MC10E197FNR2 [ONSEMI]
5V ECL Data Separator; 5V ECL数据分离型号: | MC10E197FNR2 |
厂家: | ONSEMI |
描述: | 5V ECL Data Separator |
文件: | 总16页 (文件大小:318K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
MC10E197
5VꢀECL Data Separator
The MC10E197 is an integrated data separator designed for use in
high speed hard disk drive applications. With data rate capabilities of
up to 50 Mb/s the device is ideally suited for today’s and future
state-of-the-art hard disk designs.
The E197 is typically driven by a pulse detector which reads the
magnetic information from the storage disk and changes it into ECL
pulses. The device is capable of operating on both 2:7 and 1:7 RLL
coding schemes. Note that the E197 does not do any decoding but
rather prepares the disk data for decoding by another device.
For applications with higher data rate needs, such as tape drive
systems, the device accepts an external VCO. The frequency
capability of the integrated VCO is the factor which limits the device
to 50 Mb/s.
A special anti-equivocation circuit has been employed to ensure
timely lock-up when the arriving data and VCO edges are coincident.
Unlike the majority of the devices in the ECLinPS family, the E197
is available in only 10H compatible ECL. The device is available in
the standard 28-lead PLCC.
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MARKING
DIAGRAM
1 28
MC10E197FN
AWLYYWW
PLCC−28
CASE 776
FN SUFFIX
A
= Assembly Location
Since the E197 contains both analog and digital circuitry, separate
supply and ground pins have been provided to minimize noise
coupling inside the device. The device can operate on either standard
negative ECL supplies or, as is more common, on positive voltage
supplies.
WL = Wafer Lot
YY = Year
WW = Work Week
• 2:7 and 1:7 RLL Format Compatible
• Fully Integrated VCO for 50 Mb/s Operation
• External VCO Input for Higher Operating Frequency
• Anti-equivocation Circuitry to Ensure PLL Lock
ORDERING INFORMATION
Device
Package
Shipping
MC10E197FN
PLCC−28
37 Units/Rail
• PECL Mode Operating Range: V = 4.2 V to 5.7 V
CC
MC10E197FNR2
PLCC−28
500 Units/Reel
with V = 0 V
EE
• NECL Mode Operating Range: V = 0 V
CC
with V = −4.2 V to −5.7 V
EE
• Internal Input Pulldown Resistors
• ESD Protection: > 1 KV HBM, > 75 V MM
• Meets or Exceeds JEDEC Spec EIA/JESD78 IC Latchup Test
• Moisture Sensitivity Level 1
For Additional Information, see Application Note AND8003/D
• Flammability Rating: UL−94 code V−0 @ 1/8″,
Oxygen Index 28 to 34
• Transistor Count = 483 devices
©
Semiconductor Components Industries, LLC, 2006
1
Publication Order Number:
June, 2006 − Rev. 6
MC10E197/D
MC10E197
25
24 23 22 21
20 19
18
RDCLK
RDCLK
LOGIC DIAGRAM AND PINOUT ASSIGNMENT
TEST
EXTVCO
ENVCO
26
27
17
* All V and V
pins are tied together on the die.
CCOX
28
V
CC
16
15
CC
1
Pinout: 28-Lead PLCC
V
RSDATA
RSDATA
EE
Warning: All V , V
, and V pins must be externally
CCO EE
CC
(Top View)
connected to Power Supply to guarantee proper operation.
ACQ
TYPE
RDEN
2
3
4
14
13
12
PUMPUP
RSETDN
5
6
7
8
9
10 11
PIN DESCRIPTIONS
PIN
FUNCTION
REFCLK
REFCLK
RDEN
ECL Reference clock equivalent to one clock cycle per decoding window.
ECL Reference clock equivalent to one clock cycle per decoding window.
ECL Enable data synchronizer when HIGH. When LOW enable the phase/frequency detector steered by REFCLK.
ECL Data Input to Synchronizer logic.
RAWD
VCOIN
CAP1/CAP2
ENVCO
EXTVCO
ACQ
ECL VCO control voltage input
ECL VCO frequency controlling capacitor inputs
ECL VCO select pin. LOW selects the internal VCO and HIGH selects the external VCO input. Pin floats LOW when left open.
ECL External VCO pin selected when ENVCO is HIGH
ECL Acquisition circuitry select pin. This pin must be driven HIGH at the end of the data sync field for some sync field types.
TYPE
ECL Selects between the two types of commonly used sync fields. When LOW it selects a sync field interspersed with 3
zeroes (2:7 RLL code). When HIGH it selects a sync field interspersed with 2 zeroes (1:7 RLL code).
TEST
ECL Input included to initialize the clock flip-flop for test purposes only. Pin should be left open (LOW) in actual application.
ECL Open collector charge pump output for the signal pump
ECL Open collector charge pump output for the reference pump
ECL Current setting resistor for the signal pump
PUMPUP
PUMPDN
RSETUP
RSETDN
RDATA
ECL Current setting resistor for the reference pump
ECL Synchronized data output
RDCLK
ECL Synchronized clock output
CCOX
V
V
, V
,
Most positive supply rails. Digital and analog supplies are independent on chip
CC
CCVCO
V
, V
Most negative supply rails. Digital and analog supplies are independent on chip
EE
EEVCO
RDEN
LOGIC DIAGRAM
PHASE FREQUEN-
CY DETECTOR
REFCLK
CAP1
CAP2
VCOIN
INTERNAL
VCO
CHARGE
PUMP
CURRENT-
SOURCES
PUMPUP
PHASE
DETECTOR
MUX
VCO
MUX
PUMPDN
EXTVCO
DATA
PHASE
DETECTOR
RSETUP
RSETDN
ENVCO
RAWD
RDATA
RDCLK
CLOCK &
DATA
BUFFER
ACQ
ACQUISITION
CIRCUITRY
TYPE
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2
MC10E197
MAXIMUM RATINGS (Note 1)
Symbol Parameter
Condition 1
Condition 2
Rating
Units
V
V
V
PECL Mode Power Supply
NECL Mode Power Supply
V
V
= 0 V
= 0 V
8
V
V
CC
EE
I
EE
CC
−8
PECL Mode Input Voltage
NECL Mode Input Voltage
V
V
= 0 V
= 0 V
V ꢀ V
6
V
V
EE
CC
I
CC
V ꢁ V
−6
I
EE
I
Output Current
Continuous
Surge
50
100
mA
mA
out
TA
Operating Temperature Range
0 to +85
°C
°C
T
stg
Storage Temperature Range
−65 to +150
θ
Thermal Resistance (Junction to Ambient)
0 LFPM
500 LFPM
28 PLCC
28 PLCC
63.5
43.5
°C/W
°C/W
JA
θ
Thermal Resistance (Junction to Case)
std bd
28 PLCC
22 to 26
°C/W
JC
V
PECL Operating Range
NECL Operating Range
4.2 to 5.7
V
V
EE
−5.7 to −4.2
T
sol
Wave Solder
<2 to 3 sec @ 248°C
265
°C
1. Maximum Ratings are those values beyond which device damage may occur.
10E SERIES PECL DC CHARACTERISTICS V = 5.0 V; V = 0.0 V (Note 1)
CCx
EE
0°C
25°C
Typ
85°C
Symbol
Characteristic
Power Supply Current
Min
Typ
150
Max
180
Min
90
Max
180
Min
Typ
150
Max
180
Unit
mA
mV
mV
mV
mV
μA
I
90
150
90
EE
V
Output HIGH Voltage (Note 2)
Output LOW Voltage (Note 2)
Input HIGH Voltage
3980
3050
3830
3050
4070
3210
3995
3285
4160
3370
4160
3520
150
4020
3050
3870
3050
4105
3210
4030
3285
4190
3370
4190
3520
150
4090
3050
3940
3050
4185
3227
4110
3302
4280
3405
4280
3555
150
OH
OL
IH
V
V
V
Input LOW Voltage
IL
I
I
Input HIGH Current
IH
IL
Input LOW Current
0.5
0.3
0.5
0.25
0.3
0.2
μA
NOTE: Devices are designed to meet the DC specifications shown in the above table, after thermal equilibrium has been established. The
circuit is in a test socket or mounted on a printed circuit board and transverse air flow greater than 500 lfpm is maintained.
1. Input and output parameters vary 1:1 with V . V can vary +0.46 V / −0.06 V.
CC
EE
2. Outputs are terminated through a 50 ohm resistor to V −2 volts.
CC
10E SERIES NECL DC CHARACTERISTICS V = 0.0 V; V = −5.0 V (Note 1)
CCx
EE
0°C
25°C
Typ
85°C
Typ
Symbol
Characteristic
Power Supply Current
Min
90
Typ
Max
180
Min
90
Max
180
Min
90
Max
180
Unit
mA
mV
mV
mV
mV
μA
I
150
150
150
EE
V
Output HIGH Voltage (Note 2)
Output LOW Voltage (Note 2)
Input HIGH Voltage
−1020 −930
−840
−980
−895
−810
−910
−815
−720
OH
OL
IH
V
V
V
−1950 −1790 −1630 −1950 −1790 −1630 −1950 −1773 −1595
−1170 −1005 −840 −1130 −970 −810 −1060 −890 −720
−1950 −1715 −1480 −1950 −1715 −1480 −1950 −1698 −1445
150 150 150
Input LOW Voltage
IL
I
I
Input HIGH Current
IH
IL
Input LOW Current
0.5
0.3
0.5
0.065
0.3
0.2
μA
NOTE: Devices are designed to meet the DC specifications shown in the above table, after thermal equilibrium has been established. The
circuit is in a test socket or mounted on a printed circuit board and transverse air flow greater than 500 lfpm is maintained.
1. Input and output parameters vary 1:1 with V . V can vary +0.46 V / −0.06 V.
CC
EE
2. Outputs are terminated through a 50 ohm resistor to V −2 volts.
CC
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3
MC10E197
AC CHARACTERISTICS V = 5.0 V; V = 0.0 V or
V
CCx
= 0.0 V; V = −5.0 V (Note 1)
CCx
EE
EE
0°C
25°C
85°C
Symbol
Characteristic
Min
Typ
Max
Min
Typ
Max
Min
Typ
Max
Unit
f
Frequency of the VCO (Note 5)
150
150
150
MH-
z
VCO
Tuning Ratio (Note 6)
1.53
1.87
1.53
1.87
1.53
1.87
t
t
t
t
Time from RDATA Valid to
Rising Edge of RDCLK (Notes 4)
T
T
T
ps
ps
ps
ps
s
VCO
VCO
VCO
− 550
− 500
− 500
Time from Rising Edge of RDCLK
to RDATA invalid (Notes 4)
T
T
T
VCO
H
VCO
VCO
Skew Between RDATA and
RDATA
300
300
300
SKEW
Cycle−to−Cycle Jitter
TBD
TBD
TBD
JITTER
1. V can vary +0.46 V / −0.06 V
EE
1
2
Applies to the input current for each input except VCOIN
For a nominal set current of 3.72 mA, the resistor values for RSETUP and RSETDN should be 130Ω(0.1%). Assuming no variation between
these two resistors, the current match between the PUMPUP and PUMPDN output signals should be within ±3%. I is calculated as (V
+
EE
SET
1.3v − V )/R; where R is RSETUP or RSETDN and a nominal value for V is 0.85 volts.
BE
BE
3
4
5
6
Output leakage current of the PUMPUP or PUMPDN output signals when at a LOW level.
is the period of the VCO.
T
VCO
The VCO frequency determined with VCOIN = V + 0.5 volts and using a 10pF tuning capacitor.
EE
to F
The tuning ratio is defined as the ratio of f
where f
is measured at VCOIN = 1.3 V + V and f
is measured
VCOMAX
VCOMIN
VCOMAX
EE
VCOMAX
at VCOIN = 2.6 V + V
EE
RDATA
RDATA
RDCLK
RDCLK
t
t
H
S
SETUP AND HOLD TIMING DIAGRAMS
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4
MC10E197
APPLICATIONS INFORMATION
General Operation
Operation
data. For the case in which lock-up is attempted when the data
edges are coincident with the VCO edges, the pump down
signal may enter an indeterminate state for an unacceptably
long period due to the violation of internal set up and hold
times. After an initial pump down pulse, the circuit blocks
successive pump down pulses, and inserts extra pump up
pulses, during portions of the sync field that are known to
contain zeros. Thus, the data phase detector is forced to have
a nonzero output during the lock-up period, and the restoring
force ensures correction of the loop within an acceptable time.
Hence, this circuitry provides a quasi-deterministic pump
down output signal, under the condition of coincident data and
VCO edges, allowing lock-up to occur with excessive delays.
The ACQ line is provided to disable (disable = HIGH) the
acquisition circuit during the data portion of a sector block.
Typically, this circuit is enabled at the beginning of the sync
field by a one-shot timer to ensure a timely lock-up.
The E197 is a phase-locked loop circuit consisting of an
internal VCO, a Data Phase detector with associated
acquisition circuitry, and
a Phase/Frequency detector
(Figure 1). In addition, an enable pin(ENVCO) is provided to
disable the internal VCO and enable the external VCO input.
Hence, the user has the option of supplying the VCO signal.
The E197 contains two phase detectors: a data phase
detector for synchronizing to the non-periodic pulses in the
read data stream during the data read mode of operation, and
a phase/ frequency detector for frequency (and phase) locking
to an external reference clock during the “idle” mode of
operation. The read enable (RDEN) pin muxes between these
two detectors.
Data Read Mode
The data pins (RAWD) are enabled when the RDEN pin is
placed at a logic high level, thus enabling the Data Phase
detector (Figure1) and initiating the data read mode. In this
mode, the loop is servoed by the timing information taken from
the positive edges of the input data pulses. This phase detector
samples positive edges from the RAWD signal and generates
both a pump up and pump down pulse from any edge of the
input data pulse. The leading edge of the pump up pulse is time
modulated by the leading edge of the data signal, whereas the
rising edge of the pump up pulse is generated synchronous to
the VCO clock. The falling edge of the pump down pulse is
synchronous to the falling edge of the VCO clock and the rising
edge of the pump down signal is synchronous to the rising edge
of the VCO clock. Since both edges of the VCO are used the
internal clock a duty cycle of 50%. This pulse width
modulation technique is used to generate the servoing signal
which drives the VCO. The pump down signal is a reference
pulse which is included to provide an evenly balanced
differential system, thereby allowing the synthesis of a VCO
input control signal after appropriate signal processing by the
loop filter.
By using suitable external filter circuitry, a control signal for
input into the VCO can be generated by inverting the pump
down signal, summing the inverted signal with the pump up
signal and averaging the result. The polarity of this control
signal is defined as zero when the data edges lead the clock by
a half clock cycle. If the data edges are advanced with respect
to the zero polarity data/VCO edge relationship, the control
signal is defined to have a negative polarity; whereas if the
VCO is advanced with respect to the zero polarity data/VCO
edge relationship, the control signal is defined to have a
positive polarity. If there is no data edge present at the RAWD
input, the corresponding pump up and pump down outputs are
not generated and the resulting control output is zero.
The TYPE line allows the choice between two sync field
preamble types; transitions interspersed with two zeros
between transitions. These types of sync fields are used with
the 1:7 and 2:7 coding schemes, respectively.
Idle Mode
In the absence of data or when the drive is writing to the disk,
PLL servoing is accomplished by pulling the read enable line
(RDEN) low and providing a reference clock via the REFCLK
pins. The condition whereby RDEN is low selects the
Phase/Frequency detector (Figure 1) and the 10E197 is said to
be operating in the “idle mode”. In order to function as a
frequency detector the input waveform must be periodic. The
pump up and pump down pulses from the Phase/Frequency
detector will have the same frequency, phase and pulse width
only when the two clocks that are being compared have their
positive edges aligned and are of the same frequency.
As with the data phase detector, by using suitable external
filter circuitry, a VCO input control signal can be generated by
inverting the pump down signal, summing the inverted signal
with the pump up signal and averaging the result. The polarity
of this control signal is defined as zero when all positive edges
of both clocks are coincident. For the case in which the
frequencies of the two clocks are the same but the clock edges
of the reference clock are slightly advanced with respect to the
VCO clock, the control clock is defined to have a positive
polarity. A control signal with negative polarity occurs when
the edges of the reference clock are delayed with respect to
those of the VCO. If the frequencies of the two clocks are
different, the clock with the most edges per unit time will
initiate the most pulses and the polarity of the detector will
reflect the frequency error. Thus, when the reference clock is
high in frequency than the VCO clock the polarity of the
control signal is positive; whereas a control signal with
negative polarity occurs when the frequency of the reference
clock is lower than the VCO clock.
Acquisition Circuitry
The acquisition circuitry is provided to assist the data phase
detector in phase locking to the sync field that precedes the
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5
MC10E197
Phase-Lock Loop Theory
Introduction
Gain Constants
Phase lock loop (PLL) circuits are fundamentally
feedback systems used to synchronize the frequency of an
oscillator to an incoming signal. In addition to frequency
synchronization, the PLL circuitry is designed to minimize
the phase difference between the system input and output
signals. A block diagram of a feedback control system is
shown in Figure 1.
As mentioned, each of the three sections in the phase lock
loop block diagram has an associated open loop gain
constant. Further, the gain constant of the filter circuitry is
composed of the product of three gain constants, one for
each filter subsection. The open loop gain constant of the
feed-forward path is given by
Kol = Kφ * Ko * K1 * Kl * Kd
eqt. 1
where:
A(s) is the product of the feed-forward transfer functions.
and obtained by performing a root locus analysis.
Phase Detector Gain Constant
+
X (s)
e
R
The gain of the phase detector is a function of the
operating mode and the data pattern. The 10E197 provides
data separation for signals encoded in 2:7 or 1:7 RLL
encoding schemes; hence, Tables 1 and 2 are coding tables
for these schemes. Table 3 lists nominal phase detector gains
for both 2:7 and 1:7 sync fields.
A(s)
X (s)
i
X (s)
o
−
β(s)
NRZ Data Sequence
Code Sequence
Figure 1. Feedback System
00
01
1000
0100
β(s) is the product of the feedback transfer functions.
The transfer function for this closed loop system is
100
001000
101
111
100100
000100
A(s)
1 + A(s)β(s)
Xo(s)
Xi(s)
=
1100
1101
00001000
00100100
Typically, phase lock loops are modeled as feedback
systems connected in a unity feedback configuration
(β(s)=1) with a phase detector, a VCO (voltage controlled
oscillator), and a loop filter in the feed-forward path, A(s).
Figure 2 illustrates a phase lock loop as a feedback control
system in block diagram form.
Table 1. 2:7 RLL Encoding Table
NRZ Data Sequence
Code Sequence
00
X01
01
10
010
X00
V
K
CO
PHASE
DETECTOR
1100
1101
010001
X00000
LOOP FILTER
F(s)
o
F
F
o
i
K
s
f
1110
1111
X00001
010000
An X in the leading bit of a code sequence is assigned the
complement of the bit
Figure 2. Phase Lock Loop Block Diagram
Table 2. 1:7 RLL Encoding Table
The closed loop transfer function is:
Sync Pattern
Read Mode
Idle Mode
Ko
Kφ
F(s)
Xo(s)
Xi(s)
s
2:7
1:7
121 mV/radian
161 mV/radian
484 mV/radian
483 mV/radian
=
Ko
1 + Kφ
F(s)
s
where:
Kφ= the phase detector gain.
Table 3. Phase Detector Gain Constants
VCO Gain Constant
The gain of the VCO is a function of the tuning capacitor.
For a value of 10 pF a nominal value of the gain, K , is
20 MHz per volt.
Ko= the VCO gain. Since the VCO introduces a
pole at the origin of the s-plane, Ko is divided
by s.
o
F(s) = the transfer function of the loop filter.
The 10E197 is designed to implement the phase detector
and VCO functions in a unity feedback loop, while allowing
the user to select the desired filter function.
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6
MC10E197
Filter Circuitry Gain Constant(s)
The open loop gain constant of the filter circuitry is given
by:
The transfer function and the element values for the loop
filter are derived by dividing the filter into three cascaded
subsections: filter input, augmenting integrator, and the
voltage divider network (Figure 4).
Kfc = K1 * Kl * Kd
eqt. 2
Loop Filter Transfer Function
The open loop transfer function of the phase lock loop is
the product of each individual filter subsection, as well as the
phase detector and VCO. Thus, the open loop filter transfer
function is:
The individual gain constants are defined in the
appropriate subsections of this document.
Loop Filter
The two major functions of the loop filter are to remove
any noise or high frequency components present in the phase
detector output signal and, more importantly, to control the
characteristics which determine the dynamic response of the
phase lock loop; i.e. capture range, loop bandwidth, capture
time, and transient response.
Ko
s
Fo(s) = Kφ *
* F1(s) * Fl(s) * Fd(s)
where:
1
1
F1(s) = K1 *
*
[s2 + (2ζωo1) s + ω2o1
]
(s + p1)
Although a variety of loop filter configurations exist, this
section will only describe a filter capable of performing the
signal processing as described in the Data Read Mode and
the Idle Mode sections. The loop filter consists of a
differential summing amplifier cascaded with an
augmenting integrator which drives the VCOIN input to the
10E197 through a resistor divider network (Figure 3).
(s + z)
[s2 + (2ζωo2 ) s + ω2
1
*
Fl(s) = Kl *
s
]
o2
1
Fd(s) = Kd *
(s + p2)
R
R
R
R
C
A
1
1
IA
A
PUMPUP
C
IN
R
V
MC34182
MC34182
V
EEVCO
R
O
C
V
O
O
R
3
R
1
D
B
PUMPDN
V
CCVCO
C
IN
R
1
V
V
EEVCO
EEVCO
V
V
EEVCO
CCVCO
Figure 3. Loop Filter Circuitry
R
R
1
1
FILTER
INPUT
F (s)
AUGMENTING
INTEGRATOR
VOLTAGE
DIVIDER
F (s)
I
PUMPUP
F (s)
i
F
=F (s)F (s)F (s)
1 i d
(s)
F (s)
I
1
O
V
V
EEVCO
EEVCO
MC34182
Figure 4. Loop Filter Block Diagram
R
1
A root locus analysis is performed on the open loop
V
01
transfer function to determine the final pole-zero locations
and the open loop gain constant for the phase lock loop. Note
that the open loop gain constant impacts the crossover
frequency and that a lower frequency crossover point means
a much more efficient filter. Once these positions and
constants are determined the component values may be
calculated.
C
IN
I
R
1
PUMPDN
V
CCVCO
V
EEVCO
V
EEVCO
Figure 5. Filter Input Subsection
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MC10E197
Filter Input
The second order pole set arises from the two pole model for
an op-amp. The open loop gain and the first open loop pole for
the op-amp are obtained from the data sheets. Typically,
op-amp manufacturers do not provide information on the
location of the second open loop pole; however, it can be
approximated by measuring the roll off of the op-amp in the
open loop configuration. The second pole is located where the
gain begins to decrease at a rate of 40 dB per decade. The
inclusion of both poles in the differential summing amplifier
transfer function becomes important when closing the
feedback path around the op-amp because the poles migrate;
and this migration must be accounted for to accurately
determine the phase lock loop transient performance.
Typically the op-amp poles can be approximated by a pole
pair occurring as a complex conjugate pair making an angle of
45° to the real axis of the complex frequency plane. Two
constraints on the selection of the op-amp pole pair are that the
poles lie beyond the crossover frequency and they are
positioned for near unity gain operation. Performing a root
locus analysis on the op-amp open loop configuration and
adhering to the two constraints yields the pole positions
contributed by the op-amp.
The primary function of the filter input subsection is to
convert the output of the phase detector into a single ended
signal for subsequent processing by the integrator circuitry. This
subsection consists of the 10E197 charge pump current sinks,
two shunt capacitors, and a differential summing amplifier
(Figure 5).
Hence, this portion of the filter circuit contributes a real pole
and two complex poles to the overall loop transfer function F(s).
Before these pole locations are selected, appropriate values for
the current setting resistors (RSETUP and RSETDN) must be
ascertained. The goal in choosing these resistor values is to
maximize the gain of the filter input subsection while ensuring
the charge pump output transistors operate in the active mode.
The filter input gain is maximized for a charge pump current of
1.1 mA; a value of 464 Ω for both RSETUP and RSETDN
yields a nominal charge pump current of 1.1 mA.
It should be noted that a dual bandwidth implementation of
the phase lock loop may be achieved by modifying the current
setting resistors such that an electronic switch enables one of two
resistor configurations. Figure 6 shows a circuit configuration
capable of providing this dual bandwidth function. Analysis of
the filter input circuitry yields the transfer function:
Determination of Element Values
1
1
F1(s) = K1 *
*
Since the difference amplifier is configured to operate as a
differential summer the resistor values associated with the
amplifier are of equal value. Further, the typical input
resistance to the summing amplifier is 1 kΩ; thus, the op-amp
resistors are set at 1 kΩ. Having set the input resistance to the
op-amp and selected the position of the real pole, the value of
the shunt capacitors is determined using the following
relationship:
[s2 + (2ζωo1) s + ω2o1
]
(s + p1)
The gain constant is defined as:
1
K1 = A1 *
CIN
eqt. 3
where:
A1= op-amp gain constant for the
selected pole positions.
1
⎥ p1⎥ =
eqt. 4
2πR1CIN
CIN = phase detector shunt capacitor.
The real pole is a function of the input resistance to the
op-amp and the shunt capacitors connected to the phase detector
output. For stability the real pole must be placed beyond the
unity gain frequency; hence, this pole is typically placed
midway between the unity crossover and phase detector
sampling frequency, which should be about ten times greater.
Augmenting Integrator
The augmenting integrator consists of an active filter with a
lag-lead network in the feedback path (Figure 7).
C
A
R
R
A
IA
V
IN
RSETDN
RSETUP
464Ω
464Ω
464Ω
464Ω
MC34182
V
O2
V
EEVCO
R
IA
V
CCVCO
ELECTRONIC SWITCH
Figure 7. Integrator Subsection
V
EEVCO
Figure 6. Dual Bandwidth Current
Source Implementation
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MC10E197
Analysis of this portion of the filter circuit yields the transfer
Voltage Divider
function:
The input range to the VCOIN input is from 1.3 V + V to
EE
(s + z)
2.6 V + V ; hence, the output from the augmenting amplifier
1
s
EE
F1(s) = Kl *
*
[s2 + (2ζω ) s + ω2
]
o2
section must be attenuated to meet the VCOIN constraints. A
simple voltage divider network provides the necessary
attenuation (Figure 8).
o2
The gain constant is defined as:
RA
R
V
Kl = Al *
eqt. 5
V
IN
RlA
where:
R
D
O
B
Al = op-amp gain constant for selected pole positions.
RA = integrator feedback resistor.
C
V
O
d
RlA = integrator input resistor.
The integrator circuit introduces a zero, a pole at the origin,
and a second order pole set as described by the two pole model
for an op-amp. As in the case of the differential summing
amplifier, we assume the op-amp pole pair occur as a complex
conjugate pair making an angle of 45° to the real axis of the
complex frequency plane; are positioned for near unity gain
operation; and are located beyond the crossover frequency.
Since both the summing and integrating op-amps are realized
by the same type of op-amp (MC34182D), the open loop pole
positions for both amplifiers will be the same.
Figure 8. Voltage Divider Subsection
In addition, a shunt filter capacitor connected between the
VCOIN input pin and V provides the voltage divider
EE
subsection with a single time constant transfer function that adds
a pole to the overall loop filter. The transfer function for the
voltage divider network is:
1
Fd(s) = Kd *
(s + p2)
Further, the loop transfer function contains two poles located
at the origin, one introduced by the integrator and the other by
the VCO; hence a zero is necessary to compensate for the phase
shift produced by these poles and ensure loop stability. The
op-amp will be stable if the crossover point occurs before the
transfer function phase angle becomes 180°. The zero should
be positioned much less than one decade before the unity gain
frequency.
As in the case of the filter input circuitry, the poles and zero
from this analysis will be used as open loop poles and a zero
when performing the root locus analysis for the complete
system.
The gain constant, Kd, is defined as:
1
eqt. 9
Kd =
Rv Cd
he value of K is easily extracted by rearranging Equation 1:
d
Kol
Kd =
eqt. 10
Kφ * Ko * K1 * Kl
The gain constant K is set such that the output from the
d
integrator circuit is within the range 1.3 V +V to 2.6 V +V .
EE
EE
The pole for the voltage divider network should be positioned
an octave beyond that for the filter input.
Determination of Element Values
The location of the zero is used to determine the element
values for the augmenting integrator. The value of the
Determination of Element Values
capacitor, C , is selected to provide adequate charge storage
A
when the loop is not sampling data. A value of 0.1 μF is
sufficient for most applications; this value may be increased
when the RDCLK frequency is much lower than 4 MHz. The
Once the pole location and the gain constant K are established
d
the resistor values for the voltage divider network are
determined using the design guidelines mentioned above and
from the following relationship:
value of R is governed by:
A
1
⎥ z⎥ =
eqt. 6
2πRACA
Ro
Kd
2π⎥ p2⎥
=
Ro + Rv
For unity gain operation of the integrating op-amp the value of
RlA is selected such that:
Having determined the resistor values, the filter capacitor is
calculated by rearranging Equation 9:
RlA = RA
eqt. 7
1
It should be noted that although the zero can be tuned by
varying either R or C , caution must be exercised when
eqt. 9a
Cd =
Rv Kd
A
A
adjusting the zero by varying C because the integrator gain is
A
Finally, a bias diode is included in the voltage divider network
to provide temperature compensation. The finite resistance of
this diode is neglected for these calculations.
also a function of C . Further, the gain of the loop filter can be
A
adjusted by changing the integrator input resistor R .
lA
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MC10E197
Calculations For a 2:7 Coding Scheme
Introduction
The voltage divider pole is set approximately one octave
higher than the filter input pole. Thus the open loop voltage
divider pole position is picked to be:
The circuit component values are calculated for a 2:7
coding scheme employing a data rate of 23 Mbit/sec. Since
the number of bits is doubled when the data is encoded, the
data clock is at half the frequency of the RDCLK signal.
Thus, the operating frequency for these calculations is
46 MHz. Further, the pole and zero positions are a function
of the data rate; hence, the component values derived by
these calculations must be scaled if a different operating
frequency is used. Finally, it should be noted that the values
are optimized for settling time.
P*2 = − 2.57MHz
Dynamic Zero
Finally, the zero is positioned much less than one decade
before the crossover frequency; for this design the zero is
placed at:
z = − 311Hz
The analysis is divided into three parts: static pole
positioning, dynamic pole positioning, and dynamic zero
positioning. Dynamic poles and zeros are those which the
designer may position, to yield the desired dynamic
response, through the judicious choice of element values.
Static poles are not directly controlled by the choice of
component values.
Once the dynamic pole and zero positions have been
determined, the phase margin is determined using a Bode
plot; if the phase margin is not sufficient, the dynamic poles
may be moved to improve the phase margin. Finally, a root
locus analysis is performed to obtain the optimum closed
loop pole positions for the dynamic characteristics of
interest.
Static Poles
Component Values
Each op-amp introduces a pair of “static” complex
conjugate poles which must lie beyond the crossover
frequency. As obtained from the data sheets and laboratory
measurements, the two open loop poles for the MC34182D
are:
Having determined the closed loop pole and zero
positions the component values are calculated. From the root
locus analysis the dynamic pole and zero positions are:
P1 = − 573kHz
P2 = − 3.06MHz
z = − 311Hz
P*1a = − 0.1Hz
P*1b = −11.2Hz
Performing a root locus analysis and following the two
guidelines previously stated, an acceptable pole set is:
Filter Input Subsection
Rearranging Equation 4:
P1a = − 5.65 + j5.65MHz
P1b = − 5.65 − j5.65MHz
1
CIN
=
2π R1⎥ p1⎥
Both op-amps introduce a set of static complex conjugate
poles at these positions for a total of four poles. Further, the
loop gain for each op-amp associated with these pole
positions is determined from the root locus analysis to be:
and substituting 573 kHz for the pole position and 1 kΩ for
the resistor value yields:
CIN = 278 pF
V
A1 = A2 = 2.48 e15
V
Augmenting Integrator Subsection
Rearranging Equation 6:
In addition to the op-amps, the integrator and the VCO each
contribute a static pole at the origin. Thus, there are a total
of six static poles.
1
RA =
2π ⎥ z⎥ CA
Dynamic Poles
and substituting 311 Hz for the zero position and 0.1 μF for
the capacitor value yields:
The filter input and the voltage divider sections each
contribute a dynamic pole. As stated previously, the filter
input pole should be positioned midway between the unity
crossover point and the phase detector sampling frequency.
Hence, the open loop filter input pole position is selected as:
RA = 5.11kΩ
From Equation 7 the value for the other resistors associated
with the integrator op-amp are set equal to R :
A
RlA = RA = 5.11kΩ
P*1 = −1.24MHz
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MC10E197
Voltage Divider Subsection
the capacitor value, C is:
d
The element values for the voltage divider network are
calculated using the relationships presented in Equations 8,
9, and 10 with the constraint that this divider network must
Cd = 98pF
Note that the voltage divider section can be used to set the
gain, but the designer is cautioned to be sure the input value
to VCOIN is within the correct range.
produce a voltage that lies within the range 1.3 V + V to
EE
2.6 V + V
.
EE
Restating Equation 9,
Component Scaling
Kol
As mentioned, these design equations were developed for
a data rate of 23 Mbit/sec. If the data rate is different from
the nominal design value the reactive elements must be
scaled accordingly. The following equations are provided to
facilitate scaling and were derived with the assumptions that
a 2:7 coding scheme is used and that the RDCLK signal is
twice the frequency of the data clock.
Kd =
Kφ * Ko * K1 * Kl
From the root locus analysis K is determined to be:
ol
V
Kol = 1.585 e51
mA sec3
46
f
From Equation 3
eqt. 11
CIN = 278 *
(pF)
(pF)
1
K1 = A1 *
CIN
46
Cd = 98 *
eqt. 12
f
and the gain constant K is:
1
where f is the RDCLK frequency in MHz.
V
K1 = 8.90 e21
Example for an 11 Mbit/sec Data Rate
mA sec
As an example of scaling, assume the given filter and a 2:7
code are used but the data rate is 11 Mbit/sec. The dynamic
pole positions, and therefore the bandwidth of the loop filter,
are a function of the data rate. Thus a slower data rate will
force the dynamic poles and the bandwidth to move to a
From Equation 5
RA
RlA
Kl = Al *
lower frequency. From Equation 11 the value of C is:
IN
CIN = 581pF
and the gain constant K is:
l
and from Equation 12 the value of C is:
d
V
V
Kl = 2.48 e15
Cd = 205pF
Thus the element values for the filter are:
Filter Input Subsection:
Having determined the gain constant K , the value of R , is
d
v
selected such that the constraints R > R and:
v
o
CIN = 581pF
Kd
Ro
=
R1 = 1kΩ
2π⎥ p2⎥
Ro + Rv
Integrator Subsection:
CA = 0.1μF
are fulfilled. The pole position P is determined from the
root locus analysis to be:
2
RA = 5.11kΩ
P2 = − 3.06MHz
RlA = 5.11kΩ
Hence, R is selected to be:
v
Voltage Divider Subsection:
Cd = 205pF
Rv = 2.15kΩ
and R is calculated to be:
o
Rv = 2.15kΩ
Ro = 700Ω
Ro = 700kΩ
Finally, using Equation 8a:
Note, the poles P and P are now located at:
1
2
1
Cd =
P1 = − 274kHz
eqt. 8a
Rv Kd
P2 = −1.47MHz
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MC10E197
And, the open loop filter unity crossover point is at
300 kHz. The gain can be adjusted by changing the value of
and the value of C . Varying the gain by changing C is
not recommended because this will also move the poles,
hence affect the dynamic 2 performance of the filter.
R
lA
d
d
Calculations For a 1:7 Coding Scheme
Introduction
Once the dynamic pole and zero positions have been
determined, the phase margin is determined using a Bode
plot; if the phase margin is not sufficient, the dynamic poles
may be moved to improve the phase margin. Finally, a root
locus analysis is performed to obtain the optimum closed
loop pole positions for the dynamic characteristics of
interest.
The circuit component values are calculated for a 1:7
coding scheme employing a data rate of 20 Mbit/sec. Since
the number of bits increases from two to three when the data
is encoded, the data clock is at two-thirds the frequency of
the RDCLK signal. Thus, the operating frequency for these
calculations is 30 MHz. As in the case of the 2:7 coding
scheme the pole and zero positions are a function of the data
rate, hence the component values derived by these
calculations must be scaled if a different operating
frequency is used.
Component Values
Having determined the closed loop pole and zero
positions the component values are calculated. From the root
locus analysis the dynamic pole and zero positions are:
Again, the analysis is divided into three parts: static pole
positioning, dynamic pole positioning, and dynamic zero
positioning.
P1 = − 541kHz
P2 = − 2.73MHz
z = − 311Hz
Static Poles
As in the 2:7 coding example, an MC34182D op-amp is
employed, hence the pole set is:
Filter Input Subsection
Rearranging Equation 4
P1a = − 5.65 + j5.65MHz
P1b = − 5.65 − j5.65MHz
1
CIN
=
2π R ⎥ p
⎥
1
1
and the open loop gain is:
and substituting 541 kHz for the pole position and 1.0 kΩ for
the resistor value yields:
V
Al = A2 = 2.48 e15
V
CIN = 294 pF
Since the op-amps introduce a set of complex conjugate
poles, a total of four poles are introduced by the op-amp. In
addition, the integrator and the VCO each contribute a pole
at the origin for a total of six static poles.
Augmenting Integrator Subsection
Rearranging Equation 6
1
RA =
2π ⎥ z⎥ CA
Dynamic Poles
The filter input and the voltage divider sections each
contribute a dynamic pole. As stated previously, the filter
input pole should be positioned midway between the unity
crossover point and the phase detector sampling frequency.
Hence, the open loop filter input pole position is selected as:
and substituting 311 Hz for the zero position and 0.1 μF for
the capacitor value yields:
RA = 5.11kΩ
From Equation 7 the value for the other resistors associated
with the integrator op-amp are set equal to R :
P*1 = −1.1MHz
A
RlA = RA = 5.11kΩ
The voltage divider pole is set approximately one octave
higher than the filter input pole. Thus, the open loop voltage
divider pole position is selected as:
Voltage Divider Subsection
The element values for the voltage divider network are
calculated using the relationships presented in Equations 8,
9, and 10 with the constraint that this divider network must
P*2 = − 2.28MHz
Dynamic Zero
produce a voltage that lies within the range 1.3 V + V to
EE
Finally, the zero is positioned much less than one decade
before the crossover frequency; for this design the zero is
placed at:
2.6 V + V
.
EE
Restating Equation 9,
z = − 311Hz
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MC10E197
Component Scaling
Kol
As mentioned, these design equations were developed for
a data rate of 20 Mbit/sec. If the data rate is different from
the nominal design value the reactive elements must be
scaled accordingly. The following equations provided are to
facilitate scaling and were derived with the assumptions that
a 1:7 coding scheme is used and that the RDCLK signal is
twice the frequency of the data clock:
Kd =
Kφ * Ko * K1 * Kl
From the root locus analysis K is determined to be:
ol
V
MA SEC
Kol = 1.258 e51
3
From Equation 3:
30
1
K1 = A1 *
CIN
CIN = 294 *
Cd = 156 *
(pF)
(pF)
eqt. 13
eqt. 14
f
30
f
and the gain constant K :
1
V
K1 = 8.42 e21
mA sec
where f is the RDCLK frequency in MHz.
Example for an 10 Mbit/sec Data Rate
From Equation 5:
As an example of scaling, assume the given filter and a 1:7
code are used but the data rate is 10 Mbit/sec. The dynamic
pole positions and, therefore, the bandwidth of the loop
filter, are a function of the data rate. Thus, a slower data rate
will force the dynamic poles and the bandwidth to move to
RA
Kl = Al *
RlA
and the gain constant K is:
a lower frequency. From Equation 13 the value of C is:
l
IN
CIN = 588pF
V
Kl = 2.48 e15
V
and from Equation 14 the value of C is:
d
Kd = 2.98 e6 sec −1
Cd = 312pF
Thus, the element values for the filter are:
Filter Input Subsection:
Having determined the gain constant K , the value of R , is
d
v
selected such that the constraints R > R and:
v
o
CIN = 588pF
Kd
2π⎥p2⎥
Ro
Ro + Rv
=
R1 = 1.0kΩ
Integrator Subsection:
CA = 0.1μF
are fulfilled. The pole position P is determined from the
root locus analysis to be:
2
P2 = − 2.73MHz
RA = 5.11kΩ
Hence, R is selected to be:
RlA = 5.11kΩ
v
Rv = 2.15kΩ
Voltage Divider Subsection:
Cd = 312pF
and R is calculated to be:
o
Ro = 453Ω
Rv = 2.15kΩ
Ro = 453kΩ
Finally, using Equation 8a:
Note, the poles P and P are now located at:
1
2
1
Cd =
eqt. 8a
Rv Kd
P1 = − 271kHz
P2 = −1.36MHz
the capacitor value, C is calculated to be:
d
And, the open loop filter unity crossover point is at
300 kHz. As in the case of the 2:7 coding scheme, the gain
Cd = 156pF
can be adjusted by changing the value of R and the value
lA
Again, note the voltage divider section can be used to set the
gain, but the designer is cautioned to be sure the input value
to VCOIN is within the correct range.
of C . Varying the gain by changing C is not recommended
d
d
because this will also move the poles, hence affect the
dynamic performance of the filter.
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MC10E197
Q
Q
D
D
Receiver
Device
Driver
Device
50
V
50
W
W
V
TT
= V − 2.0 V
TT
CC
Figure 9. Typical Termination for Output Driver and Device Evaluation
(See Application Note AND8020 − Termination of ECL Logic Devices.)
Resource Reference of Application Notes
AN1404
AN1405
AN1406
AN1503
AN1504
AN1568
AN1596
AN1650
AN1672
AND8001
AND8002
AND8020
ECLinPS Circuit Performance at Non−Standard VIH Levels
ECL Clock Distribution Techniques
Designing with PECL (ECL at +5.0 V)
ECLinPS I/O SPICE Modeling Kit
−
−
−
−
−
−
−
−
−
−
−
−
Metastability and the ECLinPS Family
Interfacing Between LVDS and ECL
ECLinPS Lite Translator ELT Family SPICE I/O Model Kit
Using Wire−OR Ties in ECLinPS Designs
The ECL Translator Guide
Odd Number Counters Design
Marking and Date Codes
Termination of ECL Logic Devices
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MC10E197
PACKAGE DIMENSIONS
PLCC−28
FN SUFFIX
PLASTIC PLCC PACKAGE
CASE 776−02
ISSUE E
0.007 (0.180)
M
S
S
N
T L −M
B
Y BRK
D
0.007 (0.180)
-N-
M
S
S
N
T L −M
U
Z
-L-
-M-
D
W
0.010 (0.250)
X
G1
S
S
S
N
T L −M
V
28
1
VIEW D-D
0.007 (0.180)
0.007 (0.180)
A
M
M
S
S
S
T L −M
T L −M
N
0.007 (0.180)
H
M
S
S
N
T L −M
Z
R
S
N
K1
C
E
0.004 (0.100)
G
K
SEATING
PLANE
-T-
J
0.007 (0.180)
M
S
S
N
T L −M
F
VIEW S
G1
VIEW S
0.010 (0.250)
S
S
S
T L −M
N
NOTES:
1. DATUMS -L-, -M-, AND -N- DETERMINED
WHERE TOP OF LEAD SHOULDER EXITS
PLASTIC BODY AT MOLD PARTING LINE.
2. DIM G1, TRUE POSITION TO BE MEASURED
AT DATUM -T-, SEATING PLANE.
3. DIM R AND U DO NOT INCLUDE MOLD FLASH.
ALLOWABLE MOLD FLASH IS 0.010 (0.250)
PER SIDE.
INCHES
MILLIMETERS
MIN MAX
DIM
MIN
MAX
A
B
C
E
0.485 0.495 12.32 12.57
0.485 0.495 12.32 12.57
4. DIMENSIONING AND TOLERANCING PER ANSI
Y14.5M, 1982.
0.165 0.180
0.090 0.110
0.013 0.019
0.050 BSC
4.20
2.29
0.33
4.57
2.79
0.48
5. CONTROLLING DIMENSION: INCH.
6. THE PACKAGE TOP MAY BE SMALLER THAN
THE PACKAGE BOTTOM BY UP TO 0.012
(0.300). DIMENSIONS R AND U ARE
DETERMINED AT THE OUTERMOST
EXTREMES OF THE PLASTIC BODY
EXCLUSIVE OF MOLD FLASH, TIE BAR
BURRS, GATE BURRS AND INTERLEAD
FLASH, BUT INCLUDING ANY MISMATCH
BETWEEN THE TOP AND BOTTOM OF THE
PLASTIC BODY.
7. DIMENSION H DOES NOT INCLUDE DAMBAR
PROTRUSION OR INTRUSION. THE DAMBAR
PROTRUSION(S) SHALL NOT CAUSE THE H
DIMENSION TO BE GREATER THAN 0.037
(0.940). THE DAMBAR INTRUSION(S) SHALL
NOT CAUSE THE H DIMENSION TO BE
SMALLER THAN 0.025 (0.635).
F
G
H
J
1.27 BSC
0.026 0.032
0.66
0.51
0.64
0.81
ꢀ
0.020
0.025
ꢀ
ꢀ
K
R
U
V
ꢀ
0.450 0.456 11.43
0.450 0.456 11.43
11.58
11.58
1.21
1.21
1.42
0.50
10°
0.042 0.048
0.042 0.048
0.042 0.056
1.07
1.07
1.07
ꢀ
W
X
Y
ꢀ
0.020
10°
Z
2°
2°
G1
K1
0.410 0.430 10.42 10.92
0.040 ꢀꢁ 1.02 ꢀꢁ
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MC10E197
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