SSS1508A

AM1508 AMD | Alldatasheet

Document overview

• Manufacturer or author: Provided By ALLDATASHEET.COM(FREE DATASHEET DOWNLOAD SITE)
• PDF pages: 4

Technical content

Am1508/1408 * SSS1508A/1408A 8-Bit Multiplying D/A Converter ee cy Distinctive Characteristics © Improved power consumption (SSS1508A/1408A) © Improved direct replacement for MC1508/1408 157mW, typ. © +0.19% nonlinearity guaranteed over temperature © Compatible with TTL, CMOS logic range © Standard supply voltage: +5.0V and —5.0V to —15V © Improved settling time (SSS150BA/1408A) © Output voltage swing: +0.5V to —5.0V 250ns, typ. © High speed multiplying input: 4.0mA/ys FUNCTIONAL DESCRIPTION The SSS150BA/140BA, Am1508/1408 are &-bit monolithic shunted to ground, therefore the maximum output current is multiplying Digital-to-Analog Converters consisting of @ 256/256 of the reference amplifier input current. For example, reference current amplifier, an R-2R ladder, and eight high a full scale output current of 1.992mA would result from a speed current switches. For many applications, only a refer- reference input current of 2.0mA. fence resistor and reference voltage need be added. Improve- The $551608A/1408A, Am1508/1408 is useful in a wide ments in design and processing techniques provide faster yariety of applications, including waveform synthesizers, settling times combined wit power Power Sore aOB ete digitally programmable gain and attenuation blocks, CRT retaining direct interchangeability with MC1508; vices. character generation, audio digitizing and decoding, stepping The R-2R ladder divides the reference current into eight — motor drives, programmable power supplies and in building binarily-related components which are fed to the switches, Tracking and Successive Approximation Analog-to-Digital A remainder eurrent equal to the least significant bit is always Converters. BLOCK DIAGRAM METALLIZATION AND PAD LAYOUT 2 onowo 2 — : 1 com cost - aS ner ihe COOCCOO ebpyee, SNAG PNR a orca ezecanoen suscncu 3 TR lat Ur sates a tour + —reBe LOS 1 IO Se . a a 6 castes. DIE SIZE: 0.088" x 0.088" oxeron2 ORDERING INFORMATION* CONNECTION DIAGRAM Part Package © Temperature Order Top View Number Type Range Number D-16-1 HermeticDIP O10 +70; AMT406L8 P1641 Hormate DIP 010 +70" AN408L7 Hermetic DIP. 010 +70 AM408L6 tS SSA comerearion Hermetic DIP 010 +70 SSSt40BA-80 nde” Be ‘Amvios Hermetic DIP 10 +70" S8S1408A-TO oot? wpe Hemetc DIP 00 +70 SSS1408A-60 ode Lee Piastic IP «010 +70 AMT4OBNE a Plastic DIP 010. +70C-—AMT408N7 Gs De Plastic IP (Oto +70"C_AMI408NE wens Das Dice 010 +70 _LO1408 ede b. Hermetic DIP S510 + 125° AMISOBLB : ‘Am1508 = Hermetic DIP-_—55to +125°C SSS1508A-60 is ad Dice 8510 +1250 _LD 1608 »o th. "Riso available with burn-in processing. To order, add sulix Bto the part number. Note: Pin 1is marked for orientation. co0196.3

37 T50198-ANA

‘Am1508/1408 + SSS1508A/1408A MAXIMUM RATINGS (Above which the useful life may be impaired) (Ta = +25°C unless otherwise noted) Power Supply Voltage Power Dissipation (Package Limitation), Pp vt +5.5Vde Ceramic Package 1000m\\ v- —16.5Vde Derate above Ta = +25°C 6.7mW/C Digital Input Voltage, V5—V12 +5.5,0Vdc Operating Temperature Range, TA Applied Output Voltage, Vo 405, —6.2Vde SSS1508A-8, Am1508 ~85°C to +125°C Reference Current, 114 BOA ‘SSS1408A Series, Am 1408 Series O°C to +75" Reference Amplifier Inputs, V14, V15 Voc. VEE Vde Storage Temperature, Tstg 65°C 10 +150 ELECTRICAL CHARACTERISTICS OVER OPERATING TEMPERATURE RANGE Veet (V+ =5.0V, V- = -15V, —- 2.0mA, SSS1S0BA-B/AMI50BLB: Ta = —55to +125°C, SSS1408A'Am1408 Series: Ta = Oto +75°C unless a otherwise noted. All digital inputs at high logic level.) Parameters Description Test Conditions Min. Typ. Max. Units Relative Accuracy SSS1508A.8, SSS1408A.8, Am1508L8, Ar 140818 20.19 $S$1408A-7, Am1408L7 es ee Oe __SSS1408A-6, Am1408L6 —_ ee a Setting Time to within 1/2 LSB lincludes tpuH $881508A/1408A Tas ns Amt 506/1408 —_ antec . 300) | tein PAL | Propogation Delay Time ee 30/100 ~| we Telo Output Full Seale Current Delft ee es Digital Input Logic Levels (MSB) vin High Level, Losie "1" 20 ve Low Level, Logic “0” [ MH oyieat input Current (M8) | Hion Level Vin=s.ov | To [008 a [towLewvuzoav [| [-o002[ -o8 | Roferonee Input Bias Current (Pin 15) 851508A/1408A -10 | 30 A Am 808/408 ee tpt Curent Ran [vecsw fo [20 Ta Yo | Sutpur Curent Range ee ee a2 i “io Surpat Gurrent Veet = 2.000V, Ry4= 10000 21 7a [Yo tminy | Ourput Gurrens (Ail Bits Low) Te pe ao a Ourput Voltage Compliance _ [ves feos tos yy Reference Current Slew Rate — [| mals | P8SIg | OurpurGurrent Power Supply Sanaitiity [oa eal Power Supply Current __. $881508A/1408A ma [i ammts00/1408 a XO se Power Supply Voltage Range Ta 125" [$8 | eo eS ae wv [4s [15 | 168 | Power Dissipation ‘All Bits Low V- = -50vde 136 ve = ~18Vde 265 S881508A/1408A 5084/1408) ‘All Bits High Vv = -50Vde 34 | w= tov toe ow {—— Parsi Low V> * -8.0vde 34 vo = ~15¥e 108 ‘amt 508/14\\

1408 All Bits High

v> = -S0vde vo = -18vde

Am1508/1408 - SSS1508A/1408A TYPICAL APPLICATIONS RELATIVE ACCURACY TEST CIRCUIT USE WITH CURRENT-TO-VOLTAGE CONVERTING OP AMP Ao oer joro-1ov vse 2 Mryaatv an | Sao wo] sh = roestka =LT] wo noe] ents} a tr “™ SF iollas : THEORETICAL Vo Ee va Ar Ap Ag Aa AB Ag AD AY er une ee eee Vo = —— (Ro)| 1+ 2+ 2 88,2 ne oc Ria 204 8 16 32 64 126 256 Se) "SERIES eS OS I | ADJUST Vr. R14 OR Ro SO THAT Vo WITH ALL DIGITAL a Er INPUTS AT HIGH LEVEL IS EQUAL TO 9.961 VOLTS oT 2 Tot to ovo4 4 1 1 vo owes tetas ett tt hoe 1k 2 4 8 16 32 64 126 256) tose 255 = 10v|==|- 2.961v own cones USE WITH POSITIVE Vrer USE WITH NEGATIVE Vper pen ae a 0 pba) et a ou ne] Sg ETL Soo Se prio i aco] “Snes = aoe sence < Apart 7° UF Nea mye OU ~ 030196-6 7 0991987 I TRANSIENT RESPONSE AND SETTLING TIME TEST CIRCUIT = 5 if rd ra sa Lo Lal pel ae Ss .@ ii Gee Pl itt . aime re

Am1508/1408 - SSS1: 1408A GENERAL INFORMATION AND APPLICATION NOTES REFERENCE AMPLIFIER ORIVE AND COMPENSATION ACCURACY The reference amplifier provides a voltage at pin 14 for con- Absolute accuracy is the measure of each output current level verting the reference voltage to a current and a turn-around —_with respect to its intended value, and is dependent upon rela- circuit or current mirror for feeding the ladder. The reference tive accuracy and full scale current drift. Relative accuracy is amplifier input current, I14 must always flow into pin 14 re- _the measure of each output current level as a fraction of the full gardless of the setup method or reference voltage polarity. scale current. The relative accuracy of the SSS1508A-8, ‘Am'1508 is essentially constant with temperature due to the ex- nnectic fora itive voltage are shown on the previous cape ihe veterense votage sauce supplies the ful current colent temperature tracking ofthe manoticresitr ladder Ihe For bipolar reference signals, as in the multiplying mode, }@ reference current may drift with temperature, causing a change in the absolute accuracy of output current. However, Ris can be tied to a negative voltage corresponding to the he Ssc1sqgA-8 has ey ak ne minimum input level. It is possible to eliminate Ris with only a a very hun scale currant ciitt wtih small sacrifice in accuracy and temperature drift temperature. The compensation capacitor value must be increased with in- THe SSS1S0BA-S/AI50B Series is guaranteed accurate to creases in Ry4 to maintain phase margin; for R14 val within + 1/2 LSB at a full scale output current of 1.992mA. This 4 proper Gi ues of 1.0, 2.5 and 5.0 kilohms, minumum capacitor values are Corresponds to a reference amplifier output current drive to the 15, 37, and 75pF. The capacitor may be tied to elther V- or _‘[@dder network of 2.0mA. with the loss of one LSB (8.0A) ground, but using V~ increases negative supply rejection. which is the ladder remainder shunted to ground. The input * current to pin 14 has a guaranteed value of between 1.9 and ‘A negative reference voltage may be used if Rs is grounded 2. 1mA, allowing some mismatch in the NPN current source and the reference voltage is applied to Ry5 as shown. A high —_pair. The accuracy test circuit is shown on page 3. The 12-bit input impedance is the main advantage of this method. Com- —_— converter is calibrated for a full scale output current of pensation involves a capacitor to V~ on pin 16, using the valk —4.992mA. This is an optional step since the SSS1508A-8, ues of the previous paragraph. The negative reference voltage Am1508 accuracy is essentially the same between 1.5 and must be at least 4.0 volts above the V~ supply. Bipolar input —_2.5mA. Then the SSS1508A-8, Am1508 circuits’ full scale cur- signals may be handled by connecting R14 to a positive refer- —_rent is trimmed to the same value with Ry4 so that a zero value ence voltage equal to the peak positive input level at pin 15. appears at the error amplifier output. The counter is activated When a DC reference voltage is used, capacitive bypass to and the error band may be displayed on an oscilloscope, de- ‘ground is recommended. The 5.0V logic supply is not recom- _tected by comparators, or stored in a peak detector. mended as a reference voltage. If a well regulated 5.0V supply Two 8-bit D-to-A converters may not be used to construct a which drives logic is to be used as the reference. Ria should —16-bit accuracy D-to-A converter. 16-bit accuracy implies a be decoupled by connecting it to +5.0V through another resis- total error of + 1/2 of one part in 65,536 or +0.00076%, which tor and bypassing the junction of the two resistors with 0.14F to is much more acourate than the +0.19% specification provided ‘ground. For reference voltages greater than 5.0V, a clamp by the SSS1508A-8, Am1508 diode is recommended between pin 14 and ground. It pin 14 is driven by a high impedance such as a transistor MULTIPLYING ACCURACY current source, none of the above compensation methods The SSS1508A-8, Am1508 may be used in the multiplying apply and the amplifier must be heavily compensated, de- mode with eight-bit accuracy when the reference current is creasing the overall bandwidth. varied over a range of 256:1. If the reference current in the multiplying mode ranges from 16nA to 4.0mA, the additional OUTPUT VOLTAGE RANGE error contributions are less than 1.6A. This is well within The voltage on pin 4 is restricted to a range of -0.6 to +0.5 —_eight-bit accuracy when referred to full scale. volts when V- = —5.0V due to the current switching methods A monotonic converter is one which supplies an increase in employed in the SSS1508A-8, Am1508. ‘current for each increment in the binary word. Typically, the The negative output voltage compliance of the SSS1508A.8, SSS150BA-8, Am1508 is monotonic for al values of reference ‘Am1508 is extended to —5.0V where the negative supply volt-_Surrent above 0.5mA. The recommended range for operation age is more negative than ~10 volts. Using a full scale current with a DC reference current is 0.5 to 4.0mA. of 1.992mA and load resistor of 25 kilohms between pin4 and SETTLING TIME i a voltage wut of 256 levels between 0 and one goo wore Fleatng pin 1 rf does not affect tho converter The “worst case” switching condition occurs when af bits are Speed or power dissipation. However, the valve of the load re- _Swiched “on,” which corresponds to a LOW.to-HIGH transition sistor determines the switching time due to increased voltage for all bits. This time is typically 250ns for settling to within = 1/2 ‘swing. Values of RL up to 500 ohms do not significantly affect LSB: for 8-bit accuracy, and 200ns to 1/2 LSB for 7 and 6-bit performance but a 2.5-kilohm load increases “worst case” _00uracy. The tum of is typically under _t00ns. These times settling time to 1.2us (when all bits are switched on). Refer to SPY when R_ =500 ohms and Co =25pF. the subsequent text section on Settling Time for more details The slowest single switch is the least significant bit. In applica ‘on output loading, tions where the D-to-A converter functions in a positive-going ramp mode, the “worst case" switching condition does not OUTPUT CURRENT RANGE ‘occur, and a settling time of less than 250ns may be realized. The output current maximum rating of 4.2mA may be used only Extra care must be taken in board layout since this is usually for negative supply voltages more negative than —12.0 volts, the dominant factor in satisfactory test results when measuring due to the increased voltage drop across the resistors in the _ settling time. Short leads, 100, supply bypassing for low fre~ reference current amplifier. quencies, and minimum scope lead length are all mandatory. 310