AD ADCMP563 Dual, high speed ecl comparator Datasheet

Dual, High Speed ECL Comparators
ADCMP563/ADCMP564
FUNCTIONAL BLOCK DIAGRAM
FEATURES
HYS*
NONINVERTING
INPUT
INVERTING
INPUT
The ADCMP563/ADCMP564 are high speed comparators
fabricated on Analog Devices’ proprietary XFCB process. The
devices feature a 700 ps propagation delay with less than 75 ps
overdrive dispersion. Dispersion, a measure of the difference in
propagation delay under differing overdrive conditions, is a
particularly important characteristic of high speed comparators.
A separate programmable hysteresis pin is available on the
ADCMP564.
A differential input stage permits consistent propagation delay
with a wide variety of signals in the common-mode range from
−2.0 V to +3.0 V. Outputs are complementary digital signals
04650-0-001
*ADCMP564 ONLY
QA 1
16
15
GND 3
LEA 4
LEA 5
VEE 6
–INA 7
+INA 8
14
ADCMP563
BRQ
TOP VIEW
(Not to Scale)
13
12
11
10
9
GND 1
20
GND
QA 2
19
QB
QA 3
18
QB
17
GND
16
LEB
15
LEB
VEE 7
14
VCC
–INA 8
13
–INB
+INA 9
12
+INB
HYSA 10
11
HYSB
QB
QB
GND 4
GND
LEA 5
LEB
VCC
–INB
+INB
Figure 2. ADCMP563 16-Lead QSOP
Figure 3. ADCMP564 20-Lead QSOP
QA
QA
QB
QB
16
15
14
13
PIN1
ADCMP563
BCP
LEA 2
LEA 3
TOP VIEW
(Not to Scale)
5
TOP VIEW
(Not to Scale)
LEA 6
LEB
GND 1
ADCMP564
BRQ
6
7
12
GND
11
LEB
10
LEB
9
VCC
8
–INA +INA +INB –INB
Figure 4. ADCMP563 16-Lead LFCSP
that are fully compatible with ECL 10 K and 10 KH logic
families. The outputs provide sufficient drive current to directly
drive transmission lines terminated in 50 Ω to −2 V. A latch
input, which is included, permits tracking, track-and-hold, or
sample-and-hold modes of operation. The latch input pins
contain internal pull-ups that set the latch in tracking mode
when left open.
The ADCMP563/ADCMP564 are specified over the industrial
temperature range (−40°C to +85°C).
Rev. B
Information furnished by Analog Devices is believed to be accurate and reliable.
However, no responsibility is assumed by Analog Devices for its use, nor for any
infringements of patents or other rights of third parties that may result from its use.
Specifications subject to change without notice. No license is granted by implication
or otherwise under any patent or patent rights of Analog Devices. Trademarks and
registered trademarks are the property of their respective owners.
04650-0-012
Figure 1.
VEE 4
GENERAL DESCRIPTION
LATCH ENABLE
INPUT
111151-0-026
Automatic test equipment
High speed instrumentation
Scope and logic analyzer front ends
Window comparators
High speed line receivers
Threshold detection
Peak detection
High speed triggers
Patient diagnostics
Hand-held test instruments
Zero crossing detectors
Line receivers and signal restoration
Clock drivers
Q OUTPUT
LATCH ENABLE
INPUT
QA 2
APPLICATIONS
Q OUTPUT
ADCMP563/
ADCMP564
04650-0-002
Differential ECL-compatible outputs
700 ps propagation delay input to output
75 ps propagation delay dispersion
Input common-mode range: –2.0 V to +3.0 V
Robust input protection
Differential latch control
Internal latch pull-up resistors
Power supply rejection greater than 85 dB
700 ps minimum pulse width
1.5 GHz equivalent input rise time bandwidth
Typical output rise/fall time of 500 ps
ESD protection > 4kV HBM, >200V MM
Programmable hysteresis
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
www.analog.com
Fax: 781.461.3113
©2005 Analog Devices, Inc. All rights reserved.
ADCMP563/ADCMP564
TABLE OF CONTENTS
Specifications..................................................................................... 3
Clock Timing Recovery............................................................. 11
Absolute Maximum Ratings............................................................ 5
Optimizing High Speed Performance ..................................... 11
Thermal Considerations.............................................................. 5
Comparator Propagation Delay Dispersion ........................... 11
ESD Caution.................................................................................. 5
Comparator Hysteresis .............................................................. 12
Pin Configurations and Function Descriptions ........................... 6
Minimum Input Slew Rate Requirement ................................ 12
Typical Performance Characteristics ............................................. 8
Typical Application Circuits ......................................................... 13
Timing Information ....................................................................... 10
Outline Dimensions ....................................................................... 14
Application Information................................................................ 11
Ordering Guide .......................................................................... 14
REVISION HISTORY
5/05—Rev. A to Rev. B
Added 16-Lead LFCSP.......................................................Universal
Changes to Applications .................................................................. 1
Changes to Table 1............................................................................ 3
Changes to Optimizing High Speed Performance Section....... 11
Changes to Comparator Hysteresis Section................................ 12
Changes to Minimum Input Slew Rate Requirement Section.. 12
Changes to Ordering Guide .......................................................... 14
7/04—Rev. 0 to Rev. A
Changes to Specification Table ....................................................... 4
Changes to Figure 14........................................................................ 9
Changes to Figure 21...................................................................... 12
Changes to Figure 23...................................................................... 13
4/04—Revision 0: Initial Version
Rev. B | Page 2 of 16
ADCMP563/ADCMP564
SPECIFICATIONS
VCC = +5.0 V, VEE = −5.2 V, TA = −40°C to +85°C. Typical values are at TA = +25°C, unless otherwise noted.
Table 1. Electrical Characteristics
Parameter
DC INPUT CHARACTERISTICS
Input Voltage Range
Input Differential Voltage
Input Offset Voltage
Input Offset Voltage Channel Matching
Offset Voltage Temperature Coefficient
Input Bias Current
Input Bias Current Temperature Coefficient
Input Offset Current
Input Capacitance
Input Resistance, Differential Mode
Input Resistance, Common Mode
Active Gain
Common-Mode Rejection Ratio
Hysteresis
LATCH ENABLE CHARACTERISTICS
Latch Enable Voltage Range
Latch Enable Differential Input Voltage
Latch Enable Input High Current
Latch Enable Input Low Current
LE Voltage, Open
LE Voltage, Open
Latch Setup Time
Latch Hold Time
Latch to Output Delay
Latch Minimum Pulse Width
DC OUTPUT CHARACTERISTICS
Output Voltage—High Level
Output Voltage—Low Level
Rise Time
Fall Time
AC PERFORMANCE
Propagation Delay
Propagation Delay Temperature Coefficient
Prop Delay Skew—Rising Transition to Falling
Transition
Within Device Propagation Delay Skew—
Channel-to-Channel
Overdrive Dispersion
Slew Rate Dispersion
Pulse Width Dispersion
Duty Cycle Dispersion
Common-Mode Voltage Dispersion
Symbol
Conditions
Min
VOS
VCM = 0 V
−2.0
−5
−10.0
∆VOS/dT
IBC
@ −IN = −2 V, +IN = +3 V
−10.0
CIN
AV
CMRR
tS
tH
tPLOH,
tPLOL
tPL
VCM = −2.0 V to +3.0 V
RHYS = ∞
@ 0.0 V
@ −2.0 V
Latch inputs not connected
Latch inputs not connected
VOD = 250 mV
VOD = 250 mV
VOD = 250 mV
VOD = 250 mV
VOH
VOL
tR
tF
ECL 50 Ω to −2.0 V
ECL 50 Ω to −2.0 V
10% to 90%
10% to 90%
tPD
∆tPD /dT
−2.0
0.4
−300
−300
−0.2
−2.8
Typ
±2.0
±2.0
2.0
±3
0.5
±1.0
0.75
750
1800
63
80
±1.0
0
−2.6
200
200
500
Max
Unit
3.0
+5
+10.0
V
V
mV
mV
μV/°C
μA
nA/°C
μA
pF
kΩ
kΩ
dB
dB
mV
+10.0
0
2.0
+300
+300
+0.1
−2.4
500
ps
530
450
V
V
ps
ps
VOD = 1 V
VOD = 20 mV
VOD = 1 V
VOD = 1 V
700
830
0.25
50
ps
ps
ps/°C
ps
VOD = 1 V
50
ps
20 mV ≤ VOD ≤ 100 mV
100 mV ≤ VOD ≤ 1.5 V
0.4 V/ns ≤ SR ≤ 1.33 V/ns
750ps ≤ PW ≤ 10ns
33 MHz, 1 V/ns, 0.5 V
1 V swing, −1.5 V ≤ VCM ≤ +2.5 V
75
75
50
25
10
10
ps
ps
ps
ps
ps
ps
Rev. B | Page 3 of 16
−1.15
−1.95
V
V
μA
μA
V
V
ps
ps
ps
−0.81
−1.54
ADCMP563/ADCMP564
Parameter
AC PERFORMANCE (Continued)
Equivalent Input Rise Time Bandwidth 1
Maximum Toggle Rate
Minimum Pulse Width
RMS Random Jitter
Unit to Unit Propagation Delay Skew
POWER SUPPLY
Positive Supply Current
Negative Supply Current
Positive Supply Voltage
Negative Supply Voltage
Power Dissipation
DC Power Supply Rejection Ratio—VCC
DC Power Supply Rejection Ratio—VEE
HYSTERESIS (ADCMP564 Only)
Hysteresis
Hysteresis Pin Bias Voltage
Hysteresis Pin Series Resistance
1
Symbol
Conditions
BWEQ
0 V to 1 V swing, 2 V/ns
>50% output swing, 50% duty cycle
ΔtPD < 25 ps
VOD = 400 mV, 1.3 V/ns, 312 MHz,
50% duty cycle
PWMIN
IVCC
IVEE
VCC
VEE
PD
@ +5.0 V
@ −5.2 V
Dual
Dual
Dual, without load
Dual, with load
Min
2
10
4.75
−4.96
90
150
Typ
RHYS = 23.5 kΩ
RHYS = 9.0 kΩ
Referred to AGND
Unit
1500
800
700
1.0
MHz
MHz
ps
ps
100
ps
3.2
19
5.0
−5.2
120
180
85
85
PSRRVCC
PSRRVEE
Max
20
70
−1
3
5
25
5.25
−5.45
150
230
mA
mA
V
V
mW
mW
dB
dB
mV
mV
V
kΩ
Equivalent input rise time bandwidth assumes a first-order input response and is calculated by the following formula: BWEQ = 0.22/√(trCOMP2 – trIN2), where trIN is the
20/80 input transition time applied to the comparator and trCOMP is the effective transition time, as digitized by the comparator input.
P
Rev. B | Page 4 of 16
ADCMP563/ADCMP564
ABSOLUTE MAXIMUM RATINGS
Table 2.
Parameter
Supply Voltages
Positive Supply Voltage (VCC to GND)
Negative Supply Voltage (VEE to GND)
Ground Voltage Differential
Input Voltages
Input Common-Mode Voltage
Differential Input Voltage
Input Voltage, Latch Controls
Output
Output Current
Temperature
Operating Temperature, Ambient
Operating Temperature, Junction
Storage Temperature Range
Rating
Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only; 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 device reliability.
−0.5 V to +6.0 V
−6.0 V to +0.5 V
−0.5 V to +0.5 V
−3.0 V to +4.0 V
−7.0 V to +7.0 V
VEE to +0.5 V
THERMAL CONSIDERATIONS
The ADCMP563 QSOP 16-lead package option has a θJA
(junction-to-ambient thermal resistance) of 104°C/W in
still air.
30 mA
−40°C to +85°C
125°C
−65°C to +150°C
The ADCMP563 LFCSP 16-lead package option has a θJA
(junction-to-ambient thermal resistance) of 70°C/W in
still air.
The ADCMP564 QSOP 20-lead package option has a θJA
(junction-to-ambient thermal resistance) of 80°C/W in
still air.
ESD CAUTION
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on
the human body and test equipment and can discharge without detection. Although this product features
proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy
electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance
degradation or loss of functionality.
Rev. B | Page 5 of 16
ADCMP563/ADCMP564
16
QB
GND 1
20
GND
19
QB
18
QB
17
GND
15
QB
GND 3
14
GND
QA 3
13
LEB
GND 4
12
LEB
LEA 5
11
VCC
LEA 6
LEA 4
LEA 5
ADCMP563
BRQ
TOP VIEW
(Not to Scale)
VEE 6
–INA 7
10
–INB
+INA 8
9
+INB
04650-0-002
QA 2
QA 2
ADCMP564
BRQ
16
LEB
15
LEB
VEE 7
14
VCC
–INA 8
13
–INB
+INA 9
12
+INB
HYSA 10
11
HYSB
TOP VIEW
(Not to Scale)
Figure 6. ADCMP564 20-Lead QSOP
Pin Configuration
Figure 5. ADCMP563 16-Lead QSOP
Pin Configuration
QA
QA
QB
QB
16
15
14
13
PIN1
GND 1
ADCMP563
BCP
LEA 2
LEA 3
TOP VIEW
(Not to Scale)
VEE 4
5
6
7
12
GND
11
LEB
10
LEB
9
VCC
8
–INA +INA +INB –INB
04650-0-012
QA 1
111151-0-026
PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS
Figure 7. ADCMP563 16-Lead LFCSP
Pin Configuration
Table 3. Pin Function Descriptions
ADCMP563
16-Lead
QSOP
Pin No.
ADCMP563
16-Lead
LFCSP
1
15
ADCMP564
20-Lead
QSOP
1
2
Mnemonic
GND
QA
2
16
3
QA
3
4
1
2
4
5
GND
LEA
5
3
6
LEA
6
7
4
5
7
8
VEE
−INA
8
6
9
+INA
9
7
10
11
12
HYSA
HYSB
+INB
10
8
13
−INB
11
9
14
VCC
Function
Analog Ground.
One of Two Complementary Outputs for Channel A. QA is logic high if the
analog voltage at the noninverting input is greater than the analog voltage
at the inverting input (provided the comparator is in compare mode). See
the description of the LEA pin for more information.
One of Two Complementary Outputs for Channel A. QA is logic low if the
analog voltage at the noninverting input is greater than the analog voltage
at the inverting input (provided the comparator is in compare mode). See
the description of the LEA pin for more information.
Analog Ground.
One of Two Complementary Inputs for Channel A Latch Enable. In compare
mode (logic high), the output tracks change at the input of the comparator.
In latch mode (logic low), the output reflects the input state just prior to the
comparator being placed in the latch mode. LEA must be driven in
conjunction with LEA. If left unconnected, the comparator defaults to
compare mode.
One of Two Complementary Inputs for Channel A Latch Enable. In compare
mode (logic low), the output tracks change at the input of the comparator.
In latch mode (logic high), the output reflects the input state just prior to the
comparator being placed in the latch mode. LEA must be driven in
conjunction with LEA. If left unconnected, the comparator defaults to
compare mode.
Negative Supply Terminal.
Inverting Analog Input of the Differential Input Stage for Channel A. The
Inverting A input must be driven in conjunction with the Noninverting A input.
Noninverting Analog Input of the Differential Input Stage for Channel A. The
Noninverting A input must be driven in conjunction with the Inverting A input.
Programmable Hysteresis Input.
Programmable Hysteresis Input.
Noninverting Analog Input of the Differential Input Stage for Channel B. The
Noninverting B input must be driven in conjunction with the Inverting B input.
Inverting Analog Input of the Differential Input Stage for Channel B. The
Inverting B input must be driven in conjunction with the Noninverting B input.
Positive Supply Terminal.
Rev. B | Page 6 of 16
ADCMP563/ADCMP564
ADCMP563
16-Lead
QSOP
12
Pin No.
ADCMP563
16-Lead
LFCSP
10
ADCMP564
20-Lead
QSOP
15
Mnemonic
LEB
13
11
16
LEB
14
15
12
13
17
18
GND
QB
16
14
19
QB
20
GND
Function
One of Two Complementary Inputs for Channel B Latch Enable. In compare
mode (logic low), the output tracks change at the input of the comparator.
In latch mode (logic high), the output reflects the input state just prior to the
comparator being placed in the latch mode. LEB must be driven in conjunction
with LEB. If left unconnected, the comparator defaults to compare mode.
One of Two Complementary Inputs for Channel B Latch Enable. In compare
mode (logic high), the output tracks change at the input of the comparator.
In latch mode (logic low), the output reflects the input state just prior to the
comparator being placed in the latch mode. LEB must be driven in conjunction
with LEB. If left unconnected, the comparator defaults to compare mode.
Analog Ground.
One of Two Complementary Outputs for Channel B. QB is logic low if the
analog voltage at the noninverting input is greater than the analog voltage
at the inverting input (provided the comparator is in compare mode). See
the description of the LEB pin for more information.
One of Two Complementary Outputs for Channel B. QB is logic high if the
analog voltage at the noninverting input is greater than the analog voltage
at the inverting input (provided the comparator is in compare mode). See the
description of the LEB pin for more information.
Analog Ground.
Rev. B | Page 7 of 16
ADCMP563/ADCMP564
TYPICAL PERFORMANCE CHARACTERISTICS
VCC = 3.3 V, TA = 25°C, unless otherwise noted.
3.0
2.80
2.78
1.5
1.0
0.5
0
–0.5
–1.0
–2.5
–1.5
–0.5
0.5
1.5
2.5
2.76
2.74
2.72
2.70
2.68
2.66
2.64
04650-0-016
+IN INPUT BIAS CURRENT (μA)
(+IN = 3V, –IN = 0V)
2.0
04650-0-013
INPUT BIAS CURRENT (μA)
2.5
2.62
2.60
–40
3.5
–20
0
NONINVERTING INPUT VOLTAGE (INVERTING VOLTAGE = 0V)
20
40
60
80
TEMPERATURE (°C)
Figure 8. Input Bias Current vs. Input Voltage
Figure 11. Input Bias Current vs. Temperature
2.00
–0.8
1.95
–1.0
OUTPUT RISE AND FALL (V)
1.85
1.80
1.75
1.70
1.65
1.60
1.50
–40
–20
0
20
40
60
–1.4
–1.6
–1.8
04650-0-014
1.55
–1.2
04650-0-017
OFFSET VOLTAGE (mV)
1.90
–2.0
0
80
0.25
0.50
0.75
TEMPERATURE (°C)
475
545
470
540
465
535
460
530
455
525
520
440
435
505
30
40
2.00
445
510
20
1.75
450
515
10
1.50
50
60
70
80
04650-0-018
TIME (ps)
550
0
1.25
Figure 12. Rise and Fall of Outputs vs. Time
04650-0-015
TIME (ps)
Figure 9. Input Offset Voltage vs. Temperature
500
–40 –30 –20 –10
1.00
TIME (ns)
430
425
–40 –30 –20 –10
90
TEMPERATURE (°C)
0
10
20
30
40
50
60
TEMPERATURE (°C)
Figure 10. Rise Time vs. Temperature
Figure 13. Fall Time vs. Temperature
Rev. B | Page 8 of 16
70
80
90
705
715
704
710
705
700
695
690
685
680
–40 –30 –20 –10
0
10
20
30
40
50
60
70
80
703
702
701
700
699
04650-0-022
PROPAGATION DELAY (ps)
720
04650-0-019
PROPAGATION DELAY (ps)
ADCMP563/ADCMP564
698
697
–2
90
–1
TEMPERATURE (°C)
Figure 14. Propagation Delay vs. Temperature
2
3
25
100
80
60
40
04650-0-020
20
0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
20
15
10
5
0
–5
0.7
1.6
04650-0-023
PROPAGATION DELAY ERROR (ps)
120
0
1.7
2.7
3.7
OVERDRIVE VOLTAGE (V)
140
140
120
100
80
60
04650-0-021
40
20
30
20
6.7
7.7
8.7
9.7
10
120
100
80
60
40
04650-0-024
PROGRAMMED HYSTERESIS (mV)
160
40
5.7
Figure 18. Propagation Delay Error vs. Pulse Width
160
0
50
4.7
PULSE WIDTH (ns)
Figure 15. Propagation Delay Error vs. Overdrive Voltage
PROGRAMMED HYSTERESIS (mV)
1
Figure 17. Propagation Delay vs. Common-Mode Voltage
140
PROPAGATION DELAY ERROR (ps)
0
INPUT COMMON-MODE VOLTAGE (V)
20
0
0
0
50
100
IHYS (μA)
RHYS (kΩ)
Figure 19. Comparator Hysteresis vs. IHYS
Figure 16. Comparator Hysteresis vs. RHYS
Rev. B | Page 9 of 16
150
ADCMP563/ADCMP564
TIMING INFORMATION
LATCH ENABLE
50%
LATCH ENABLE
tS
tPL
tH
DIFFERENTIAL
INPUT VOLTAGE
VIN
VREF ± VOS
VOD
tPDL
tPLOH
Q OUTPUT
50%
tF
tPDH
tPLOL
tR
04650-0-003
50%
Q OUTPUT
Figure 20. System Timing Diagram
Figure 20 shows the compare and latch features of the ADCMP563. Table 4 describes the terms in the diagram.
Table 4. Timing Descriptions
Symbol
tPDH
Timing
Input-to-Output High Delay
tPDL
Input-to-Output Low Delay
tPLOH
Latch Enable to Output High Delay
tPLOL
Latch Enable to Output Low Delay
tH
Minimum Hold Time
tPL
tS
Minimum Latch Enable Pulse Width
Minimum Setup Time
tR
Output Rise Time
tF
Output Fall Time
VOD
Voltage Overdrive
Description
Propagation delay measured from the time the input signal crosses the reference (± the
input offset voltage) to the 50% point of an output low-to-high transition.
Propagation delay measured from the time the input signal crosses the reference (± the
input offset voltage) to the 50% point of an output high-to-low transition.
Propagation delay measured from the 50% point of the latch enable signal low-to-high
transition to the 50% point of an output low-to-high transition.
Propagation delay measured from the 50% point of the latch enable signal low-to-high
transition to the 50% point of an output high-to-low transition.
Minimum time after the negative transition of the latch enable signal that the input signal
must remain unchanged to be acquired and held at the outputs.
Minimum time the latch enable signal must be high to acquire an input signal change.
Minimum time before the negative transition of the latch enable signal that an input
signal change must be present to be acquired and held at the outputs.
Amount of time required to transition from a low to a high output as measured at the
20% and 80% points.
Amount of time required to transition from a high to a low output as measured at the
20% and 80% points.
Difference between the differential input and reference input voltages.
Rev. B | Page 10 of 16
ADCMP563/ADCMP564
APPLICATION INFORMATION
The ADCMP563/ADCMP564 comparators are very high speed
devices. Consequently, high speed design techniques must be
employed to achieve the best performance. The most critical
aspect of any ADCMP563/ADCMP564 design is the use of a
low impedance ground plane. A ground plane, as part of a
multilayer board, is recommended for proper high speed
performance. Using a continuous conductive plane over the
surface of the circuit board can create this, allowing breaks in
the plane only for necessary signal paths. The ground plane
provides a low inductance ground, eliminating any potential
differences at different ground points throughout the circuit
board caused by ground bounce. A proper ground plane also
minimizes the effects of stray capacitance on the circuit board.
It is also important to provide bypass capacitors for the power
supply in a high speed application. A 1 μF electrolytic bypass
capacitor should be placed within 0.5 inches of each power
supply pin to ground. These capacitors reduce any potential
voltage ripples from the power supply. In addition, a 10 nF
ceramic capacitor should be placed as close as possible from the
power supply pins on the ADCMP563/ADCMP564 to ground.
These capacitors act as a charge reservoir for the device during
high frequency switching.
The LATCH ENABLE input is active low (latched). If the
latching function is not used, the LATCH ENABLE input can be
left open or grounded (ground is an ECL logic high). The
complementary input, LATCH ENABLE, can be left open or
tied to −2.0 V. Leaving the latch inputs unconnected or
providing the proper voltages disables the latching function.
Occasionally, one of the two comparator stages within the
ADCMP563/ADCMP564 is not used. The inputs of the unused
comparator should not be allowed to float. The high internal
gain can cause the output to oscillate (possibly affecting the
comparator that is being used), unless the output is forced into
a fixed state. This is easily accomplished by ensuring that the
two inputs are at least one diode drop apart, while also
appropriately connecting the LATCH ENABLE and
LATCH ENABLE inputs as described previously.
The best performance is achieved with the use of proper ECL
terminations. The open emitter outputs of the ADCMP563/
ADCMP564 are designed to be terminated through 50 Ω
resistors to −2.0 V, or any other equivalent ECL termination. If a
−2.0 V supply is not available, an 82 Ω resistor to ground and a
130 Ω resistor to −5.2 V provide a suitable equivalent. If high
speed ECL signals must be routed more than a centimeter,
microstrip or stripline techniques may be required to ensure
proper transition times and prevent output ringing.
CLOCK TIMING RECOVERY
Comparators are often used in digital systems to recover clock
timing signals. High speed square waves transmitted over a
distance, even tens of centimeters, can become distorted due to
stray capacitance and inductance. Poor layout or improper
termination can also cause reflections on the transmission line,
further distorting the signal waveform. A high speed
comparator can be used to recover the distorted waveform
while maintaining a minimum of delay.
OPTIMIZING HIGH SPEED PERFORMANCE
As with any high speed comparator amplifier, proper design
and layout techniques should be used to ensure optimal
performance from the ADCMP563/ADCMP564. The performance limits of high speed circuitry all too often are the result
of stray capacitance, improper ground impedance, or other
layout issues.
Minimizing resistance from source to the input is an important
consideration in maximizing the high speed operation of the
ADCMP563/ADCMP564. Source resistance, in combination
with equivalent input capacitance, could cause a lagged
response at the input, thus delaying the output. The input
capacitance of the ADCMP563/ADCMP564, in combination
with stray capacitance from an input pin to ground, could result
in several picofarads of equivalent capacitance. A combination
of 3 kΩ source resistance and 5 pF input capacitance yields a
time constant of 15 ns, which is significantly slower than the
750 ps capability of the ADCMP563/ADCMP564. Source
impedances should be significantly less than 100 Ω for best
performance.
Sockets should be avoided due to stray capacitance and inductance. If proper high speed techniques are used, the devices
should be free from oscillation when the comparator input
signal passes through the switching threshold.
COMPARATOR PROPAGATION DELAY DISPERSION
The ADCMP563/ADCMP564 have been specifically designed
to reduce propagation delay dispersion over an input overdrive
range of 100 mV to 1.5 V. Propagation delay overdrive
dispersion is the change in propagation delay that results from a
change in the degree of overdrive (how far the switching point
is exceeded by the input). The overall result is a higher degree of
timing accuracy because the ADCMP563/ADCMP564 are far
less sensitive to input variations than most comparator designs.
Rev. B | Page 11 of 16
ADCMP563/ADCMP564
Propagation delay dispersion is important in critical timing
applications such as ATE, bench instruments, and nuclear
instrumentation. Overdrive dispersion is defined as the variation in propagation delay as the input overdrive conditions are
changed (Figure 21). For the ADCMP563/ADCMP564, overdrive dispersion is typically 75 ps as the overdrive is changed
from 100 mV to 1.5 V. This specification applies for both
positive and negative overdrive because the ADCMP563 and
the ADCMP564 have equal delays for positive and negative
going inputs.
A current may be sourced into the HYS pin. The pin is biased
approximately 1 V below AGND and has a 3 kΩ series
resistance. The relationship between the current applied to the
HYS pin and the resulting hysteresis is shown in Figure 19.
–VH
2
+VH
2
0V
INPUT
1
1.5V OVERDRIVE
INPUT VOLTAGE
20mV OVERDRIVE
0
04650-0-005
VREF ± VOS
DISPERSION
Q OUTPUT
03633-0-004
OUTPUT
Figure 22. Comparator Hysteresis Transfer Function
Figure 21. Propagation Delay Dispersion
160
COMPARATOR HYSTERESIS
140
The customary technique for introducing hysteresis into a
comparator uses positive feedback from the output back to the
input. A limitation of this approach is that the amount of
hysteresis varies with the output logic levels, resulting in
hysteresis that can be load dependent and is not symmetrical
about the threshold. The external feedback network can also
introduce significant parasitics, which reduce high speed
performance and can induce oscillation in some cases.
In the ADCMP564, hysteresis is generated through the
programmable hysteresis pin. A resistor from the HYS pin to
GND creates a current into the part that is used to generate
hysteresis. Hysteresis generated in this manner is independent
of output swing and is symmetrical around the trip point. The
hysteresis vs. resistance curve is shown in Figure 23.
120
100
80
60
40
04650-0-021
PROGRAMMED HYSTERESIS (mV)
The addition of hysteresis to a comparator is often useful in a
noisy environment, or where it is not desirable for the comparator to toggle between states when the input signal is at the
switching threshold. The transfer function for a comparator
with hysteresis is shown in Figure 22. If the input voltage
approaches the threshold from the negative direction, the
comparator switches from 0 to 1 when the input crosses +VH/2.
The new switching threshold becomes −VH/2. The comparator
remains in a 1 state until the threshold −VH/2 is crossed while
coming from the positive direction. In this manner, noise
centered on 0 V input does not cause the comparator to switch
states unless it exceeds the region bounded by ±VH/2.
20
0
50
40
30
20
10
0
RHYS (kΩ)
Figure 23. Comparator Hysteresis vs. RHYS
MINIMUM INPUT SLEW RATE REQUIREMENT
As for all high speed comparators, a minimum slew rate must
be met to ensure that the device does not oscillate as the input
crosses the threshold. This oscillation is due in part to the high
input bandwidth of the comparator and the parasitics of the
package. ADI recommends a slew rate of 1 V/μs or faster to
ensure a clean output transition. If slew rates less than 1 V/μs
are used, hysteresis can be added to prevent the oscillation.
Rev. B | Page 12 of 16
ADCMP563/ADCMP564
TYPICAL APPLICATION CIRCUITS
VIN
VREF
VIN
ADCMP563/
ADCMP564
ADCMP564
OUTPUTS
VREF
OUTPUTS
HYS
–2.0V
–2.0V
046500-007
LATCH
ENABLE
INPUTS
ALL RESISTORS 50Ω
ALL RESISTORS 50Ω, UNLESS OTHERWISE NOTED
Figure 26. Adding Hysteresis Using the HYS Control Pin
Figure 24. High Speed Sampling Circuits
+VREF
VIN
ADCMP563/
ADCMP564
04650-0-009
0Ω TO 80kΩ
OUTPUTS
–2V
ADCMP563/
ADCMP564
OUTPUTS
VIN
127Ω
–2V
ALL RESISTORS 50Ω UNLESS OTHERWISE NOTED
04650-0-008
LATCH
ENABLE
INPUTS
ADCMP563/
ADCMP564
–5.2V
Figure 25. High Speed Window Comparator
30Ω
50Ω
30Ω
50Ω
127Ω
04650-0-011
–VREF
Figure 27. One Method to Interface an ECL Output to an
Instrument with a 50 Ω to Ground Input
Rev. B | Page 13 of 16
ADCMP563/ADCMP564
OUTLINE DIMENSIONS
0.341
BSC
0.193
BSC
20
9
16
11
0.154
BSC
0.154
BSC
1
0.236
BSC
8
1
0.236
BSC
10
PIN 1
PIN 1
0.069
0.053
0.065
0.049
0.010
0.025
0.004
BSC
COPLANARITY
0.004
0.012
0.008
SEATING
PLANE
0.065
0.049
0.010
0.006
8°
0°
0.010
0.004
0.050
0.016
0.025
BSC
13
12
2.75
BSC SQ
8°
0°
0.80 MAX
0.65 TYP
16
1
PIN 1
INDICATOR
*1.65
1.50 SQ
1.35
EXPOSED
PAD
0.50
BSC
SEATING
PLANE
0.50
0.40
0.30
0.60 MAX
0.45
12° MAX
0.010
0.006
Figure 29. 20-Lead Shrink Small Outline Package [QSOP]
(RQ-20)
Dimensions shown in inches
3.00
BSC SQ
0.90
0.85
0.80
SEATING
PLANE
COMPLIANT TO JEDEC STANDARDS MO-137-AD
Figure 28. 16-Lead Shrink Small Outline Package [QSOP]
(RQ-16)
Dimensions shown in inches
TOP
VIEW
0.012
0.008
COPLANARITY
0.004
COMPLIANT TO JEDEC STANDARDS MO-137-AB
PIN 1
INDICATOR
0.069
0.053
9 (BOTTOM VIEW) 4
8
5
0.25 MIN
1.50 REF
0.05 MAX
0.02 NOM
0.30
0.23
0.18
0.20 REF
*COMPLIANT TO JEDEC STANDARDS MO-220-VEED-2
EXCEPT FOR EXPOSED PAD DIMENSION.
Figure 30. 16-Lead Lead Frame Chip Scale Package [LFCSP_VQ]
3 mm × 3 mm Body, Very Thin Quad
(CP-16-3)
Dimensions shown in millimeters
ORDERING GUIDE
Model
ADCMP563BRQ
ADCMP563BRQZ 1
ADCMP563BCP-R2
ADCMP563BCP-RL7
ADCMP563BCP-WP
EVAL-ADCMP563BRQ
ADCMP564BRQ
ADCMP564BRQZ1
EVAL-ADCMP564BRQ
1
Temperature Range
−40°C to +85°C
−40°C to +85°C
−40°C to +85°C
−40°C to +85°C
−40°C to +85°C
−40°C to +85°C
−40°C to +85°C
Package Description
16-Lead QSOP
16-Lead QSOP
16-Lead LFCSP_VQ, 250 Unit Reel
16-Lead LFCSP_VQ, 1,500 Unit Reel
16-Lead LFCSP_VQ, 50 Unit Waffle Pack
Evaluation Board
20-Lead QSOP
20-Lead QSOP
Evaluation Board
Z = Pb-free part.
Rev. B | Page 14 of 16
Package Option
RQ-16
RQ-16
CP-16-3
CP-16-3
CP-16-3
RQ-20
RQ-20
0.050
0.016
ADCMP563/ADCMP564
NOTES
Rev. B | Page 15 of 16
ADCMP563/ADCMP564
NOTES
©2005 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D04650–0–5/05(B)
Rev. B | Page 16 of 16
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