,~ ijjl4:-1s08jl/1408jl 8-bit multiplying d/ a converters . l '~ion mol1olithics inc. l'rc~ . the r-2r ladder divides the reference current into eight binarily-related components which are fed to the switches. a remainder current equal to the least significant bit is always shunted to ground, therefore the maximum output current is 255/256 of the reference amplifier input current. forexample, a full-scale output current of 1.992ma would result from a reference input current of 2.0ma. the dac-1508a/1408a is useful in a wide variety of applica- tions, including waveform synthesizers, digitally program- mable gain and attenuation blocks, crt character genera- tion, audio digitizing and decoding, stepping motor drives, programmable power supplies and in building tracking and v) successive approximation analog-to-digital converters. ~ for significantly improved speed and applications flexibility ~ your attention is directed to the dac-da a-bit high-speed ~ multiplying d/a converter data sheet. for d/a converters, ;>- which include precision voltage references on the chip, z please refer to the dac-210 or the dac-100 data sheet. 0 u 0 0 :i ~ <: , 0 ~ , ~ - 0 - q f~1ures i"'proved direct replacement for mc1508/mc1408 i 0 19'1\1 nonlinearity maximum over temperature range i . . i"'proved settling time.. . . . .. . . .. .. . . . . .. 250ns, typ : i"'proved power consumption. . . . . . . . . .. 157mw, typ i compatible with ttl, cmos logic i standard supply voltages +5.0v and -5.0v to -15v i output voltage swing +0.5v to -5.0v , high-speed multiplying input. . . . . . . . . . . .. .. 4.0ma/ ps ordering informationt - 16-pin dual-in-line package relative accuracy hermetic plastic in fs military commercial commercial - :to.19% dac150sa-so' dac140sa-so dac140sa-sp ,,/" :to.39% - dac140sa-70 dac140sa-7p :to.78% - dac140sa-60 dac140sa-6p :;;devices processed in total compliance to mil-std-ss3. add /ss3 after part number. consult factory for 883 data sheet. tburn-in is available on commercial and industrial temperature range parts in cerdip, plastic dip, and to-can packages. for ordering information, see 1988 data book. section 2. pin connections general description the dac-1508a/1408a are a-bit monolithic multiplying digital-to-analog converters consisting of a reference cur- rent amplifier, r-2r ladder, and eight high-speed current switches. for many applications, only a reference resistor and reference voltage need be added. improvements in design and processing techniques provide faster settling times combined with lower power consumption while retain~ ing direct interchangeability with mc1508/1408 devices. '61 compensation msb ai 15 simplified schematic ms8 ai a6 a7 lsb ai a2 a3 a4 as gnq vref(+! 14 vrefc-i 15 compen 16-pin dual-in-line package hermetic (0) epoxy (p) 11-115 8/87, rev. a1 ---- iii obsolete
'pmi) dac-1508a11408a 8-bit multiplying dla converters absolute maximum ratings power supply voltage' vcc ," +5.5vdc vee """"'~"""""""""""""."" -16.5vdc digital input voltage,'vs through v12 +5.5, ovdc ' applied output voltage. . . . . . . . . . . . . . . . . .. +0.5, -5.2vdc reference current, 114 5ma power dissipation(package limitation), pd ceramic package (or epoxyb package) 1oomw derateaboveta='+25c 6.7mw/oc derate above t a = + 100 c for , ',' epoxy,b r;.'ackage ~ . ,.. . .. .. h"" s.3mw/oc toperetingtemperature range. ta . dac-1508a -55c to +125c dac-1408a octo +75c dice junction temperature (tj) -65c to 150c storage temperature range. t stg ; .-65 c to + 150 c ,plasticpackageonly -65c10+125c note: ratings apply to both dice and packaged parts: unless otherwise noted. electrical characteristics at vcc = +5vdc, vee = -15vdc, vref/r14 = 2ma. -55c:5 ta:5 +.125c for dac-15d8a-8. doc :5ta:5 +75c for dac-14d8a, unless otherwise noted. all digital inputs at logic high level. units %ifs ns ns ppm/oc vdc' ma /loa ma ma /loa vdc ma//io~ /loan - ma - vdc - mw --- note: 1, guaranteed by design. 11-116 --:; 8/87, rev. ai -- """'i"~ .. -~~ dac-1508a/1408a parameter symbol conditions min typ max relative accuracy lerror relative to full-scale 101 dac-1508a-b, dac-1408a-8 - - :to.19 dac-1408a-7 'e, - - :to.39 dac-1408a-6 - - :to,78 settling time to within 1/2 lsb ts ta = +25c - 250, lincludes tplhi propagation delay time tplh' tphl ta=+25c, i note 11 - 30 100 output fu1l-'scale current drift tclo - :t20 digital input logic levels (msbi high level, logic "1" v1h 2 low level, logic "1" vil - - 0.8 digitalln'put current (msbi iih high level, vih = 5.0v - 0 0.04 ill low level, v1l = 0.8v - -0.4 -0.8 reference input bias current ipin 151 '15 - -1 -3 output current range lor vee = -5v 0 2.0 2.1 vee = -15v 0 2.0 4.2 output current '0 vref = 2.000v, r14 = 1000n 1,9 1.99 2.1 output current 10imini all bits low - 0 4 output voltage compliance iref= 1ma ier$0,19%atta=+25ci vo vee = -5v -0,6 - +0.5 vee = -10v -5 - +0.5 reference current slew rate sriref - 4 output current power supply psslo- 0.5 2.7 sensitivity - power supply current ice all bits low - +9 +14 lee - -7.5 -13 power supply voltage veer ta = +25c +4.5 +5 +5.5 veer -4.5 -15 -16.5 all bits low vee = -5vdc ,- 82 135 power dissipation pd vee = -15vdc - 157 265 all bits high vee = -5vdc - 70 vee = -15vdc - 132 obsolete
!pmi) dac-150aa/140aa a-bit multiplying d/a converters --- "ice characteristics die size 0.087 x 0.063 inch, 5481 sq. mils (2.21 x 1.60 mm, 3.54 sq. mm) 1. n.c. 2. ground 3. vee 4.10 5. a1 (msb) 6. a2 7. a3 a. a4 9. a5 10. a6 11. a7 12. aa (lsb) 13. vcc 14. vref(+) 15. vref(-) 16. comp for additional dice ordering information, refer to 1988 data book, section 2. dac-1408a-g limit 8 - wafer test limits at v+ = 5v, v- = 15v, iref = 2ma, ta = 25 c, unless otherwise noted. parameter symbol conditions resolution monotonicity nonlinearity 8 output voltage compliance vo full-scale current change, 'ref = 1 ma <1/2 lsb v-=-5v v- = -10v :to.19 +0.5 -0.6 -5 full-scale current zero-scale current ifs izs vref=2.000v. r14' r15= 1.000ko (all bits low) v- = -5v v- = -15v output current range lor logic "0" input level logic "1" input level logic input current logic "0" logic "1" reference bias current vil vih ill iih 115 low level, vil = -0.8v high level, vih=5v output current power supply sensitivity power supply current (all bits low) psslo- 1+ 1- power supply voltage range vccr veer 2, :to.1 4 2.1 4.2 0.8 2 :t10 :t10 -3 2.7 +14 -13 +5. :to.5 -16.5, -4.5 power dissipation (all bits low) v- = 5v v- = -15v 135 265 pd note: electrical tests are performed at wafer probe to the limits shown. due to variations in assembly methods and normal yield loss, yield after packaging is not guaranteed for standard product dice. consult factory to negotiate specifications based on dice lot qualification through sample lot assembly and testing. typical electrical characteristics at v+ = +5v. v- = -15v, ta = 25 c, vlc and lout connected to ground. and iref = 2ma, unless otherwise noted. output characteristics refer to lout only. symbol dl/dt conditions parameter reference input slew rate propagation delay tplh' tphl any bit to :t1/2 lsb. all bits switched on or off settling time ts dac-1408g typical 4 units majp.s 30 os 250 ns 11-117 8/87, rev. a1 -~~ -- c/) p::: units > - z bitsmin 0 bitsmin u %fs max 0 - 0 vmax vmin < vmin z - ma max < i p.amax 0 f-4 ma max i - v max - - vmin 0 - - 0 p.amax ii p.amax p.ajv max ma max v maximin mw max obsolete
'ipmi) dac-1508a/1408a 8-bit multiplying d/a converters applications relative accuracy test circuit msb or 1%) vee- use with negative vref use with positive v ref 'tc 13 vee - - c see text for values ofc 3 11-118 :-; 8/87, rev. ai .~ ai a2 a3 a4 12-8it 0 d-toa- as converter ito.oi% a6 error max) a7 ' a6 61d1 vref'" 2v 6okfl vcc r14 950fj -: 14 13 msb 5 6 7 b-8it s dac-i508a/ counter 9 dac-i408a 4 10 11 12 15 16 3 2 c ikfj - - r14" r15 5 r14 ai 6 14 vref(+) ..jl a2 15 r15 7 a3 - m ='- 9 oac-i408a - ...j.... rl a5 10 4 - a6 11 16 a 7 0--'-' 12 ...lc as 0-- i ---.j see t text 3 for values of c -: -: vee r14" r15 ny-- r15 iirefh lr -: rl :3 a3 7 15 s dac-i508a/ a4 dac-i408a 9 a5 0-- a6 101 1 4 a7 a6 obsolete
r i - i i transient response and settling time test circuit ipmi) dac-1508a11408a 8-bit multiplying dia converters use with current -to-voltage converting op amp ms8 ai . 5 a2 vcc vref' 2.0vdc r14 . r15 '" 1.11kn 13 ro . 5.01<11- ---. 14 vref a3 a4 6 vo 15 r15 as 8 ""1dac-15o8a1 91 dac-1408a ro a7 a8 lsb vee theoretical vo vo . ~ (rol [++~+~+tt+ti+mi+~] adjust vref r15 or ro so that vo with all digital inputs at high level is equal to 9.961 volts. vo' ~ (5ki[t+f+i+;i+i+i4+1~+~] . 10v[~~} 9.961v ~ ~ general information and application notes reference amplifier drive and compensation the reference amplifier provides a voltage at pin 14 for converting the reference voltage to a current. and a turn- around circuit or current mirror for feeding the ladder. the reference amplifier input current, 114, must always flow into pin 14 regardless of the setup method or reference voltage polarity. connections for a positive voltage are shown on the preceding page. the reference voltage source supplies the full current 114. for bipolar reference signals, as in the multiplying mode, r15 can be tied to a negative voltage corresponding to the minimum input level. it is possible to eliminate r15 with only a small sacrifice in accuracy and temperature drift. the compensation capacitor value must be increased with increases in r14 to maintain proper phase margin; for r14 values of 1.0, 2.5 and 5.0kn, minimum capacitor values are 15. 37, and 75pf. the capacitor may be tied to either vee or ground, but using vee increases negative supply rejection. a negative reference voltage may be used if r14 is grounded and the reference voltage is applied to r15 as shown. a high input impedance is the main advantage of this method. compensation involves a capacitor to vee on pin 16, using the values of the previous paragraph. the negative reference voltage must be at least 4.0v above the vee supply. bipolar input signals may be handled by connecting r14 to a positive reference voltage equal to the peak positive input level at pin 15. when a dc reference voltage is used. capacitive bypass to ground is recommended as a reference voltage. if a well regulated 5.0v supply, which drives logic is to be used as the reference, r14 should be decoupled by connecting it to + 5.0v through another resistor and bypassing the junction of the two resistors with 0.1 ~f to ground. for reference voltages greater than 5.0y. a clamp diode is recommended between pin 14 and ground. if pin 14 is driven by a high impedance such as a transistor current source, none of the above compensation methods apply and the amplifier must be heavily compensated, decreasing the overall bandwidth. output voltage range the voltage on pin 4 is restricted to a range of -0.6v to +0.5v when vee = -5v due to the current switching methods employed in the dac-1508a-8. the negative output voltage compliance of the dac-1508a-8 is extended to -5.0v where the negative supply voltage is more negative than -10v. using a full-scale current of 1.992ma and load resistor of 2.5kn between pin 4 and ground will yield a voltage output of 256 levels between 0 and -4.980v. the value of the load resistor determines the switching time due to increased voltage swing. values of rl up to 500n do not significantly affect performance but a 2.5kn load increases "worst case" settling time to 1.2~s (when all bits are switched on). refer to the subsequent text section of settling time for more details on output loading. output current range the output current maximum rating of 4.2ma may be used only for negative supply voltages more negative than -7.0v, due to the increased voltage drop across the resistors in the reference current amplifier. - 11-119 8/87, rev. a1 r.rj ~ ~ ~ ~ ~ 0 u {j 0 ~ ~ -< i 0 f-i i ~ - {j - 0 ii o.if '( vee 0 +2.0vdc r , 14 101< 15 10k 1k '" i grr i eo 10 4 11 16 12 51 ir' t-f-l. '.. eo for settling time measurement (all bits switched low to high) obsolete
~ dac-150aal140aa a-bit multiplying d/a converters accuracy absolute accuracy is the measure of each output current level with respect to its intended value, and is dependent upon relative accuracy and full-scale current drift. relative accuracy is the measure of each output current level as a fraction of the full-scale current. the relative accuracy of the dac-1508a-8 is essentially constant with temperature due to the excellent temperature tracking of the monolithic resistor ladder. the reference current may drift with temperature, causing a change in the absolute accuracy of output current. however, the dac-1508a-8 has a very low full-scale current drift with temperature. the dac-1508a-8/dac-1408a series is guaranteed accurate to within :t 1/2 lsb at a full-scale output current of 1.992ma. this corresponds to a reference amplifier output current drive to the ladder network of 2.0ma, with the loss of one lsb (8.0pa), which is the ladder remainder shunted to ground. the input current to pin 14 has a guaranteed value of between 1.9 and 2.1ma, allowing some mismatch in the npn current source pair. testing relative accuracy is accomplished by the circuit labelled "relative accuracy test circuit". the 12-bit converter is calibrated for a full-scale output current of 1.992ma. this is an optional step since the dac-1508a-8 accuracy is essentially the same between 1.5 and 2.5ma. then the dac-1508a-8 circuit's full-scale current is trimmed to the same value with r14 so that a zero value appears at the error amplifier output. the counter is activated and the error band may be displayed on an oscilloscope, detected by comparators, or stored in a peak detector. two 8-bit d/a converters may not be used to construct a 16-bit accuracy d/a converter. 16-bit accuracy implies a total errorof:t 1/2 of one part in 65, 536, or:t0.00076% which is much more accurate than the :to.19% specification pro- vided by the dac-1508a-8. multiplying accuracy the dac-1508a-8 may be used in the multiplying mode with eight-bit accuracy when the reference current is varied over a range of 256:1. if the reference current in the multiplying mode ranges from 16pa to 4.0ma, the additional error contributions are less than 1.6pa. this is well within eight-bit accuracy when referred to full scale. a monotonic converter is one which supplies an increase in current for each increment in the binary word. typically, the dac-1508a-8 is monotonic for all values of reference current above 0.5ma. the recommended range for operation with a dc reference current is 0.5 to 4.0ma. settling time the "worst case" switching condition occurs when all bits are switched "on", which corresponds to a low-to-high transi- tion for all bits. this time is typically 250ns for settling to within:t 1/2 lsb, for 8-bit accuracy, and 200ns to 1/2 lsb for 7 and 6-bit accuracy. the turn off is typically under 1oon5. these times apply when rl:5 500n and co:5 25pf. the slowest single switch is the least significant bit. in applications where the d/a converter functions in a positive- going ramp mode, the "worst case" switching condition does not occur, and a settling time of less than 250ns may be realized. extra care must be taken in board layout since this is usually the dominant factor in satisfactory test results when measur- ing settling time. short leads, 100pf supply bypassing for low frequencies, and a minimum scope lead length are all mandatory. 11-120 -----. 8/87, rev. a1 -- ~ obsolete
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