Functional description

LM7221 is a micro-power CMOS comparator Micro 5-pin SOT-23 packaging saving space to save space to save space for 5 stitches SOT-23 packaging. The thickness of the packaging is less than 1.43 mm, which makes the comparison instrumental and ensure that the specifications of 2.7V, 5V, and 15V provide a key key design. LMC7221 is also a typical power supply current at 5V in the 8 -pin SOIC packaging. LMC7221 provides two offset voltage levels, and the response time at 5 MV and 155V MV is 4μs. LMC7221 Fully open road output opening road leakage output can be pulled up in the input covarurative range of V and V. Essence Please apply for a micro comparator with push -pull output

Hybrid battery power supply products see the LMC7211 data table.

Notebook computer and PDA

PCMCIA card

Mobile communication

123] Direct sensor interface

(1) Absolute maximum rated value indicates the limit of damage to the device. The work rated value represents the expected function of the device, but the specific performance cannot be guaranteed. Ensure the standards and test conditions, see electrical characteristics.

(2) Human model, applicable standard MIL-STD-883, method 3015.7. Machine model, applicable standard JESD22-A115-A (ESD MM standard field charging device model, applicable standard JESD22-C101-C (Jedec's ESD FICDM standard).

(3) All limits are trials Or statistical analysis regulations.

(4) Suitable for single power supply and distribution operations. Continuous short -circuit operations when the environmental temperature rises may cause a maximum allowable of 150 ° C. The output current of more than ± 30 mA may It adversely affects reliability.

(5) Only when the input voltage exceeds the absolute maximum input voltage rated value, it is necessary to limit the input pin current. TJ (max), θja function. The maximum allowable power consumption at any ambient temperature is pd (tj (max) – TA)/θJa. All numbers are suitable for packaging directly welded to PC boards.

] 2.7V electrical characteristics

Unless there are other regulations, it should be ensured that TJ 25 ° C, V+ 2.7V, V 0V, VCM VO V. All limit+/2. Rich body restrictions are suitable for extremesTemperature

(1) Typical values indicate the most likely parameter specifications determined during the characterization. The actual typical value may be different over time, and it will depend on the application and configuration. The typical value cannot be guaranteed during transportation, and production materials cannot be guaranteed.

(2) All limits are stipulated by the test or statistical analysis.

(3) CL includes probes and test fixture capacitors.

2.7V electrical characteristics (continued)

Unless there are other regulations, it should be ensured that TJ 25 ° C, V+ 2.7V, V 0V, vcm vo V All limits+/2. Rough body restrictions are suitable for extreme temperatures.

5.0V and 15.0V electrical characteristics

Unless there are other regulations, it should be ensured that TJ 25 ° C, V+ 5.0V and 15V, V V V V V V V V V V V V V V V V V V V V V V V V ize #8722; 0v, all limits of vcm vo v+/2. Limited by the body is used at extreme temperature

(1) The typical value indicates the most likely parameter specification determined when the character is. The actual typical value may be different over time, and it will depend on the application and configuration. The typical value cannot be guaranteed during transportation, and production materials cannot be guaranteed.

(2) All limits are stipulated by the test or statistical analysis.

(3) CL includes probes and test fixture capacitors

AC electrical characteristics

Unless there are other regulations, it should be ensured that TJ 25 ° C, V+ 5V, V V V V #8722; 0v, all limits of vcm vo v+/2. Rough body restrictions are suitable for extreme temperatures.

(1) Typical values indicate the most likely parameter specifications determined during the characterization. The actual typical value may be different over time, and it will depend on the application and configuration. The typical value cannot be guaranteed during transportation, and production materials cannot be guaranteed.

(2) All limits are stipulated by the test or statistical analysis.

(3) When the voltage is V, do not shorten the output to V ++ greater than 12V or reliability, which will be adversely affected.

(4) The average drift of the input offset voltage is calculated with an equivalent working time with accelerated working life VOS drift. This indicates the input conditions in the worst case, including the drift of the previous 30 days.

Typical performance features

LMC7221 micro comparator advantage of 5 stitches SOT-23 packaging micro comparator Small volume (0.120 x 0. 118 inches, 3.05 x 3.00 mm) saves the space of printing circuit boards and makes the design of small electronic products possible. Because they are easy to carry, many customers prefer products with smaller size and lighter weight.

Height

The height of the micro comparator (0.056 inches, 1.43 mm) enables it to be used for PCMCIA III cards. Simplified board layouts this micro comparator can simplify the circuit board layout in various ways. First of all, put the comparator on the need for comparators, instead of the signal routing to double or four -way device, which can avoid long PC trajectories. By using multiple miniature comparators instead of dual or four -yuan group, complex signal routing and possible string can be reduced.

Low -power supply current

The typical 7μA power current of LMC7221 extends the battery life in portable applications and allows the size of the small battery in certain applications.

Wide voltage range

LMC7221 is characterized by 15V, 5V and 2.7V. Performance data is provided under these popular voltages. This wide voltage range makes LMC7221 a good choice, and the voltage of the device may change the battery with the life expectancy.

The digital output of the signal level

The voltage levels of the comparator based on (+) and ( #8722) are provided with high or low digital output. This enables the comparator to connect the analog signal to the microprocessor and other digital circuits. This LMC7221 can be regarded as a bit A/D converter.

Opening output

Open leakage output similar to the logic door open -circuit output. This makes LMC7221 for a hybrid voltage system.

Drive LED (Lighting Diodes)

At a 5 volts of power, the output sinking current of LMC7221 can drive small, high -efficiency LED indicators and test point circuits. The small size of the small packaging makes it easy to find the space to add this function or even a compact design.

The input range from the input range to the orbit to the orbit

LMC7221 is slightly greater than the actual power supply range. Such a wide input range means that the comparator can be used to detect signals near the power rail. Such a wide input range can be used to eliminate the regulator, amplifier, and other front -end circuits to make it easier to match the limited input range of the signal with the early comparator. This is a useful monitoring circuit to sense its own power supply, and compare it to the reference voltage closer to the power supply voltage. The wide input range can also be used to detect the current response resistor of the battery charger.

Over zero detector

Because the co -mode input range of LMC7221 extends below the ground, even if it is a positive power supply power supply, it can use large input resistance as over zero inspection as over zero inspections.The tester. The characteristics of low input current and high input impedance make LMC7221 can be used to detect high impedance signals from sensors. They also make it possible to use LMC7221 in timing circuits with large value resistors. This can reduce the loss of the time -timing circuit. For very long timing circuits, high-value resistors can reduce the large-value capacitors under the same R-C time constant of the same R-C time.

Direct sensor interface

The wide input voltage range and high impedance of LMC7221 make the sensor directly and non -use of amplifiers or bias circuits. In the circuit with a sensor, you can compare the sensor signal with the appropriate small reference signal in dozens of to hundreds of millivoli. This can be carried out near the ground or the positive electrode power rail. Direct sensor interface can eliminate a sensor signal amplifier. Elimination of the amplifier can save costs, space and design time.

Low -voltage operation

The comparator is a common device for analog signal and digital circuit interface. LMC7221 is designed to work at a power supply of 2.7V without sacrificing performance to meet the 3V requirements digital system. When the power supply voltage is 2.7V, the co -mode voltage range is extended to 200 MV (ensured) below the negative voltage. This feature, in addition to the signal near the orbit, is extremely important for low -voltage applications

Figure 16. Even at the low power voltage of 2.7V, the input signal exceeding the power supply voltage does not generate phase reversal at the output end

When V+ 2.7V, the transmission delay is TPLH 4 μs, TPHL 4μs , Overvoltage is 100mv. Please refer to the performance curve to learn more about the more extensive characteristics.

The push -pull output will have traditional high or low digital output, the same as the logic door. Low will be the negative electrode power supply track (usually ground) and high voltage will be the positive electrode power rail. This is useful, if you are the interface chip run at the same power voltage comparator. An example will be a full+5V system. The leakage output is only lowered to the high output dependent on the external pull -up resistor. This jar is pulled up to the voltage higher than or lower than the comparator's power supply voltage. This voltage can be as high as 15 volts. The open -road drain component is useful in the hybrid voltage system. For example, the operating position of the comparator is 5V, and the logic circuit is 3.3V. The pull -up resistor will access the 3.3V power supply. Open leakage output and open -the -road set output equivalent.

Output short -circuit current

LMC7221 has a short circuit protection of 40 mAh. However, its design cannot withstand continuous short -circuit circuit, transient voltage or current peak, or any voltage short circuit other than power supply. The output of the series with ... series should reduce the effect of short circuit. Add to the output of the signal from the PC board, addProtection can use equipment, such as diode and pressure -sensitive resistance on the power rail.

Input protection

If the input signal is likely to exceed the co -mode range of LMC7221, or it is likely that when the power supply is closed, LMC7221 may be damaged. The input resistance of large value (100 kΩ to mΩ) may reduce the possibility of damage by limiting the input current. Because the LMC7221 has a very low input leakage current, the impact on accuracy will be small. Additional protection may need to use diode, as shown in Figure 18. Note that the leakage current of the diode may affect the accuracy during the normal operation. Rin's R-C time constant and diode capacitors also slow down the response time.

Layout Note

LMC7221 is not a particularly fast comparator, so it does not require high -speed design practice. This LMC7221 can work under very high impedance input, so preventive measures should be taken to reduce the noise pickups in the design and electrical noise environment in high impedance (～ 100kΩ and above). It is a good way to keep the high -value resistance near LMC7221 and minimize the size of the input node. For multi -layer design, try to avoid long circuits because it may act as a inductor (coil). In order to reduce the noise, the comparator may require a twisted or shielded connection in order to reduce the noise. Push output, the dual version of LMC7211 is a comparator similar to LMC7221, but has a push -pull output that can generate current. The performance of LMC7221 is available in dual device. See LMC6772 product introduction. For a dual identity, please refer to the LMC6762 product introduction. Input low power comparator in the rail-push-pull output

LMC7221 5-pin SOT-23, 8-pin SOIC single core

lmc6762 8-needle SOIC dual

Opening output output

LMC7221 5-pin SOT-23, 8-pin SOIC single core

lmc6772 8-needle SOIC dual

additional 5-pin SOT-23 miniature device

TI There are additional components in SOT-23 miniature packaging saving SOT-23, including amplifiers, voltage

reference and voltage regulator, including: 1MHz gain bandwidth rail input and output amplifier high input impedance and high gain, high gain 700 μA typical LMC7101 current 2.7V, 3V, 5V and 15V specifications. The low -power 50 kHz gain bandwidth rail input and output amplifier, the typical current is 25 μA, the specified current is 2.7V, LMC7111, 3.0V, 3.3V, 5V, and 10V. LM7131 micro video amplifier, 70MHz gain bandwidth 3V, 5V and ± 5V specifications. LP2980Micro -power SOT 50 mAh ultra low -pressure difference regulator.LM4040 precision micro power parallel voltage benchmark.The fixed voltage is 2.500V, 4.096V, 5.000V, 8.192V and 10.000V.LM4041 Precision Microcontrollers Break -voltage Base 1.225V, adjustable.LM385 low -current voltage benchmark.1.2V and 2.5V fixed voltage.