Rail-to-Rail, Fast, Low Power 2.5 V to 5.5 V, Single-Supply TTL/CMOS Comparator ADCMP609 Fully specified rail to rail at VCC = 2.5 V to 5.5 V Input common-mode voltage from −0.2 V to VCC + 0.2 V Low glitch CMOS-/TTL-compatible output stage 40 ns propagation delay Low power 1 mW at 2.5 V Shutdown pin Programmable hysteresis Power supply rejection > 60 dB −40°C to +125°C operation FUNCTIONAL BLOCK DIAGRAM NONINVERTING INPUT + ADCMP609 INVERTING INPUT Q OUTPUT – SDN 06918-001 FEATURES Figure 1. APPLICATIONS High speed instrumentation Clock and data signal restoration Logic level shifting or translation High speed line receivers Threshold detection Peak and zero-crossing detectors High speed trigger circuitry Pulse-width modulators Current-/voltage-controlled oscillators GENERAL DESCRIPTION The ADCMP609 is a fast comparator fabricated on XFCB2, an Analog Devices, Inc. proprietary process. These comparators are exceptionally versatile and easy to use. Features include an input range from VEE − 0.2 V to VCC + 0.2 V, low noise, TTL-/ CMOS-compatible output drivers, and adjustable hysteresis and/or shutdown inputs. The device offers 40 ns propagation delay driving a 15 pF load with 10 mV overdrive on 500 μA typical supply current. A flexible power supply scheme allows the devices to operate with a single +2.5 V positive supply and a −0.2 V to +3.0 V input signal range up to a +5.5 V positive supply with a −0.2 V to +5.7 V input signal range. The TTL-/CMOS-compatible output stage is designed to drive up to 15 pF with full rated timing specifications and to degrade in a graceful and linear fashion as additional capacitance is added. The comparator’s input stage offers robust protection against large input overdrive, and the outputs do not phase reverse when the valid input signal range is exceeded. A programmable hysteresis features is also provided. The ADCMP609, available in an 8-lead MSOP package, features a shutdown pin and hysteresis control. Rev. 0 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. 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 ©2007 Analog Devices, Inc. All rights reserved. ADCMP609 TABLE OF CONTENTS Features .............................................................................................. 1 Application Information...................................................................8 Applications....................................................................................... 1 Power/Ground Layout and Bypassing........................................8 Functional Block Diagram .............................................................. 1 TTL-/CMOS-Compatible Output Stage ....................................8 General Description ......................................................................... 1 Optimizing Performance..............................................................8 Revision History ............................................................................... 2 Comparator PropagationDelay Dispersion ...............................8 Specifications..................................................................................... 3 Comparator Hysteresis .................................................................9 Electrical Characteristics............................................................. 3 Crossover Bias Point .................................................................. 10 Absolute Maximum Ratings............................................................ 4 Minimum Input Slew Rate Requirement ................................ 10 Thermal Resistance ...................................................................... 4 Typical Application Circuits ......................................................... 11 ESD Caution.................................................................................. 4 Outline Dimensions ....................................................................... 12 Pin Configuration and Function Descriptions............................. 5 Ordering Guide .......................................................................... 12 Typical Performance Characteristics ............................................. 6 REVISION HISTORY 7/07—Revision 0: Initial Version Rev. 0 | Page 2 of 12 ADCMP609 SPECIFICATIONS ELECTRICAL CHARACTERISTICS VCC = 2.5 V, TA = −40 °C to +125 °C; typical value is TA = 25°C, unless otherwise noted. Table 1. Parameter DC INPUT CHARACTERISTICS Voltage Range Common-Mode Range Differential Voltage Offset Voltage Bias Current Offset Current Capacitance Resistance, Differential Mode Resistance, Common Mode Active Gain Common-Mode Rejection Hysteresis HYSTERESIS MODE AND TIMING Hysteresis Mode Bias Voltage Minimum Resistor Value SHUTDOWN PIN CHARACTERISTICS1 VIH VIL IIH Sleep Time Wake-Up Time DC OUTPUT CHARACTERISTICS Output Voltage High Level Output Voltage Low Level AC PERFORMANCE2 Rise Time/Fall Time Propagation Delay Symbol Conditions Min VP, VN VCC = 2.5 V to 5.5 V VCC = 2.5 V to 5.5 V VCC = 2.5 V to 5.5 V −0.2 −0.2 VOS IP, IN CP, CN AV CMRR tSD tH VOH VOL tR/tF tPD Propagation Delay Skew—Rising to Falling Transition Propagation Delay Skew—Q to QB Overdrive Dispersion Common-Mode Dispersion POWER SUPPLY Supply Voltage Range Positive Supply Current −5.0 −0.4 −1.0 VCC IVCC Power Dissipation PD Power Supply Rejection Ratio Shutdown Current PSRR ISD Typ ±3 Max Unit VCC + 0.2 V VCC + 0.2 V VCC +5.0 +0.4 +1.0 V V V mV μA μA pF kΩ kΩ dB dB 1 −0.5 V to VCC + 0.5 V −0.5 V to VCC + 0.5 V 200 100 VCC = 2.5 V VCM = −0.2 V to +2.7 V VCC = 5.5 V RHYS = ∞ 50 Current −1 μA Hysteresis = 120 mV 1.145 30 Comparator is operating Shutdown guaranteed VIH = VCC lCC < 100 μA VPP = 10 mV, output valid VCC = 2.5 V to 5.5 V IOH = 0.8 mA, VCC = 2.5 V IOL = 0.8 mA, VCC = 2.5 V VCC = 2.5 V to 5.5 V 10% to 90%, VCC = 2.5 V 10% to 90%, VCC = 5.5 V VOD = 10 mV, VCC = 2.5 V VOD = 50 mV, VCC = 5.5 V VCC = 2.5 V VCC = 5.5 V VCC = 2.5 V VCC = 5.5 V 10 mV < VOD < 125 mV −0.2 V < VCM < VCC + 0.2 V 2.0 −0.2 −6 7000 4000 80 50 1.25 +0.4 1 1.35 120 V kΩ VCC +0.4 +6 V V μA ns ns 300 150 VCC − 0.4 0.4 25 to 50 45 to 75 30 to 50 35 to 60 4.5 8 3 4 12 1.5 2.5 VCC = 2.5 V VCC = 5.5 V VCC = 2.5 V VCC = 5.5 V VCC = 2.5 V to 5.5 V VCC = 2.5 V to 5.5 V dB mV 0.1 V V ns ns ns ns ns ns ns ns ns ns 550 800 1.4 4.5 5.5 650 1100 1.7 7 150 260 −50 V μA μA mW mW dB μA The output is a high impedance mode when the device is in shutdown mode. Note that this feature should be used with care since the enable/disable time is much longer than with a true tristate output. 2 VIN = 100 mV square input at 1 MHz, VCM = 0 V, CL = 15 pF, VCCI = 2.5 V, unless otherwise noted. Rev. 0 | Page 3 of 12 ADCMP609 ABSOLUTE MAXIMUM RATINGS Table 2. Parameter Supply Voltages Supply Voltage (VCC to GND) Supply Differential Input Voltages Input Voltage Differential Input Voltage Maximum Input/Output Current Shutdown Control Pin Applied Voltage (SDN to GND) Maximum Input/Output Current Hysteresis Control Pin Applied Voltage (HYS to GND) Maximum Input/Output Current Output Current Operating Temperature Ambient Temperature Junction Temperature Rating −0.5 V to +6.0 V −6.0 V to +6.0 V 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 section of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. −0.5 V to VCC + 0.5 V ±(VCC + 0.5 V) ±50 mA THERMAL RESISTANCE −0.5 V to VCC + 0.5 V ±50 mA Table 3. −0.5 V to VCC + 0.5 V ±50 mA ±50 mA θJA is specified for the worst-case conditions, that is, a device soldered in a circuit board for surface-mount packages. Package Type ADCMP609 8-Lead MSOP 1 Measurement in still air. ESD CAUTION −40°C to +125°C 150°C Rev. 0 | Page 4 of 12 θJA1 130 Unit °C/W ADCMP609 VCC 1 VP 2 VN 3 SDN 4 8 Q ADCMP609 7 TOP VIEW (Not to Scale) Q 6 VEE 5 HYS 06918-002 PIN CONFIGURATION AND FUNCTION DESCRIPTIONS Figure 2. ADCMP609 Pin Configuration Table 4. ADCMP609 Pin Function Descriptions Pin No. 1 2 3 4 5 6 7 Mnemonic VCC VP VN SDN HYS VEE Q 8 Q Description VCC Supply. Noninverting Analog Input. Inverting Analog Input. Shutdown. Drive this pin low to shut down the device. Hysteresis Control. Bias with resistor or current source for hysteresis. Negative Supply Voltage. Noninverting Output. Q is at logic low if the analog voltage at the noninverting input (VP) is greater than the analog voltage at the inverting input (VN) provided the comparator is in compare mode. Inverting Output. Q is at logic high if the analog voltage at the noninverting input (VP) is greater than the analog voltage at the inverting input (VN) provided the comparator is in compare mode. Rev. 0 | Page 5 of 12 ADCMP609 TYPICAL PERFORMANCE CHARACTERISTICS VCC = 2.5 V, TA = 25°C, unless otherwise noted. 400 160 150 300 140 130 120 110 VCC = 5.5V HYSTERESIS (mV) CURRENT (µA) VCC = 2.5V 100 0 –100 –200 –400 –1 0 1 2 3 4 5 6 60 50 40 30 VCC = 2.5 VCC = 5.5 20 10 06918-003 –300 100 90 80 70 0 7 0 06918-006 200 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 HYS PIN VOLTAGE (V) HYS RESISTOR (kΩ) Figure 3. HYS Pin Current (μA) vs. Voltage (V) Figure 6. Hysteresis vs. HYS Resistor 5 1.5 4 SOURCE 3 1.0 SINK LOAD CURRENT (mA) 2 0 –1 –2 +125°C –3 06918-004 –40°C –5 –1.0 –0.5 0 0 –0.5 +25°C –4 0.5 0.5 1.0 1.5 2.0 2.5 3.0 –1.0 –1.0 –0.5 3.5 06918-007 IB (µA) 1 0 VCM AT VCC (2.5V) 1.5 2.0 2.5 3.0 3.5 4.0 Figure 7. VOH/VOL vs. Load Current (mA) 38.0 60 37.8 PROPAGATION DELAY (ns) 55 50 45 VCC = 5.5V RISE DELAY 40 35 VCC = 5.5V FALL DELAY 30 VCC = 2.5V FALL DELAY 25 06918-005 50 37.4 37.2 37.0 PROPAGATION DELAY RISE 36.8 36.6 36.4 VCC = 2.5V RISE DELAY 0 PROPAGATION DELAY FALL 37.6 100 06918-008 TPD (ns) 1.0 VOUT (V) Figure 4. Input Bias Current vs. Input Common-Mode Voltage (V) 20 0.5 36.2 36.0 0.5 150 OD (mV) 1.0 1.5 2.0 2.5 3.0 VCM AT VCC (2.5V) Figure 5. Propagation Delay vs. Input Overdrive at VCC = 2.5 V and 5.5 V Rev. 0 | Page 6 of 12 Figure 8. Propagation Delay vs. Input Common-Mode Voltage (V) ADCMP609 Q Q Q 1V/DIV Figure 9. 1 MHz Output Voltage Waveform at VCC = 2.5 V 10ns/DIV 06918-010 10ns/DIV 06918-009 0.5V/DIV Q Figure 10. 1 MHz Output Voltage Waveform at VCC = 5.5 V Rev. 0 | Page 7 of 12 ADCMP609 APPLICATION INFORMATION The ADCMP609 comparator is a high speed device. Despite the low noise output stage, it is essential to use proper high speed design techniques to achieve the specified performance. Because comparators are uncompensated amplifiers, feedback in any phase relationship is likely to cause oscillations or undesired hysteresis. Of critical importance is the use of low impedance supply planes, particularly the output supply plane (VCC) and the ground plane (GND). Individual supply planes are recommended as part of a multilayer board. Providing the lowest inductance return path for switching currents ensures the best possible performance in the target application. It is also important to adequately bypass the input and output supplies. A 0.1 μF bypass capacitor should be placed as close as possible to each VCC supply pin. The capacitor should be connected to the GND plane with redundant vias placed to provide a physically short return path for output currents flowing back from ground to the VCC pin. High frequency bypass capacitors should be carefully selected for minimum inductance and ESR. Parasitic layout inductance should also be strictly controlled to maximize the effectiveness of the bypass at high frequencies. TTL-/CMOS-COMPATIBLE OUTPUT STAGE Specified propagation delay performance can be achieved only by keeping the capacitive load at or below the specified minimums. The outputs of the ADCMP609 are designed to directly drive one Schottky TTL or three low power Schottky TTL loads (or an equivalent). For large fan outputs, buses, or transmission lines, use an appropriate buffer to maintain the excellent speed and stability of the comparator. With the rated 15 pF load capacitance applied, more than half of the total device propagation delay is output stage slew time. Because of this, the total propagation delay decreases as VCC decreases, and instability in the power supply may appear as excess delay dispersion. Delay is measured to the 50% point for whatever supply is in use; thus, the fastest times are observed with the VCC supply at 2.5 V, and larger values are observed when driving loads that switch at other levels. The TTL-/CMOS-compatible output stage is shown in the simplified schematic diagram (Figure 11). Because of its inherent symmetry and generally good behavior, this output stage is readily adaptable for driving various filters and other unusual loads. VLOGIC A1 Q1 +IN –IN OUTPUT AV A2 GAIN STAGE Q2 OUTPUT STAGE 06918-011 POWER/GROUND LAYOUT AND BYPASSING Figure 11. Simplified Schematic Diagram of TTL-/CMOS-Compatible Output Stage OPTIMIZING PERFORMANCE As with any high speed comparator, proper design and layout techniques are essential for obtaining the specified performance. Stray capacitance, inductance, common power and ground impedances, or other layout issues can severely limit performance and often cause oscillation. The source impedance should be minimized as much as is practicable. High source impedance, in combination with the parasitic input capacitance of the comparator, causes an undesirable degradation in bandwidth at the input, thus degrading the overall response. Higher impedances encourage undesired coupling. COMPARATOR PROPAGATION DELAY DISPERSION The ADCMP609 comparator is designed to reduce propagation delay dispersion over a wide input overdrive range of 10 mV to VCC – 1 V. Propagation delay dispersion is the variation in propagation delay that results from a change in the degree of overdrive or slew rate (how far or how fast the input signal exceeds the switching threshold). Overdrive and input slew rate dispersions are not significantly affected by output loading and VCC variations. Rev. 0 | Page 8 of 12 ADCMP609 Propagation delay dispersion is a specification that becomes important in high speed, time-critical applications, such as data communication, automatic test and measurement, and instrumentation. It is also important in event-driven applications, such as pulse spectroscopy, nuclear instrumentation, and medical imaging. Dispersion is defined as the variation in propagation delay as the input overdrive conditions are changed (see Figure 12 and Figure 13). 500mV OVERDRIVE INPUT VOLTAGE 10mV OVERDRIVE VN ± VOS VOL –VH 2 Figure 12. Propagation Delay—Overdrive Dispersion INPUT VOLTAGE 1V/ns INPUT The customary technique for introducing hysteresis into a comparator uses positive feedback from the output back to the input. One limitation of this approach is that the amount of hysteresis varies with the output logic levels, resulting in hysteresis that is not symmetric about the threshold. The external feedback network can also introduce significant parasitics that reduce high speed performance and can even induce oscillation in some cases. 160 150 HYSTERESIS (mV) 06918-013 Figure 13. Propagation Delay—Slew Rate Dispersion COMPARATOR HYSTERESIS The addition of hysteresis to a comparator is often desirable in a noisy environment, or when the differential input amplitudes are relatively small or slow moving. The transfer function for a comparator with hysteresis is shown in Figure 14. As the input voltage approaches the threshold (0.0 V, in this example) from below the threshold region in a positive direction, the comparator switches from low to high when the input crosses +VH/2. The new switching threshold becomes −VH/2. The comparator remains in the high state until the threshold, −VH/2, is crossed from below the threshold region in a negative direction. In this manner, noise or feedback output signals centered on 0.0 V input cannot cause the comparator to switch states unless it exceeds the region bounded by ±VH/2. 140 130 120 110 100 90 80 70 60 50 40 30 VCC = 2.5 VCC = 5.5 20 10 0 0 06918-006 VN ± VOS Q/Q OUTPUT +VH 2 Figure 14. Comparator Hysteresis Transfer Function 10V/ns DISPERSION 0 The ADCMP609 comparator offers a programmable hysteresis feature that significantly improves accuracy and stability. Connecting an external pull-down resistor or a current source from the HYS pin to GND varies the amount of hysteresis in a predictable, stable manner. Leaving the HYS pin disconnected or driving it high removes the hysteresis. The maximum hysteresis that can be applied using this pin is approximately 160 mV. Figure 15 illustrates the amount of hysteresis applied as a function of the external resistor value. 06918-012 DISPERSION Q/Q OUTPUT VOH 06918-014 ADCMP609 dispersion is typically <12 ns as the overdrive varies from 10 mV to 125 mV. This specification applies to both positive and negative signals because the device has very closely matched delays for both positive-going and negative-going inputs, and very low output skews. Remember to add the actual device offset to the overdrive for repeatable dispersion measurements. OUTPUT 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 HYS RESISTOR (kΩ) Figure 15. Hysteresis vs. HYS Resistor The hysteresis control pin appears as a 1.25 V bias voltage seen through a series resistance of 7 kΩ ± 20% throughout the hysteresis control range. The advantages of applying hysteresis in this manner are improved accuracy, improved stability, reduced component count, and maximum versatility. An external bypass capacitor is not recommended on the HYS pin because it impairs the latch function and often degrades the jitter performance of the device. Rev. 0 | Page 9 of 12 ADCMP609 With the pin driven low, hysteresis may become large, but in this device, the effect is not reliable or intended as a latch function. CROSSOVER BIAS POINT Rail-to-rail inputs of this type, in both op amps and comparators, have a dual front-end design. Certain devices are active near the VCC rail and others are active near the VEE rail. At some predetermined point in the common-mode range, a crossover occurs. At this point, normally VCC/2, the direction of the bias current reverses and there are changes in measured offset voltages and currents. The ADCMP609 slightly elaborates on this scheme. Crossover points can be found at approximately 0.8 V and 1.6 V. MINIMUM INPUT SLEW RATE REQUIREMENT With the rated load capacitance and normal good PC board design practice (as discussed in the Optimizing Performance section), these comparators should be stable at any input slew rate with no hysteresis. Broadband noise from the input stage is observed in place of the violent chattering seen with most other high speed comparators. With additional capacitive loading or poor bypassing, oscillation may be encountered. These oscillations are due to the high gain bandwidth of the comparator in combination with feedback through parasitics in the package and PC board. In many applications, chattering is not harmful. Rev. 0 | Page 10 of 12 ADCMP609 TYPICAL APPLICATION CIRCUITS 5V 20kΩ 39kΩ ADCMP609 CONTROL VOLTAGE 0V TO 2.5V 150kΩ 06918-016 HYS 470pF 39kΩ OUTPUT 150kΩ Figure 16. Voltage-Controlled Oscillator 5V 10kΩ INPUT ADCMP609 VREF 0.02µF 10kΩ 0.1µF + OUTPUT – 06918-017 HYS Figure 17. Duty Cycle to Differential Voltage Converter 2.5V ADCMP608 INPUT 1.25V ±50mV 10kΩ 10kΩ ADCMP609 10kΩ 220pF HYS 100kΩ Figure 18. Oscillator and Pulse Width Modulator Rev. 0 | Page 11 of 12 06918-018 INPUT 1.25V REF CMOS PWM OUTPUT ADCMP609 OUTLINE DIMENSIONS 3.20 3.00 2.80 8 3.20 3.00 2.80 1 5 5.15 4.90 4.65 4 PIN 1 0.65 BSC 0.95 0.85 0.75 1.10 MAX 0.15 0.00 0.38 0.22 COPLANARITY 0.10 0.23 0.08 8° 0° 0.80 0.60 0.40 SEATING PLANE COMPLIANT TO JEDEC STANDARDS MO-187-AA Figure19. 8-Lead Mini Small Outline Package (MSOP) (RM-8) Dimensions shown in millimeters ORDERING GUIDE Model ADCMP609BRMZ 1 ADCMP609BRMZ-REEL1 ADCMP609BRMZ-REEL71 1 Temperature Range −40°C to +125°C −40°C to +125°C −40°C to +125°C Package Description 8-Lead Mini Small Outline Package (MSOP) 8-Lead Mini Small Outline Package (MSOP) 8-Lead Mini Small Outline Package (MSOP) Z = RoHS Compliant Part. ©2007 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D06918-0-7/07(0) Rev. 0 | Page 12 of 12 Package Option RM-8 RM-8 RM-8 Branding GW GW GW