d a t a sh eet product speci?cation file under integrated circuits, ic04 january 1995 integrated circuits hef40244b buffers octal buffers with 3-state outputs for a complete data sheet, please also download: the ic04 locmos he4000b logic family specifications hef, hec the ic04 locmos he4000b logic package outlines/information hef, hec
january 1995 2 philips semiconductors product speci?cation octal buffers with 3-state outputs hef40244b buffers description the hef40244b is an octal non-inverting buffer with 3-state outputs. it features output stages with high current output capability suitable for driving highly capacitive loads. the 3-state outputs are controlled by the output enable inputs eo a and eo b . a high on eo causes the outputs to assume a high impedance off-state. the device also features hysteresis on all inputs to improve noise immunity. schmitt-trigger action in the inputs makes the circuit highly tolerant to slower input rise and fall times. the hef40244b is pin and functionally compatible with the ttl 244 device. fig.1 functional diagram. pinning family data, i dd limits category buffers see family specifications hef40244bp(n): 20-lead dil; plastic (sot146-1) hef40244bd(f): 20-lead dil; ceramic (cerdip) (sot152) hef40244bt(d): 20-lead so; plastic (sot163-1) ( ): package designator north america i a1 to i a4 inputs i b1 to i b4 inputs o a1 to o a4 bus outputs o b1 to o b4 bus outputs eo a , eo b output enable inputs (active low) fig.2 pinning diagram.
january 1995 3 philips semiconductors product speci?cation octal buffers with 3-state outputs hef40244b buffers fig.3 logic diagram (one buffer). truth table notes 1. h = high state (the more positive voltage) l = low state (the less positive voltage) x = state is immaterial z = high impedance off state inputs output i n eo o n hl h ll l xh z ratings limiting values in accordance with the absolute maximum system (iec 134). see family speci?cations, except for: dc characteristics v ss =0 v d.c. current into any input i i max. 10 ma d.c. source or sink current into any output i o max. 25 ma d.c. current into the supply terminals i max. 100 ma v dd v v oh v v ol v symbol t amb ( c) - 40 + 25 + 85 min. typ. min. typ. min. typ. output current 5 4,6 0,75 0,6 1,2 0,45 ma high 10 9,5 - i oh 1,85 1,5 3,0 1,1 ma 15 13,5 14,5 15 50 15,5 ma output current 5 3,6 9,3 10 24 10,7 ma high 10 8,4 - i oh 14,4 15 46 15,0 ma 15 13,2 19,5 20 62 19,8 ma output current 5 0,4 2,9 2,3 5,4 1,75 ma low 10 0,5 i ol 9,5 7,6 17 5,50 ma 15 1,5 30,0 25 45 19,0 ma hysteresis 5 220 mv voltage 10 v h 250 mv (any input) 15 320 mv
january 1995 4 philips semiconductors product speci?cation octal buffers with 3-state outputs hef40244b buffers fig.4 typical output source current characteristic. (1) p-channel mos transistor conducting. (2) p-channel mos transistor and bipolar n-p-n transistor conducting. fig.5 schematic diagram of output stage. ac characteristics v ss = 0 v; t amb =25 c; input transition times 20 ns all buffers switching v dd v typical formula for p ( m w) dynamic power 5 4 250 f i +? (f o c l ) v dd 2 where dissipation per 10 17 000 f i +? (f o c l ) v dd 2 f i = input freq. (mhz) package (p) 15 46 000 f i +? (f o c l ) v dd 2 f o = output freq. (mhz) c l = load capacitance (pf) ? (f o c l ) = sum of outputs v dd = supply voltage (v)
january 1995 5 philips semiconductors product speci?cation octal buffers with 3-state outputs hef40244b buffers ac characteristics v ss = 0 v; t amb =25 c; c l = 50 pf; input transition times 20 ns v dd v symbol min. typ. max. typical extrapolation formula propagation delays i an/bn ? o an/bn 5 95 190 ns 83 ns + (0,24 ns/pf) c l high to low 10 t phl 40 80 ns 35 ns + (0,10 ns/pf) c l 15 30 60 ns 26 ns + (0,07 ns/pf) c l i an/bn ? o an/bn 5 85 170 ns 82 ns + (0,06 ns/pf) c l low to high 10 t plh 40 80 ns 38 ns + (0,03 ns/pf) c l 15 30 60 ns 29 ns + (0,02 ns/pf) c l output transition 5 40 80 ns see fig.6 times 10 t thl 20 40 ns high to low 15 15 30 ns 53060ns low to high 10 t tlh 20 40 ns 15 15 30 ns 3-state propagation delays output disable times eo ? o an/bn 5 70 140 ns high 10 t phz 35 70 ns 15 30 60 ns 5 75 150 ns low 10 t plz 40 80 ns 15 30 60 ns output enable times eo ? o an/bn 5 80 160 ns high 10 t pzh 35 70 ns 15 30 60 ns 5 90 180 ns low 10 t pzl 40 80 ns 15 30 60 ns
january 1995 6 philips semiconductors product speci?cation octal buffers with 3-state outputs hef40244b buffers fig.6 output transition times as a function of the load capacitance. ??? t tlh - - - - t thl
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