DESCRIPTION
s
2.5GHz min f
max
s
2.3V to 5.7V power supply
s
Single bit latch
s
Stores or flows through 1 bit of data
s
Optimized to work with SuperLiteTM family
s
Fully differential
s
Source terminated CML outputs for fast edge rates
s
Accepts CML, PECL, LVPECL input logic levels
s
Available in a tiny 10-pin MSOP
The SY55853U is a latch. Its differential output will
flow through the input while it's enable is high. The output
will remain static while the enable is low. In addition, an
asynchronous, level sensitive reset is provided.
SY55853U inputs can be terminated with a single
resistor between the true and the complement pins of a
given input.
The SY55853U is a member of Micrel's SuperLiteTM
family of high-speed CML logic. This family features very
small packaging and 2.3V to 5.7V operation.
FEATURES
D LATCH
SuperLiteTM
SY55853U
FINAL
APPLICATIONS
s
High-speed logic
s
OC-48 communication systems
PIN CONFIGURATION
FUNCTIONAL BLOCK DIAGRAM
1
Rev.: B
Amendment: /0
Issue Date:
March 2003
PIN NAMES
Pin
Function
D, /D
CML/PECL/LVPECL Data Input
LE, /LE
CML/PECL/LVPECL Latch Enable Input
R, /R
CML/PECL/LVPECL Reset Input
Q, /Q
Data Output
GND
Ground
V
CC
V
CC
SuperLite is a trademark of Micrel, Inc.
D
Q
R
LATCH ENABLE
RESET
DATA
OUT
LE
1
D
/D
LE
/LE
GND
10 VCC
/R
R
Q
/Q
9
8
7
6
2
3
4
5
MSOP
SuperLiteTM
2
SuperLiteTM
SY55853U
Micrel
PIN DESCRIPTIONS
D, /D CML/PECL/LVPECL Input (Differential)
This is the single bit of data that gets latched.
LE, /LE CML/PECL/LVPECL Input (Differential)
A high on this input causes the D, /D input to flow through
to the Q, /Q output. A low on the input causes the Q, /Q
output to remain static, except for a possible reset.
R, /R CML/PECL/LVPECL Input (Differential)
This is an asynchronous active high level reset, that
forces the latch into a known state, namely zero. It has
priority over the LE, /LE input.
Q, /Q CML Output (Differential)
This is the output of the latch.
FUNCTIONAL DESCRIPTION
V
CC
NC
X
/X
Figure 1. Hard Wiring A Logic "1"
(1)
Note 1.
X is either D, LE, R input. /X is either /D, /LE, /R input.
NC
NC
V
CC
> 3.0V
X
/X
NC
VCC
3.0V
V
CC
X
/X
Figure 2. Hard Wiring A Logic "0"
(1)
Establishing Static Logic Inputs
The true pin of an input pair is internally biased to ground
through a 75k
resistor. The complement pin of an input
pair is internally biased halfway between V
CC
and ground
by a voltage divider consisting of two 75k
resistors. To
keep an input at static logic zero at V
CC
> 3.0V, leave both
inputs unconnected. For V
CC
3.0V, connect the
complement input to V
CC
and leave the true input
unconnected.
To make an input static logic one, connect
the true input to V
CC
, leave the complement input
unconnected. These are the only ;safe ways to cause inputs
to be at a static value. In particular, no input pin should be
directly connected to ground. All NC (no connect) pins
should be unconnected.
D
LE
R
Q
/Q
X
0
0
Latched
(1)
Latched
(1)
0
1
0
0
1
1
1
0
1
0
X
X
1
0
1
TRUTH TABLE
Note 1.
Retains data before LE falling transition.
3
SuperLiteTM
SY55853U
Micrel
CML TERMINATION
100
100
100
100
SY55853U
v
cc
v
cc
100
50
50
8mA
Figure 3a.
Differentially Terminated
(50
Load CML Output)
All inputs accept the output from any other member of
this family. All outputs are source terminated 100
CML
differential drivers as shown in Figures 3 and 4. SY55853U
expects the inputs to be terminated, and that good high
speed design practices be adhered to. SY55853U inputs
are designed to accept a termination resistor between the
true and complement inputs of a differential pair. 0402 form
factor chip resistors will fit with some trace fanout.
100
100
100
50
SY55853U
v
cc
50
8mA
50
100
50
Figure 3b.
Individually Terminated
(50
Load CML Output)
Symbol
Rating
Value
Unit
V
CC
Power Supply Voltage
0.5 to +6.0
V
V
IN
Input Voltage
0.5 to V
CC
+0.5
V
V
OUT
CML Output Voltage
V
CC
1.0 to V
CC
+0.5
V
T
A
Operating Temperature Range
40 to +85
°
C
T
store
Storage Temperature Range
65 to +150
°
C
ABSOLUTE MAXIMUM RATINGS
(1)
Note 1.
Permanent device damage may occur if ABSOLUTE MAXIMUM RATINGS are exceeded. This is a stress rating only and functional operation
is not implied at conditions other than those detailed in the operational sections of this data sheet. Exposure to ABSOLUTE MAXIMUM
RATlNG conditions for extended periods may affect device reliability.
100
100
200
SY55853U
V
CC
8mA
100
100
Figure 4.
100
Load CML Output
4
SuperLiteTM
SY55853U
Micrel
T
A
= 40
°
C
T
A
= 0
°
C
T
A
= +25
°
C
T
A
= +85
°
C
Symbol
Parameter
Min.
Max.
Min.
Max.
Min.
Max.
Min.
Max.
Unit
V
CC
Power Supply Voltage
2.3
5.7
2.3
5.7
2.3
5.7
2.3
5.7
V
I
CC
Power Supply Current
--
37
--
37
--
37
--
37
mA
Note 1.
Specification for packaged product only.
DC ELECTRICAL CHARACTERISTICS
(1)
V
CC
= 2.3V to 5.7V; GND = 0V
Symbol
Parameter
Min.
Typ.
Max.
Unit
Condition
V
ID
Differential Input Voltage
100
--
--
mV
V
IH
Input HIGH Voltage
(3)
1.6
--
V
CC
V
V
IL
Input LOW Voltage
(3)
1.5
--
V
CC
0.1
V
V
OH
Output HIGH Voltage
V
CC
0.020
V
CC
0.010
V
CC
V
No Load
V
OL
Output LOW Voltage
V
CC
0.97
V
CC
0.825
V
CC
0.660
V
No Load
V
OS
Output Voltage Swing
(4)
0.660
0.800
0.950
V
No Load
0.400
100
Environment
(5)
0.200
50
Environment
(6)
R
DRIVE
Output Source Impedance
80
100
120
CML DC ELECTRICAL CHARACTERISTICS
(1)
V
CC
= 2.3V to 5.7V; GND = 0V; T
A
= 40
°
C to +85
°
C
(2)
Note 1.
Specification for packaged product only.
Note 2.
Equilibrium temperature.
Note 3.
Inputs Must be biased to logic LOW or HIGH when V
CC
is less than 3.0V.
Note 4.
Actual voltage levels and differential swing will depend on customer termination scheme. Typically, a 400mV swing is available in the 100
environment and a 200mV swing in the 50
environment. Refer to the "CML Termination" diagram for more details.
Note 5.
See Figure 4.
Note 6.
See Figure 3a and 3b.
Symbol
Parameter
Min.
Typ.
Max.
Unit
Condition
f
MAX
Max. Operating Frequency
2.5
--
--
GHz
t
PLH
Propagation Delay
D to Q
--
--
400
ps
t
PHL
LE to Q
--
--
400
R to Q
--
--
500
t
S
Set-Up Time
D to LE
70
--
--
ps
D to R
--
--
--
t
H
Hold Time
LE to D
40
--
--
ps
t
RR
Reset Recovery
400
--
--
ps
t
PW
Minimum Pulse Width
LE High
160
--
--
ps
R High
250
--
--
t
r
CML Output Rise/Fall Times
ps
t
f
(20% to 80%)
40
°
C to 0
°
C
--
--
175
0
°
C to 85
°
C
35
--
160
AC ELECTRICAL CHARACTERISTICS
(1, 2)
V
CC
= 2.3V to 5.7V; GND = 0V; T
A
= 40
°
C to +85
°
C
Note 1.
Specification for packaged product only.
Note 2.
Tested using environment of Figure 3b, 50
load CML output.
5
SuperLiteTM
SY55853U
Micrel
PRODUCT ORDERING CODE
Ordering
Package
Operating
Code
Type
Range
SY55853UKC
K10-1
Commercial
TIMING DIAGRAMS
CLK
DATA
RESET
Q
50%
tH
50%
tS
tRR
tPLH
50%
50%
tPHL
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