4-bit magnitude comparator

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1 FEATURES High-impedance NPN base inputs for reduced loading (0µA in High and ow states) Magnitude comparison of any binary words Serial or parallel expaion without extra gating PIN CONFIGURATION B V CC A B DESCRIPTION The F8 is a that can be expanded to almost any length. It compares two -bit binary, BCD, or other monotonic codes and presents the three possible magnitude results at the outputs. The -bit inputs are weighted ( A) and ( B) where A and B are the most significant bits. The operation of the is described in the Function Table, showing all possible logic conditio. The upper part of the table describes the normal operation under all conditio that will occur in a single device or in a series expaion scheme. In the upper part of the table the three outputs are mutually exclusive. In the lower part of the table, the outputs reflect the feed-forward conditio that exist in the parallel expaion scheme. The expaion inputs, and and are the least significant bit positio. When used for series expaion, the, and outputs of the lease significant word are connected to the corresponding, and inputs of the next higher stage. Stages can be added in this manner to any length, but a propagation delay penalty of about is added with each additional stage. For proper operation, the expaion inputs of the least significant word should be tied as follows: = ow, = High, and = ow. TYPE GND 8 TYPICA PROPAGATION DEAY A SF000 TYPICA SUPPY CURRENT (TOTA).0 0mA ORDERING INFORMATION DESCRIPTION -pin plastic DIP -pin plastic SO COMMERCIA RANGE V CC = V ±%, T amb = 0 C to +0 C NN ND INPUT AND OUTPUT OADING AND FAN OUT TABE PINS DESCRIPTION F (U..) HIGH/OW OAD VAUE HIGH/OW A Comparing inputs.0/0.0 0µA/0µA B Comparing inputs.0/0.0 0µA/0µA,, Expaion inputs (active High).0/0.0 0µA/0µA,, Data outputs (active High) 0/.0mA/0mA NOTE: One (.0) FAST unit load is defined as: 0µA in the High state and 0.mA in the ow state. OGIC SYMBO IEC/IEEE SYMBO 0 COMP P V CC = Pin GND = Pin 8 A A B B SF000 0 < = > Q P<Q P=Q P>Q SF000 September,

2 OGIC DIAGRAM A B A B V CC = Pin GND = Pin 8 SF0008 FUTION TABE COMPARING INPUTS EXPANSION INPUTS OUTPUTS A,B A,B,, X X X X X X H X X X X X X H X X X X X H X X X X X H > X X X X H < X X X X H = > X X X H = < X X X H = = H H = = H H = = H H = = X X H H = = H H = = H H H = High voltage level = ow voltage level X = Don t care September,

3 APPICATION INPUTS (SB) B A B A 8 8 B A B A B A B A B A B A The parallel expaion scheme shown in Figure demotrates the most efficient general use of these comparators. The expaion inputs can be used as a fifth input bit position except on the least significant device, which must be connected as in the serial scheme. The expaion inputs used by labeling as an A input, as a B input and setting = ow. The can be used as a -bit comparator only when the outputs are used to drive the ( A) and ( B) inputs of another device. The parallel technique can be expanded to any number of bits as shown in Table. Table. WORD ENGTH NUMBER OF PACKAGES TYPICA SPEEDS F bits bits bits 8 B B A A B B B A A OUTPUTS A B A B A B8 B A8 A B B A A B A B A B A B B A A B B A A (SB) H SF000 Figure. Comparison of Two -Bit Words September,

4 ABSOUTE MAXIMUM RATINGS (Operation beyond the limits set forth in this table may impair the useful life of the device. Unless otherwise noted these limits are over the operating free-air temperature range.) SYMBO PARAMETER RATING UNIT V CC Supply voltage 0. to +.0 V V IN Input voltage 0. to +.0 V I IN Input current 0 to + ma V OUT Voltage applied to output in High output state 0. to V CC V I OUT Current applied to output in ow output state 0 ma T amb Operating free-air temperature range 0 to +0 C T stg Storage temperature range to +0 C RECOMMENDED OPERATING CONDITIONS SYMBO PARAMETER IMITS MIN NOM MAX UNIT V CC Supply voltage..0. V V IH High-level input voltage.0 V V I ow-level input voltage 0.8 V I IK Input clamp current 8 ma I OH High-level output current ma I O ow-level output current 0 ma T amb Operating free-air temperature range 0 +0 C DC EECTRICA CHARACTERISTICS (Over recommended operating free-air temperature range unless otherwise noted.) IMITS SYMBO PARAMETER TEST CONDITIONS MIN TYP MAX UNIT V OH High-level output voltage V CC = MIN, V I = MAX ±%V CC. V IH = MIN, I OH = MAX ±%V CC.. V V O ow-level output voltage V CC = MIN, V I = MAX ±%V CC V IH = MIN, I O = MAX ±%V CC V V IK Input clamp voltage V CC = MIN, I I = I IK 0.. V I I Input current at maximum input voltage V CC = 0.0V, V I =.0V 0 µa I IH High-level input current V CC = MAX, V I =.V 0 µa I I ow-level input current V CC = MAX, V I = 0.V 0 µa I OS Short-circuit output current V CC = MAX 0 0 ma I CCH V IN = GND 0 I CC Supply current (total) V CC = MAX An = Bn = I = GND, ma CC 0 = =.V NOTES:. For conditio shown as MIN or MAX, use the appropriate value specified under recommended operating conditio for the applicable type.. All typical values are at V CC = V, T amb = C.. Not more than one output should be shorted at a time. For testing I OS, the use of high-speed test apparatus and/or sample-and-hold techniques are preferable in order to minimize internal heating and more accurately reflect operational values. Otherwise, prolonged shorting of a High output may raise the chip temperature well above normal and thereby cause invalid readings in other parameter tests. In any sequence of parameter tests, I OS tests should be performed last. September,

5 AC EECTRICA CHARACTERISTICS SYMBO t PH t PH t PH t PH t PH t PH t PH t PH t PH t PH AC WAVEFORMS PARAMETER A or B to, A or B to and to to and to TEST CONDITION Waveform logic levels Waveform logic levels Waveform logic level Waveform logic levels Waveform logic level IMITS V CC = +.0V V CC = +.0V ± % T amb = + C T amb = 0 C to +0 C UNIT C = 0pF, R = 00Ω C = 0pF, R = 00Ω MIN TYP MAX MIN MAX V IN t PH t PH V OUT SF00080 NOTE: For all waveforms, =.V. TEST CIRCUIT AND WAVEFORMS Waveform. Propagation Delay Input to Output PUSE GENERATOR V IN V CC D.U.T. V OUT NEGATIVE PUSE 0% % t TH ( t f ) t w t TH ( t r ) % 0% AMP (V) 0V R T C Test Circuit for Totem-Pole Outputs DEFINITIONS: R = oad resistor; see AC electrical characteristics for value. C = oad capacitance includes jig and probe capacitance; see AC electrical characteristics for value. R T = Termination resistance should be equal to Z OUT of pulse generators. R POSITIVE PUSE family F % 0% amplitude t TH ( t r ) t w 0% Input Pulse Definition INPUT PUSE REQUIREMENTS.0V.V t TH ( t f ) % rep. rate t w t TH t TH MHz 00.. AMP (V) 0V SF0000 September,

INTEGRATED CIRCUITS. 74F85 4-bit magnitude comparator. Product specification 1994 Sep 27 IC15 Data Handbook. Philips Semiconductors

INTEGRATED CIRCUITS. 74F85 4-bit magnitude comparator. Product specification 1994 Sep 27 IC15 Data Handbook. Philips Semiconductors INTEGRATED CIRCUITS 1994 Sep 27 IC15 Data Handbook Philips Semiconductors FEATURES High-impedance NPN base inputs for reduced loading (20µA in High and ow states) Magnitude comparison of any binary words