Micrel, Inc.
8-BIT RIPPLE
COUNTER
SY10E137
SY100E137
SY10E137
SY100E137
FEATURES
s
1.8GHz min. count frequency
s
Extended 100E V
EE
range of –4.2V to –5.5V
s
s
s
s
Synchronous and asynchronous enable pins
Differential clock input and data output pins
V
BB
output for single-ended use
Asynchronous Master Reset
DESCRIPTION
The SY10/100E137 are very high speed binary ripple
counters. The two least significant bits were designed
with very fast edge rates, while the more significant bits
maintain standard ECLinPS output edge rates. This allows
the counters to operate at very high frequencies, while
maintaining a moderate power dissipation level.
The devices are ideally suited for multiple frequency
clock generation, as well as for counters in high-
performance ATE time measurement boards.
Both asynchronous and synchronous enables are
available to maximize the device's flexibility for various
applications. The asynchronous enable input, A_Start,
when asserted, enables the counter while overriding any
synchronous enable signals. The E137 features XOR'ed
enable inputs, EN
1
and EN
2
, which are synchronous to
the CLK input. When only one synchronous enable is
asserted, the counter becomes disabled on the next CLK
transition. All outputs remain in the previous state poised
for the other synchronous enable or A_Start to be
asserted in order to re-enable the counter. Asserting
both synchronous enables causes the counter to become
enabled on the next transition of the CLK. EN
1
(or EN
2
)
and CLK edges are coincident. Sufficient delay has been
inserted in the CLK path (to compensate for the XOR
gate delay and the internal D-flip-flop set-up time) to
ensure that the synchronous enable signal is clocked
correctly; hence, the counter is disabled.
The E137 can also be driven single-endedly utilizing
the V
BB
output supply as the voltage reference for the
CLK input signal. If a single-ended signal is to be used,
the V
BB
pin should be connected to the CLK input and
bypassed to ground via a 0.01µF capacitor. V
BB
can
only source/sink 0.5mA; therefore, it should be used as
a switching reference for the E137 only.
All input pins left open will be pulled LOW via an input
pull-down resistor. Therefore, do not leave the differential
CLK inputs open. Doing so causes the current source
transistor of the input clock gate to become saturated,
thus upsetting the internal bias regulators and
jeopardizing the stability of the device.
The asynchronous Master Reset resets the counter to
an all zero state upon assertion.
s
Internal 75K
Ω
input pull-down resistors
s
Available in 28-pin PLCC packge
PIN NAMES
Pin
CLK, CLK
Q
0
–Q
7
, Q
0
–Q
7
A_Start
EN
1
, EN
2
MR
V
BB
V
CCO
Function
Differential Clock Inputs
Differential Q Outputs
Asynchronous Enable Input
Synchronous Enable Inputs
Asynchronous Master Reset
Switching Reference Output
V
CC
to Output
M9999-032006
hbwhelp@micrel.com or (408) 955-1690
Rev.: E
Amendment: /0
1
Issue Date: March 2006
Micrel, Inc.
SY10E137
SY100E137
28-PIN PLCC (J28-1)
Rev. 03
MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131
TEL
USA
+ 1 (408) 944-0800
FAX
+ 1 (408) 474-1000
WEB
http://www.micrel.com
The information furnished by Micrel in this data sheet is believed to be accurate and reliable. However, no responsibility is assumed by Micrel for its use.
Micrel reserves the right to change circuitry and specifications at any time without notification to the customer.
Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product can
reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical implant into
the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. A Purchaser’s
use or sale of Micrel Products for use in life support appliances, devices or systems is at Purchaser’s own risk and Purchaser agrees to fully indemnify
Micrel for any damages resulting from such use or sale.
© 2006 Micrel, Incorporated.
M9999-032006
hbwhelp@micrel.com or (408) 955-1690
5