MIC39100/39101/39102 Micrel MIC39100/39101/39102 1A Low-Voltage Low-Dropout Regulator General Description Features The MIC39100, MIC39101, and MIC39102 are 1A lowdropout linear voltage regulators that provide low-voltage, high-current output from an extremely small package. Utilizing Micrel’s proprietary Super βeta PNP™ pass element, the MIC39100/1/2 offers extremely low dropout (typically 410mV at 1A) and low ground current (typically 11mA at 1A). The MIC39100 is a fixed output regulator offered in the SOT-223 package. The MIC39101 and MIC39102 are fixed and adjustable regulators, respectively, in a thermally enhanced power 8-lead SOP (small outline package). The MIC39100/1/2 is ideal for PC add-in cards that need to convert from standard 5V to 3.3V, 3.3V to 2.5V or 2.5V to 1.8V. A guaranteed maximum dropout voltage of 630mV over all operating conditions allows the MIC39100/1/2 to provide 2.5V from a supply as low as 3.13V and 1.8V from a supply as low as 2.43V. The MIC39100/1/2 is fully protected with overcurrent limiting, thermal shutdown, and reversed-battery protection. Fixed voltages of 5.0V, 3.3V, 2.5V, and 1.8V are available on MIC39100/1 with adjustable output voltages to 1.24V on MIC39102. • Fixed and adjustable output voltages to 1.24V • 410mV typical dropout at 1A Ideal for 3.0V to 2.5V conversion Ideal for 2.5V to 1.8V conversion • 1A minimum guaranteed output current • 1% initial accuracy • Low ground current • Current limiting and thermal shutdown • Reversed-battery protection • Reversed-leakage protection • Fast transient response • Low-profile SOT-223 package • Power SO-8 package Applications • • • • • • • For other voltages, contact Micrel. LDO linear regulator for PC add-in cards PowerPC™ power supplies High-efficiency linear power supplies SMPS post regulator Multimedia and PC processor supplies Battery chargers Low-voltage microcontrollers and digital logic Ordering Information Part Number Voltage Junction Temp. Range Package MIC39100-1.8BS 1.8V –40°C to +125°C SOT-223 MIC39100-2.5BS 2.5V –40°C to +125°C SOT-223 MIC39100-3.3BS 3.3V –40°C to +125°C SOT-223 MIC39100-5.0BS 5.0V –40°C to +125°C SOT-223 MIC39101-1.8BM 1.8V –40°C to +125°C SOP-8 MIC39101-2.5BM 2.5V –40°C to +125°C SOP-8 MIC39101-3.3BM 3.3V –40°C to +125°C SOP-8 MIC39101-5.0BM 5.0V –40°C to +125°C SOP-8 MIC39102BM Adj. –40°C to +125°C SOP-8 Typical Applications 100k VIN 3.3V MIC39100 IN OUT GND VIN 3.3V 2.5V 10µF tantalum ENABLE SHUTDOWN 2.5V/1A Regulator Error Flag Output MIC39101 IN OUT 2.5V R1 EN FLG GND 10µF tantalum 2.5V/1A Regulator with Error Flag VIN 2.5V ENABLE SHUTDOWN MIC39102 IN OUT 1.5V R1 EN ADJ GND R2 10µF tantalum 1.5V/1A Adjustable Regulator Super βeta PNP is a trademark of Micrel, Inc. Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com June 2000 1 MIC39100/39101/39102 MIC39100/39101/39102 Micrel Pin Configuration GND TAB 1 IN 2 3 GND OUT MIC39100-x.x Fixed SOT-223 (S) EN 1 8 GND EN 1 8 GND IN 2 7 GND IN 2 7 GND OUT 3 6 GND OUT 3 6 GND FLG 4 5 GND ADJ 4 5 GND MIC39101-x.x Fixed SOP-8 (M) MIC39102 Adjustable SOP-8 (M) Pin Description Pin No. Pin No. Pin No. MIC39100 MIC39101 MIC39102 1 3 Pin Function 1 1 EN Enable (Input): CMOS-compatible control input. Logic high = enable, logic low or open = shutdown. 2 2 IN Supply (Input) 3 3 OUT Regulator Output FLG Flag (Output): Open-collector error flag output. Active low = output undervoltage. 4 ADJ Adjustment Input: Feedback input. Connect to resitive voltage-divider network. 5–8 GND Ground 4 2, TAB Pin Name 5–8 MIC39100/39101/39102 2 June 2000 MIC39100/39101/39102 Micrel Absolute Maximum Ratings (Note 1) Operating Ratings (Note 2) Supply Voltage (VIN) ..................................... –20V to +20V Enable Voltage (VEN) .................................................. +20V Storage Temperature (TS) ....................... –65°C to +150°C Lead Temperature (soldering, 5 sec.) ....................... 260°C ESD, Note 3 Supply Voltage (VIN) .................................. +2.25V to +16V Enable Voltage (VEN) .................................................. +16V Maximum Power Dissipation (PD(max))..................... Note 4 Junction Temperature (TJ) ....................... –40°C to +125°C Package Thermal Resistance SOT-223 (θJC) ..................................................... 15°C/W SOP-8 (θJC) ......................................................... 20°C/W Electrical Characteristics VIN = VOUT + 1V; VEN = 2.25V; TJ = 25°C, bold values indicate –40°C ≤ TJ ≤ +125°C; unless noted Symbol Parameter Condition VOUT Output Voltage 10mA 10mA ≤ IOUT ≤ 1A, VOUT + 1V ≤ VIN ≤ 8V Line Regulation IOUT = 10mA, VOUT + 1V ≤ VIN ≤ 16V Load Regulation VIN = VOUT + 1V, 10mA ≤ IOUT ≤ 1A, ∆VOUT/∆T Output Voltage Temp. Coefficient, Note 5 VDO Dropout Voltage, Note 6 Min Max Units 1 2 % % 0.06 0.5 % 0.2 1 % 40 100 ppm/°C IOUT = 100mA, ∆VOUT = –1% 140 200 250 mV mV IOUT = 500mA, ∆VOUT = –1% 275 IOUT = 750mA, ∆VOUT = –1% 330 500 mV 410 550 630 mV mV –1 –2 IOUT = 1A, ∆VOUT = –1% IGND IOUT(lim) Typ mV IOUT = 100mA, VIN = VOUT + 1V 400 µA IOUT = 500mA, VIN = VOUT + 1V 4 mA IOUT = 750mA, VIN = VOUT + 1V 6.5 mA IOUT = 1A, VIN = VOUT + 1V 11 20 mA Current Limit VOUT = 0V, VIN = VOUT + 1V 1.8 2.5 A Enable Input Voltage logic low (off) 0.8 V Ground Current, Note 7 Enable Input VEN logic high (on) IEN Enable Input Current VEN = 2.25V 2.25 1 V 15 VEN = 0.8V 30 75 µA µA 2 4 µA µA Flag Output IFLG(leak) Output Leakage Current VOH = 16V 0.01 1 2 µA µA VFLG(do) Output Low Voltage VIN = 2.250V, IOL, = 250µA, Note 9 210 300 400 mV mV VFLG Low Threshold % of VOUT High Threshold % of VOUT 93 99.2 Hysteresis June 2000 % 1 3 % % MIC39100/39101/39102 MIC39100/39101/39102 Symbol Parameter Micrel Condition Min Typ Max Units 1.228 1.215 1.203 1.240 1.252 1.265 1.277 V V V 40 80 120 nA nA MIC39102 Only Reference Voltage Note 10 Adjust Pin Bias Current Reference Voltage Temp. Coefficient Note 7 Adjust Pin Bias Current Temp. Coefficient Note 1. Exceeding the absolute maximum ratings may damage the device. Note 2. The device is not guaranteed to function outside its operating rating. Note 3. Devices are ESD sensitive. Handling precautions recommended. 20 ppm/°C 0.1 nA/°C Note 4. PD(max) = (TJ(max) – TA) ÷ θJA, where θJA depends upon the printed circuit layout. See “Applications Information.” Note 5. Output voltage temperature coefficient is ∆VOUT(worst case) ÷ (TJ(max) – TJ(min)) where TJ(max) is +125°C and TJ(min) is –40°C. Note 6. VDO = VIN – VOUT when VOUT decreases to 98% of its nominal output voltage with VIN = VOUT + 1V. For output voltages below 2.25V, dropout voltage is the input-to-output voltage differential with the minimum input voltage being 2.25V. Minimum input operating voltage is 2.25V. Note 7. IGND is the quiescent current. IIN = IGND + IOUT. Note 8. VEN ≤ 0.8V, VIN ≤ 8V, and VOUT = 0V. Note 9. For a 2.5V device, VIN = 2.250V (device is in dropout). Note 10. VREF ≤ VOUT ≤ (VIN – 1V), 2.25V ≤ VIN ≤ 16V, 10mA ≤ IL ≤ 1A, TJ = TMAX. Note 11. Thermal regulation is defined as the change in output voltage at a time t after a change in power dissipation is applied, excluding load or line regulation effects. Specifications are for a 200mA load pulse at VIN = 16V for t = 10ms. MIC39100/39101/39102 4 June 2000 MIC39100/39101/39102 Micrel Typical Characteristics Power Supply Rejection Ratio Power Supply Rejection Ratio 80 80 80 VIN = 5V VOUT = 3.3V VIN = 5V VOUT = 3.3V 60 PSRR (dB) 40 IOUT = 1A COUT = 47µF CIN = 0 0 1E+1 1k 1E+4 10k 1E+5 1M 10 1E+2 100k 1E+6 100 1E+3 FREQUENCY (Hz) 20 IOUT = 1A COUT = 10µF CIN = 0 0 1E+1 1k 1E+4 10k 1E+5 1M 10 1E+2 100k 1E+6 100 1E+3 FREQUENCY (Hz) Dropout Voltage vs. Output Current Dropout Voltage vs. Temperature Power Supply Rejection Ratio 40 20 IOUT = 1A COUT = 47µF CIN = 0 0 1E+1 1k 1E+4 10k 1E+5 1M 10 1E+2 100k 1E+6 100 1E+3 FREQUENCY (Hz) 500 450 2.6 2.2 ILOAD =750mA ILOAD =1A 1.6 2.3 2.6 2.9 3.2 SUPPLY VOLTAGE (V) TA = 25°C 100 50 0 500 450 350 300 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (°C) Ground Current vs. Output Current 14 ILOAD =100mA 3.4 3.2 3.0 ILOAD =750mA 2.8 ILOAD =1A 2.6 3.2 3.6 4.0 SUPPLY VOLTAGE (V) Ground Current vs. Supply Voltage (2.5V) GROUND CURRENT (mA) ILOAD =100mA 1.2 1.0 0.8 0.6 0.4 ILOAD =10mA 0.2 0 0 June 2000 2 4 6 SUPPLY VOLTAGE (V) 8 10 8 6 25 ILOAD =1A 15 10 5 1.8V 2.5V 3.3V 4 2 200 400 600 800 1000 OUTPUT CURRENT (mA) Ground Current vs. Supply Voltage (3.3V) 1.4 30 20 12 0 0 4.4 35 1.6 1.4 2.5V 400 Dropout Characteristics (3.3V) Ground Current vs. Supply Voltage (2.5V) 2.0 1.8 1.8V 3.3V 250 500 750 1000 1250 OUTPUT CURRENT (mA) 2.4 2.8 3.5 ILOAD = 1A 550 0 1.4 2 1.8V 200 150 OUTPUT VOLTAGE (V) 2.4 1.8 3.3V 300 250 3.6 ILOAD =100mA 2.0 2.5V 400 350 Dropout Characteristics (2.5V) 2.8 600 GROUND CURRENT (mA) PSRR (dB) 60 DROPOUT VOLTAGE (mV) VIN = 3.3V VOUT = 2.5V DROPOUT VOLTAGE (mV) 20 80 40 GROUND CURRENT (mA) 40 20 IOUT = 1A COUT = 10µF CIN = 0 0 1E+1 1k 1E+4 10k 1E+5 1M 10 1E+2 100k 1E+6 100 1E+3 FREQUENCY (Hz) OUTPUT VOLTAGE (V) VIN = 3.3V VOUT = 2.5V 60 PSRR (dB) PSRR (dB) 60 GROUND CURRENT (mA) Power Supply Rejection Ratio 1.2 1.0 ILOAD =100mA 0.8 0.6 ILOAD =10mA 0.4 0.2 0 0 0 2 4 6 SUPPLY VOLTAGE (V) 5 8 0 2 4 6 SUPPLY VOLTAGE (V) 8 MIC39100/39101/39102 MIC39100/39101/39102 Micrel 1.0 GROUND CURRENT (mA) ILOAD =1A 30 20 10 0.8 0.6 3.3V 0.4 0.2 8 ILOAD = 1A 15 1.8V 2.5V 10 3.3V 5 0 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (°C) 3.40 3.35 3.25 3.20 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (°C) 12 FLAG VOLTAGE (V) 4 FLAG HIGH (OK) 3 2 1 0 0.01 0.1 FLAG LOW (FAULT) 1 10 100 100010000 RESISTANCE (kΩ) MIC39100/39101/39102 ENABLE CURRENT µA) 6 5 Typical 3.3V Device 3.30 Error Flag Pull-Up Resistor VIN = 5V 1.8V 5.0 4.5 10 Enable Current vs. Temperature VIN = VOUT + 1V VEN = 2.4V 8 6 4 2 0 -40 -20 0 20 40 60 80 100120140 TEMPERATURE (°C) 6 Ground Current vs. Temperature 2.5V 3.3V 4.0 3.5 3.0 2.5 1.8V 2.0 1.5 1.0 ILOAD = 500mA 0.5 0 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (°C) Output Voltage vs. Temperature Ground Current vs. Temperature OUTPUT VOLTAGE (V) GROUND CURRENT (mA) 20 2 4 6 SUPPLY VOLTAGE (V) 2.5V 0 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (°C) 0 0 ILOAD =10mA SHORT CIRCUIT CURRENT (A) 40 2.5 2.0 Short Circuit vs. Temperature 3.3V 1.5 2.5V 1.8V 1.0 0.5 0 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (°C) 250 FLAG VOLTAGE (mV) GROUND CURRENT (mA) 50 Ground Current vs. Temperature GROUND CURRENT (mA) Ground Current vs. Supply Voltage (3.3V) 200 Flag-Low Voltage vs. Temperature FLAG-LOW VOLTAGE 150 100 VIN = 2.25V RPULL-UP = 22kΩ 50 0 -40 -20 0 20 40 60 80 100120140 TEMPERATURE (°C) June 2000 MIC39100/39101/39102 Micrel Functional Characteristics Load Transient Response OUTPUT VOLTAGE (200mV/div.) OUTPUT VOLTAGE (200mV/div.) Load Transient Response VOUT = 2.5V COUT = 10µF VOUT = 2.5V COUT = 47µF 1A LOAD CURRENT (500mA/div.) LOAD CURRENT (500mA/div.) 1A 100mA TIME (250µs/div.) 10mA TIME (500µs/div.) VOUT = 2.5V COUT = 10µF INPUT VOLTAGE (2V/div.) OUTPUT VOLTAGE (50mV/div.) Line Transient Response TIME (25µs/div.) June 2000 7 MIC39100/39101/39102 MIC39100/39101/39102 Micrel Functional Diagrams OUT IN OV ILIMIT 1.240V Ref. 18V Thermal Shutdown MIC39100 GND MIC39100 Fixed Regulator Block Diagram OUT IN O.V. ILIMIT 1.180V FLAG Ref. 18V 1.240V EN Thermal Shutdown GND MIC39101 MIC39101 Fixed Regulator with Flag and Enable Block Diagram OUT IN O.V. ILIMIT Ref. 18V 1.240V ADJ EN Thermal Shutdown GND MIC39102 MIC39102 Adjustable Regulator Block Diagram MIC39100/39101/39102 8 June 2000 MIC39100/39101/39102 Micrel Input Capacitor An input capacitor of 1µF or greater is recommended when the device is more than 4 inches away from the bulk ac supply capacitance or when the supply is a battery. Small, 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. Error Flag The MIC39101 features an error flag (FLG), which monitors the output voltage and signals an error condition when this voltage drops 5% below its expected value. The error flag is an open-collector output that pulls low under fault conditions and may sink up to 10mA. Low output voltage signifies a number of possible problems, including an overcurrent fault (the device is in current limit) or low input voltage. The flag output is inoperative during overtemperature conditions. A pull-up resistor from FLG to either VIN or VOUT is required for proper operation. For information regarding the minimum and maximum values of pull-up resistance, refer to the graph in the typical characteristics section of the data sheet. Enable Input The MIC39101 and MIC39102 versions feature an activehigh enable input (EN) that allows on-off control of the regulator. Current drain reduces to “zero” when the device is shutdown, with only microamperes of leakage current. The EN input has TTL/CMOS compatible thresholds for simple logic interfacing. EN may be directly tied to VIN and pulled up to the maximum supply voltage Transient Response and 3.3V to 2.5V or 2.5V to 1.8V Conversion The MIC39100/1/2 has excellent transient response to variations in input voltage and load current. The device has been designed to respond quickly to load current variations and input voltage variations. Large output capacitors are not required to obtain this performance. A standard 10µF output capacitor, preferably tantalum, is all that is required. Larger values help to improve performance even further. By virtue of its low-dropout voltage, this device does not saturate into dropout as readily as similar NPN-based designs. When converting from 3.3V to 2.5V or 2.5V to 1.8V, the NPN based regulators are already operating in dropout, with typical dropout requirements of 1.2V or greater. To convert down to 2.5V or 1.8V without operating in dropout, NPNbased regulators require an input voltage of 3.7V at the very least. The MIC39100 regulator will provide excellent performance with an input as low as 3.0V or 2.5V respectively. This gives the PNP based regulators a distinct advantage over older, NPN based linear regulators. Minimum Load Current The MIC39100/1/2 regulator is specified between finite loads. If the output current is too small, leakage currents dominate and the output voltage rises. A 10mA minimum load current is necessary for proper regulation. Applications Information The MIC39100/1/2 is a high-performance low-dropout voltage regulator suitable for moderate to high-current voltage regulator applications. Its 630mV dropout voltage at full load and overtemperature makes it especially valuable in batterypowered systems and as high-efficiency noise filters in postregulator applications. Unlike older NPN-pass transistor designs, where the minimum dropout voltage is limited by the base-to-emitter voltage drop and collector-to-emitter saturation voltage, dropout performance of the PNP output of these devices is limited only by the low VCE saturation voltage. A trade-off for the low dropout voltage is a varying base drive requirement. Micrel’s Super βeta PNP™ process reduces this drive requirement to only 2% of the load current. The MIC39100/1/2 regulator is fully protected from damage due to fault conditions. Linear current limiting is provided. Output current during overload conditions is constant. Thermal shutdown disables the device when the die temperature exceeds the maximum safe operating temperature. Transient protection allows device (and load) 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. VIN MIC39100-x.x IN CIN VOUT OUT GND COUT Figure 1. Capacitor Requirements Output Capacitor The MIC39100/1/2 requires an output capacitor to maintain stability and improve transient response. Proper capacitor selection is important to ensure proper operation. The MIC39100/1/2 output capacitor selection is dependent upon the ESR (equivalent series resistance) of the output capacitor to maintain stability. When the output capacitor is 10µF or greater, the output capacitor should have an ESR less than 2Ω. This will improve transient response as well as promote stability. Ultra-low-ESR capacitors (<100mΩ), such as ceramic chip capacitors, may promote instability. These very low ESR levels may cause an oscillation and/or underdamped transient response. A low-ESR solid tantalum capacitor works extremely well and provides good transient response and stability over temperature. Aluminum electrolytics can also be used, as long as the ESR of the capacitor is <2Ω. The value of the output capacitor can be increased without limit. Higher capacitance values help to improve transient response and ripple rejection and reduce output noise. June 2000 9 MIC39100/39101/39102 MIC39100/39101/39102 Micrel sink thermal resistance) and θSA (sink-to-ambient thermal resistance). Using the power SOP-8 reduces the θJC dramatically and allows the user to reduce θCA. The total thermal resistance, θJA (junction-to-ambient thermal resistance) is the limiting factor in calculating the maximum power dissipation capability of the device. Typically, the power SOP-8 has a θJC of 20°C/W, this is significantly lower than the standard SOP-8 which is typically 75°C/W. θCA is reduced because pins 5 through 8 can now be soldered directly to a ground plane which significantly reduces the case-to-sink thermal resistance and sink to ambient thermal resistance. Low-dropout linear regulators from Micrel are rated to a maximum junction temperature of 125°C. It is important not to exceed this maximum junction temperature during operation of the device. To prevent this maximum junction temperature from being exceeded, the appropriate ground plane heat sink must be used. Adjustable Regulator Design VIN MIC39102 OUT IN VOUT R1 ENABLE SHUTDOWN EN ADJ GND COUT R2 R1 VOUT = 1.240V 1 + R2 Figure 2. Adjustable Regulator with Resistors The MIC39102 allows programming the output voltage anywhere between 1.24V and the 16V maximum operating rating of the family. Two resistors are used. Resistors can be quite large, up to 1MΩ, because of the very high input impedance and low bias current of the sense comparator: The resistor values are calculated by: V R1 = R2 OUT − 1 1.240 Where VO is the desired output voltage. Figure 2 shows component definition. Applications with widely varying load currents may scale the resistors to draw the minimum load current required for proper operation (see above). Power SOP-8 Thermal Characteristics One of the secrets of the MIC39101/2’s performance is its power SO-8 package featuring half the thermal resistance of a standard SO-8 package. Lower thermal resistance means more output current or higher input voltage for a given package size. Lower thermal resistance is achieved by joining the four ground leads with the die attach paddle to create a singlepiece electrical and thermal conductor. This concept has been used by MOSFET manufacturers for years, proving very reliable and cost effective for the user. Thermal resistance consists of two main elements, θJC (junction-to-case thermal resistance) and θCA (case-to-ambient thermal resistance). See Figure 3. θJC is the resistance from the die to the leads of the package. θCA is the resistance from the leads to the ambient air and it includes θCS (case-to- SOP-8 θJA θJC printed circuit board Figure 3. Thermal Resistance Figure 4 shows copper area versus power dissipation with each trace corresponding to a different temperature rise above ambient. From these curves, the minimum area of copper necessary for the part to operate safely can be determined. The maximum allowable temperature rise must be calculated to determine operation along which curve. COPPER AREA (mm2) ∆TJA = 100°C 900 40°C 50°C 55°C 65°C 75°C 85°C COPPER AREA (mm2) 700 600 500 400 300 200 100 0 0 ground plane heat sink area AMBIENT 900 800 θCA 800 T = 125°C J 700 TA = 85°C 50°C 25°C 600 500 400 300 200 100 0 0 0.25 0.50 0.75 1.00 1.25 1.50 POWER DISSIPATION (W) Figure 4. Copper Area vs. Power-SOP Power Dissipation MIC39100/39101/39102 0.25 0.50 0.75 1.00 1.25 1.50 POWER DISSIPATION (W) Figure 5. Copper Area vs. Power-SOP Power Dissipation 10 June 2000 MIC39100/39101/39102 Micrel ∆T = TJ(max) – TA(max) TJ(max) = 125°C TA(max) = maximum ambient operating temperature For example, the maximum ambient temperature is 50°C, the ∆T is determined as follows: ∆T = 125°C – 50°C ∆T = 75°C Using Figure 4, the minimum amount of required copper can be determined based on the required power dissipation. Power dissipation in a linear regulator is calculated as follows: PD = (VIN – VOUT) IOUT + VIN · IGND Quick Method Determine the power dissipation requirements for the design along with the maximum ambient temperature at which the device will be operated. Refer to Figure 5, which shows safe operating curves for three different ambient temperatures: 25°C, 50°C and 85°C. From these curves, the minimum amount of copper can be determined by knowing the maximum power dissipation required. If the maximum ambient temperature is 50°C and the power dissipation is as above, 836mW, the curve in Figure 5 shows that the required area of copper is 160mm2. The θJA of this package is ideally 63°C/W, but it will vary depending upon the availability of copper ground plane to which it is attached. If we use a 2.5V output device and a 3.3V input at an output current of 1A, then our power dissipation is as follows: PD = (3.3V – 2.5V) × 1A + 3.3V × 11mA PD = 800mW + 36mW PD = 836mW From Figure 4, the minimum amount of copper required to operate this application at a ∆T of 75°C is 160mm2. June 2000 11 MIC39100/39101/39102 MIC39100/39101/39102 Micrel Package Information 3.15 (0.124) 2.90 (0.114) CL 3.71 (0.146) 7.49 (0.295) 3.30 (0.130) 6.71 (0.264) CL 2.41 (0.095) 2.21 (0.087) 1.04 (0.041) 0.85 (0.033) 4.7 (0.185) 4.5 (0.177) 0.10 (0.004) 0.02 (0.0008) DIMENSIONS: MM (INCH) 6.70 (0.264) 6.30 (0.248) 1.70 (0.067) 16° 1.52 (0.060) 10° 10° MAX 0.38 (0.015) 0.25 (0.010) 0.84 (0.033) 0.64 (0.025) 0.91 (0.036) MIN SOT-223 (S) 0.026 (0.65) MAX) PIN 1 0.157 (3.99) 0.150 (3.81) DIMENSIONS: INCHES (MM) 0.020 (0.51) 0.013 (0.33) 0.050 (1.27) TYP 0.064 (1.63) 0.045 (1.14) 45° 0.0098 (0.249) 0.0040 (0.102) 0.197 (5.0) 0.189 (4.8) 0°–8° SEATING PLANE 0.010 (0.25) 0.007 (0.18) 0.050 (1.27) 0.016 (0.40) 0.244 (6.20) 0.228 (5.79) 8-Lead SOP (M) MICREL INC. 1849 FORTUNE DRIVE SAN JOSE, CA 95131 TEL + 1 (408) 944-0800 FAX + 1 (408) 944-0970 WEB USA http://www.micrel.com This information is believed to be accurate and reliable, however no responsibility is assumed by Micrel for its use nor for any infringement of patents or other rights of third parties resulting from its use. No license is granted by implication or otherwise under any patent or patent right of Micrel Inc. © 2000 Micrel Incorporated MIC39100/39101/39102 12 June 2000