mv 0.40 % b grade 5.00 mv 0.20 % temperature coefficient tcv out ?40c < t a < +125c a grade 30 ppm/c b grade 15 ppm/c dropout (v out C v in ) v do i out = 0 ma 0.3 v line regulation ?v out /?v in v in = 2.8 v to 15 v, ?40c < t a < +125c 20 50 ppm/v load regulation ?v out /?i load i load = 0 ma to 5 ma, ?40c < t a < +125c, v in = 5 v 400 ppm/ma i load = 0 ma to 5 ma, v in = 5 v 80 200 ppm/ma i load = ?3 ma to 0 ma, ?40c < t a < +125c, v in = 5 v 600 ppm/ma i load = ?3 ma to +5 ma, v in = 5 v 80 300 ppm/ma voltage noise e n p-p 0.1 hz to 10 hz 16 v p-p broadband noise 10 hz to 10 khz 430 v p-p turn-on settling time t r c in = 0 f 80 s power supply positive supply current i sy+ no load, ?40c < t a < +125c 400 a negative supply current i sy? no load, ?40c < t a < +125c 300 a on-board resistors r 1 , r 2 resistor tolerance 8 10 12 k resistor matching 0.5 % resistor temperature coefficient tc 100 ppm/c
adr821/adr827 rev. 0 | page 4 of 20 adr821 electrical charac teristicsamplifier (v s = 2.8 v) v cm = 0 v, t a = 25c, unless otherwise noted. table 3. parameter symbol conditions min typ max unit input characteristics input offset voltage v os ?40c < t a < +125c 100 500 v input offset voltage drift tcv os ?40c < t a < +125c 2 5 v/c input bias current i b ?40c < t a < +125c 15 50 na input offset bias current i os ?40c < t a < +125c 5 25 na large signal voltage gain a vo v out = ?1.5 v to +1.5 v r load = 10 k, ?40c < t a < +125c 99 108 db r load = 2 k, ?40c < t a < +125c 94 100 db common-mode rejection ratio cmrr v cm = ?1.5 v to +1.5 v, ?40c < t a < +125c 75 100 db 85 db output characteristics output voltage high v oh i load = 1 ma 2.6 2.7 v i load = 1 ma, ?40c < t a < +125c 2.55 v output voltage low v ol i load = 1 ma ?2.7 ?2.6 v i load = 1 ma, ?40c < t a < +125c ?2.55 v power supply positive supply current i sy+ no load, ?40c < t a < +125c 400 a negative supply current i sy? no load, ?40c < t a < +125c 300 a power supply rejection ratio psrr v s = 2.8 v to 15 v 75 100 db dynamic performance slew rate sr r load = 10 k, c load = 10 pf, a v = +1 0.5 v/s gain bandwidth product gbp c load = 14 pf 1.0 mhz phase margin m c load = 14 pf 72.5 degrees noise performance voltage noise e n p-p f = 0.1 hz to 10 hz 0.2 v p-p voltage noise density e n f = 1 khz 16 nv/hz
adr821/adr827 rev. 0 | page 5 of 20 adr821 electrical charac teristicsamplifier (v s = 15 v) v cm = 0 v, t a = 25c, unless otherwise noted. table 4.a parameter symbol conditions min typ max unit input characteristics input offset voltage v os ?40c < t a < +125c 100 500 v input offset voltage drift tcv os ?40c < t a < +125c 2 5 v/ o c input bias current i b ?40c < t a < +125c 10 50 na input offset bias current i os ?40c < t a < +125c 5 25 na large signal voltage gain a vo v out = ?14 v to +14 v r load = 10 k, ?40c < t a < +125c 109.5 118 db r load = 2 k, ?40c < t a < +125c 100 111 db common-mode rejection ratio cmrr v cm = ?14 v to +14 v, ?40c < t a < +125c 75 100 db 85 db output characteristics output voltage high v oh i load = 1 ma 14.8 14.9 v i load = 1 ma, ?40c < t a < +125c 14.75 v output voltage low v ol i load = 1 ma ?14.9 ?14.8 v i load = 1 ma, ?40c < t a < +125c ?14.75 v output current i sc short-circuit current 20 ma power supply positive supply current i sy+ no load, ?40c < t a < +125c 400 a negative supply current i sy? no load, ?40c < t a < +125c 300 a power supply rejection ratio psrr v s = 2.8 v to 15 v 75 100 db dynamic performance slew rate sr r load = 10 k, c load = 10 pf, a v = +1 0.5 v/s gain bandwidth product gbp c load = 14 pf 1.0 mhz phase margin m c load = 14 pf 75.4 degrees noise performance voltage noise e n p-p f = 0.1 hz to 10 hz 0.2 v p-p voltage noise density e n f = 1 khz 16 nv/hz
adr821/adr827 rev. 0 | page 6 of 20 adr827 electrical characteristicsreference v in = 2.7 v to 15 v, t a = 25c, c in = c out = 0.1 f, unless otherwise noted. table 5. parameter symbol conditions min typ max unit output voltage v out a grade 1.245 1.250 1.255 v b grade 1.2475 1.250 1.2525 v initial accuracy v oerr a grade 5 mv 0.40 % b grade 2.50 mv 0.20 % temperature coefficient tcv out ?40c < t a < +125c a grade 30 ppm/c b grade 15 ppm/c dropout (v out C v in ) v do i out = 0 ma 1.45 v line regulation ?v out /?v in v in = 2.7 v to 15 v, ?40c < t a < +125c 20 50 ppm/v load regulation ?v out /?i load i load = 0 ma to 5 ma, ?40c < t a < +125c, v in = 3 v 400 ppm/ma i load = 0 ma to 5 ma, v in = 3 v 80 200 ppm/ma i load = ?3 ma to 0 ma, ?40c < t a < +125c, v in = 3 v 600 ppm/ma i load = ?3 ma to +5 ma, v in = 3 v 80 300 ppm/ma voltage noise e n p-p 0.1 hz to 10 hz 8 v p-p broadband noise 10 hz to 10 khz 260 v p-p turn-on settling time t r c in = 0 f, c out = 0.1 f 80 s power supply positive supply current i sy+ no load, ?40c < t a < +125c 400 a negative supply current i sy? no load, ?40c < t a < +125c 300 a on-board resistors r 1 , r 2 resistor tolerance 8 10 12 k resistor matching 0.5 % resistor temperature coefficient tc 100 ppm/c
adr821/adr827 rev. 0 | page 7 of 20 adr827 electrical charac teristicsamplifier (v s = 2.7 v) v cm = 0 v, t a = 25c, unless otherwise noted. table 6. parameter symbol conditions min typ max unit input characteristics input offset voltage v os ?40c < t a < +125c 100 500 v input offset voltage drift tcv os ?40c < t a < +125c 2 5 v/c input bias current i b ?40c < t a < +125c 15 50 na input offset bias current i os ?40c < t a < +125c 5 25 na large signal voltage gain a vo v out = ?1.5 v to +1.5 v r load = 10 k, ?40c < t a < +125c 99 108 db r load = 2 k, ?40c < t a < +125c 94 100 db common-mode rejection ratio cmrr v cm = ?1.5 v to +1.5 v, ?40c < t a < +125c 75 100 db 85 db output characteristics output voltage high v oh i load = 1 ma 2.5 2.6 v i load = 1 ma, ?40c < t a < +125c 2.45 v output voltage low v ol i load = 1 ma ?2.6 ?2.5 v i load = 1 ma, ?40c < t a < +125c ?2.45 v power supply positive supply current i sy+ no load, ?40c < t a < +125c 400 a negative supply current i sy? no load, ?40c < t a < +125c 300 a power supply rejection ratio psrr v s = 2.7 v to 15 v 75 100 db dynamic performance slew rate sr r load = 10 k, c load = 10 pf, a v = +1 0.5 v/s gain bandwidth product gbp c load = 14 pf 1.0 mhz phase margin m c load = 14 pf 71.3 degrees noise performance voltage noise e n p-p f = 0.1 hz to 10 hz 0.2 v p-p voltage noise density e n f = 1 khz 16 nv/hz
adr821/adr827 rev. 0 | page 8 of 20 adr827 electrical charac teristicsamplifier (v s = 15 v) v cm = 0 v, t a = 25c, unless otherwise noted. table 7. parameter symbol conditions min typ max unit input characteristics input offset voltage v os ?40c < t a < +125c 100 500 v input offset voltage drift tcv os ?40c < t a < +125c 2 5 v/c input bias current i b ?40c < t a < +125c 10 50 na input offset bias current i os ?40c < t a < +125c 5 25 na large signal voltage gain a vo v out = ?14 v to +14 v r load = 10 k, ?40c < t a < +125c 109.5 118 db r load = 2 k, ?40c < t a < +125c 100 111 db common-mode rejection ratio cmrr v cm = ?14 v to +14 v, ?40c < t a < 125c 75 100 db 85 db output characteristics output voltage high v oh i load = 1 ma 14.8 14.9 v i load = 1 ma, ?40c < t a < +125c 14.75 v output voltage low v ol i load = 1 ma ?14.9 ?14.8 v i load = 1 ma, ?40c < t a < +125c ?14.75 v output current i sc short-circuit current 20 ma power supply positive supply current i sy+ no load, ?40c < t a < +125c 400 a negative supply current i sy? no load, ?40c < t a < +125c 300 a power supply rejection ratio psrr v s = 2.7 v to 15 v 75 100 db dynamic performance slew rate sr r load = 10 k, c load = 10 pf, a v = +1 0.5 v/s gain bandwidth product gbp c load = 14 pf 1.0 mhz phase margin m c load = 14 pf 75.4 degrees noise performance voltage noise e n p-p f = 0.1 hz to 10 hz 0.2 v p-p voltage noise density e n f = 1 khz 16 nv/hz
adr821/adr827 rev. 0 | page 9 of 20 absolute maximum ratings t a = 25c, unless otherwise noted. table 8. parameter rating supply voltage 18 v output short-circuit duration to gnd indefinite storage temperature range C65c to +125c operating temperature range C40c to +125c junction temperature range C65c to +125c lead temperature (soldering, 60 sec) 300c stresses above those listed under absolute maximum ratings may cause permanent damage to the device. this is a stress rating only; functional operation of the device at these or any other conditions above those indicated in the operational section of this specification is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. thermal resistance ja is specified for the worst-case conditions, that is, ja is specified for device soldered in circuit board for surface-mount packages. table 9. thermal resistance package type ja jc unit 10-lead msop (rm-10) 172 50 c/w esd caution
adr821/adr827 rev. 0 | page 10 of 20 pin configuration and fu nction descriptions v+ 1 r 1 2 g nd 3 nc 4 v? 5 amp_out 10 r 2 9 +in 8 ?in 7 ref_out 6 adr821/ adr827 top view (not to scale) 0 6665-002 nc = no connect figure 2. pin configuration table 10. pin function descriptions pin no. mnemonic description 1 v+ input voltage of the reference/positive supply of the amplifier 2 r 1 resistance tied to positive input of the amplifier 3 gnd ground 4 nc do not connect any extern al components to this pin 5 v? negative supply of the amplifier 6 ref_out output voltage of the reference 7 +in positive input of the amplifier 8 ?in negative input of the amplifier 9 r 2 resistance tied to positive input of the amplifier 10 amp_out output pin of the amplifier
adr821/adr827 rev. 0 | page 11 of 20 typical performance characteristics reference 2.512 2.488 ?40 125 temperature (c) v out (v) 2.508 2.504 2.500 2.496 2.492 ?25 ?10 5 20 35 50 65 80 95 110 c in = 0.1f c out = 0.1f v in = 15v 06665-005 figure 3. adr821 v out vs. temperature 4 ?2 125 temperature (c) line regulation (ppm/v) ?40 ?25 ?10 5 20 35 50 65 80 95 110 06665-006 3 2 1 0 ?1 c in = 0.1f c out = 0.1f v in = 15v figure 4. adr821 line regulation vs. temperature 0.40 0.05 2.5 15.0 supply voltage (v) i sy+ (ma) 0.35 0.30 0.25 0.20 0.15 0.10 5.0 7.5 10.0 12.5 c in = 0.1f c out = 0.1f +125c +25c ?40c 06665-007 figure 5. adr821 supply cu rrent (+) vs. supply voltage 1.260 1.240 ?40 125 temperature (c) v out (v) 1.258 1.256 1.254 1.252 1.250 1.248 1.246 1.244 1.242 ?25?105 203550658095110 c in = 0.1f c out = 0.1f v in = 15v 06665-008 figure 6. adr827 v out vs. temperature 14 0 125 temperature (c) line regulation (ppm/v) 12 10 8 6 4 2 c in = 0.1f c out = 0.1f v in = 15v ?40 ?25 ?10 5 20 35 50 65 80 95 110 06665-009 figure 7. adr827 line regulation vs. temperature 0.40 0 2.5 15.0 supply voltage (v) i sy+ (ma) 0.35 0.30 0.25 0.20 0.15 0.10 0.05 5.0 7.5 10.0 12.5 c in = 0.1f c out = 0.1f +125c +25c ?40c 06665-010 figure 8. adr827 supply cu rrent (+) vs. supply voltage
adr821/adr827 rev. 0 | page 12 of 20 0.25 0 2.5 15.0 supply voltage (v) i sy? (ma) 0.20 0.15 0.10 0.05 5.0 7.5 10.0 12.5 c in = 0.1f c out = 0.1f +125c +25c ?40c 06665-011 figure 9. adr821 supply cu rrent (?) vs. supply voltage 1.2 0 ?3 7 load current (ma) dropout (v) 1.0 0.8 0.6 0.4 0.2 ?2?10123456 c in = 0.1f c out = 0.1f +125c +25c ?40c 06665-012 figure 10. adr821 dropout vs. load current 50 5 temperature (c) load regulation (ppm/ma) 45 40 35 30 25 20 15 10 ?40 ?25 ?10 5 20 35 50 65 80 95 110 125 i sink = 3ma c in = c out = 0.1f v s = 5v v s = 15v 06665-013 figure 11. adr821 load regulation vs. temperature 0.25 0 2.5 15.0 supply voltage (v) i sy? (ma) 0.20 0.15 0.10 0.05 5.0 7.5 10.0 12.5 c in = 0.1f c out = 0.1f +125c +25c ?40c 06665-014 figure 12. adr827 supply cu rrent (?) vs. supply voltage 2.0 0 ?3 7 load current (ma) dropout (v) ?2 ?1 0 1 2 3 4 5 6 1.8 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 c in = 0.1f c out = 0.1f +125c +25c ?40c 06665-015 figure 13. adr827 dropout vs. load current 80 30 temperature (c) load regulation (ppm/ma) ?40 ?25 ?10 5 20 35 50 65 80 95 110 125 i sink = 3ma c in = c out = 0.1f 70 60 50 40 v s = 15v v s = 3v 06665-016 figure 14. adr827 load regulation vs. temperature
adr821/adr827 rev. 0 | page 13 of 20 0 ?140 ?40 125 temperature (c) load regulation (ppm/ma) ?25 ?10 5 20 35 50 65 80 95 110 ?20 ?40 ?60 ?80 ?100 ?120 i source = 5ma c in = c out = 0.1f v s = 15v v s = 5v 06665-017 figure 15. adr821 load regulation vs. temperature 1 time (1s/div) 10v/div 06665-018 c in = c out = 0.1f 15.6v p-p 2.78v rms figure 16. adr821 0.1 hz to 10 hz noise 1 time (1s/div) 100v/div 06665-019 c in = c out = 0.1f 426v p-p 55.6v rms figure 17. adr821 10 hz to 10 khz noise 0 ?140 ?40 125 temperature (c) load regulation (ppm/ma) ?25 ?10 5 20 35 50 65 80 95 110 ?20 ?40 ?60 ?80 ?100 ?120 i source = 5ma c in = c out = 0.1f v s = 15v v s = 3v 06665-020 figure 18. adr827 load regulation vs. temperature 1 time (1s/div) 5v/div 06665-021 c in = c out = 0.1f 8.3v p-p 1.33v rms figure 19. adr827 0.1 hz to 10 hz noise 1 time (1s/div) 100v/div 06665-022 c in = c out = 0.1f 258v p-p 34.6v rms figure 20. adr827 10 hz to 10 khz noise
adr821/adr827 rev. 0 | page 14 of 20 1 2 0 6665-023 channel 1: v in = 2v/div c in = 0f c l = 0.1f time = 20s/div channel 2: v out = 1v/div figure 21. adr821 turn-on response 1 2 0 6665-024 channel 1: v in = 2v/div c in = 0f c l = 0.1f time = 20s/div channel 2: v out = 500mv/div figure 22. adr827 turn-on response
adr821/adr827 rev. 0 | page 15 of 20 amplifier (ad821/ad827) 120 0 ?500 ?400 ?300 ?200 ?100 0 100 200 300 400 500 v os (v) number of samples 100 80 60 40 20 v sy = 15v t a = 25c 06665-025 figure 23. input offset voltage distribution 160 0 ?5 ?4 ?3 ?2 ?1 0 1 2 3 4 5 tcv os (v/c) number of samples 140 120 100 80 60 40 20 06665-026 v sy = 15v figure 24. offset voltage drift distribution 60 ?40 ?13 ?11 ?9 ?7 ?5 ?3 ?1 1 3 5 7 9 11 13 v cm (v) i b (na) 50 40 30 20 10 0 ?10 ?20 ?30 06665-030 v sy = 15v t a = 25c figure 25. input bias current vs. common-mode voltage 500 ?500 ?15 15 v cm (v) v os (v) 400 300 200 100 0 ?100 ?200 ?300 ?400 ?12?9?6?3036912 v sy = 15v t a = 25c 06665-029 figure 26. input offset voltage vs. common-mode voltage 200 ?200 ?55 155 temperature (c) v os (v) 100 0 ?100 ?40 ?25 ?10 5 20 35 50 65 80 95 110 125 140 v sy = 15v 06665-027 figure 27. input offset voltage vs. temperature 100000 0.1 0.01 100 load current (ma) output swing saturation voltage (mv) 0.1 1 10 1 10 100 1000 10000 v sy = 15v t a = 25c v sy ? v oh sourcing v ol sinking 06665-028 figure 28. output swing saturation voltage vs. load current
adr821/adr827 rev. 0 | page 16 of 20 70 ?50 100 100m frequency (hz) gain (db) phase (degrees) 1k 10k 100k 1m 10m 50 30 10 ?10 ?30 120 ?60 105 90 75 60 45 30 15 0 ?15 ?30 ?45 phase gain 06665-031 v sy = 15v t a = 25c figure 29. open-loop gain and phase vs. frequency 50 ?60 100 100m frequency (hz) a cl (db) 1k 10k 100k 1m 10m 40 30 20 10 0 ?10 ?20 ?30 ?40 ?50 g = 100 g = 10 g = 1 06665-032 v sy = 15v t a = 25c figure 30. closed-loop gain vs. frequency 1200 0 10 10m frequency (hz) z out ( ? ) 100 1k 10k 100k 1m 1000 800 600 400 200 v sy = 15v t a = 25c g = 100 g = 10 g = 1 06665-033 figure 31. z out vs. frequency 140 0 100 100m frequency (hz) cmrr (db) 1k 10k 100k 1m 10m 120 100 80 60 40 20 v sy = 15v t a = 25c 06665-034 figure 32. cmrr vs. frequency 140 0 100 100m frequency (hz) psrr (db) 1k 10k 100k 1m 10m 120 100 80 60 40 20 v sy = 15v t a = 25c psrr? psrr+ 06665-035 figure 33. psrr vs. frequency r load = 10k ? c load = 10pf v sy = 15v 06665-036 2 time = 10s/div v out = 2v/di v figure 34. large signal transient response
adr821/adr827 rev. 0 | page 17 of 20 06665-037 2 time = 1s/div v out = 50mv/di v r l = 10k ? c l = 10pf v sy = 15v figure 35. small signal transient response, c l = 10 pf 06665-038 2 time = 1s/div v out = 50mv/di v r l = 10k ? c l = 100pf v sy = 15v figure 36. small signal transient response, c l = 100 pf 1000 1 1 10000 frequency (hz) en (nv/ hz) 10 100 1000 10 100 v sy = 15v t a = 25c 06665-039 figure 37. voltage noise density
adr821/adr827 rev. 0 | page 18 of 20 applications information +2.5 v and ?2.5 v outputs (adr821) 0 6665-003 ref ref_out amp_out v? v+ 10k ? 10k ? r 1 r 2 +2.5v ?2.5v +in 0.1f figure 38. +2.5 v and ?2.5 v outputs in many dual-supply applications, it is desirable to have 2.5 v references. using the configuration shown in figure 38, it is possible to generate ?2.5 v with the help of a +2.5 v reference, an internal op amp, and 10 k resistors. the supply voltages v+ and v? should be greater than +2.8 v and ?2.8 v, respectively. the op amp is configured as an inverting amplifier with a gain of ?1, which produces ?2.5 v at the output of the op amp. the output of the reference is fed to the amplifier inverting input. because the op amp has very low input offset voltage (500 v over the full temperature range) and the tc ratio of the resistors is typically 25 ppm/c, the ?2.5 v output is less than 7 mv away from the theoretical value. 2.5 v and 5.0 v outputs (adr821) 06665-004 ref_out amp_out v? v+ 10k ? 10k ? r 1 r 2 2.5v 5.0v +in ?in 0.1f ref figure 39. 2.5 v and 5.0 v outputs in many single-supply applications, it is desirable to have multiple reference voltages. using the configuration shown in figure 39, it is possible to generate 5.0 v with the help of a 2.5 v reference, an internal op amp, and resistors. v+ should be kept at greater than 5.8 v and v? can be connected either to ground or to negative supply. the output of the reference is fed to the amplifier noninverting input. the op amp is config- ured as a noninverting amplifier with a gain of +2, which produces 5 v at the output of the op amp. using the guaranteed maximum offset voltage over the temperature, and the typical tc ratio of the resistors over the full temperature range, the output is within 15 mv of the calculated value. multiple 2.5 v outputs (adr821) 06665-040 ref_out amp_out v? v+ 10k ? 10k ? r 1 r 2 2.5v 2.5v +in ?in 0.1f ref figure 40. multiple 2.5 v outputs on some boards, sensitive analog circuits, such as a vco, exist with noisy digital circuits. if the supply current requirements are low (less than 3 ma), series references and op amps can be used. using the configuration shown in figure 40, two different 2.5 v supplies can be created using a single adr821. the supply voltage v+ should be greater than 2.8 v and v? can be con- nected to ground or a negative voltage. the op amp is configured as a voltage follower with a gain of +1, which produces 2.5 v at the output of the op amp. the output of the reference is fed to the amplifier noninverting input. because the op amp has very low input offset voltage (500 v maximum over the full temperature range), the output voltage from the op amp section tracks the reference voltage within 1 mv. for a dynamic load, such as the reference input pin on some analog-to-digital converters, the load should be connected to an op amp output and the noise sensitive circuitry, such as a vco, should be connected to the reference output. if the dynamic load is con- nected to the reference voltage, any perturbations appear as a signal to the input of the voltage follower and appear on the other output.
adr821/adr827 rev. 0 | page 19 of 20 outline dimensions compliant to jedec standards mo-187-ba 0.23 0.08 0.80 0.60 0.40 8 0 0.15 0.05 0.33 0.17 0.95 0.85 0.75 seating plane 1.10 max 10 6 5 1 0.50 bsc pin 1 coplanarity 0.10 3.10 3.00 2.90 3.10 3.00 2.90 5.15 4.90 4.65 figure 41. 10-lead mini small outline package [msop] (rm-10) dimensions shown in millimeters ordering guide initial accuracy models temperature range output voltage (v out ) (mv) (%) temperature coefficient (ppm/c) package description package option ordering quantity branding adr821armz-reel7 1 ?40c to +125c 2.500 10.00 0.40 30 10-lead msop rm-10 1,000 r2g adr821armz-r2 1 ?40c to +125c 2.500 10.00 0.40 30 10-lead msop rm-10 250 r2g adr821brmz-reel7 1 ?40c to +125c 2.500 5.00 0.20 15 10-lead msop rm-10 1,000 r2h adr821brmz-r2 1 ?40c to +125c 2.500 5.00 0.20 15 10-lead msop rm-10 250 r2h adr827armz-reel7 1 ?40c to +125c 1.250 5.00 0.40 30 10-lead msop rm-10 1,000 r0z adr827armz-r2 1 ?40c to +125c 1.250 5.00 0.40 30 10-lead msop rm-10 250 r0z adr827brmz-reel7 1 ?40c to +125c 1.250 2.50 0.20 15 10-lead msop rm-10 1,000 r2b adr827brmz-r2 1 ?40c to +125c 1.250 2.50 0.20 15 10-lead msop rm-10 250 r2b 1 z = rohs compliant part.
adr821/adr827 rev. 0 | page 20 of 20 notes ?2007 analog devices, inc. all rights reserved. trademarks and registered trademarks are the prop erty of their respective owners. d06665-0-10/07(0)

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