IDT5V991A
3.3V PROGRAMMABLE SKEW PLL CLOCK DRIVER TURBOCLOCK
COMMERCIAL AND INDUSTRIAL TEMPERATURE
RANGES
3.3V PROGRAMMABLE SKEW
PLL CLOCK DRIVER
TURBOCLOCK™
FEATURES:
•
•
•
•
•
•
•
•
REF is 5V tolerant
4 pairs of programmable skew outputs
Low skew: 200ps same pair, 250ps all outputs
Selectable positive or negative edge synchronization:
Excellent for DSP applications
Synchronous output enable
Output frequency: 3.75MHz to 85MHz
2x, 4x, 1/2, and 1/4 outputs
3 skew grades:
IDT5V991A-2: t
SKEW0
<250ps
IDT5V991A-5: t
SKEW0
<500ps
IDT5V991A-7: t
SKEW0
<750ps
3-level inputs for skew and PLL range control
PLL bypass for DC testing
External feedback, internal loop filter
12mA balanced drive outputs
Low Jitter: <200ps peak-to-peak
Available in 32-pin PLCC Package
Not Recommended for New Design
IDT5V991A
NRND
•
•
•
•
•
•
•
The IDT5V991A is a high fanout 3.3V PLL based clock driver
intended for high performance computing and data-communications
applications. A key feature of the programmable skew is the ability of
outputs to lead or lag the REF input signal. The IDT5V991A has eight
programmable skew outputs in four banks of 2. Skew is controlled by
3-level input signals that may be hard-wired to appropriate HIGH-MID-
LOW levels.
When the GND/sOE pin is held low, all the outputs are synchro-
nously enabled. However, if GND/sOE is held high, all the outputs
except 3Q0 and 3Q1 are synchronously disabled.
Furthermore, when the V
CCQ
/PE is held high, all the outputs are
synchronized with the positive edge of the REF clock input. When
V
CCQ
/PE is held low, all the outputs are synchronized with the negative
edge of REF. Both devices have LVTTL outputs with 12mA balanced
drive outputs.
DESCRIPTION:
FUNCTIONAL BLOCK DIAGRAM
GND/sOE
1Q
0
3
1F1:0
V
CCQ
/PE
Skew
Select
REF
PLL
FB
3
FS
Skew
Select
3
3
3F1:0
Skew
Select
3
3
4F1:0
4Q
0
4Q
1
3Q
0
3Q
1
3
3
2F1:0
2Q
0
2Q
1
1Q
1
Skew
Select
3
The IDT logo is a registered trademark of Integrated Device Technology, Inc.
COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES
1
c
2013 Integrated Device Technology, Inc.
NOVEMBER 7, 2013
DSC 5963/3
IDT5V991A
3.3V PROGRAMMABLE SKEW PLL CLOCK DRIVER TURBOCLOCK
PIN CONFIGURATION
V
C CQ
GND
REF
TEST
3F0
FS
2F1
COMMERCIAL AND INDUSTRIAL TEMPERATURE
RANGES
ABSOLUTE MAXIMUM RATINGS
(1)
Symbol
V
I
Description
Supply Voltage to Ground
DC Input Voltage
REF Input Voltage
T
J
T
STG
Junction Temperature
Storage Temperature
Max
–0.5 to +7
–0.5 to V
CC
+0.5
–0.5 to +5.5
150
–65 to +150
Unit
V
V
V
°C
°C
4
3F1
4F0
4F1
V
CC Q
/PE
V
CCN
4Q1
4Q0
GND
GND
5
6
7
8
9
10
11
12
13
14
3Q1
3
2
1 32
31
30
29
28
27
26
2F0
GND/sOE
1F1
1F0
V
CCN
1Q0
1Q1
GND
GND
32-PLCC
25
24
23
22
21
NOTE:
1. Stresses beyond those listed under ABSOLUTE MAXIMUM RATINGS may cause per-
manent damage to the device. These are stress ratings 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-rated condi-
tions for extended periods may affect device reliability.
15
3Q0
16
V
CCN
17
FB
18
V
CCN
19
2Q1
20
2Q0
CAPACITANCE
(T
A
= +25°C, f = 1MHz, V
IN
= 0V)
Parameter
C
IN
Description
Input Capacitance
Typ.
5
Max.
7
Unit
pF
PLCC
TOP VIEW
NOTE:
1. Capacitance applies to all inputs except TEST, FS, and nF1:0.
PIN DESCRIPTION
Pin Name
REF
FB
TEST
(1)
GND/
sOE
(1)
Type
IN
IN
IN
IN
Description
Reference Clock Input
Feedback Input
When MID or HIGH, disables PLL (except for conditions of Note 1). REF goes to all outputs. Skew selections (see Control
Summary Table) remain in effect. Set LOW for normal operation.
Synchronous Output Enable. When HIGH, it stops clock outputs (except 3Q
0
and 3Q
1
) in a LOW state - 3Q
0
and 3Q
1
may be
used as the feedback signal to maintain phase lock. When TEST is held at MID level and GND/sOE is HIGH, the nF[
1:0
] pins
act as output disable controls for individual banks when nF[
1:0
] = LL. Set GND/sOE LOW for normal operation.
V
CCQ
/PE
nF[
1:0
]
FS
nQ[
1:0
]
V
CCN
V
CCQ
GND
IN
IN
IN
OUT
PWR
PWR
PWR
Selectable positive or negative edge control. When LOW/HIGH the outputs are synchronized with the negative/positive edge of
the reference clock.
3-level inputs for selecting 1 of 9 skew taps or frequency functions
Selects appropriate oscillator circuit based on anticipated frequency range. (See PLL Programmable Skew Range.)
Four banks of two outputs with programmable skew
Power supply for output buffers
Power supply for phase locked loop and other internal circuitry
Ground
NOTE:
1.When TEST = MID and GND/sOE = HIGH, PLL remains active with nF[
1:0
] = LL functioning as an output disable control for individual output banks. Skew selections remain in effect
unless nF[
1:0
] = LL.
PROGRAMMABLE SKEW
Output skew with respect to the REF input is adjustable to com-
pensate for PCB trace delays, backplane propagation delays or to
accommodate requirements for special timing relationships between
clocked components. Skew is selectable as a multiple of a time unit
t
U
which is of the order of a nanosecond (see PLL Programmable
Skew Range and Resolution Table). There are nine skew configura-
tions available for each output pair. These configurations are chosen
2
by the nF
1:0
control pins. In order to minimize the number of control
pins, 3-level inputs (HIGH-MID-LOW) are used, they are intended for
but not restricted to hard-wiring. Undriven 3-level inputs default to
the MID level. Where programmable skew is not a requirement, the
control pins can be left open for the zero skew default setting. The
Control Summary Table shows how to select specific skew taps by
using the nF
1:0
control pins.
IDT5V991A
3.3V PROGRAMMABLE SKEW PLL CLOCK DRIVER TURBOCLOCK
EXTERNAL FEEDBACK
By providing external feedback, the IDT5V991A gives users flex-
ibility with regard to skew adjustment. The FB signal is compared
with the input REF signal at the phase detector in order to drive the
VCO. Phase differences cause the VCO of the PLL to adjust upwards
or downwards accordingly.
COMMERCIAL AND INDUSTRIAL TEMPERATURE
RANGES
An internal loop filter moderates the response of the VCO to the
phase detector. The loop filter transfer function has been chosen to
provide minimal jitter (or frequency variation) while still providing ac-
curate responses to input frequency changes.
PLL PROGRAMMABLE SKEW RANGE AND RESOLUTION TABLE
FS = LOW
Timing Unit Calculation (t
U
)
VCO Frequency Range (F
NOM
)
(1,2)
Skew Adjustment Range
(3)
Max Adjustment:
±9.09ns
±49º
±14%
Example 1, F
NOM
= 15MHz
Example 2, F
NOM
= 25MHz
Example 3, F
NOM
= 30MHz
Example 4, F
NOM
= 40MHz
Example 5, F
NOM
= 50MHz
Example 6, F
NOM
= 80MHz
t
U
= 1.52ns
t
U
= 0.91ns
t
U
= 0.76ns
—
—
—
±9.23ns
±83º
±23%
—
t
U
= 1.54ns
t
U
= 1.28ns
t
U
= 0.96ns
t
U
= 0.77ns
—
±9.38ns
±135º
±37%
—
—
—
t
U
= 1.56ns
t
U
= 1.25ns
t
U
= 0.78ns
ns
Phase Degrees
% of Cycle Time
1/(44 x F
NOM
)
15 to 35MHz
FS = MID
1/(26 x F
NOM
)
25 to 60MHz
FS = HIGH
1/(16 x F
NOM
)
40 to 85 MHz
Comments
NOTES:
1. The device may be operated outside recommended frequency ranges without damage, but functional operation is not guaranteed. Selecting the appropriate FS value based on input
frequency range allows the PLL to operate in its ‘sweet spot’ where jitter is lowest.
2. The level to be set on FS is determined by the nominal operating frequency of the VCO and Time Unit Generator. The VCO frequency always appears at 1Q
1:0
, 2Q
1:0
, and the higher
outputs when they are operated in their undivided modes. The frequency appearing at the REF and FB inputs will be the same as the VCO when the output connected to FB is undivided.
The frequency of the REF and FB inputs will be 1/2 or 1/4 the VCO frequency when the part is configured for a frequency multiplication by using a divided output as the FB input.
3. Skew adjustment range assumes that a zero skew output is used for feedback. If a skewed Q output is used for feedback, then adjustment range will be greater. For example if a 4t
U
skewed
output is used for feedback, all other outputs will be skewed –4t
U
in addition to whatever skew value is programmed for those outputs. ‘Max adjustment’ range applies to output pairs 3 and
4 where ± 6t
U
skew adjustment is possible and at the lowest F
NOM
value.
CONTROL SUMMARY TABLE FOR FEEDBACK SIGNALS
nF1:0
LL
(1)
LM
LH
ML
MM
MH
HL
HM
HH
Skew (Pair #1, #2)
–4t
U
–3t
U
–2t
U
–1t
U
Zero Skew
1t
U
2t
U
3t
U
4t
U
Skew (Pair #3)
Divide by 2
–6t
U
–4t
U
–2t
U
Zero Skew
2t
U
4t
U
6t
U
Divide by 4
Skew (Pair #4)
Divide by 2
–6t
U
–4t
U
–2t
U
Zero Skew
2t
U
4t
U
6t
U
Inverted
(2)
NOTES:
1. LL disables outputs if TEST = MID and GND/sOE = HIGH.
2. When pair #4 is set to HH (inverted), GND/sOE disables pair #4 HIGH when V
CCQ
/PE = HIGH, GND/sOE disables pair #4 LOW when V
CCQ
/PE = LOW.
3
IDT5V991A
3.3V PROGRAMMABLE SKEW PLL CLOCK DRIVER TURBOCLOCK
COMMERCIAL AND INDUSTRIAL TEMPERATURE
RANGES
IDT5V991A-2, -5, -7
(Industrial)
IDT5V991A-2
(Commercial)
Max.
3.6
+85
Min.
3
0
Max.
3.6
+70
Unit
V
°C
RECOMMENDED OPERATING RANGE
Symbol
Vcc
T
A
Description
Power Supply Voltage
Ambient Operating Temperature
Min.
3
-40
DC ELECTRICAL CHARACTERISTICS OVER OPERATING RANGE
Symbol
V
IH
V
IL
V
IHH
V
IMM
V
ILL
I
IN
Parameter
Input HIGH Voltage
Input LOW Voltage
Input HIGH Voltage
(1)
Input MID Voltage
(1)
Input LOW Voltage
(1)
Input Leakage Current
(REF, FB Inputs Only)
I
3
I
PU
I
PD
V
OH
V
OL
3-Level Input DC Current (TEST, FS, nF
1:0
)
Input Pull-Up Current (V
CCQ
/PE)
Input Pull-Down Current (GND/sOE)
Output HIGH Voltage
Output LOW Voltage
Conditions
Guaranteed Logic HIGH (REF, FB Inputs Only)
Guaranteed Logic LOW (REF, FB Inputs Only)
3-Level Inputs Only
3-Level Inputs Only
3-Level Inputs Only
V
IN
= V
CC
or GND
V
CC
= Max.
V
IN
= V
CC
V
IN
= V
CC
/2
V
IN
= GND
V
CC
= Max., V
IN
= GND
V
CC
= Max., V
IN
= V
CC
V
CC
= Min., I
OH
=
−
12mA
V
CC
= Min., I
OL
= 12mA
HIGH Level
MID Level
LOW Level
—
—
—
—
—
2.4
—
±200
±50
±200
±100
±100
—
0.55
µA
µA
V
V
µA
Min.
2
—
V
CC
/2
−
0.3
—
—
V
CC
−
0.6
Max.
—
0.8
—
V
CC
/2+0.3
0.6
±5
Unit
V
V
V
V
V
µA
NOTE:
1. These inputs are normally wired to V
CC
, GND, or unconnected. Internal termination resistors bias unconnected inputs to V
CC
/2. If these inputs are switched, the function and timing of the
outputs may be glitched, and the PLL may require an additional t
LOCK
time before all datasheet limits are achieved.
POWER SUPPLY CHARACTERISTICS
Symbol
I
CCQ
Parameter
Quiescent Power Supply Current
Test Conditions
(1)
V
CC
= Max., TEST = MID, REF = LOW,
V
CCQ
/PE = LOW, GND/sOE = LOW
All outputs unloaded
ΔI
CC
I
CCD
I
TOT
Power Supply Current per Input HIGH
Dynamic Power Supply Current per Output
Total Power Supply Current
V
CC
= Max., V
IN
= 3V
V
CC
= Max., C
L
= 0pF
V
CC
= 3.3V, F
REF
= 20MHz, C
L
= 160pF
(1)
V
CC
= 3.3V, F
REF
= 33MHz, C
L
= 160pF
(1)
V
CC
= 3.3V, F
REF
= 66MHz, C
L
= 160pF
(1)
NOTE:
1. For eight outputs, each loaded with 20pF.
Typ.
(2)
8
Max.
25
Unit
mA
1
55
29
42
76
30
90
—
—
—
μA
μA/MHz
mA
INPUT TIMING REQUIREMENTS
Symbol
t
R
, t
F
t
PWC
D
H
R
EF
Description
(1)
Maximum input rise and fall times, 0.8V to 2V
Input clock pulse, HIGH or LOW
Input duty cycle
Reference Clock Input
Min.
—
3
10
3.75
Max.
10
—
90
85
Unit
ns/V
ns
%
MHz
NOTE:
1. Where pulse width implied by D
H
is less than t
PWC
limit, t
PWC
limit applies.
4
IDT5V991A
3.3V PROGRAMMABLE SKEW PLL CLOCK DRIVER TURBOCLOCK
COMMERCIAL AND INDUSTRIAL TEMPERATURE
RANGES
SWITCHING CHARACTERISTICS OVER OPERATING RANGE
IDT5V991A-2
Symbol
F
NOM
t
RPWH
t
RPWL
t
U
t
SKEW0
t
SKEW1
t
SKEW2
t
SKEW3
t
SKEW4
t
DEV
t
PD
t
ODCV
t
PWH
t
PWL
t
ORISE
t
OFALL
t
LOCK
t
JR
Parameter
VCO Frequency Range
REF Pulse Width HIGH
(11)
REF Pulse Width LOW
(11)
Programmable Skew Time Unit
—
—
—
—
—
—
—
0.05
0.1
0.25
0.3
0.25
0.5
—
0
0
—
—
1
1
—
—
—
0.2
0.25
0.5
1.2
0.5
0.9
0.75
0.25
1.2
2
1.5
1.2
1.2
0.5
25
200
Zero Output Skew (All Outputs)
(1,4,5)
Output Skew
(Rise-Rise, Fall-Fall, Same Class Outputs)
(1,6)
Output Skew
(Rise-Fall, Nominal-Inverted, Divided-Divided)
(1,6)
Output Skew
(Rise-Rise, Fall-Fall, Different Class Outputs)
(1,6)
Output Skew
(Rise-Fall, Nominal-Divided, Divided-Inverted)
(1,2)
Device-to-Device Skew
(1,2,7)
REF Input to FB Propagation Delay
(1,9)
Output Duty Cycle Variation from 50%
(1)
Output HIGH Time Deviation from 50%
(1,10)
Output LOW Time Deviation from 50%
(1,11)
Output Rise Time
(1)
Output Fall Time
(1)
PLL Lock Time
(1,8)
Cycle-to-Cycle Output Jitter
(1)
RMS
Peak-to-Peak
—
—
0
0
—
—
1
1
—
—
—
1.25
0.5
1.2
2.5
3
1.5
1.5
0.5
25
200
—
—
0
0
—
—
1.5
1.5
—
—
—
1.65
0.7
1.2
3
3.5
2.5
2.5
0.5
25
200
ns
ns
ns
ns
ns
ns
ns
ms
ps
—
0.5
1
—
1.2
1.7
ns
—
0.5
0.7
—
0.7
1.2
ns
—
0.5
1.2
—
1
1.5
ns
3
3
—
—
Min.
Typ.
Max.
—
—
Min.
3
3
—
—
—
IDT5V991A-5
Typ.
—
—
0.1
0.25
0.6
Max.
—
—
0.25
0.5
0.7
IDT5V991A-7
Min.
3
3
—
—
—
Typ.
—
—
0.1
0.3
0.6
Max.
—
—
0.25
0.75
1
Unit
ns
ns
ns
ns
ns
See PLL Programmable Skew Range and Resolution Table
See Control Summary Table
t
SKEWPR
Zero Output Matched-Pair Skew (xQ
0
, xQ
1
)
(1,2,3)
−
0.25
−
1.2
—
—
0.15
0.15
—
—
—
−
0.5
−
1.2
—
—
0.15
0.15
—
—
—
−
0.7
−
1.2
—
—
0.15
0.15
—
—
—
NOTES:
1. All timing and jitter tolerances apply for F
NOM
> 25MHz.
2. Skew is the time between the earliest and the latest output transition among all outputs for which the same t
U
delay has been selected when all are loaded with the specified load.
3. t
SKEWPR
is the skew between a pair of outputs (xQ
0
and xQ
1
) when all eight outputs are selected for 0t
U
.
4. t
SKEW0
is the skew between outputs when they are selected for 0t
U
.
5. For IDT5V991A-2 t
SKEW0
is measured with C
L
= 0pF; for C
L
= 30pF, t
SKEW0
= 0.35ns Max.
6. There are 3 classes of outputs: Nominal (multiple of t
U
delay), Inverted (4Q
0
and 4Q
1
only with 4F
0
= 4F
1
= HIGH), and Divided (3Qx and 4Qx only in Divide-by-2 or Divide-by-4 mode).
7. t
DEV
is the output-to-output skew between any two devices operating under the same conditions (V
CC
, ambient temperature, air flow, etc.)
8. t
LOCK
is the time that is required before synchronization is achieved. This specification is valid only after V
CC
is stable and within normal operating limits. This parameter is measured
from the application of a new signal or frequency at REF or FB until t
PD
is within specified limits.
9. t
PD
is measured with REF input rise and fall times (from 0.8V to 2V) of 1ns.
10. Measured at 2V.
11. Measured at 0.8V.
5
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