SN54ALS569A, SN74ALS568A, SN74ALS569A SYNCHRONOUS 4-BIT UP/DOWN DECADE AND BINARY COUNTERS WITH 3-STATE OUTPUTS

SDAS229A - APRIL 1982 - REVISED JANUARY 1995

features

3-State Q Outputs Drive Bus Lines Directly
Counter Operation Independent of 3-State Output
Fully Synchronous Clear, Count, and Load
Asynchronous Clear Is Also Provided
Fully Cascadable
Package Options Include Plastic Small-Outline (DW) Packages, Ceramic Chip Carriers (FK), and Standard Plastic (N) and Ceramic (J) 300-mil DIPs

description

The SN74ALS568A decade counter and ´ALS569A binary countersare programmable, count up or down, and offer both synchronous andasynchronous clearing. All synchronous functions are executed on thepositive-going edge of the clock (CLK) input.

The clear function is initiated by applying a low level to eitherasynchronous clear (ACLR\) or synchronous clear (SCLR\). Asynchronous(direct) clearing overrides all other functions of the device, whilesynchronous clearing overrides only the other synchronous functions.Data is loaded from the A, B, C, and D inputs by holding load () low during a positive-going clocktransition. The counting function is enabled only when enable P(ENP\) and enable T (ENT\) are low and ACLR\, SCLR\, and are high. The up/down (U/D\) inputcontrols the direction of the count. These counters count up whenU/D\ is high and count down when U/D\ is low.

A high level at the output-enable () input forces the Q outputs intothe high-impedance state, and a low level enables those outputs.Counting is independent of .ENT\ is fed forward to enable the ripple-carry output (RCO\) toproduce a low-level pulse while the count is zero (all Q outputs low)when counting down or maximum (9 or 15) when counting up. The clockedcarry output (CCO\) produces a low-level pulse for a duration equalto that of the low level of the clock when is low and the counter is enabled(both ENP\ and ENT\ are low); otherwise, CCO\ is high. CCO\ does nothave the glitches commonly associated with a ripple-carry output.Cascading is normally accomplished by connecting or CCO\ of the first counter toENT\ of the next counter. However, for very high-speed counting, should be used for cascading sinceCCO\ does not become active until the clock returns to the low level.

The SN54ALS569A is characterized for operation over the fullmilitary temperature range of -55°C to 125°C. TheSN74ALS568A and SN74ALS569A are characterized for operation from0°C to 70°C.

Title: SYNCHRONOUS 4-BIT UP/DOWN DECADE AND BINARY COUNTERS WITH 3-STATE OUTPUTS
Product Family: BINARY
Device Functionality: DECADE/BINARY
Orderable Devices: SN54ALS569AJ, SNJ54ALS569AFK, SNJ54ALS569AJ, SNJ54ALS569AW, SN74ALS568AN, SN74ALS569ADW, SN74ALS569ADWR, SN74ALS569AN

View the complete PDF datasheet: sdas229a.pdf (199 K Bytes) (Requires Acrobat Reader 3.x)

View more information about generic part numbers:SN54ALS569A, SN74ALS568A, SN74ALS569A

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