MIC37100/37101/37102 1A Low-Voltage µCap LDO General Description Features The MIC37100, MIC37101, and MIC37102 are 1A low• Fixed and adjustable output voltages to 1.24V dropout, linear voltage regulators that provide low-voltage, • µCap Regulator, 10µF ceramic output capacitor stable high-current output from an extremely small package. • 280mV typical dropout at 1A Utilizing Micrel’s proprietary Super βeta PNP® pass – Ideal for 3.0V to 2.5V conversion element, the MIC37100/01/02 offers extremely low dropout – Ideal for 2.5V to 1.8V, 1.65V or 1.5V conversion (typically 280mV at 1A) and low ground current (typically • 1A minimum guaranteed output current 11mA at 1A). • 1% initial accuracy The MIC37100 is a fixed output regulator offered in the SOT-223 package. The MIC37101 and MIC37102 are • Low ground current fixed and adjustable regulators, respectively, in a thermally • Current limiting and thermal shutdown enhanced power 8-pin SOIC (small outline package) and • Reversed-leakage protection the SOT-223 package. The MIC37102 is also available in • Fast transient response the S-PAK power package, for applications that require • Low-profile SOT-223 package higher power dissipation or higher operating ambient • Power SO-8 package temperatures. • S-PAK package (MIC37102 only) The MIC37100/01/02 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 or lower. A guaranteed maximum dropout Applications voltage of 500mV over all operating conditions allows the • LDO linear regulator for PC add-in cards MIC37100/01/02 to provide 2.5V from a supply as low as 3V and 1.8V from a supply as low as 2.3V. • PowerPC® power supplies The MIC37100/01/02 is fully protected with overcurrent • High-efficiency linear power supplies limiting and thermal shutdown. Fixed output voltages of • SMPS post regulator 1.5V, 1.65V, 1.8V, 2.5V and 3.3V are available on • Multimedia and PC processor supplies MIC37100/01 with adjustable output voltages to 1.24V on • Battery chargers MIC37102. • Low-voltage microcontrollers and digital logic Data sheets and support documentation can be found on Micrel’s web site at: www.micrel.com. ___________________________________________________________________________________________________________ Typical Application 350 GND 300 2.5V 10F ceramic DROPOUT (mV) VIN 3.3V MIC37100 OUT IN Dropout vs. Output Current 2.5VOUT 250 200 150 3.3VOUT 100 50 2.5V/1A Regulator 0 0 0.25 0.5 0.75 OUTPUT CURRENT (A) 1 Super βeta PNP is a registered trademark of Micrel, Inc. PowerPC is a registered trademark of IBM Corporation Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com September 2007 M9999-090607 Micrel, Inc. MIC37100/37101/37102 Ordering Information Part Number Voltage Temperature Range Package Pb-Free / RoHS Compliant Standard MIC37100-1.5BS MIC37100-1.5WS* 1.5V –40° to +125°C SOT-223 MIC37100-1.65BS MIC37100-1.65WS* 1.65V –40° to +125°C SOT-223 MIC37100-1.8BS MIC37100-1.8WS* 1.8V –40° to +125°C SOT-223 MIC37100-2.5BS MIC37100-2.5WS* 2.5V –40° to +125°C SOT-223 MIC37100-3.3BS MIC37100-3.3WS* 3.3V –40° to +125°C SOT-223 MIC37101-1.5BM MIC37101-1.5YM 1.5V –40° to +125°C 8-Pin SOIC MIC37101-1.65BM MIC37101-1.65YM 1.65V –40° to +125°C 8-Pin SOIC MIC37101-1.8BM MIC37101-1.8YM 1.8V –40° to +125°C 8-Pin SOIC Contact Factory MIC37101-2.1YM 2.1V –40° to +125°C 8-Pin SOIC MIC37101-2.5BM MIC37101-2.5YM 2.5V –40° to +125°C 8-Pin SOIC MIC37101-3.3BM MIC37101-3.3YM 3.3V –40° to +125°C 8-Pin SOIC MIC37102BM MIC37102YM Adj. –40° to +125°C 8-Pin SOIC MIC37102BR MIC37102WR* Adj. –40° to +125°C 5-Pin S-PAK * RoHS compliant with ‘high-melting solder’ exemption. Pin Configuration GND 5 4 3 2 1 TAB TAB 1 IN 2 ADJ OUT GND IN EN 3 GND OUT SOT-223 (S) MIC37100-x.x (Fixed) 5-Pin S-PAK (R) MIC37102 (Adjustable) 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 8-Pin SOIC MIC37101-x.x (Fixed) September 2007 8-Pin SOIC MIC37102 (Adjustable) 2 M9999-090607 Micrel, Inc. MIC37100/37101/37102 Pin Description Pin Number MIC37100 SOT-223 Pin Number MIC37101 SOIC-8 Pin Number MIC37102 SOIC-8 Pin Number MIC37102 S-PAK Pin Name — 1 1 1 EN Enable (Input): CMOS-compatible control input. Logic high = enable, logic low or open = shutdown. Supply (Input). Pin Description 1 2 2 2 IN 3 3 3 4 OUT Regulator Output. — 4 — — FLG Flag (Output): Open-collector error flag output. Active low = output under voltage. — — 4 5 ADJ Adjustment Input: Feedback input. Connect to resistive voltage-divider network. 2, TAB 5–8 5–8 3, TAB GND Ground. September 2007 3 M9999-090607 Micrel, Inc. MIC37100/37101/37102 Absolute Maximum Ratings(1) Operating Ratings(2) Supply Voltage (VIN) .......................................... 0V to +6.5V Enable Voltage (VEN)...................................................+6.5V Lead Temperature (soldering, 5 sec.)........................ 260°C Storage Temperature (Ts) .........................–65°C to +150°C ESD Rating(3) Supply Voltage (VIN)...................................... +2.25V to +6V Enable Voltage (VEN)............................................ 0V to +6V Maximum Power Dissipation (PD(max))(4) Junction Temperature (TJ) ........................ –40°C to +125°C Package Thermal Resistance SOT-223 (θJC) ....................................................15°C/W SOIC-8 (θJC).......................................................20°C/W S-PAK-5 (θJC).......................................................2°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 ≤ 6V Line Regulation IOUT = 10mA, VOUT + 1V ≤ VIN ≤ 6V VIN = VOUT + 1V, 10mA ≤ IOUT ≤ 1A Load Regulation ∆VOUT/∆T Output Voltage Temp. Coefficient VDO Dropout Voltage IGND IOUT(lim) Ground Current (6) (7) Current Limit Min Typ Max Units 1 2 % % 0.06 0.5 % 0.2 1 –1 –2 (6) 40 % pm/°C IOUT = 100mA, ∆VOUT = –1% 125 200 mV IOUT = 500mA, ∆VOUT = –1% 210 350 mV IOUT = 750mA, ∆VOUT = –1% 250 400 mV IOUT = 1A, ∆VOUT = –1% 280 500 mV IOUT = 100mA, VIN = VOUT + 1V 650 µA IOUT = 500mA, VIN = VOUT + 1V 3.5 mA IOUT = 750mA, VIN = VOUT + 1V 6.7 mA IOUT = 1A, VIN = VOUT + 1V 11 25 mA VOUT = 0V, VIN = VOUT + 1V 1.6 2.5 A 0.8 V Enable Input VEN Enable Input Voltage logic low (off) logic high (on) IEN Enable Input Current V 2.25 VEN = 2.25V 1 10 30 µA 2 4 µA µA 0.01 1 2 µA µA 210 500 mV VEN = 0.8V Flag Output IFLG(leak) Output Leakage Current VOH = 6V VFLG(do) Output Low Voltage VIN = 2.250V, IOL, = 250µA VFLG Low Threshold % of VOUT High Threshold % of VOUT 93 % 99.2 Hysteresis 1 % % MIC37102 Only 1.228 1.215 Reference Voltage Adjust Pin Bias Current September 2007 4 1.240 1.252 1.265 V V 40 80 120 nA nA M9999-090607 Micrel, Inc. MIC37100/37101/37102 Notes: 1. Exceeding the absolute maximum rating may damage the device. 2. The device is not guaranteed to function outside its operating rating. 3. Devices are ESD sensitive. Handling precautions recommended. 4. PD(max) = (TJ(max) – TA) ÷ θJA, where θJA depends upon the printed circuit layout. See “Applications Information” section. 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. 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. 7. IGND is the quiescent current. IIN = IGND + IOUT. 8. VEN ≤ 0.8V, VIN ≤ 6V, and VOUT = 0V. September 2007 5 M9999-090607 Micrel, Inc. MIC37100/37101/37102 Typical Characteristics September 2007 6 M9999-090607 Micrel, Inc. MIC37100/37101/37102 Typical Characteristics (continued) September 2007 7 M9999-090607 Micrel, Inc. MIC37100/37101/37102 Typical Characteristics (continued) September 2007 8 M9999-090607 Micrel, Inc. MIC37100/37101/37102 Functional Characteristics September 2007 9 M9999-090607 Micrel, Inc. MIC37100/37101/37102 Functional Diagrams OUT IN Ref. 1.240V Thermal Shutdown MIC37100 MIC37100 Fixed Regulator Block Diagram OUT IN 1.180V FLAG Ref. 1.240V EN Thermal Shutdown GND MIC37101 MIC37101 Fixed Regulator with Flag and Enable Block Diagram OUT IN Ref. 1.240V ADJ EN Thermal Shutdown GND MIC37102 MIC37102 Adjustable Regulator Block Diagram September 2007 10 M9999-090607 Micrel, Inc. MIC37100/37101/37102 much as 50% and 60% respectively over their operating temperature ranges. To use a ceramic chip capacitor with Y5V dielectric, the value must be much higher than an X7R ceramic capacitor to ensure the same minimum capacitance over the equivalent operating temperature range. Application Information The MIC37100/01/02 is a high-performance low-dropout voltage regulator suitable for moderate to high-current voltage regulator applications. Its 500mV dropout voltage at full load and overtemperature makes it especially valuable in battery-powered systems and as highefficiency noise filters in post-regulator 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 MIC37100/01/02 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. The output structure of these regulators allows voltages in excess of the desired output voltage to be applied without reverse current flow. VIN CIN MIC37100-x.x IN OUT GND 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 MIC37101 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. VOUT COUT Enable Input The MIC37101 and MIC37102 versions feature an active-high 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 Figure 1. Capacitor Requirements Output Capacitor The MIC37100/01/02 requires an output capacitor to maintain stability and improve transient response. As a µCap LDO, the MIC37100/01/02 can operate with ceramic output capacitors as long as the amount of capacitance is 10µF or greater. For values of output capacitance lower than 10µF, the recommended ESR range is 200mΩ to 2Ω. The minimum value of output capacitance recommended for the MIC37100/01/02 is 4.7µF. For 10µF or greater the ESR range recommended is less than 1Ω. Ultra-low ESR ceramic capacitors are recommended for output capacitance of 10µF or greater to help improve transient response and noise reduction at high frequency. X7R/X5R dielectric-type ceramic capacitors are recommended because of their temperature performance. X7R-type capacitors change capacitance by 15% over their operating temperature range and are the most stable type of ceramic capacitors. Z5U and Y5V dielectric capacitors change value by as September 2007 Transient Response and 3.3V to 2.5V or 2.5V to 1.8V, 1.65V or 1.5V Conversion The MIC37100/01/02 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, 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, or lower, 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 11 M9999-090607 Micrel, Inc. MIC37100/37101/37102 without operating in dropout, NPN-based regulators require an input voltage of 3.7V at the very least. The MIC37100 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. Thermal resistance consists of two main elements, θJC (junction-to-case thermal resistance) and θCA (case-toambient 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-sink thermal resistance) and θSA (sink-to-ambient thermal resistance). Minimum Load Current The MIC37100/01/02 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. SOIC-8 Adjustable Regulator Design MIC37102 VIN IN VOUT OUT JA R1 EN ENABLE SHUTDOWN ADJ GND R2 JC ground plane heat sink area CA COUT AMBIENT printed circuit board R1 ⎞ ⎛ VOUT = 1.240V ⎜1 + ⎟ R2 ⎠ ⎝ Figure 3. Thermal Resistance Figure 2. Adjustable Regulator with Resistors The MIC37102 allows programming the output voltage anywhere between 1.24V and the 6V 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). September 2007 COPPER AREA (mm 2) Power SOIC-8 Thermal Characteristics One of the secrets of the MIC37101/02’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 single-piece electrical and thermal conductor. This concept has been used by MOSFET manufacturers for years, proving very reliable and cost effective for the user. 700 TJA = 50°C 55°C 65°C 75°C 85°C Using the power SOIC-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 SOIC-8 has a θJC of 20°C/W, this is significantly lower than the standard SOIC-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. 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 SO-8 Power Dissipation 12 M9999-090607 Micrel, Inc. MIC37100/37101/37102 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. ∆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 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. September 2007 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. COPPER AREA (mm 2) 900 800 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 5. Copper Area vs. Power-SOIC Power Dissipation 13 M9999-090607 Micrel, Inc. MIC37100/37101/37102 Package Information SOT-223 (S) 5-Pin S-PAK (R) September 2007 14 M9999-090607 Micrel, Inc. MIC37100/37101/37102 8-Pin SOIC (M) MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA TEL +1 (408) 944-0800 FAX +1 (408) 474-1000 WEB http://www.micrel.com The information furnished by Micrel in this data sheet is believed to be accurate and reliable. However, no responsibility is assumed by Micrel for its use. Micrel reserves the right to change circuitry and specifications at any time without notification to the customer. Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product can reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical implant into the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. A Purchaser’s use or sale of Micrel Products for use in life support appliances, devices or systems is a Purchaser’s own risk and Purchaser agrees to fully indemnify Micrel for any damages resulting from such use or sale. © 2005 Micrel, Incorporated. September 2007 15 M9999-090607