MIC2937A-12BU TR

MIC2937A/29371/29372 Micrel, Inc. MIC2937A/29371/29372 750mA Low-Dropout Voltage Regulator General Description Features The MIC2937A family are “bulletproof” efficient voltage regulators with very low dropout voltage (typically 40mV at light loads and 300mV at 500mA), and very low quiescent current (160µA typical). The quiescent current of the MIC2937A increases only slightly in dropout, thus prolonging battery life. Key MIC2937A features include protection against reversed battery, fold-back current limiting, and automotive “load dump” protection (60V positive transient). • • • • • • • • The MIC2937 is available in several configurations. The MIC2937A-xx devices are three pin fixed voltage regulators with 3.3V, 5V, and 12V outputs available. The MIC29371 is a fixed regulator offering logic compatible ON/OFF switching input and an error flag output. This flag may also be used as a power-on reset signal. A logic-compatible shutdown input is provided on the adjustable MIC29372, which enables the regulator to be switched on and off. • • • • High output voltage accuracy Guaranteed 750mA output Low quiescent current Low dropout voltage Extremely tight load and line regulation Very low temperature coefficient Current and thermal limiting Input can withstand –20V reverse battery and +60V positive transients Error flag warns of output dropout Logic-controlled electronic shutdown Output programmable from 1.24V to 26V(MIC29372) Available in TO-220, TO-263, TO-220-5, and TO-263-5 packages. Applications • • • • • • • • Battery Powered Equipment Cellular Telephones Laptop, Notebook, and Palmtop Computers PCMCIA VCC and VPP Regulation/Switching Bar Code Scanners Automotive Electronics SMPS Post-Regulator/ DC to DC Modules High Efficiency Linear Power Supplies Pin Configuration 1 2 3 1 2 3 4 5 INPUT GROUND OUTPUT TO-263 Package (MIC2937A-xxBU/WU) TO-263-5 Package (MIC29371/29372BU/WU) Five Lead Package Pin Functions: MIC29371 MIC29372 1) Error Adjust 2) Input Shutdown 3) Ground Ground 4) Output Input 5) Shutdown Output 1 2 3 INPUT GROUND OUTPUT TO-220 Package (MIC2937A-xxBT/WT) 1 2 3 4 5 TO-220-5 Package (MIC29371/29372BT/WT) The TAB is Ground on the TO-220 and TO-263 packages. Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com May 2006 1 MIC2937A/29371/29372 MIC2937A/29371/29372 Micrel, Inc. Ordering Information Part Number Voltage Junction Temp. Range Package MIC2937A-3.3WU 3.3V –40ºC to +125ºC TO-263-3 MIC2937A-3.3BT MIC2937A-3.3WT 3.3V –40ºC to +125ºC TO-220-3 MIC2937A-5.0BU MIC2937A-5.0WU 5.0V –40ºC to +125ºC TO-263-3 MIC2937A-5.0BT MIC2937A-5.0WT 5.0V –40ºC to +125ºC TO-220-3 MIC2937A-12BU MIC2937A-12WU 12V –40ºC to +125ºC TO-263-3 MIC2937A-12BT MIC2937A-12WT 12V –40ºC to +125ºC TO-220-3 MIC29371-3.3BU MIC29371-3.3WU 3.3V –40ºC to +125ºC TO-263-5 MIC29371-3.3BT MIC29371-3.3WT 3.3V –40ºC to +125ºC TO-220-5 MIC29371-5.0BU MIC29371-5.0WU 5.0V –40ºC to +125ºC TO-263-5 MIC29371-5.0BT MIC29371-5.0WT 5.0V –40ºC to +125ºC TO-220-5 MIC29371-12BU MIC29371-12WU 12V –40ºC to +125ºC TO-263-5 MIC29371-12BT MIC29371-12WT 12V –40ºC to +125ºC TO-220-5 MIC29372BU MIC29372WU ADJ –40ºC to +125ºC TO-263-5 MIC29372BT MIC29372WT ADJ –40ºC to +125ºC TO-220-5 Standard RoHS Compliant* MIC2937A-3.3BU * RoHS compliant with ‘high-melting solder’ exemption. MIC2937A/29371/29372 2 May 2006 MIC2937A/29371/29372 Micrel, Inc. Absolute Maximum Ratings Operating Input Supply Voltage..................................................2V† to 26V Adjust Input Voltage (Notes 9 and 10).................................–1.5V to +26V Shutdown Input Voltage .......................................................–0.3V to +30V Error Comparator Output Voltage.........................................–0.3V to +30V Power Dissipation (Note 1)...............................................Internally Limited Lead Temperature (Soldering, 5 seconds).........................................260°C Storage Temperature Range.............................................–65°C to +150°C Operating Junction Temperature Range ..........................–40°C to +125°C TO-220 θJC .....................................................................................2.5°C/W TO-263 θJC .....................................................................................2.5°C/W Input Supply Voltage..............................................................–20V to +60V Across the full operating temperature, the minimum input voltage range for full output current is 4.3V to 26V. Output will remain in-regulation at lower output voltages and low current loads down to an input of 2V at 25°C. † Electrical Characteristics Limits in standard typeface are for TJ = 25°C and limits in boldface apply over the full operating temperature range. Unless otherwise specified, VIN = VOUT + 1V, IL = 5mA, CL = 10µF. The MIC29372 are programmed for a 5V output voltage, and VSHUTDOWN ≤ 0.6V (MIC29371-xx and MIC29372 only). Symbol VO Parameter Output Voltage Accuracy Conditions Variation from factory trimmed VOUT 5mA ≤ IL ≤ 500mA MIC2937A-12 and 29371-12 only: ΔVO ΔT ΔVO VO ΔVO VO VIN – VO Output Voltage Temperature Coef. Line Regulation Load Regulation Dropout Voltage (Note 4) 5mA ≤ IL ≤ 500mA (Note 2) Output voltage > 10V VIN = VOUT + 1V to 26V IGNDDO ILIMIT ΔVO ΔPD en Ground Pin Current (Note 5) Ground Pin Current at Dropout (Note 5) Current Limit Thermal Regulation Output Noise Voltage (10Hz to 100kHz) IL = 100mA May 2006 Typical 20 80 0.03 IL = 5 to 500mA (Note 3) IL = 5mA 0.04 IL = 100mA IL = 750mA 200 240 300 420 370 IL = 5mA 160 IL = 500mA IGND Min –1 –2 –2.5 –1.5 –3 –4 80 Output voltage > 10V Output voltage > 10V IL = 100mA 1 IL = 500mA 8 IL = 750mA VIN = 0.5V less than designed VOUT (VOUT ≥ 3.3V) IO = 5mA VOUT = 0V (Note 6) (Note 7) 0.05 CL = 10µF 400 CL = 100µF 260 3 15 200 1.1 Max 1 2 2.5 1.5 3 4 100 350 0.10 0.40 0.16 0.30 150 180 600 750 250 300 2.5 3 13 16 25 500 1.5 2 0.2 Units % ppm/°C % % mV µA mA µA A %/W µV RMS MIC2937A/29371/29372 MIC2937A/29371/29372 Micrel, Inc. Electrical Characteristics (Continued) MIC29372 Parameter Conditions Reference Voltage Reference Voltage (Note 8) Min Typical Max 1.223 1.210 1.235 1.247 1.260 V V max 1.266 V 40 60 nA 1.204 Adjust Pin Bias Current Reference Voltage Temperature Coefficient 20 (Note 7) Adjust Pin Bias Current Temperature Coefficient Error Comparator Units 20 ppm/°C 0.1 nA/°C MIC29371 Output Leakage Current VOH = 26V 0.01 1.00 2.00 µA Output Low Voltage VIN = 4.5V IOL = 250µA 150 250 400 mV Upper Threshold Voltage (Note 9) Lower Threshold Voltage (Note 9) 75 Hysteresis (Note 9) 15 Shutdown Input Input Logic Voltage Low (ON) Shutdown Pin Input Current Regulator Output Current in Shutdown 40 25 60 mV 95 140 mV mV MIC29371/MIC29372 1.3 2.0 High (OFF) 0.7 V VSHUTDOWN = 2.4V 30 50 100 µA VSHUTDOWN = 26V 450 600 750 µA 3 10 20 µA (Note 10) MIC2937A/29371/29372 4 May 2006 MIC2937A/29371/29372 Micrel, Inc. Note 1: Absolute maximum ratings indicate limits beyond which damage to the component may occur. Electrical specifications do not apply when operating the device outside of its rated operating conditions. The maximum allowable power dissipation is a function of the maximum junction temperature, TJ (MAX), the junction-to-ambient thermal resistance, θJA, and the ambient temperature, TA. The maximum allowable power dissipation at any ambient temperature is calculated using: P(MAX) = (TJ(MAX) – TA) / θJA. Exceeding the maximum allowable power dissipation will result in excessive die temperature, and the regulator will go into thermal shutdown. Note 2: Output voltage temperature coefficient is defined as the worst case voltage change divided by the total temperature range. Note 3: Regulation is measured at constant junction temperature using low duty cycle pulse testing. Changes in output voltage due to heating effects are covered by the thermal regulation specification. Note 4: Dropout Voltage is defined as the input to output differential at which the output voltage drops 100 mV below its nominal value measured at 1V differential. At low values of programmed output voltage, the minimum input supply voltage of 4.3V over temperature must be taken into account. The MIC2937A operates down to 2V of input at reduced output current at 25°C. Note 5: Ground pin current is the regulator quiescent current. The total current drawn from the source is the sum of the load current plus the ground pin current. Note 6: The MIC2937A family features fold-back current limiting. The short circuit (VOUT = 0V) current limit is less than the maximum current with normal output voltage. Note 7: 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 = 20V (a 4W pulse) for T = 10ms. Note 8: VREF ≤ VOUT ≤ (VIN – 1 V), 4.3V ≤ VIN ≤ 26V, 5mA < IL ≤ 750 mA, TJ ≤ TJ MAX. Note 9: Comparator thresholds are expressed in terms of a voltage differential at the Adjust terminal below the nominal reference voltage measured at 6V input (for a 5V regulator). To express these thresholds in terms of output voltage change, multiply by the error amplifier gain = VOUT /VREF = (R1 + R2)/R2. For example, at a programmed output voltage of 5V, the Error output is guaranteed to go low when the output drops by 95 mV x 5V/1.235 V = 384 mV. Thresholds remain constant as a percent of VOUT as VOUT is varied, with the dropout warning occurring at typically 5% below nominal, 7.7% guaranteed. Note 10: Circuit of Figure 3 with R1 ≥ 150kΩ. VSHUTDOWN ≥ 2V and VIN ≤ 26V,VOUT = 0. Note 11: When used in dual supply systems where the regulator load is returned to a negative supply, the output voltage must be diode clamped to ground. Note 12: Maximum positive supply voltage of 60V must be of limited duration (< 100ms) and duty cycle ( ≤ 1%). The maximum continuous supply voltage is 26V. Schematic Diagram FEEDBACK IN R18 20 kΩ Q15A Q15B Q24 Q25 Q9 Q3 R11 18 kΩ Q4 Q5 Q1 10 R2 50 kΩ Q40 Q17 Q16 R27 R17 12 kΩ Q14 V TAP R28 Q20 R5 180 kΩ R6 140 kΩ Q13 R12 110 kΩ Q11 R13 100 kΩ Q18 R3 50 kΩ Q21 C2 40 pF R9 27.8 k Ω Q12 Q22 R10 150 kΩ R8 31.4 k Ω Q41 R30 30 kΩ SENSE Q8 R11 20.6 kΩ Q2 R1 20 kΩ Q42 OUT Q7 C1 20 pF Q6 Q26 Q23 R15 100 k Ω R14 350 kΩ R16 30 kΩ Q29 Q19 R17 10Ω Q28 R4 13 kΩ R21 8 Ω 50 kΩ Q30 Q37 10 kΩ R22 150 k Ω Q36 R24 50 kΩ R23 60 k Ω SHDN ERROR Q38 Q34 R26 60 kΩ DENOTES CONNECTION ON MIC2937A-xx AND MIC29371-xx VERSIONS ONLY R25 2.8 kΩ GND Q39 May 2006 Q31 5 MIC2937A/29371/29372 MIC2937A/29371/29372 Micrel, Inc. Typical Characteristics DROPOUT VOLTAGE (mV) 0 0 0.1 1 GROUND CURRENT (mA) 0 -60 -30 0 30 60 90 120 150 TEMPERATURE °C) ( 100 0 10 100 1000 OUTPUT CURRENT (mA) 0.15 0.10 ILOAD = 5mA 0.00 -60 -30 0 30 60 90 120 150 TEMPERATURE °C) ( MIC2937A/29371/29372 2 3 4 5 6 7 SUPPLY VOLTAGE (V) 1.2 0.6 VOUT = VNOMINAL – 0.5V VOUT = 0V 0.4 0.2 FIXED 5V VERSION 0.0 -60 -30 0 30 60 90 120 150 TEMPERATURE °C) ( 6 2 ILOAD = 750mA 1 0 1 2 3 4 5 INPUT VOLTAGE (V) 6 Ground Current vs. Supply Voltage 25 20 15 10 5 30 25 0 FIXED 5V ILOAD = 750mA 2 4 6 8 INPUT VOLTAGE (V) 10 Ground Current vs. Temperature ILOAD = 750mA 20 15 10 5 0 -60 -30 0 30 60 90 120 150 TEMPERATURE °C) ( Short Circuit and Maximum Current vs. Temperature 1.0 0.8 ILOAD = 5mA 3 0 8 2.0 1.8 1.6 1.4 ILOAD = 100mA 1.2 1.0 0.8 0.6 0.4 0.2 0.0 -60 -30 0 30 60 90 120 150 TEMPERATURE °C) ( 1.4 CURRENT (A) OUTPUT VOLTAGE (V) Fixed 3.3V Output Voltage vs. Temperature 3.40 3.38 3.36 3.34 3.32 3.30 3.28 3.26 3.24 3.22 3.20 -60 -30 0 30 60 90 120 150 TEMPERATURE °C) ( 1 Ground Current vs. Temperature Ground Current vs. Temperature 0.20 FIXED 5V VERSION ILOAD = 5mA 0 4 30 150 50 5 0 Ground Current vs. Supply Voltage 200 GROUND CURRENT (µA) GROUND CURRENT (mA) 1 0.05 100 200 400 600 800 OUTPUT CURRENT (mA) 10 0.25 200 Ground Current vs. Output Current 30 ILOAD = 750mA 300 GROUND CURRENT (mA) 100 400 GROUND CURRENT (mA) 200 500 500 GROUND CURRENT (µA) 300 Dropout Characteristics 6 600 GROUND CURRENT (mA) DROPOUT VOLTAGE (mV) 400 Dropout Voltage vs. Temperature 700 OUTPUT VOLTAGE (V) Dropout Voltage vs. Output Current 500 400 Ground Current vs. Input Voltage RLOAD = 100Ω 300 200 100 0 -100 -30 -20 -10 0 10 20 INPUT VOLTAGE (V) 30 May 2006 MIC2937A/29371/29372 Micrel, Inc. 25 VEN = 2V 0 -60 -30 0 30 60 90 120 150 TEMPERATURE °C) ( 0 -300 1000 750 500 5mA 250 0 -250 -5 MIC29372/3 Adjust Pin Current vs. Temperature 40 COUT = 10 µF -150 ∆ OUTPUT (mV) ADJUST PIN CURRENT (nA) 50 OUTPUT (mA) ∆ OUTPUT (mV) 50 VEN = 5V 150 Load Transient 40 0 5 TIME (ms) 10 COUT = 10 µF IL = 5mA 20 0 0 -60 -30 0 30 60 90 120 150 TEMPERATURE °C) ( 8 6 4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 TIME (ms) -200 1000 750 500 5mA 250 0 -250 -5 20 10 0 5 TIME (ms) 10 Line Transient COUT = 100 µF IL = 5mA 0 8 6 4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 TIME (ms) 1 0.1 1x106 100x103 1x100 0.01 10x103 ILOAD = 10mA 1x103 OUTPUT IMPEDANCE (Ω) 10 0 Output Impedance vs. Frequency 100x100 ILOAD = 1mA COUT = 100 µF -10 10 10x100 10 Load Transeint -100 INPUT (V) -40 10 20 100 Line Transient -20 30 200 ∆ OUTPUT (mV) 75 300 INPUT (V) ENABLE CURRENT (µA) 100 OUTPUT (mA) ∆ OUTPUT (mV) MIC29371/2 Shutdown Current vs. Temperaure 125 FREQUENCY (Hz) May 2006 7 MIC2937A/29371/29372 MIC2937A/29371/29372 Micrel, Inc. Applications Information External Capacitors A 10µF (or greater) capacitor is required between the MIC2937A output and ground to prevent oscillations due to instability. Most types of tantalum or aluminum electrolytics will be adequate; film types will work, but are costly and therefore not recommended. Many aluminum electrolytics have electrolytes that freeze at about –30°C, so solid tantalums are recommended for operation below –25°C. The important parameters of the capacitor are an effective series resistance of about 5Ω or less and a resonant frequency above 500kHz. The value of this capacitor may be increased without limit. The error comparator has an NPN open-collector output which requires an external pull-up resistor. Depending on system requirements, this resistor may be returned to the 5V output or some other supply voltage. In determining a value for this resistor, note that while the output is rated to sink 250µA, this sink current adds to battery drain in a low battery condition. Suggested values range from 100k to 1MΩ. The resistor is not required if this output is unused. At lower values of output current, less output capacitance is required for output stability. The capacitor can be reduced to 0.5µF for current below 10mA or 0.15µF for currents below 1 mA. Adjusting the MIC29372 to voltages below 5V runs the error amplifier at lower gains so that more output capacitance is needed. For the worst-case situation of a 750mA load at 1.23V output (Output shorted to Adjust) a 22µF (or greater) capacitor should be used. The MIC29372 may programmed for any output voltage between its 1.235V reference and its 26V maximum rating. An external pair of resistors is required, as shown in Figure 3. Programming the Output Voltage (MIC29372) The complete equation for the output voltage is VOUT = VREF x { 1 + R1/R2 } – |IFB| R1 where VREF is the nominal 1.235 reference voltage and IFB is the Adjust pin bias current, nominally 20nA. The minimum recommended load current of 1µA forces an upper limit of 1.2MΩ on the value of R2, if the regulator must work with no load (a condition often found in CMOS in standby), IFB will produce a –2% typical error in VOUT which may be eliminated at room temperature by trimming R1. For better accuracy, choosing R2 = 100k reduces this error to 0.17% while increasing the resistor program current to 12µA. Since the MIC29372 typically draws 100µA at no load with SHUTDOWN open-circuited, this is a negligible addition. The MIC2937A/29371 will remain in regulation with a minimum load of 5mA. When setting the output voltage of the MIC29372 version with external resistors, the current through these resistors may be included as a portion of the minimum load. A 0.1µF capacitor should be placed from the input to ground if there is more than 10 inches of wire between the input and the AC filter capacitor or if a battery is used as the input. Error Detection Comparator Output (MIC29371) Reducing Output Noise A logic low output will be produced by the comparator whenever the MIC29371 output falls out of regulation by more than approximately 5%. This figure is the comparator’s built-in offset of about 75mV divided by the 1.235V reference voltage. (Refer to the block diagram on Page 1). This trip level remains “5% below normal” regardless of the programmed output voltage of the MIC29371. For example, the error flag trip level is typically 4.75V for a 5V output or 11.4V for a 12V output. The out of regulation condition may be due either to low input voltage,extremely high input voltage, current limiting, or thermal limiting. In reference applications it may be advantageous to reduce the AC noise present at the output. One method is to reduce the regulator bandwidth by increasing the size of the output capacitor. This is relatively inefficient, as increasing the capacitor from 1µF to 220µF only decreases the noise from 430µV to 160µVRMS for a 100kHz bandwidth at 5V output. Noise can be reduced by a factor of four with the adjustable regulators Figure 1 is a timing diagram depicting the ERROR signal and the regulated output voltage as the MIC29371 input is ramped up and down. The ERROR signal becomes valid (low) at about 1.3V input. It goes high at about 5V input (the input voltage at which VOUT = 4.75). Since the MIC29371’s dropout voltage is load-dependent (see curve in Typical Performance Characteristics), the input voltage trip point (about 5V) will vary with the load current. The output voltage trip point (approximately 4.75V) does not vary with load. OUTPUT VOLTAGE 4.75V NOT* VALID ERROR NOT* VALID INPUT VOLTAGE 5V 1.3V * SEE APPLICATIONS INFORMATION Figure 1. ERROR Output Timing MIC2937A/29371/29372 8 May 2006 MIC2937A/29371/29372 Micrel, Inc. Automotive Applications with a bypass capacitor across R1, since it reduces the high frequency gain from 4 to unity. Pick CBYPASS ≅ The MIC2937A is ideally suited for automotive applications for a variety of reasons. It will operate over a wide range of input voltages with very low dropout voltages (40mV at light loads), and very low quiescent currents (100µA typical). These features are necessary for use in battery powered systems, such as automobiles. It is a “bulletproof” device with the ability to survive both reverse battery (negative transients up to 20V below ground), and load dump (positive transients up to 60V) conditions. A wide operating temperature range with low temperature coefficients is yet another reason to use these versatile regulators in automotive designs. 1 2 π R1 • 200 Hz or about 0.01µF. When doing this, the output capacitor must be increased to 10µF to maintain stability. These changes reduce the output noise from 430µV to 100µVRMS for a 100 kHz bandwidth at 5V output. With the bypass capacitor added, noise no longer scales with output voltage so that improvements are more dramatic at higher output voltages. Typical Applications VIN VIN VOUT +VIN VOUT VOUT = 5V SHUTDOWN INPUT + 10µF SHUTDOWN OFF GND ADJUST ON VOUT 1.2V R1 .01 µF 26V 10µF 1.23V GND V REF R VOUT = VREF x (1 + 1 ) R2 Figure 2. MIC2937A-5.0 Fixed +5V Regulator R2 Figure 3. MIC29372 Adjustable Regulator +5V to +7V +VIN +V IN VIN VOUT SHUTDOWN INPUT VOUT ≈ VIN V CC OUT VOUT SHUTDOWN OFF ON GND GND ADJUST ADJUST 5V 470 k Ω 100pF 220k Ω 1% 300k Ω 1% + 10µF 180k Ω 1% 2N2222 3.3V Input 0 1 Output 3.3V 5.0V *MINIMUM INPUT-OUTPUT VOLTAGE RANGES FROM 40mV TO 400mV, DEPENDING ON LOAD CURRENT. SHUTDOWN PIN LOW= ENABLE OUTPUT. Q1 ON = 3.3V, Q1 OFF = 5.0V. Figure 4. MIC29372 Wide Input Voltage Range Current Limiter Figure 5. MIC29372 5.0V or 3.3V Selectable Regulator with Shutdown. May 2006 9 MIC2937A/29371/29372 MIC2937A/29371/29372 Micrel, Inc. Package Information 3-Pin TO-263 (U) 3-Pin TO-220 (T) MIC2937A/29371/29372 10 May 2006 MIC2937A/29371/29372 Micrel, Inc. θ4 θ1 θ2 θ1 θ1 θ2 θ3 θ4 θ1 θ3 5-Pin TO-263 (U) 5-Pin TO-220 (T) May 2006 11 MIC2937A/29371/29372 MIC2937A/29371/29372 Micrel, Inc. MICREL INC. TEL 2180 FORTUNE DRIVE + 1 (408) 944-0800 FAX SAN JOSE, CA 95131 + 1 (408) 474-1000 WEB USA http://www.micrel.com This 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. © 1999 Micrel, Inc. MIC2937A/29371/29372 12 May 2006