ADCMP341 AD | Alldatasheet
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Dual Comparators with 400mV Reference and programmable Hysteresis Preliminary Technical Data ADCMP341/ADCMP343 Rev. PrD 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. Tel: 781.329.4700 www.analog.com Fax: 781.461.3113 ©2006 Analog Devices, Inc. All rights reserved.
FEATURES
Low Quiescent Current: 6.5µA Typ Supply Range: 1.7V to 5.5V 400mV Reference ±0.8% Accuracy Over Temperature Input Range Includes Ground User programmable Hysteresis via resistor string Low Input Bias Current: ±10nA Max Open drain outputs with 40mA Typical Sink Current Supports Wired-AND Connections Input Polarities: ADCMP341 noninverting ADCMP343 inverting Small SOT-23 Package
APPLICATIONS
Battery-Powered System Monitoring Threshold Detectors Relay Driving Optoisolator Driving Handheld Instruments GENERAL DESCRIPTION The ADCMP341/ADCMP343 combine two low power, low voltage comparators with a 400mV reference in the 5-lead SOT-23 package. Operating within a supply range of 1.7V to 5.5V, the devices only draw 6.5µA typical, making them ideal for low voltage system monitoring and portable applications. Hysteresis is determined using three resistors in a string configuration with the upper and lower tap points connected to the INA_U and INA_L pins of each comparator respectively. The state of the comparators output internally selects which pin is connected to the comparator inputs. So a change of state in the comparator output will result in one of the inputs being switched in to the comparator and the other being switched out. This will provide the user with a fully flexible and simple method of setting the hysteresis. Although there are two pins available on each comparator, there is only actually one input available externally at any one time, the other inputs are connected internally to the reference. The comparator outputs are open drain with the output stage sinking capability guaranteed greater than 5mA over temperature. The ADCMP341 have noninverting inputs and the ADCMP343 have inverting inputs. Available in commercial, industrial and automotive temperature ranges. FUNCTIONAL BLOCK DIAGRAM GND VS OUTA 400mV OUTB MUX VINA INA_U INA_L MUX VINB INB_U INB_L ADCMP341 GND VS OUTA 400mV OUTB MUX VINA INA_U INA_L MUX VINB INB_U INB_L ADCMP343 Figure 1
ADCMP341/ADCMP343 Preliminary Technical Data Rev. PrD | Page 2 of 13 TABLE OF CONTENTS
REVISION HISTORY
Preliminary Technical Data ADCMP341/ADCMP343 Rev. PrD | Page 3 of 13 SPECIFICATIONS Table 1. VCC = 1.7V to 5.5V , -40°C ≤ TA ≤ 125°C , unless otherwise noted. Note1: RL=100K, VO=2V Swing Note2: 10mV input overdrive Note3: Vin = 40mV overdrive Note4: RL=10K Note5: No load Parameter Min Typ Max Unit Test Conditions/Comments Reference Voltage 396.8 400 403.2 mV Vs = 1.7V, Note1 396.8 400 403.2 mV Vs = 5V, Note1 Reference Voltage Accuracy ±0.8 ±1.0 % Vs = 1.7V, Note1 ±0.8 ±1.0 % Vs = 5V, Note1 Input Bias Current 0.01 10 nA Vs = 1.7V, Vin = Vs 4 10 nA Vs = 1.7V, Vin = 0.1V Output Low Voltage 60 200 mV Vs = 1.7V, Iout = 3mA, Note2 70 200 mV Vs = 5V, Iout = 5mA, Note2 Output Leakage Current 0.01 1 µA Vs=1.7V, Vout = Vs, Note3 0.01 1 µA Vs=1.7V, Vout = 5.5V, Note3 High-to-Low Propagation Delay 29 µs Vs = 5V, Vol = 400mV, Note2,4 Low-to-High Propagation Delay 18 µs Vs = 5V, Voh = 0.9 X Vs, Note2,4 Output Rise time 2.2 µs Vs = 5V, Vo = (0.1 to 0.9) X Vs, Note2,4 Output Fall time 0.22 µs Vs = 5V, Vo = (0.1 to 0.9) X Vs, Note2,4 Supply Current 6.5 10 µA Vs = 1.7V 6.5 10 µA Vs = 5.5V
TA = 25°C, unless otherwise noted. Table 2. . degradation or loss of functionality.
8 OUTB
Figure 2. Pin Configuration Table 3. Pin Function Descriptions 1 OUTA Open Drain Output for comparator A. Capable of sinking up to 40mA of current. 2 INA_U Monitors Analog Input Voltage on comparator A. Connect to the upper tap point of the resistor string. 3 INA_L Monitors Analog Input Voltage on comparator A. Connect to the lower tap point of the resistor string.
4 GND Ground
5 INB_L Monitors Analog Input Voltage on comparator B. Connect to the lower tap point of the resistor string. 6 INB_U Monitors Analog Input Voltage on comparator B. Connect to the upper tap point of the resistor string. 7 Vs Power Supply. Operates from 1.7V to 5.5V. 8 OUTB Open Drain Output for comparator B. Capable of sinking up to 40mA of current.
Preliminary Technical Data ADCMP341/ADCMP343 Rev. PrD | Page 11 of 13 APPLICATIONS INFORMATION The ADCMP341/3 is a dual low power comparators with a built in 400mV reference that operates from 1.7V to 5.5V . The comparators are approx 0.8% accurate with fully programmable accurate hysteresis implementing a new technique of a three resistor string on the input. The outputs are open drain capable of sinking up to 40mA. COMPARATORS AND INTERNAL REFERENCE Each of the comparators has one input available externally, the other comparator inputs are connected internally to the 400mV reference. The ADCMP341 has two noninverting comparators and the ADCMP343 has two inverting comparators. There are two input pins available to each comparator. However, these two input pins(INx_U, INx_U) connect to the same input leg of the comparator via a muxing system. This is to provide fully programmable rising and falling trip points. The output of the said comparator determines which pin is connected to the input of the same comparator. Taking Figure 30. as an example, when OUTA is high INA_U is connected to the comparator input. When the input voltage drops and passes below the 400mV reference the output goes low. This in turn disconnects INA_U from the comparator and connects INA_L. This leg of the string will be at a lower voltage and thus instantaneously the effect of hysteresis is applied. Therefore, using a resistor string on the input as shown in Figure 30., the voltages for the rising and falling trip points can be programmed by selecting the appropriate resistors in the string. PROGRAMMING HYSTERESIS The resistor values can be calculated as follows. The total resistance of the string is first determined based on the power budget available. Using the maximum voltage expected on the pin and the maximum acceptable current available to flow through the string 1, the total resistance of the string is calculated as follows: MAX INMAX TOT I VR =
1 Assuming the leakage current into the comparator to be negligible
Now calculate the three resistor values as follows: FALLING FALLINGTOT V VRR )4.0( −×= RISING TOT V RR 4.0 ×= ;
312 RRRR TOT −−= ;
Where: R1, R2 and R3 are the three resistors as shown in Figure 30. RTOT is the sum of R1, R2 and R3. VFALLING is the desired falling trip voltage and lower of the two. VRISING is the desired rising trip voltage and higher of the two. VHYST is therefore = VRISING -VFALLING VCC OUTA 400mV MUX VINA INA_U INA_L ADCMP341 Figure 30.
2.90 BSC
1.60 BSC
0.65 BSC
0.15 MAX
2.80 BSC
Figure 31. . 8-Lead SOT-23 Package (RJ-8)—Dimensions shown in millimeters
Preliminary Technical Data ADCMP341/ADCMP343 Rev. PrD | Page 13 of 13 NOTES ©2006 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the prop erty of their respective owners.