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SY10E136

SY100E136

Micrel, Inc.

M9999-032006

hbwhelp@micrel.com or (408) 955-1690

Pin

Function

Preset Data Inputs

Differential Data Outputs

Mode Control Pins

MR

Master Reset

CLK

Clock Input

Carry Out Output (Active LOW)

Look-Ahead-Carry Output

Carry-In Input (Active LOW)

Look-Ahead-Carry Input

DESCRIPTION

FEATURES

s 550MHz count frequency

s Look-ahead-carry input and output

s Fully synchronous up and down counting

s Asynchronous Master Reset

s Internal 75K

s Available in 28-pin PLCC package

The SY10/100E136 are 6-bit synchronous, presettable,

cascadable universal counters. These devices generate

a look-ahead-carry output and accept a look-ahead-carry

input. These two features allow for the cascading of

multiple E136s for wider bit width counters that operate

at very nearly the same frequency as the stand-alone

counter.

one count before the E136 reaches terminal count. The

the counter reaches terminal count. For more information

on utilizing the look-ahead-carry features of the device,

please refer to the applications section of this data sheet.

programmable divider and self-stopping counter

applications.

Unlike the H136 and other similar universal counter

designs, the E136 carry-out and look-ahead-carry-out

signals are registered on chip. This design alleviates the

glitch problem seen on many counters where the carry-

out signals are merely gated. Because of this architecture,

there are some minor functional differences between the

E136 and H136 counters. The user, regardless of

familiarity with the H136, should read this data sheet

carefully. Note specifically (see block diagram) the

operation of the carry-out outputs and the look-ahead-

carry-in input when utilizing the Master Reset.

When left open, all of the input pins will be pulled

LOW via an input pulldown resistor. The Master Reset is

an asynchronous signal which, when asserted, will force

the Q outputs LOW.

The Q outputs need not be terminated for the E136 to

function properly. In fact, if these outputs will not be

used in a system, it is recommended that they be left

open to save power and minimize noise. This practice

will minimize switching noise which can reduce the

maximum count frequency of the device, or significantly

reduce margins against other noise in the system.

PIN NAMES

SY10E136

SY100E136

6-BIT UNIVERSAL

UP/DOWN COUNTER

Rev.: F

Amendment: 0

Issue Date:

March 2006