TS2940 1A Ultra Low Dropout Fixed Positive Voltage Regulator

Transcription

1 TO-263 TS Ultra Low ropout ixed Positive Voltage Regulator eneral escription Pin assignment: 1. nput 2. round 3. Output Low ropout Voltage 0.6V (typ.) The TS2940 series of fixed-voltage monolithic micro-power voltage regulators is designed for a wide range of applications. This device excellent choice of use in battery-power application. urthermore, the quiescent current increases on slightly at dropout, which prolongs battery life. This series of fixed-voltage regulators features very low ground current (100u Typ.) and very low drop output voltage (Typ. 60mV at light load and 600mV at 1). This includes a tight initial tolerance of 1% typ., extremely good line regulation of 0.05% typ., and very low output temperature coefficient. This series is offered in 3-pin TO-263, TO-220, TO-252 & SOT-223 package. eatures ropout voltage typically Output current up to 1 Output voltage trimmed before assembly -18V Reverse peak voltage +30V nput over voltage protection +60V Transient peak voltage nternal current limit Thermal shutdown protection lock iagram Ordering nformation Part No. Operation Temp. Package TS2940Zxx TS2940Mxx TS2940Pxx TS2940Wxx -40 ~ +125 o -40 ~ +85 o TO-220 TO-263 TO-252 SOT-223 Note: Where xx denotes voltage option, available are 5.0V, 3.3V, 2.5V and 1.8V. ontact factory for additional voltage options. bsolute Maximum Rating (Note 1) nput Supply Voltage (Note 2) Vin -18 ~ +60 V Operation nput Supply Voltage Vin (operate) 30V V Power issipation (Note 3) P nternally Limited W Operating Junction Temperature Range T J -40 ~ +125 Storage Temperature Range T ST -65 ~ +150 Lead Soldering Temperature (260 o ) TO-220 TO-263 Package 5 TO-252 / SOT-223Package 4 o o S TS /12 rev.

2 lectrical haracteristics Vin = Vout + 5V, L = 5m, o = 10u, Ta = 25 o, unless otherwise specified. Parameter onditions Min Typ Max Unit Output Voltage Vo 5.0 / Vo V Output Voltage 5m L 1, Vo 2.5 / Vo V Vo+5V Vin 26V nput Supply Voltage 26 V Output Voltage Temperature ppm/ o oefficient Line Regulation Vo+2V Vin 26V % Load Regulation 5m L % ropout Voltage (Note 4) L =100m L =500m mv L =800m Quiescent urrent (Note 5) L =5m 10 m L =800m 30 Short ircuit urrent (Note 6) Vout=0 1.5 Output Noise, 10z to 100Kz, L =10m L =2.2u L =3.3u L =33u uvrms Thermal Performance ondition Package type Typ Unit Thermal Resistance TO Junction to mbient TO o /W TO SOT Note 1: bsolute Maximum Rating is limits beyond which damage to the device may occur. or guaranteed specifications and test conditions see the lectrical haracteristics. Note 2: Maximum positive supply voltage of 60V must be limited duration (<100mS) and duty cycle (<1%). Note 3: The maximum allowable power dissipation is a function of the maximum junction temperature, Tj, the junction to ambient thermal resistance, θja, and the ambient temperature, Ta. xceeding the maximum allowable power dissipation will cause excessive die temperature, and the regulator will go into thermal shutdown. The effective value of θja can be reduced by using a heatsink. Note 4: ropout voltage is defined as the input to output differential at which the output voltage drops 2% below its nominal value measured at 1V differential. Note 5: round pin current is the regulator quiescent current. The total current drawn from the source is the sum of the ground pin current and output load current. Note 6: Output current will decrease with increasing temperature, but it will be not dropped below 1 at the maximum specified temperature. TS /12 rev.

3 pplication nformation The TS2940 series is a high performance with low dropout voltage regulator suitable for moderate to high current and voltage regulator application. ts 600m(typ) dropout voltage at full load and over temperature makes it especially valuable in battery power systems and as high efficiency noise filters in post regulator applications. Unlike normal NPN transistor design, where the base to emitter voltage drop and collector to emitter saturation voltage limit the minimum dropout voltage, dropout performance of the PNP output of these devices is limited only by low Vce saturation voltage. The TS2940 series is fully protected from damage due to fault conditions. Linear current limiting is provided. Output current during overload conditions is constant. Thermal shutdown the device when the die temperature exceeds the maximum safe operating temperature. Transient protection allows device survival even when the input voltage spikes above and below nominal. The output structure of these regulators allows voltages in excess of the desired output voltage to be applied without reverse current flow. Typical pplication ircuit Output apacitor The TS2940 series requires an output capacitor to maintain stability and improve transient response. Proper capacitor selection is important to ensure proper operation. The output capacitor selection is dependent upon the SR of the output capacitor the maintain stability. When the output capacitor is 10u or greater, the output capacitor should have an SR less than 2 ohm. This will improve transient response as well as promoted stability. Ultra low SR capacitors (<100mohm), such as ceramic chip capacitors may promote instability. These very low SR levels may cause an oscillation and/or under damped transient response. low SR solid tantalum capacitor works extremely well and provides good transient response and stability over temperature. luminum electrolytic can also be used, as long as the SR of the capacitor is <2ohm. The value of the output capacitor can be increased without limit. igher capacitance values help to improved transient response and ripple rejection and reduce output noise. Minimum Load urrent The TS2940 series is specified between finite loads. f the output current is too small leakage currents dominate and the output voltage rises. 10m minimum load current is necessary for proper regulation. nput apacitor n input capacitor of 1u or greater is recommended when the device is more that 4 inches away from the bulk supply capacitance or when the supply is a battery. Small and surface mount ceramic chip capacitors can be used for bypassing. Larger values will help to improve ripple rejection by bypassing the input to the regulator, further improving the integrity of the output voltage. Thermal haracteristics heatsink may be required depending on the maximum power dissipation and maximum ambient temperature of the application. Under all possible operating conditions, the junction temperature must be within the range specified under absolute maximum ratings. To determine if the heatsink is required, the power dissipated by the regulator, P must be calculated. The below formula shows the voltages and currents for calculating the P in the regulator: in = L / P = (Vin-Vout) * L + (Vin) * x. P = (3.3V-2.5V) * V * 11m = 800mW + 36mW = 836mW Remark: L is output load current, is ground current. Vin is input voltage Vout is output voltage TS /12 rev.

4 pplication nformation (continued) The next parameter which must be calculated is the maximum allowable temperature rise, T R (max). this is calculated by the using to formula: T R (max) = T J (max) T (max) Where: T J (max) is the maximum allowable junction temperature, which is 125 o for commercial grade parts. T (max) is the maximum ambient temperature which will be encountered in the application. Using the calculated values for T R (max) and P, the maximum allowable value for the junction to ambient thermal resistance, θja, can now be found: θja = T R (max) / P MPORTNT: if the maximum allowable value for is found to be 60 o /W for the TO-220 package, 80 o /W for the TO-263 package, 150 o /W for the TO-252 package, or 170 o /W for the SOT-223 package, no heatsink is needed since the package alone will dissipate enough heat to satisfy these requirements. f the calculated value for θja falls below these limits, a heatsink is required. TS /12 rev.

5 TO-220 Mechanical rawing K L M TO-220 MNSON MLLMTRS NS P J M J K L M O N N O P TO-263 Mechanical rawing TO-263 MNSON MLLMTRS NS M J TS /12 rev.

6 TO-252 Mechanical rawing J M TO-252 MNSON MLLMTRS NS J SOT-223 Mechanical rawing SOT-223 MNSON M MLLMTRS NS J K J K TS /12 rev.