2.5V LVDS, 1:2 Glitchless Clock Buffer
IDT5T93GL02
NRND
TERABUFFER™ II
DATA SHEET
General Description
The IDT5T93GL02 2.5V differential clock buffer is a user-selectable
differential input to two LVDS outputs. The fanout from a differential
input to two LVDS outputs reduces loading on the preceding driver
and provides an efficient clock distribution network. The
IDT5T93GL02 can act as a translator from a differential HSTL,
eHSTL, LVEPECL (2.5V), LVPECL (3.3V), CML, or LVDS input to
LVDS outputs. A single-ended 3.3V / 2.5V LVTTL input can also be
used to translate to LVDS outputs. The redundant input capability
allows for a glitchless change-over from a primary clock source to a
secondary clock source up to 450MHz. Selectable inputs are
controlled by SEL. During the switchover, the output will disable low
for up to three clock cycles of the previously-selected input clock.
The outputs will remain low for up to three clock cycles of the
newly-selected clock, after which the outputs will start from the
newly-selected input. A FSEL pin has been implemented to control
the switchover in cases where a clock source is absent or is driven to
DC levels below the minimum specifications.
The IDT5T93GL02 outputs can be asynchronously
enabled/disabled. When disabled, the outputs will drive to the value
selected by the GL pin. Multiple power and grounds reduce noise.
Features
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Guaranteed low skew: <50ps (maximum)
Very low duty cycle distortion: <100ps (maximum)
High speed propagation delay: <2.2ns (maximum)
Up to 450MHz operation
Selectable inputs
Hot insertable and over-voltage tolerant inputs
3.3V/2.5V LVTTL, HSTL, eHSTL, LVEPECL (2.5V), LVPECL
(3.3V), CML or LVDS input interface
Selectable differential inputs to two LVDS outputs
Power-down mode
At power-up, FSEL should be LOW
2.5V V
DD
-40°C to 85°C ambient operating temperature
Available in TSSOP package
Reccommends IDT5T9302 if glitchless input selection is not
required
Applications
•
Clock distribution
Pin Assignment
GND
PD
FSEL
V
DD
Q1
Q1
V
DD
SEL
G
GND
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
A2
A2
GND
V
DD
Q2
Q2
V
DD
GL
A1
A1
20-Lead TSSOP
4.4mm x 6.5mm x 0.925mm package body
G Package
Top View
IDT5T93GL02 REVISION B AUGUST 17, 2010
1
©2010 Integrated Device Technology, Inc.
IDT5T93GL02 Data Sheet
2.5V LVDS 1:2 GLITCHLESS CLOCK BUFFER TERABUFFER™ II
Block Diagram
GL
G
OUTPUT
CONTROL
Q1
Q1
PD
OUTPUT
CONTROL
Q2
Q2
A1
A1
1
A2
A2
0
SEL
FSEL
IDT5T93GL02 REVISION B AUGUST 17, 2010
2
©2010 Integrated Device Technology, Inc.
IDT5T93GL02 Data Sheet
2.5V LVDS 1:2 GLITCHLESS CLOCK BUFFER TERABUFFER™ II
Table 1. Pin Descriptions
Name
A[1:2]
Input
Type
Adjustable
(1, 4)
Description
Clock input. A
[1:2]
is the "true" side of the differential clock input.
Complementary clock inputs. A[1:2] is the complementary side of A[1:2]
.
For LVTTL single-ended operation, A[1:2] should be set to the desired toggle voltage for
A[1:2]:
3.3V LVTTL V
REF
= 1650mV
2.5V LVTTL V
REF
= 1250mV
Gate control for differential outputs Q1 and Q1 through Q2 and Q2. When G is LOW, the
differential outputs are active. When G is HIGH, the differential outputs are asynchronously
driven to the level designated by GL
(2)
.
Specifies output disable level. If HIGH, "true" outputs disable HIGH and "complementary"
outputs disable LOW. If LOW, "true" outputs disable LOW
and "complementary" outputs disable HIGH.
Clock outputs.
Complementary clock outputs.
Reference clock select. When LOW, selects A2 and A2.
When HIGH, selects A1 and A1.
Power-down control. Shuts off entire chip. If LOW, the device goes into low power mode.
Inputs and outputs are disabled. Both "true" and "complementary" outputs will pull to V
DD
.
Set HIGH for normal operation.
(3)
At a rising edge, FSEL forces select to the input designated by SEL.
Set LOW for normal operation. At power-up, FSEL should be LOW.
Power supply for the device core and inputs.
Ground.
A[1:2]
Input
Adjustable
(1, 4)
G
Input
LVTTL
GL
Q[1:2]
Q[1:2]
SEL
PD
FSEL
V
DD
GND
Input
Output
Output
Input
Input
Input
LVTTL
LVDS
LVDS
LVTTL
LVTTL
LVTTL
Power
Power
NOTES:
1.
Inputs are capable of translating the following interface standards:
Single-ended 3.3V and 2.5V LVTTL levels
Differential HSTL and eHSTL levels
Differential LVEPECL (2.5V) and LVPECL (3.3V) levels
Differential LVDS levels
Differential CML levels
2.
Because the gate controls are asynchronous, runt pulses are possible. It is the user's responsibility to either time the gate control
signals to minimize the possibility of runt pulses or be able to tolerate them in down stream circuitry.
3.
It is recommended that the outputs be disabled before entering power-down mode. It is also recommended that the outputs remain
disabled until the device completes power-up after asserting PD.
4.
The user must take precautions with any differential input interface standard being used in order to prevent instability when there is
no input signal.
Table 2. Pin Characteristics
(T
A
= +25°C, F = 1.0MHz)
Symbol
C
IN
Parameter
Input Capacitance
Test Conditions
Minimum
Typical
Maximum
3
Units
pF
NOTE: This parameter is measured at characterization but not tested.
IDT5T93GL02 REVISION B AUGUST 17, 2010
3
©2010 Integrated Device Technology, Inc.
IDT5T93GL02 Data Sheet
2.5V LVDS 1:2 GLITCHLESS CLOCK BUFFER TERABUFFER™ II
Function Tables
Table 3A. Gate Control Output Table
Control Output
GL
0
0
1
1
G
0
1
0
1
Q[1:2]
Toggling
LOW
Toggling
HIGH
Outputs
Q[1:2]
Toggling
HIGH
Toggling
LOW
Table 3B. Input Selection Table
Selection SEL pin
0
1
Inputs
A2/A2
A1/A1
Absolute Maximum Ratings
NOTE: Stresses beyond those listed under
Absolute Maximum Ratings
may cause permanent damage to the device. These ratings are stress
specifications only. Functional operation of product at these conditions or any conditions beyond those listed in the
DC Characteristics or AC
Characteristics
is not implied. Exposure to absolute maximum rating conditions for extended periods may affect product reliability.
Item
Power Supply Voltage, V
DD
Input Voltage, V
I
Output Voltage, V
O
Not to exceed 3.6V
Storage Temperature, T
STG
Junction Temperature, T
J
Rating
-0.5V to +3.6V
-0.5V to +3.6V
-0.5 to V
DD
+0.5V
-65°C to 150°C
150°C
Recommended Operating Range
Symbol
T
A
V
DD
Description
Ambient Operating Temperature
Internal Power Supply Voltage
Minimum
-40
2.3
Typical
+25
2.5
Maximum
+85
2.7
Units
°C
V
IDT5T93GL02 REVISION B AUGUST 17, 2010
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©2010 Integrated Device Technology, Inc.
IDT5T93GL02 Data Sheet
2.5V LVDS 1:2 GLITCHLESS CLOCK BUFFER TERABUFFER™ II
DC Electrical Characteristics
Table 4A. LVDS Power Supply DC Characteristics
(1)
,
T
A
= -40°C to 85°C
Symbol
I
DDQ
I
TOT
I
PD
Parameter
Quiescent V
DD
Power Supply Current
Total Power
V
DD
Supply Current
Total Power Down
Supply Current
Test Conditions
V
DD
= Max.,
All Input Clocks = LOW
(2)
; Outputs enabled
V
DD
= 2.7V;
F
REFERENCE
Clock = 450MHz
PD = LOW
Minimum
Typical
Maximum
240
250
5
Units
mA
mA
mA
NOTE 1: These power consumption characteristics are for all the valid input interfaces and cover the worst case conditions.
NOTE 2: The true input is held LOW and the complementary input is held HIGH.
Table 4B. LVTTL DC Characteristics
(1)
,
T
A
= -40°C to 85°C
Symbol
I
IH
I
IL
V
IK
V
IN
V
IH
V
IL
V
THI
V
REF
Parameter
Input High Current
Input Low Current
Clamp Diode Voltage
DC Input Voltage
DC Input High Voltage
DC Input Low Voltage
DC Input Threshold Crossing Voltage
Single-Ended Reference Voltage
(3)
3.3V LVTTL
2.5V LVTTL
V
DD
/2
1.65
1.25
Test Conditions
V
DD
= 2.7V
V
DD
= 2.7V
V
DD
= 2.3V, I
IN
= -18mA
-0.3
1.7
0.7
-0.7
Minimum
Typical
(2)
Maximum
±5
±5
-1.2
3.6
Units
μA
μA
V
V
V
V
V
V
V
NOTE 1: See
Recommended Operating Range
table.
NOTE 2: Typical values are at V
DD
= 2.5V, +25°C ambient.
NOTE 3: For A[1:2] single-ended operation, A[1:2] is tied to a DC reference voltage.
Table 4C. Differential DC Characteristics
(1)
,
T
A
= -40°C to 85°C
Symbol
I
IH
I
IL
V
IK
V
IN
V
DIF
V
CM
Parameter
Input High Current
Input Low Current
Clamp Diode Voltage
DC Input Voltage
DC Differential Voltage
(2)
DC Common Mode Input Voltage
(3)
Test Conditions
V
DD
= = 2.7V
V
DD
= = 2.7V
V
DD
= 2.3V, I
IN
= -18mA
-0.3
0.1
0.05
V
DD
-0.7
Minimum
Typical
(4)
Maximum
±5
±5
-1.2
3.6
Units
μA
μA
V
V
V
V
NOTE 1: See
Recommended Operating Range
table.
NOTE 2: V
DIF
specifies the minimum input differential voltage (V
TR
- V
CP
) required for switching where V
TR
is the "true" input level and V
CP
is
the "complement" input level. The DC differential voltage must be maintained to guarantee retaining the existing HIGH or LOW input. The AC
differential voltage must be achieved to guarantee switching to a new state.
NOTE 3: V
CM
specifies the maximum allowable range of (V
TR
+ V
CP
) /2.
NOTE 4: Typical values are at V
DD
= 2.5V, +25°C ambient.
IDT5T93GL02 REVISION B AUGUST 17, 2010
5
©2010 Integrated Device Technology, Inc.
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