Abstract: MSK5101 is one kind of new low differential pressure which, the big electric current, the low power loss linear voltage regulator American MSKennedy Corporation develops. This component has 3V, 5V, 12V and the variable voltage output. The smallest differential pressure only then 350mV, simultaneously has the high efficiency and the low power loss characteristic. In the article introduced the MSK5101 chief feature and the application method.
Key word: MSK5101 big electric current output low voltage depreciation
1 outline
Integrates the manostat to be very quick in the nearly more than ten years development, at present domestic and foreign has developed to several hundred varieties. According to electric circuit’s working minute, has the linearity to integrate the manostat and the switch type integration manostat. According to the circuit structure form minute, has the one piece type to integrate the manostat and the combined integration manostat. According to base pin’s connection mode minute, three end type integration manostat and in many ways type integration manostat. According to the fabrication technology minute, has the semiconductor to integrate the manostat, the thin film mix integration manostat and the heavy film mix integration manostat. But in the linear integration manostat aspect, by the low differential pressure, the big electric current, the small volume’s development is quite swift and violent.
MSK5101 is one kind of new low differential pressure which, the big electric current, the low power loss linear voltage regulator American MSKennedy Corporation develops, it has 3V, 5V, 12V and the adjustable output. Outputs the transistor to use the monolithic craft manufacture the super PNP tube, therefore this series model’s input output voltage difference is very small. Shown in Figure 1 is the MSK5101 internal structure diagram.
Figure 1
When the MSK5101 output current is 1.5A, its differential pressure only then 350mV, its efficiency is very therefore high, the power loss is low. And the output voltage precision may guarantee 1%. In addition, this series manostat also has TTL/CMOS compatible on/off to enable the foot as well as the fault signal output foot. MSK5100 uses may use spatial effectively 10 foot power SOIC seal, and in the outer covering has the radiator copper attachment.
The MSK5101 volume is very small. Its contour as shown in Figure 2, size dimension for 6.35mm×6.35mm×2.08mm, therefore is having the volume and in the weight restriction high efficiency manostat application, this series manostat has the very good performance-to-price ratio. Therefore, but widely applies in the highly effective linear voltage regulator, the constant pressure/constant flow regulator, the system power source, switching power supply equipment and so on output manostat as well as battery power supply.
The MSK5101 main feature is as follows:
* uses the belt radiator attachment the close 10 foot SOIC seal form;
* the input output voltage difference is small, when the output current is 1.5A, differential pressure only then 350mV;
* has 3.3V, 5V, 12V and the adjustable output;
* uses the opening collecting electrode error signal output mode;
* has the TTL level to enable the foot; But zero electric current shutdown;
* has the power source to tie hands behind the back the protection and the load short circuit protection function;
* ground terminal electric current when 22mA (full load);
* the output voltage precision may reach 1%;
* the output current may reach 1.5A.
2 main parameters
The MSK5101 main electrical specification parameter like table 1 arranges in order.
Table 1 MSK5101 main electrical specification parameter
| Parameter name | Test condition | MSK5101 series | Unit | ||
| Is smallest | Model | Biggest | |||
| Output voltage common difference | Iout=1A, Vin=Vout 1V | ±0.5 | ±1.0 | % | |
| Input output voltage difference | δvout=-1%, Iout=100mA | 80 | 225 | mV | |
| δvout=-1%, Iout=1.5A | 350 | 625 | mV | ||
| Load relative regulation | Vin=Vout 5V | ±0.2 | ±1.2 | % | |
| 10mA≤Iout≤1.5 | ±0.3 | % | |||
| Power source relative regulation | (Vout 1V) ≤Vin≤26VIout=10mA | ±0.05 | ±0.6 | % | |
| ±0.5 | % | ||||
| Output current limiting value | Vout=0V, Vin=Vout 1V | 2.1 | 3.5 | A | |
| Ground terminal electric current | Vin=Vout 1V, Iout=0.75 | 8 | 20 | mA | |
| Output noise | Vin=Vout 1V, Iout=1.5A | 22 | mA | ||
| Enables the foot input voltage | CL=10μF, 10Hz≤f≤100kHZ | 400 | μV | ||
| Enables the foot input voltage | High level/breakover | 2.4 | 1.2 | V | |
| Low level/shutdown | 1.2 | 0.8 | V | ||
| Enables the foot input current | High level/breakover | 20 | 75 | μA | |
| Low level/shutdown | 1 | 2 | μA | ||
| Shutdown output current | VENABLE≤08V | 10 | 20 | μA | |
| The output leaks the electric current | VOH=26V | 0.01 | 2 | μA | |
| Signal output voltage | IOL≤250μA, Vin=Vout-2V | 0.2 | 0.4 | V | |
| Signal threshold | Vin=Vout-7% | 75 | mV | ||
| Voltage reference | Normal work | 1.22 | 1.24 | 1.26 | V |
| The voltage reference floats warm | Normal work | 20 | PPm/℃ | ||
| Adjustment foot bias electric current | Complete temperature range, Vin=Vout 1V | 40 | 150 | mA | |
| Thermal resistance | Ties the outer covering | 4.5 | 5 | ℃/W | |
| Overheated shutdown temperature | Junction temperature JT1 | 135 | ℃ | ||
3 using explanation
3.1 manostat protections
The MSK5101 series manostat has the input power source polarity to tie hands behind the back, the electric current, the excess temperature (Pd oversized) and the transient voltage peak achieves 60V and so on each kind of protection function, if uses in this manostat the load meeting the negative supply in the double power source, then the output voltage must use the diode clamping to arrive.
3.2 output capacities
Turns on a filter electric capacity between the out-port and the ground terminal to be possible to reduce the MKS5101 series manostat’s output voltage ripple, this electric capacity’s optimum capacity is decided by the application situation, but should at least in 10μF above. May also turn on a capacitor in the load both sides to improve the load directly transient response ability.
3.3 load connections
In practical application, when the manostat load current is very big, the load connection is important. For does not affect the load relative regulation, the manostat outputs between the load the segment impedance to be small, because of this impedance may with the load composition voltage divider. In order to maintain the constant voltage, the MSK5101 series manostat’s minimum load electric current should be 10mA.
3.4 enable the base pin
The MSK5101 series manostat has one compatibly to enable (ENABLE) with the TTL signal the base pin, when this foot is the TTL high level, the interior bias circuit work, and causes the manostat power source connection. But works as when this foot is the TTL low level, the internal controller shuts off, this time flows in this component’s quiescent current only then 5μA. If does not need to enable the function, enables the base pin to be possible to receive inputs the foot.
3.5 fault signal output foot
In the MSK5101 series all fixed output voltage’s manostat product has a fault signal output foot. Because in signal output foot to lead the way the collecting electrode output circuit, this foot voltage may rise to 3V~26V between the random voltage. This characteristic permits this foot and the random logic level connection. When the signal comparator examines “not the constant voltage” the condition, this foot outputs the effective low level (typical voltage is 0.22V). The MSK5101 fault signal condition is excessively low including the input voltage, the excess temperature shutdown and the output current limiting and so on. In fact, when the input voltage transient state is excessively high, the fault signal base pin will also output the high level.
3.6 radiator choices
Uses when the convection radiation 熡 PI the acute hearing rate cellar ≡ scars stops the cherry to play guarantees Egypt Bi Daoxing to pregnant the radiator which the kind of witchcraft liang needs:
TJ=Pd (Rθjc Rθcs Rθsa) Ta
In the formula: TJ is a junction temperature;
Pd is the total power loss;
Rθjc is the knot to the outer covering thermal resistance;
Rθcs is the outer covering to radiator’s thermal resistance;
Rθsa is the radiator to the environment thermal resistance;
Ta is the ambient temperature.
When design, may first calculate power loss P according to equation below:
P= (Vin-Vout) ×Iout
Then, chooses the highest junction temperature again. Generally highest permission junction temperature for 125℃. In order to calculate needs the radiator to the environment thermal resistance, should the above junction temperature expression reorganization be:
Rθsa= [(TJ-Ta) /Pd] - Rθjc-Rθcs
The example which the following to act according to this type to list a radiator which chooses:
If MSK5101_3.3 manostat’s input Vin is 5V 熓 su zhi Zheng Zheng acid radical cake 3.3V 熈 continues direct current Iout is 1A. The ambient temperature is 25℃, the highest junction temperature is 125℃. Rθjc is 5℃/W, Rθsa is 0.5℃/W. Then:
P= (5V-3.3V) ×1A=1.7W
Rθsa= [(125℃-25℃) /1.7W] - 5℃/W-0.5℃/W=53.32℃/W
Therefore, in this example, to guarantee that the junction temperature does not surpass 125℃, elected is smaller than with the thermal resistance 53℃/W radiator.
4 MSK5101-00 output voltage alignment circuits
MSK5101-00 is one kind of output voltage adjustable high performance manostat. Output voltage alignment circuit as shown in Figure which designs with it 3. In the chart, series resistance R1 and R2 should act according to must through the smallest manostat output current (10mA) chooses.
The MSK5101 series manostat is one kind of high heat conduction component, ties the outer covering radiator the heat conduction circuit which to internal PN is short. When this component welds on the circuit wafer, must use the standard the surface to paste installs the technology. In the high efficiency application, on the printed wiring board should open a heat conduction hole, so that in the outer covering radiator can conduct the quantity of heat to the external connection radiator on. The external connection radiator must earth, because the MSK5101 place pan is the earth, user when design printed wiring board, must keep firmly in mind this point. In addition, on printed wiring board’s wiring cannot be connected with component’s place pan.
