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1-to-64 bit variable length shift register

The HEF4557B is a static clocked serial shift register whose length may be programmed to be any number of bits between 1 and 64. The number of bits selected is equal to the sum of the subscripts of the enabled length control inputs (L1, L2, L4, L8, L16, and L32) plus one. Serial data may be selected from the DA or DB data inputs with the A/B select input. This feature is useful for recirculation purposes. Information on DA or DB is shifted into the first register position and all the data in the register is shifted one position to the right on the LOW to HIGH transition of CP0 while CP1 is LOW or on the HIGH to LOW transition of CP1 while CP0 is HIGH. A HIGH on master reset (MR) resets the register and forces Q to LOW and Q to HIGH, independent of the other inputs.

It operates over a recommended VDD power supply range of 3 V to 15 V referenced to VSS (usually ground). Unused inputs must be connected to VDD, VSS, or another input.

This product has been discontinued, click here for discontinuation information and replacement parts.

Orderable parts

Type number Orderable part number Ordering code (12NC) Package Buy from distributors

Features and benefits

  • Fully static operation
  • 5 V, 10 V, and 15 V parametric ratings
  • Standardized symmetrical output characteristics
  • Specified from -40 °C to +85 °C
  • Complies with JEDEC standard JESD 13-B



Type numberProduct statusVCC (V)Logic switching levelsOutput drive capability (mA)tpd (ns)fmax (MHz)No of bitsPower dissipation considerationsTamb (°C)Rth(j-a) (K/W)Ψth(j-top) (K/W)Rth(j-c) (K/W)Package name
HEF4557BTEnd of life3.0 - 15CMOS± 2.4652064medium-40~85491.08SO16


All type numbers in the table below are discontinued. See the table Discontinuation information for more information.

Type numberOrderable part number, (Ordering code (12NC))StatusMarkingPackagePackage informationReflow-/Wave solderingPacking
( 9333 733 30653 )
Discontinued / End-of-lifeHEF4557BT
Reel 13" Q1/T1 CECC
( 9333 733 30652 )
Discontinued / End-of-lifeHEF4557BTBulk Pack, CECC

Discontinuation information

Type numberOrderable part numberOrdering codeLast time buy dateLast time delivery dateReplacement productStatusComments
HEF4557BTHEF4557BT,6539333733306532021-06-302021-12-31No replacementVersion withdrawal
HEF4557BTHEF4557BT,6529333733306522021-06-302021-12-31No replacementVersion withdrawal

Quality, reliability & chemical content

All type numbers in the table below are discontinued. See the table Discontinuation information for more information.

Type numberOrderable part numberChemical contentRoHS / RHFMSLMSL leadfree
Quality and reliability disclaimer

Documentation (4)

File nameTitleTypeDate
HEF4557B1-to-64 bit variable length shift registerData sheet2017-03-17
AN11051Pin FMEA HEF4000 familyApplication note2019-01-09
SO-SOJ-REFLOWFootprint for reflow solderingReflow soldering2009-10-08
SO-SOJ-WAVEFootprint for wave solderingWave soldering2009-10-08


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