INTEGRATED CIRCUITS MC1408-8

Transcription

1 INTEGRATED CIRCUITS Supersedes data of 99 Aug File under Integrated Circuits, IC Handbook 00 Aug 0

2 DESCRIPTION The is an -bit monolithic digital-to-analog converter which provides high-speed performance with low cost. It is designed for use where the output current is a linear product of an -bit digital word and an analog reference voltage. FEATURES Fast settling time: 0 ns (typ) Relative accuracy ±0.9% (max error) Non-inverting digital inputs are TTL and CMOS compatible High-speed multiplying rate.0 ma/µs (input slew) Output voltage swing +0. V to.0 V Standard supply voltages +.0 V and.0 V to V PIN CONFIGURATIONS N Package NC GND EE I O MSB A A A 0 A 9 D Package V+ COMPEN V REF( ) V REF(+) A A A A A LSB LSB APPLICATIONS Tracking A-to-D converters /-digit panel meters and DVMs Waveform synthesis Sample-and-Hold Peak detector Programmable gain and attenuation CRT character generation Audio digitizing and decoding Programmable power supplies Analog-digital multiplication Digital-digital multiplication Analog-digital division Digital addition and subtraction Speech compression and expansion Stepping motor drive modems Servo motor and pen drivers V REF(+) A V REF( ) A COMPEN A NC A GND A V 0 A I O 9 A MSB TOP VIEW NOTE:. SO and non-standard pinouts. SL000 Figure. Pin Configurations ORDERING INFORMATION DESCRIPTION TEMPERATURE RANGE ORDER CODE DWG # -Pin Plastic Dual In-Line Package (DIP) 0 C to +0 C N SOT- -Pin Small Outline (SO) Package 0 C to +0 C D SOT09-00 Aug 0-09

3 BLOCK DIAGRAM MSB LSB A A A A A A A A 9 0 I O CURRENT SWITCHES R-R LADDER BIAS CURRENT GND V REF (+) ( ) V REF REFERENCE CURRENT AMPLIFIER COMPEN NPN CURRENT SOURCE PAIR SL0009 Figure. Block Diagram CIRCUIT DESCRIPTION The consists of a reference current amplifier, an R-R ladder, and high-speed current switches. For many applications, only a reference resistor and reference voltage need be added. The switches are non-inverting in operation; therefore, a high state on the input turns on the specified output current component. The switch uses current steering for high speed, and a termination amplifier consisting of an active load gain stage with unity gain feedback. The termination amplifier holds the parasitic capacitance of the ladder at a constant voltage during switching, and provides a low impedance termination of equal voltage for all legs of the ladder. The R-R ladder divides the reference amplifier current into binary-related components, which are fed to the remainder current which is equal to the least significant bit. This current is shunted to ground, and the maximum output current is / of the reference amplifier current, or.99 ma for a.0 ma reference amplifier current if the NPN current source pair is perfectly matched. ABSOLUTE MAXIMUM RATINGS SYMBOL PARAMETER RATING UNIT Positive power supply voltage +. V Negative power supply voltage. V V V Digital input voltage 0 to V V O Applied output voltage. to + V I Reference current.0 ma V, V Reference amplifier inputs to Maximum power dissipation, T amb = C (still-air) P D N package 0 mw D package 00 mw T amb Operating temperature range 0 to + C T stg Storage temperature range to +0 C T sld Lead soldering temperature (0 sec) +0 C NOTES:. Derate above C, at the following rates: N package at. mw/ C; D package at. mw/ C 00 Aug 0

4 DC ELECTRICAL CHARACTERISTICS Pin must be V more negative than the potential to which R is returned. = +.0 V DC, = V DC, V REF /R =.0 ma unless otherwise specified. T amb = 0 C to C, unless otherwise noted. SYMBOL PARAMETER TEST CONDITIONS Min Typ Max E r Relative accuracy Error relative to full-scale I O, Figure ±0.9 % t S Settling time To within / LSB, includes t PLH ; T amb = + C, Figure UNIT 0 ns Propagation delay time t PLH Low-to-High T amb = + C, Figure 00 ns t PHL High-to-Low TCI O Output full-scale current drift 0 ppm/ C Digital input logic level (MSB) V IH High Figure.0 V DC V IL Low 0. Digital input current (MSB) Figure I IH High V IH =.0 V ma I IL Low V IL = 0. V I Reference input bias current Pin, Figure.0.0 µa Figure I OR Output current range =.0 V 0.0. ma =.0 V to V 0.0. I O Output current Figure V REF =.000 V, ma R = 000 Ω I O(min) Off-state All bits low 0.0 µa V O Output voltage compliance E r 0.9% at T A = + C, Figure = V 0. 0., below 0V.,.0, SRI REF Reference current slew rate Figure 9.0 ma/µs PSRR( ) Output current power supply sensitivity V DC I REF = ma 0.. µa/v Power supply current I CC Positive All bits low, Figure +. + ma I EE Negative. Power supply voltage range R Positive T amb = + C, Figure V DC R Negative.. All bits low, Figure P D Power dissipation =.0 V DC 0 mw =.0 V DC 0 0 NOTES:. All bits switched. 00 Aug 0

5 TYPICAL PERFORMANCE CHARACTERISTICS I O OUTPUT CURRENT (ma) D-to-A TRANSFER CHARACTERISTICS ( ) INPUT DIGITAL WORD () Figure. Typical Performance Characteristics SL0000 FUNCTIONAL DESCRIPTION Reference Amplifier Drive and Compensation The reference amplifier input current must always flow into Pin. regardless of the setup method or reference supply voltage polarity. Connections for a positive reference voltage are shown in Figure. The reference voltage source supplies the full reference current. For bipolar reference signals, as in the multiplying mode, R can be tied to a negative voltage corresponding to the minimum input level. R may be eliminated and Pin grounded, with only a small sacrifice in accuracy and temperature drift. A A A A A A A A 9 0 MC0 R = R I O C R R R L Figure. Positive V REF (+)V REF SEE TEXT FOR VALUES OF C. SL000 The compensation capacitor value must be increased with increasing values of R to maintain proper phase margin. For R values of.0,., and.0 kω, minimum capacitor values are,, and pf. The capacitor may be tied to either or ground, but using increases negative supply rejection. (Fluctuations in the negative supply have more effect on accuracy than do any changes in the positive supply.) A negative reference voltage may be used if R is grounded and the reference voltage is applied to R, as shown in Figure. A high input impedance is the main advantage of this method. The negative reference voltage must be at least.0 V above the supply. Bipolar input signals may be handled by connecting R to a positive reference voltage equal to the peak positive input level at Pin. Capacitive bypass to ground is recommended when a DC reference voltage is used. The.0 V logic supply is not recommended as a reference voltage, but if a well regulated.0 V supply which drives logic is to be used as the reference, R should be formed of two series resistors and the junction of the two resistors bypassed with 0. µf to ground. For reference voltages greater than.0 V, a clamp diode is recommended between Pin and ground. If Pin 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. A A A A A A A A 9 0 MC0 R = R I O R R C R L Figure. Negative V REF ( )V REF SEE TEXT FOR VALUES OF C. SL000 Output Voltage Range The voltage at Pin must always be at least. V more positive than the voltage of the negative supply (Pin ) when the reference current is ma or less, and at least V more positive than the negative supply when the reference current is between ma and ma. This is necessary to avoid saturation of the output transistors, which would cause serious degradation of accuracy. Philips Semiconductors does not need a range control because the design extends the compliance range down to. V (or V see above) above the negative supply voltage without significant degradation of accuracy. Philips Semiconductors can be used in sockets designed for other manufacturers MC0 without circuit modification. 00 Aug 0

6 Output Current Range Any time the full-scale current exceeds ma, the negative supply must be at least V more negative than the output voltage. This is due to the increased internal voltage drops between the negative supply and the outputs with higher reference currents. Accuracy Absolute accuracy is the measure of each output current level with respect to its intended value, and is dependent upon relative accuracy, full-scale accuracy and full-scale current drift. Relative accuracy is the measure of each output current level as a fraction of the full-scale current after zero-scale current has been nulled out. The relative accuracy of the is essentially constant over the operating temperature range because of 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 has a very low full-scale current drift over the operating temperature range. The series is guaranteed accurate to within ±/ LSB at + C at a full-scale output current of.99 ma. The relative accuracy test circuit is shown in Figure. The -bit converter is calibrated to a full-scale output current of.999 ma; then the s full-scale current is trimmed to the same value with R so that a zero value appears at the error amplifier output. The counter is activated and the error band may be displayed on the oscilloscope, detected by comparators, or stored in a peak detector. Two -bit D-to-A converters may not be used to construct a -bit accurate D-to-A converter. -bit accuracy implies a total of ±/ part in,, or ±0.000%, which is much more accurate than the ±0.9% specification of the. Monotonicity A monotonic converter is one which always provides an analog output greater than or equal to the preceding value for a corresponding increment in the digital input code. The is monotonic for all values of reference current above 0. ma. The recommended range for operation is a DC reference current between 0. ma and.0 ma. Settling Time The worst case switching condition occurs when all bits are switched on, which corresponds to a low-to-high transition for all input bits. This time is typically 0 ns for settling to within /LSB for -bit accuracy. This time applies when R L < 00 Ω and C O < pf. The slowest single switch is the least significant bit, which typically turns on and settles in ns. In applications where the D-to-A converter functions in a positive going ramp mode, the worst-case condition does not occur and settling times less than 0 ns may be realized. Extra care must be taken in board layout since this usually is the dominant factor in satisfactory test results when measuring settling time. Short leads, 00 µf supply bypassing for low frequencies, minimum scope lead length, good ground planes, and avoidance of ground loops are all mandatory. MSB A A -BIT A D-TO-A A CONVERTER A (±0.0% A ERROR MAX) A A A9 A0 A A LSB k 0 TO +0V OUTPUT 0k V REF = V 0.µF R + NE0 ERROR (V = %) -BIT COUNTER MSB 9 MC0 0 LSB k C Figure. Relative Accuracy SL Aug 0

7 0.µF e IN µF MC0.0k.0k pf +V DC R R L e O C O pf 0.µF FOR SETTLING TIME MEASUREMENT (ALL BITS SWITCHED LOW TO HIGH) e IN.V 0.V.0V SETTLING TIME 0 0 TRANSIENT RESPONSE 00 mv t PHL = t PLH = 0ns t S = 0ns TYPICAL TO ±/LSB t PLH.V USE R L to GND FOR TURN OFF MEASUREMENT R L = 00Ω R L = 0Ω PIN TO GND t PHL SL000 Figure. Transient Response and Settling Time DIGITAL INPUTS A A A A A 9 A 0 A A (+) I V I I I EE I CC MC0 TYPICAL VALUES R = R = k V REF = +.0V C = pf I R I I O R R L V REF(+) V O OUTPUT (SEE TEXT FOR VALUES OF C.) V I AND I I APPLY TO INPUTS A THROUGH A THE RESISTOR TIED TO PIN IS TO TEMPERATURE COMPENSATE THE BIAS CURRENT AND MAY NOT BE NECESSARY FOR ALL APPLICATIONS I O K A V REF where K R Figure. Notation Definitions A A and A N = IF A N IS AT HIGH LEVEL A N = 0 IF A N IS AT LOW LEVEL A A A A A SL MC0 pf k k V REF R L = 0 SCOPE di dt I R L dv dt 0% 90% SLEWING TIME 0.0mA SL000 Figure 9. Reference Current Slew Rate Measurement 00 Aug 0

8 DIP: plastic dual in-line package; leads (00 mil) SOT- 00 Aug 0

9 SO: plastic small outline package; leads; body width.9 mm SOT09-00 Aug 0 9

10 Data sheet status Data sheet status [] Product status [] Definitions Objective data Preliminary data Development Qualification This data sheet contains data from the objective specification for product development. Philips Semiconductors reserves the right to change the specification in any manner without notice. This data sheet contains data from the preliminary specification. Supplementary data will be published at a later date. Philips Semiconductors reserves the right to change the specification without notice, in order to improve the design and supply the best possible product. Production Definitions Short-form specification The data in a short-form specification is extracted from a full data sheet with the same type number and title. For detailed information see the relevant data sheet or data handbook. Limiting values definition Limiting values given are in accordance with the Absolute Maximum Rating System (IEC 0). Stress above one or more of the limiting values may cause permanent damage to the device. These are stress ratings only and operation of the device at these or at any other conditions above those given in the Characteristics sections of the specification is not implied. Exposure to limiting values for extended periods may affect device reliability. Application information Applications that are described herein for any of these products are for illustrative purposes only. Philips Semiconductors make no representation or warranty that such applications will be suitable for the specified use without further testing or modification. Disclaimers Life support These products are not designed for use in life support appliances, devices or systems where malfunction of these products can reasonably be expected to result in personal injury. Philips Semiconductors customers using or selling these products for use in such applications do so at their own risk and agree to fully indemnify Philips Semiconductors for any damages resulting from such application. Right to make changes Philips Semiconductors reserves the right to make changes, without notice, in the products, including circuits, standard cells, and/or software, described or contained herein in order to improve design and/or performance. Philips Semiconductors assumes no responsibility or liability for the use of any of these products, conveys no license or title under any patent, copyright, or mask work right to these products, and makes no representations or warranties that these products are free from patent, copyright, or mask work right infringement, unless otherwise specified. Contact information For additional information please visit Fax: + 0 For sales offices addresses send to: sales.addresses@ This data sheet contains data from the product specification. Philips Semiconductors reserves the right to make changes at any time in order to improve the design, manufacturing and supply. Changes will be communicated according to the Customer Product/Process Change Notification (CPCN) procedure SNW-SQ-0A. [] Please consult the most recently issued data sheet before initiating or completing a design. [] The product status of the device(s) described in this data sheet may have changed since this data sheet was published. The latest information is available on the Internet at URL Koninklijke Philips Electronics N.V. 00 All rights reserved. Printed in U.S.A. Date of release: 0-0 Document order number: Aug 0 0

11 This datasheet has been download from: Datasheets for electronics components.