IDT 74FCT388915T150J

IDT74FCT388915T
3.3V LOW SKEW PLL-BASED CMOS CLOCK DRIVER (3-STATE)
COMMERCIAL TEMPERATURE RANGE
3.3V LOW SKEW PLL-BASED
CMOS CLOCK DRIVER
(WITH 3-STATE)
IDT74FCT388915T
70/100/133/150
FEATURES:
DESCRIPTION:
• 0.5 MICRON CMOS Technology
• Input frequency range: 10MHz – f2Q Max. spec
(FREQ_SEL = HIGH)
• Max. output frequency: 150MHz
• Pin and function compatible with FCT88915T, MC88915T
• 5 non-inverting outputs, one inverting output, one 2x output,
one ÷2 output; all outputs are TTL-compatible
• 3-State outputs
• Duty cycle distortion < 500ps (max.)
• 32/–16mA drive at CMOS output voltage levels
• VCC = 3.3V ± 0.3V
• Inputs can be driven by 3.3V or 5V components
• Available in 28 pin PLCC and SSOP packages
The FCT388915T uses phase-lock loop technology to lock the frequency and phase of outputs to the input reference clock. It provides low
skew clock distribution for high performance PCs and workstations. One of
the outputs is fed back to the PLL at the FEEDBACK input resulting in
essentially zero delay across the device. The PLL consists of the phase/
frequency detector, charge pump, loop filter and VCO. The VCO is
designed for a 2Q operating frequency range of 40MHz to f2Q Max.
The FCT388915T provides 8 outputs, the Q5 output is inverted from the
Q outputs. The 2Q runs at twice the Q frequency and Q/2 runs at half the
Q frequency.
The FREQ_SEL control provides an additional ÷ 2 option in the output
path. PLL _EN allows bypassing of the PLL, which is useful in static test
modes. When PLL_EN is low, SYNC input may be used as a test clock. In
this test mode, the input frequency is not limited to the specified range and
the polarity of outputs is complementary to that in normal operation (PLL_EN
= 1). The LOCK output attains logic HIGH when the PLL is in steady-state
phase and frequency lock. When OE/RST is low, all the outputs are put in
high impedance state and registers at Q, Q and Q/2 outputs are reset.
The FCT388915T requires one external loop filter component as
recommended in Figure 3.
FUNCTIONAL BLOCK DIAGRAM
FEED BAC K
SYNC (0)
SYNC (1)
LOCK
0M
u
1x
Phase/Freq.
Detector
Voltage
Controlled
Oscilator
Charge Pum p
LF
REF_SEL
PLL_EN
0
1
M ux
Divide
-By-2
2Q
( ÷ 1)
1M
( ÷ 2)
0
u
x
D
Q
D
FREQ_SEL
CP
OE/RST
Q0
CP R Q
D
CP
Q
Q1
Q
Q2
Q
Q3
Q
Q4
Q
Q5
Q
Q/2
R
R
D
CP R
D
CP
R
D
CP R
D
CP R
The IDT logo is a registered trademark of Integrated Device Technology, Inc.
COMMERCIAL TEMPERATURE RANGE
OCTOBER 2008
1
© 2004 Integrated Device Technology, Inc.
DSC-4243/7
IDT74FCT388915T
3.3V LOW SKEW PLL-BASED CMOS CLOCK DRIVER (3-STATE)
COMMERCIAL TEMPERATURE RANGE
VCC
2
1
28
27
26
REF_SEL
6
24
GND
SYNC(0)
7
23
Q3
VCC(AN)
8
22
VCC
LF
9
21
Q2
GND(AN)
10
20
GND
SYNC(1)
11
19
LOCK
25
Q/2
24
GND
REF_SEL
6
23
Q3
SYNC(0)
7
22
VCC
VCC(AN)
8
21
Q2
LF
9
20
GND
GND(AN)
10
19
LOCK
SYNC(1)
11
18
PLL_EN
FREQ_SEL
12
17
GND
GND
13
14
16
15
Q1
VCC
12
13
14
SSOP
TOP VIEW
15
16
17
18
PLL_EN
4
5
GND
OE/RST
Q1
Q/2
VCC
25
Q0
2Q
FEEDBACK
Q0
3
5
GND
26
4
FEEDBK
FREQ_SEL
3
VCC
2Q
27
VCC
2
Q4
Q4
Q5
GND
28
Q5
1
VCC
GND
OE/RST
PIN CONFIGURATION
PLCC
TOP VIEW
PIN DESCRIPTION
Pin Name
I/O
SYNC(0)
I
Description
Reference clock input
SYNC(1)
I
Reference clock input
REF_SEL
I
Chooses reference between SYNC (0) & SYNC (1) (refer to functional block diagram)
FREQ_SEL
I
Selects between ÷ 1 and ÷ 2 frequency options (refer to functional block diagram)
FEEDBACK
I
Feedback input to phase detector
LF
I
Input for external loop filter connection
Q0-Q4
O
Clock output
Q5
O
Inverted clock output
2Q
O
Clock output (2 x Q frequency)
Q/2
O
Clock output (Q frequency ÷ 2)
LOCK
O
Indicates phase lock has been achieved (HIGH when locked)
OE/RST
I
Asynchronous reset (active LOW) and output enable (active HIGH). When HIGH, outputs are enabled. When LOW, outputs are in
HIGH impedance.
PLL_EN
I
Disables phase-lock for low frequency testing (refer to functional block diagram)
2
IDT74FCT388915T
3.3V LOW SKEW PLL-BASED CMOS CLOCK DRIVER (3-STATE)
COMMERCIAL TEMPERATURE RANGE
CAPACITANCE (TA = +25°C, F = 1.0MHz)
ABSOLUTE MAXIMUM RATINGS(1)
Symbol
Description
Max
Unit
VTERM(2)
Terminal Voltage with Respect to GND
–0.5 to +4.6
V
CIN
Input Capacitance
VIN = 0V
4.5
6
pF
VTERM(3)
Terminal Voltage with Respect to GND
–0.5 to +7
V
COUT
Output Capacitance
VOUT = 0V
5.5
8
pF
VTERM(4)
Terminal Voltage with Respect to GND
–0.5 to VCC+0.5
V
TSTG
Storage Temperature
–65 to +150
°C
IOUT
DC Output Current
–60 to +60
mA
Symbol
Parameter
Conditions
Typ.
Max.
Unit
NOTES:
1. Stresses greater than those listed under ABSOLUTE MAXIMUM RATINGS may cause
permanent damage to the device. This is a stress rating only and functional operation
of the device at these or any other conditions above those indicated in the operational
sections of this specification is not implied. Exposure to absolute maximum rating
conditions for extended periods may affect reliability.
2. Vcc terminals.
3. Input terminals.
4. Outputs and I/O terminals.
DC ELECTRICAL CHARACTERISTICS OVER OPERATING RANGE
Following Conditions Apply Unless Otherwise Specified:
Commercial: TA = 0°C to +70°C, VCC = 3.3V ± 0.3V
Symbol
Test Conditions(1)
Parameter
Min.
Typ.(2)
Max.
Unit
VIH
Input HIGH Level
Guaranteed Logic HIGH Level
2
—
5.5
V
VIL
Input LOW Level
Guaranteed Logic LOW Level
—
—
0.8
V
IIH
Input HIGH Current(4)
VCC = Max.
VI = 5.5V
—
—
±1
µA
IIL
Input LOW Current(4)
VCC = Max.
VI = GND
—
—
±1
µA
IOZH
High Impedance Output Current(4)
VCC = Max.
VI = VCC
—
—
±1
µA
IOZL
(3-State Output Pins)
VIK
Clamp Diode Voltage
IODH
Output Drive Current
VI = GND
VCC = Min., IIN = –18mA
VCC = Min., VIN = VIH or VIL, VO =
1.5V(3)
1.5V(3)
IODL
Output Drive Current
VCC = Min., VIN = VIH or VIL, VO =
VOH
Output HIGH Voltage
VCC = Min
VOL
VH
Output LOW Voltage
Input Hysteresis
VCC = Min
ICCL
ICCH
ICCZ
Quiescent Power Supply Current
VCC = Max.,VIN = GND or VCC
(Test Mode)
—
—
—
±1
—
–0.7
–1.2
V
–36
—
—
mA
50
—
—
mA
IOH = –16mA
2.4(4)
3.3
—
V
IOL = 32mA
—
—
0.3
100
0.5
—
V
mV
—
2
6
µA
NOTES:
1. For conditions shown as Min. or Max., use appropriate value specified under Electrical Characteristics for the applicable device type.
2. Typical values are at VCC = 3.3V, +25°C ambient.
3. Not more than one output should be tested at one time. Duration of the test should not exceed one second.
4. VOH = VCC - 0.6V at rated current.
3
IDT74FCT388915T
3.3V LOW SKEW PLL-BASED CMOS CLOCK DRIVER (3-STATE)
COMMERCIAL TEMPERATURE RANGE
POWER SUPPLY CHARACTERISTICS
Symbol
ΔICC
Test Conditions(1)
Parameter
Min.
Typ.(2)
Max.
Unit
VIN = VCC –0.6V(3)
—
2
30
µA
—
0.2
0.3
mA/
Quiescent Power Supply Current
VCC = Max.
TTL Inputs HIGH
VIN = VCC –2.1V(3)
ICCD
Dynamic Power Supply Current(4)
VCC = Max.
VIN = VCC
All Outputs Open
VIN = GND
CPD
Power Dissipation Capacitance
50% Duty Cycle
—
15
25
pF
IC
Total Power Supply Current(6)
VCC = Max.
—
30
60
mA
—
90
120
mA
MHz
PLL_EN = 1, LOCK = 1, FEEDBACK = Q4
SYNC frequency = 50MHz. All bits loaded with 15pF
VCC = Max.
PLL_EN = 1, LOCK = 1, FEEDBACK = Q4
SYNC frequency = 50MHz. All bits loaded with 50Ω Thevenin
termination and 20pF
NOTES:
1. For conditions shown as Max. or Min., use appropriate value specified under Electrical Characteristics for the applicable device type.
2. Typical values are at VCC = 3.3V, +25°C ambient.
3. Per TTL driven input. All other inputs at VCC or GND.
4. This parameter is not directly testable, but is derived for use in Total Power Supply Calculations. It is derived with Q frequency as the reference.
5. Values for these conditions are examples of the ICC formula. These limits are guaranteed but not tested.
6. IC = IQUIESCENT + IINPUTS + IDYNAMIC
IC = ICC + DICC DHNT + ICCD (f) + ILOAD
ICC = Quiescent Current (ICCL, ICCH and ICCZ)
ΔICC = Power Supply Current for a TTL High Input (VIN = 3.4V)
DH = Duty Cycle for TTL Inputs High
NT = Number of TTL Inputs at DH
ICCD = Dynamic Current Caused by an Input Transition Pair (HLH or LHL)
f = 2Q Frequency
ILOAD = Dynamic Current due to load.
SYNCH INPUT TIMING REQUIRMENTS
Symbol
Parameter
Min.
Max.
Unit
TRISE/FALL
Rise/Fall Times, SYNC inputs
—
3
ns
Frequency Input Frequency, SYNC Inputs
10(1)
2Q fmax
MHz
Duty Cycle Input Duty Cycle, SYNC Inputs
25%
75%
—
(0.8V to 2V)
OUTPUT FREQUENCY SPECIFICATIONS
Max. (2)
Symbol
Parameter
Min.
70
100
133 (3)
150 (3)
Unit
40
70
100
133
150
MHz
f2Q
Operating frequency 2Q Output
fQ
Operating frequency Q0-Q4, Q5 Outputs
20
35
50
66.7
75
MHz
Operating frequency Q/2 Output
10
17.5
25
33.3
37.5
MHz
fQ/2
NOTES:
1. Note 7 in "General AC Specification Notes" and Figure 3 describes this specification and its actual limits depending on the feedback connection.
2. Maximum operating frequency is guaranteed with the part in a phase locked condition and all outputs loaded.
3. At this frequency, 2Q cannot be used as feedback.
4
IDT74FCT388915T
3.3V LOW SKEW PLL-BASED CMOS CLOCK DRIVER (3-STATE)
COMMERCIAL TEMPERATURE RANGE
SWITCHING CHARACTERISTICS OVER OPERATING RANGE
Symbol
Parameter
tRISE/FALL
Rise/Fall Time
All Outputs
Output Pulse Width
Q, Q, Q/2 outputs(3)
Max.
Unit
0.2(2)
2
ns
Load = 50Ω to VCC/2, CL = 20pF
0.5tCYCLE – 0.8(5) 0.5tCYCLE + 0.8(5)
ns
Q0-Q4, Q5, Q/2, @ 1.5V
tPULSE WIDTH
Output Pulse Width
2Q Output(3)
2Q @ 1.5V
SYNC input to FEEDBACK delay
SYNC-FEEDBACK(3) (measured at SYNC0 or 1 and FEEDBACK input pins)
tSKEWr
Min.
Load = 50Ω to VCC/2, CL = 20pF
(between 0.8V and 2V)
tPULSE WIDTH (3)
tPD
Condition(1)
Output to Output Skew between outputs 2Q, Q0-Q4,
(rising)(3,4)
Q/2 (rising edges only)
tSKEWf
Output to Output Skew
(falling)(3,4)
between outputs Q0-Q4 (falling edges only)
tSKEWall (3,4)
Output to Output Skew
Load = 50Ω to VCC/2, CL = 20pF
0.5tCYCLE – 1(5)
0.5tCYCLE + 1(5)
ns
+0.1
+1.3
ns
—
600
ps
—
250
ps
—
800
ps
1(2)
10
ms
3(2)
14
ns
3(2)
14
ns
0.1µF from LF to Analog GND(5)
Load = 50Ω to VCC/2, CL = 20pF
2Q, Q/2, Q0-Q4 rising, Q5 falling
tLOCK(6)
Time required to acquire Phase-Lock from time
SYNC input signal is received
tPZH
Output Enable Time
tPZL
OE/RST (LOW-to-HIGH) to Q, 2Q, Q/2, Q
tPHZ
Output Disable Time
tPLZ
OE/RST (HIGH-to-LOW) to Q, 2Q, Q/2, Q
GENERAL AC SPECIFICATION NOTES:
1. See test circuit and waveforms.
2. Minimum limits are guaranteed but not tested.
3. These specifications are guaranteed but not production tested.
4. Under equally loaded conditions, as specified under test conditions and at a fixed temperature and voltage.
5. tCYCLE = 1/frequency at which each output (Q, Q, Q/2 or 2Q) is expected to run.
6. With VCC fully powered-on and an output properly connected to the FEEDBACK pin, tLOCK Max. is with C1 = 0.1µF, tLOCK Min. is with C1 = 0.01µF. (Where C1 is loop filter
capacitor shown in Figure 2).
7. The wiring diagrams and written explanations of Figure 3 demonstrate the input and output frequency relationships for various possible feedback configurations. The allowable
SYNC input range to stay in the phase-locked condition is also indicated. There are two allowable SYNC frequency ranges, depending on whether FREQ_SEL is HIGH or LOW.
Also it is possible to feed back the Q5 output, thus creating a 180° phase shift between the SYNC input and the Q outputs. The table below summarizes the allowable SYNC
frequency range for each possible configuration.
FREQ_SEL
Feedback
Allowable SYNC Input
Corresponding 2Q Output
Phase Relationship of the Q Outputs
Level
Output
Frequency Range (MHZ)
Frequency Range
to Rising SYNC Edge
HIGH
Q/2
10 to (2x_Q fMAX Spec)/4
40 to (2Q fMAX Spec)
0°
HIGH
Any Q (Q0-Q4)
20 to (2x_Q fMAX Spec)/2
40 to (2Q fMAX Spec)
0°
HIGH
Q5
20 to (2x_Q fMAX Spec)/2
40 to (2Q fMAX Spec)
180°
HIGH
2X_Q
40 to (2x_Q fMAX Spec)
40 to (2Q fMAX Spec)
0°
LOW
Q/2
5 to (2x_Q fMAX Spec)/8
20 to (2Q fMAX Spec)/2
0°
LOW
Any Q (Q0-Q4)
10 to (2x_Q fMAX Spec)/4
20 to (2Q fMAX Spec)/2
0°
LOW
Q5
10 to (2x_Q fMAX Spec)/4
20 to (2Q fMAX Spec)/2
180°
LOW
2X_Q
20 to (2x_Q fMAX Spec)/2
20 to (2Q fMAX Spec)/2
0°
5
IDT74FCT388915T
3.3V LOW SKEW PLL-BASED CMOS CLOCK DRIVER (3-STATE)
COMMERCIAL TEMPERATURE RANGE
GENERAL AC SPECIFICATION NOTES (continued):
8. The tPD spec describes how the phase offset between the SYNC input and the output connected to the FEEDBACK input, varies with process, temperature and voltage. The
phase measurements were made at 1.5V. The Q/2 output was terminated at the FEEDBACK input with 100Ω to VCC and 100Ω to ground. tPD measurements were made with
the loop filter connection shown in Figure 1 below:
External Loop
Filter
LF
0.1 μ F
C1
Analog GND
Figure 1
NOTES:
1. Figure 2 shows a loop filter and analog isolation scheme which will be effective in most applications. The following guidelines should be followed to ensure stable and jitter-free
operation:
a. All loop filter and analog isolation components should be tied as close to the package as possible. Stray current passing through the parasitics of long traces can cause undesirable
voltage transients at the LF pin.
b. The 10µF low frequency bypass capacitor and the 0.1µF high frequency bypass capacitor form a wide bandwidth filter that will minimize the 388915T's sensitivity to voltage
transients from the system digital VCC supply and ground planes.
If good bypass techniques are used on a board design near components which may cause digital VCC and ground noise, VCC step deviations should not occur at the 388915T's
digital VCC supply. The purpose of the bypass filtering scheme shown in figure 2 is to give the 388915T additional protection from the power supply and ground plane transients
that can occur in a high frequency, high speed digital system.
c. The loop filter capacitor (0.1µF) can be a ceramic chip capacitor, the same as a standard bypass capacitor.
2. In addition to the bypass capacitors used in the analog filter of Figure 2 there should be a 0.1µF bypass capacitor between each of the other (digital) four VCC pins and the board
ground plane. This will reduce output switching noise caused by the 388915T outputs, in addition to reducing potential for noise in the "analog" section of the chip. These bypass
capacitors should also be tied as close to the 388915T package as possible.
BOARD V CC
ANALOG V CC
10 μ F
Low
Freq.
Bypass
0.1 μ F
High
Freq.
Bypass
LF
Analog loop filter section
of the FCT388915T
0.1 μ F (Loop
Filter Cap)
ANALOG GND
BOARD GND
A separate Analog power supply is not necessary
and should not be used. Following these prescribed guidelines is all that is necessary to use
the FCT388915T in a normal digital environm ent.
Figure 2. Recommended Loop Filter and Analog Isolation Scheme for the FCT388915T
6
IDT74FCT388915T
3.3V LOW SKEW PLL-BASED CMOS CLOCK DRIVER (3-STATE)
COMMERCIAL TEMPERATURE RANGE
The frequency relationship shown here is applicable to all Q outputs (Q0, Q1,
Q2, Q3 and Q4).
50 MHz signal
25 MHz feedback signal
1:2 INPUT TO "Q" OUTPUT
FREQUENCY RELATIONSHIP
HIGH
OE/ RST
In this application, the Q/2 output is connected to the FEEDBACK input. The
internal PLL will line up the positive edges of Q/2 and SYNC, thus the Q/2
frequency will equal the SYNC frequency. The Q outputs (Q0-Q4, Q5) will
always run at 2X the Q/2 frequency, and the 2Q output will run at 4X the Q/2
frequency.
Q5
Q4
2Q
LOW
25 MHz
input
signal
REF_SEL
Q3
SYNC(0)
12.5 M Hz feedback signal
25 MHz
"Q"
Clock
O utputs
FCT388915T
V CC (AN)
50 M Hz signal
12.5 MHz
Q/2
FEEDBACK
Q2
LF
GND(AN)
HIGH
FQ_SEL
OE/ RST
Q5
Q4
FEEDBACK
LOW
12.5 MHz
input
Q0
2Q
HIGH
HIGH
Q3
SYNC(0)
FCT388915T
Q2
LF
25 MHz
"Q"
Clock
Outputs
Allowable Input Frequency Range:
20MHz to (f2Q MAX Spec)/2 (for FREQ_SEL HIGH)
10MHz to (f2Q MAX Spec)/4 (for FREQ_SEL LOW)
Figure 3b. Wiring Diagram and Frequency Relationships With
Q4 Output Feedback
GND(AN)
FQ_SEL
Q0
HIGH
PLL_EN
Q/2
REF_SEL
V CC (AN)
Q1
Q1
PLL_EN
2:1 INPUT TO "Q" OUTPUT
FREQUENCY RELATIONSHIP
HIGH
In this application, the 2Q output is connected to the FEEDBACK input. The
internal PLL will line up the positive edges of 2Q and SYNC, thus the 2Q
frequency will equal the SYNC frequency. The Q/2 output will always run at
1/4 the 2Q frequency, and the Q output will run at 1/2 the 2Q frequency.
Allowable Input Frequency Range:
10MHz to ( f2Q MAX Spec)/4 (for FREQ_SEL HIGH)
5MHz to (f2Q MAX Spec)/8 (for FREQ_SEL LOW)
50 MHz feedback signal
HIGH
Figure 3a. Wiring Diagram and Frequency Relationships With Q/
2 Output Feedback
OE/ RST
Q5
Q4
Q/2
FEEDBACK
LOW
50 MHz
input
1:1 INPUT TO "Q" OUTPUT
FREQUENCY RELATIONSHIP
12.5 MHz
input
REF_SEL
Q3
SYNC(0)
V CC (AN)
FCT388915T
LF
In this application, the Q4 output is connected to the FEEDBACK input. The
internal PLL will line up the positive edges of Q4 and SYNC, thus the Q4
frequency (and the rest of the "Q" outputs) will equal the SYNC frequency. The
Q/2 output will always run at 1/2 the Q frequency, and the 2Q output will run
at 2X the Q frequency.
2Q
Q2
25 MHz
"Q"
Clock
Outputs
GND(AN)
FQ_SEL
Q0
HIGH
Q1
PLL_EN
HIGH
Allowable Input Frequency Range:
40MHz to (f2Q MAX Spec) (for FREQ_SEL HIGH)
20MHz to (f2Q MAX Spec)/2 (for FREQ_SEL LOW)
Figure 3c. Wiring Diagram and Frequency Relationships With
2Q Output Feedback
7
IDT74FCT388915T
3.3V LOW SKEW PLL-BASED CMOS CLOCK DRIVER (3-STATE)
COMMERCIAL TEMPERATURE RANGE
CMMU
CM MU
CPU
CM MU
CMMU
CM MU
CMMU
CM MU
CPU
CM MU
CMMU
CM MU
CPU
CARD
FCT388915T
CLOCK
PLL
2f
@f
SYSTEM
CLO CK
SO UR CE
CPU
CARD
FCT388915T
PLL
2f
DISTRIBUTE
CLO CK @ f
CLOCK @ 2f
at point of use
FCT388915T
PLL
MEMORY
CO NTROL
2f
MEMORY
CAR DS
CLOCK @ 2f
at point of use
Figure 4. Multiprocessing Application Using the FCT388915T for Frequency Multiplication
and Low Board-to-Board skew
FCT388915T SYSTEM LEVEL TESTING
FUNCTIONALITY
These relationships can be seen in the block diagram. A recommended test
configuration would be to use SYNC0 or SYNC1 as the test clock input, and tie
PLL_EN and REF_SEL together and connect them to the test select logic.
When the PLL_EN pin is LOW, the PLL is bypassed and the FCT388915T
is in low frequency "test mode". In test mode (with FREQ_SEL HIGH), the 2Q
output is inverted from the selected SYNC input, and the Q outputs are divideby-2 (negative edge triggered) of the SYNC input, and the Q/2 output is divideby-4 (negative edge triggered). With FREQ_SEL LOW the 2Q output is divideby-2 of the SYNC, the Q outputs divide-by-4, and the Q/2 output divide-by-8.
This functionality is needed since most board-level testers run at 1 MHz or
below, and theFCT 388915T cannot lock onto that low of an input frequency.
In the test mode described above, any test frequency test can be used.
8
IDT74FCT388915T
3.3V LOW SKEW PLL-BASED CMOS CLOCK DRIVER (3-STATE)
COMMERCIAL TEMPERATURE RANGE
TEST CIRCUITS AND WAVEFORMS
6.0V
V CC
VCC
VCC
100 Ω
Pulse
Generator
V OU T
V IN
Pulse
Generator
D.U.T.
20pF
100 Ω
RT
GND
500 Ω
V OU T
V IN
D.U.T.
CL
RT
50Ω to VCC/2, CL = 20pF
500 Ω
Enable and Disable Test Circuit
1.5V
SYNC IN PUT
(SYNC (1) or
SYNC (0))
t CYCLE SYNC IN PUT
tP D
V CC/2
FEED BAC K
INPUT
V CC/2
Q/2 OUTPUT
t SKEW f
t SKEW ALL
t SKEW r
t SKEW f
t SKEW r
V CC/2
Q0-Q4
OUTPUTS
t CYCLE "Q" OUTPUTS
V CC/2
Q5 OUTPUT
V CC/2
2Q OUTPUT
Propagation Delay, Output Skew
(These waveforms represent the configuration of Figure 3a)
NOTES:
1. The FCT388915T aligns rising edges of the FEEDBACK input and SYNC input, therefore the SYNC input does not require a 50% duty cycle.
2. All skew specs are measured between the VCC/2 crossing point of the appropriate output edges. All skews are specified as "windows", not as ± deviation around a center point.
3. If a Q ouput is connected to the FEEDBACK input (this situation is not shown), the Q output frequency would match the SYNC input frequency, the 2Q output would run at twice
the SYNC frequency and the Q/2 output would run at half the SYNC frequency.
ENABLE
SWITCH POSITION
D ISABLE
3V
CONTROL
INPUT
1.5V
OUTPUT
NORMALLY
LOW
SW ITCH
6V
3V
1.5V
SW ITCH
GND
3V
0.3V
t PZH
OUTPUT
NORMALLY
HIGH
0V
t PLZ
t PZL
V OL
t PHZ
0.3V
VOH
1.5V
0V
Test
Switch
Disable Low
Enable Low
6V
Disable High
Enable High
GND
DEFINITIONS:
CL = Load capacitance: includes jig and probe capacitance.
RT = Termination resistance: should be equal to ZOUT of the Pulse Generator.
0V
Enable and Disable Times
NOTES:
1. Diagram shown for input Control Enable-LOW and input Control Disable-HIGH.
2. Pulse Generator for All Pulses: tF ≤ 2.5ns; tR ≤ 2.5ns.
9
IDT74FCT388915T
3.3V LOW SKEW PLL-BASED CMOS CLOCK DRIVER (3-STATE)
COMMERCIAL TEMPERATURE RANGE
ORDERING INFORMATION
XXXX
XX
FCT
Temp. Range
Device Type
XX
Speed
XX
Package
J
JG
PY
PYG
(1)
Plastic Leaded Chip Carrier
PLCC - Green
Small Shrink Outline IC
SSOP - Green
70 (1)
100 (1)
133
(1)
150
70MHz Max. Frequency
100MHz Max. Frequency
133MHz Max. Frequency
150MHz Max. Frequency
388915T
3.3V Low skew PLL-based CMOS clock driver
74
0°C to +70°C
NOTE:
1. When ordering GREEN packages, replace this numeric value with the equivalent letter below.
B= 70 MHz
(JG or PYG)
C= 100 MHz
(JG or PYG)
D= 133 MHz
(JG or PYG)
E= 150 MHz
(JG or PYG)
For example, to order a 133MHz version, Green PLCC, the nomenclature would be 74FCT388915TDJG.
CORPORATE HEADQUARTERS
6024 Silver Creek Valley Road
San Jose, CA 95138
for SALES:
800-345-7015 or 408-284-8200
fax: 408-284-2775
www.idt.com
10
for Tech Support:
[email protected]