MIC2950/2951 Micrel, Inc. MIC2950/2951 150mA Low-Dropout Voltage Regulator General Description Features * The MIC2950 and MIC2951 are "bulletproof" micropower voltage regulators with very low dropout voltage (typically 40mV at light loads and 250mV at 100mA), and very low quiescent current. Like their predecessors, the LP2950 and LP2951, the quiescent current of the MIC2950/MIC2951 increases only slightly in dropout, thus prolonging battery life. The MIC2950/ MIC2951 are pin for pin compatible with the LP2950/LP2951, but offer lower dropout, lower quiescent current, reverse battery, and automotive load dump protection. * * * * * * * * The key additional features and protection offered include higher output current (150mA), positive transient protection for up to 60V (load dump), and the ability to survive an unregulated input voltage transient of -20V below ground (reverse battery). * * * High accuracy 3.3, 4.85, or 5V, guaranteed 150mA output Extremely low quiescent current Low-dropout voltage Extremely tight load and line regulation Very low temperature coefficient Use as regulator or reference Needs only 1.5F for stability Current and thermal limiting Unregulated DC input can withstand -20V reverse battery and +60V positive transients Error flag warns of output dropout (MIC2951) Logic-controlled electronic shutdown (MIC2951) Output programmable from 1.24V to 29V (MIC2951) Applications The plastic DIP and SOIC versions offer additional system functions such as programmable output voltage and logic controlled shutdown. The 3-pin TO-92 MIC2950 is pincompatible with the older 5V regulators. * * * * * * * These system functions also include an error flag output that warns of a low output voltage, which is often due to failing batteries on the input. This may also be used as a power-on reset. A logic-compatible shutdown input is also available which enables the regulator to be switched on and off. This part may also be pin-strapped for a 5 V output, or programmed from 1.24 V to 29 V with the use of two external resistors. Automotive Electronics Battery Powered Equipment Cellular Telephones SMPS Post-Regulator Voltage Reference Avionics High Efficiency Linear Power Supplies Block Diagram Unregulated DC Supply FB IN OUT SNS Error Amp. 182k SHDN TTL/CMOS Control Logic Input 60mV 5V/150mA Output 60k Error Detection Comparator T AP 330k ERR 1.5F 1.23V REF. TTL/CMOS Compatible Error Output GND Micrel, Inc. * 2180 Fortune Drive * San Jose, CA 95131 * USA * tel + 1 (408) 944-0800 * fax + 1 (408) 474-1000 * http://www.micrel.com July 2005 1 MIC2950/2951 MIC2950/2951 Micrel, Inc. The MIC2950 and MIC2951 have a tight initial tolerance (0.5% typical), a very low output voltage temperature coefficient which allows use as a low-power voltage reference, and extremely good load and line regulation (0.04% typical). This greatly reduces the error in the overall circuit, and is the result of careful design techniques and process control. The MIC2950 is available as either an -05 or -06 version. The -05 and -06 versions are guaranteed for junction temperatures from -40C to +125C; the -05 version has a tighter output and reference voltage specification range over temperature. The MIC2951 is available as an -02 or -03 version. Ordering Information Part Number Pb-Free** Standard Voltage Accuracy Temp Range* Package MIC2950-05BZ MIC2950-05YZ 5.0V 0.5% -40C to +125C TO-92 MIC2950-06BZ MIC2950-06YZ 5.0V 1.0% -40C to +125C TO-92 MIC2951-02BM MIC2951-02YM 5.0V 0.5% -40C to +125C 8-pin SOIC MIC2951-03BM MIC2951-03YM 5.0V 1.0% -40C to +125C 8-pin SOIC MIC2951-02BN Contact Factory 5.0V 0.5% -40C to +125C 8-pin Plastic DIP MIC2951-03BN MIC2951-03YN 5.0V 1.0% -40C to +125C 8-pin Plastic DIP MIC2951-03BMM MIC2951-03YMM 5.0V 1.0% -40C to +125C 8-lead MSOP MIC2951-3.3BM MIC2951-3.3YM 3.3V 1.0% -40C to +125C 8-pin SOIC *Junction temperature **PB-Free RoHS compliant with "hot-melting solder" exemption Pin Configuration MIC2951-xx MIC2950-xx 3 2 1 OUT IN GND OUT 1 8 IN SNS 2 7 FB SHDN 3 6 T AP GND 4 5 ERR DIP (N), SOIC (M), MM8TM (MM) (Top View) TO-92 (Z) (Bottom View) Pin Description Pin # MIC2950 Pin # MIC2951 Pin Name 3 2 1 MIC2950/2951 Pin Function 1 OUT Regulated Output 2 SNS Sense (Input): Output-voltage sensing end of internal voltage divider for fixed 5V operation. Not used in adjustable configuration. 3 SHDN 4 GND Ground 5 ERR Error Flag (Output): Active low, open-collector output (low = error, floating = normal). 6 TAP 3.3V/4.85/5V Tap: Output of internal voltage divider when the regulator is configured for fixed operation. Not used in adjustable configuration. 7 FB Feedback (Input): 1.235V feedback from internal voltage divider's TAP (for fixed operation) or external resistor network (adjustable configuration). 8 IN Unregulated Supply Input Shutdown/Enable (Input): TTL compatible input. High = shutdown, low or open = enable. 2 July 2005 MIC2950/2951 Micrel, Inc. Absolute Maximum Ratings (Note 1) Operating Ratings (Note 2) Input Suppy Voltage (VIN) Note 5 ..................-20V to +60V Feedback Input Voltage (VFB) Note 6, 7 .......-1.5V to +26V Shutdown Input Voltage (VSHDN) Note 6 ........-0.3V to +30V Power Dissipation (PD) Note 4 ................ Internally Limited Storage Temperature ............................... -65C to + 150C Lead Temperature (soldering, 5 sec.) ........................ 260C ESD, Note 3 Input Supply Voltage (VIN)............................. +2.0V to +30V Junction Temperature (TJ) ........................................ Note 4 MIC2950-05/MIC2950-06 ..................... -40C to +125C MIC2951-02/MIC2950-03 ..................... -40C to +125C Electrical Characteristics (Note 16) VIN = 6V; IL = 100A; CL = 1F; TJ = 25C, bold values indicate -40C TJ +125C; Note 8; unless noted. Parameter Condition Output Voltage MIC295x-02/-05 (0.5%), TJ = 25C Output Voltage Output Voltage Over Full Temperature Range Output Voltage Over Load Variation Output Voltage Temperature Coefficient Line Regulation July 2005 Min Typ Max Units 4.975 5.000 5.025 V MIC295x-03/-06 (1%), TJ = 25C 4.950 5.000 5.050 V MIC2951-3.3 (1%), TJ = 25C 3.267 3.300 3.333 V MIC2951-4.8 (1%), TJ = 25C 4.802 4.850 4.899 V MIC295x-02/-05 (0.5%), -25C TJ +85C 4.950 5.050 V MIC295x-03/-06 (1%), -25C TJ +85C 4.925 5.075 V MIC2951-3.3 (1%), -25C TJ +85C 3.251 3.350 V MIC2951-4.8 (1%), -25C TJ +85C 4.777 4.872 V MIC295x-02/-05 (0.5%), -40C to +125C 4.940 5.060 V MIC295x-03/-06 (1%), -40C to +125C 4.900 5.100 V MIC2951-3.3 (1%), -40C to +125C 3.234 3.366 V MIC2951-4.8 (1%), -40C to +125C 4.753 4.947 V MIC295x-02/-05 (0.5%), 100A IL 150mA, TJ TJ(max) 4.930 5.070 V MIC295x-03/-06 (1%), 100A IL 150mA, TJ TJ(max) 4.880 5.120 V MIC2951-3.3 (1%), 100A IL 150mA, TJ TJ(max) 3.221 3.379 V MIC2951-4.8 (1%), 100A IL 150mA, TJ TJ(max) 4.733 4.967 V MIC295x-02/-05 (0.5%), Note 9 20 100 ppm/C MIC295x-03/-06 (1%), Note 9 50 150 ppm/C MIC2951-3.3 (1%), Note 9 50 150 ppm/C MIC2951-4.8 (1%), Note 9 50 150 ppm/C MIC295x-02/-05 (0.5%), Note 10, 11 0.03 0.10 0.20 % % MIC295x-03/-06 (1%), Note 10, 11 0.04 0.20 0.40 % % MIC2951-3.3 (1%), Note 10, 11 0.04 0.20 0.40 % % MIC2951-4.8 (1%), Note 10, 11 0.04 0.20 0.40 % % 3 MIC2950/2951 MIC2950/2951 Micrel, Inc. Parameter Condition Load Regulation Dropout Voltage Ground Current Dropout Ground Current MIC2950/2951 Min Typ Max Units MIC295x-02/-05 (0.5%), 100A IL 150mA, Note 10 0.04 0.10 0.20 % % MIC295x-03/-06 (1%), 100A IL 150mA, Note 10 0.10 0.20 0.30 % % MIC2951-3.3 (1%), 100A IL 150mA, Note 10 0.10 0.20 0.30 % % MIC2951-4.8 (1%), 100A IL 150mA, Note 10 0.10 0.20 0.30 % % MIC295x-02/-03/-05/-06, IL = 100A, Note 12 40 80 140 mV mV MIC295x-02/-03/-05/-06, IL = 100mA, Note 12 250 300 mV MIC295x-02/-03/-05/-06, IL = 150mA, Note 12 300 450 600 mV mV MIC2951-3.3 (1%), IL = 100A, Note 12 40 80 150 mV mV MIC2951-3.3 (1%), IL = 100mA, Note 12 250 350 mV MIC2951-3.3 (1%), IL = 150mA, Note 12 320 450 600 mV mV MIC2951-4.8 (1%), IL = 100A, Note 12 40 80 140 mV mV MIC2951-4.8 (1%), IL = 100mA, Note 12 250 300 mV MIC2951-4.8 (1%), IL = 150mA, Note 12 300 450 600 mV mV MIC295x-02/-03/-05/-06, IL = 100A 120 180 300 A A MIC295x-02/-03/-05/-06, IL = 100mA 1.7 2.5 3.5 mA mA MIC295x-02/-03/-05/-06, IL = 150mA 4 6 8 mA mA MIC2951-3.3 (1%), IL = 100A 100 180 300 A A MIC2951-3.3 (1%), IL = 100mA 1.7 2.5 mA MIC2951-3.3 (1%), IL = 150mA 4 6 10 mA mA MIC2951-4.8 (1%), IL = 100A 120 180 300 A A MIC2951-4.8 (1%), IL = 100mA 1.7 2.5 3.5 mA mA MIC2951-4.8 (1%), IL = 150mA 4 6 8 mA mA MIC295x-02/-03/-05/-06 (0.5%), VIN = 4.5V, IL = 100A 280 350 400 A A MIC2951-3.3 (1%), VIN = 3.0V, IL = 100A 150 350 400 A A MIC2951-4.8 (1%), VIN = 4.3V, IL = 100A 280 350 400 A A 4 July 2005 MIC2950/2951 Micrel, Inc. Parameter Condition Current Limit Thermal Regulation Output Noise Reference Voltage Reference Voltage Min Typ Max Units VOUT = 0V 300 400 450 mA mA Note 13 0.05 0.20 %/W 10Hz to 100kHz, CL = 1.5F 430 VRMS 10Hz to 100kHz, CL = 200F 160 VRMS 10Hz to 100kHz, CL = 3.3F, 0.01F bypass Feedback to Output 100 VRMS MIC295x-02/-05 (0.5%) 1.220 1.200 1.235 1.250 1.260 V V MIC295x-03/-06 (1%) 1.210 1.200 1.235 1.260 1.270 V V MIC2951-3.3 (1%) 1.210 1.200 1.235 1.260 1.270 V V MIC2951-4.8 (1%) 1.210 1.200 1.235 1.260 1.270 V V MIC295x-02/-05 (0.5%), Note 14 1.190 1.270 V MIC295x-03/-06 (1%), Note 14 1.185 1.285 V MIC2951-3.3 (1%), Note 14 1.185 1.285 V MIC2951-4.8 (1%), Note 14 1.185 1.285 V 40 60 nA nA Feedback Bias Current Reference Voltage Temperature Coefficient 20 MIC295x-02/-05 (0.5%), Note 9 20 ppm/C MIC295x-03/-06 (1%), Note 9 50 ppm/C MIC2951-3.3 (1%), Note 9 50 ppm/C 50 ppm/C 0.1 nA/C MIC2951-4.8 (1%), Note 9 Feedback Bias Current Temperature Coefficient Error Comparator (Flag) Output Leakage Current VOH = 30V 0.01 1.00 2.00 A A Error Comparator (Flag) Output Low Voltage VIN = 4.5V, IOL = 200A 150 250 400 mV mV Error Comparator Upper Threshold Voltage Note 15 Error Comparator Lower Threshold Voltage Note 15 75 Error Comparator Hysteresis Note 15 15 July 2005 40 25 5 60 mV mV 95 140 mV mV mV MIC2950/2951 MIC2950/2951 Micrel, Inc. Parameter Condition Shutdown Input Logic Voltage MIC295x-02/-05 (0.5%) Low High Min 1.3 2.0 MIC295x-03/-06 (1%) Low High 1.3 2.0 MIC2951-3.3 (1%) Low High 1.3 2.0 MIC2951-4.8 (1%) Low High Shutdown Input Current Regulator Output Current in Shutdown Typ 1.3 2.0 Max Units 0.7 V V V 0.7 V V V 0.7 V V V 0.7 V V V VSHUTDOWN = 2.4V 30 50 100 A A VSHUTDOWN = 30V 450 600 750 A A 3 10 20 A A Note 7 Note 1. Exceeding the absolute maximum rating 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 are recommended. Note 4. The junction-to-ambient thermal resistance of the TO-92 package is 180C/W with 0.4" leads and 160C/W with 0.25" leads to a PC board. The thermal resistance of the 8-pin DIP package is 105C/W junction-to-ambient when soldered directly to a PC board. Junction-to-ambient thermal resistance for the SOIC (M) package is 160C/W. Junction-to-ambient thermal resistance for the MM8TM (MM) is 250C/W. Note 5. The maximum positive supply voltage of 60V must be of limited duration (100ms) and duty cycle (1%). The maximum continuous supply voltage is 30V. Note 6. When used in dual-supply systems where the output terminal sees loads returned to a negative supply, the output voltage should be diodeclamped to ground. Note 7. VSHDN 2V, VIN 30 V, VOUT = 0, with the FB pin connected to TAP. Note 8. Additional conditions for 8-pin devices are VFB = 5V, TAP and OUT connected to SNS (VOUT = 5V) and VSHDN 0.8V. Note 9. Output or reference voltage temperature coefficient is defined as the worst case voltage change divided by the total temperature range. Note 10. Regulation is measured at constant junction temperature, using pulse testing with a low duty cycle. Changes in output voltage due to heating effects are covered in the specification for thermal regulation. Note 11. Line regulation for the MIC2951 is tested at 150C for IL = 1mA. For IL = 100A and TJ = 125C, line regulation is guaranteed by design to 0.2%. See Typical Performance Characteristics for line regulation versus temperature and load current. Note 12. Dropout voltage is defined as the input to output differential at which the output voltage drops 100mV below its nominal value measured at 1V differential. At very low values of programmed output voltage, the minimum input supply voltage of 2V (2.3V over temperature) must be taken into account. Note 13. 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 50mA load pulse at VIN = 30V (1.25W pulse) for t = 10ms. Note 14. VREF VOUT (VIN - 1 V), 2.3V VIN 30V, 100A < IL 150mA, TJ TJMAX. Note 15. Comparator thresholds are expressed in terms of a voltage differential at the FB terminal below the nominal reference voltage measured at 6V input. 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 95mV x 5V/1.235V = 384mV. Thresholds remain constant as a percent of VOUT as VOUT is varied, with the dropout warning occurring at typically 5% below nominal, 7.5% guaranteed. Note 16. Specification for packaged product only. MIC2950/2951 6 July 2005 MIC2950/2951 Micrel, Inc. Typical Characteristics O U T P U T V O L T AG E (V ) 10 4 3 1 5.06 0 1 2 3 4 5 6 7 O U T P U T V O L T AG E (V ) I N P U T C U R R E N T ( mA ) Input Current R L = 50 200 150 100 50 Q U I E S C E N T C U R R E N T ( mA ) Q U I E S C E N T C U R R E N T ( A ) IN I L = 100 A 0 -75 -50 -25 0 25 50 75 100 125 150 5 Output Voltage vs. Temperature of 3 Representative Units 4.98 0.2% 4.96 7 250 200 150 100 -75 -50 -25 0 25 50 75 100 125 150 TEMPERATURE (C) 0 1 2 3 4 IN I L = 150 mA 5 140 I L = 1 mA 120 100 IL= 0 80 60 40 20 0 0 1 I L = 150 mA 400 300 100 I L = 100 A 50 0 -75 -50 -25 0 25 50 75 100 125 150 TEMPERATURE (C) 7 2 3 4 5 6 7 8 INPUT VOLTAGE (V) Ground Pin Current 9 7 5 I L = 150 mA 3 0 0 1 2 3 4 5 6 7 8 INPUT VOLTAGE (V) Dropout Voltage 500 5 6 7 8 9 10 Ground Pin Current Ground Pin Current 6 50 TEMPERATURE (C) D R O P O U T V O L T A G E ( mV ) 300 R L= 100 180 Dropout Voltage 500 600 350 150 INPUT VOLTAGE (V) 4 -75 -50 -25 0 25 50 75 100 125 150 450 400 200 0 6 5.0 Short Circuit Current S H O R T C I R C U I T C U R R E N T ( mA ) 4 5.02 TEMPERATURE (C) July 2005 3 R L = 50k 250 TEMPERATURE (C) Ground Pin Current 250 2 5.04 INPUT VOLTAGE (V) 300 1 4.94 -75 -50 -25 0 25 50 75 100 125 150 8 9 10 350 0 300 INPUT VOLTAGE (V) LOAD CURRENT (mA) 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0 R L = 33 2 0 150 R L = 50k Q U I E S C E N T C U R R E N T ( A ) 1 350 5 Q U I E S C E N T C U R R E N T ( mA ) 0.1 Input Current 400 D R O P O U T V O L T A G E ( mV ) Q U IE S C E N T C U R R E N T 1 0.01 0.1 Dropout Characteristics 6 I N P U T C U R R E N T ( A ) Ground Pin Current 10 400 300 200 TJ = 25C 100 0 150 0.1 1 10 100 OUTPUT CURRENT (mA) MIC2950/2951 Micrel, Inc. MIC2951 Minimum Operating Voltage 20 2.0 1.9 1.8 1.7 1.6 -75 -50 -25 0 25 50 75 100 125 150 10 0 -10 -20 -30 -75 -50 -25 0 25 50 75 100 125 150 TEMPERATURE (C) HYSTERESIS 2 0 SEPARATE 5V SUPPLY 2 3 4 5 1.5 1.0 TA = -55C 0.5 0.0 6 TA = 25C INPUT VOLTAGE (V) 0 2 4 6 8 10 I 0 = 100 mA 0.5 OUT C L= 4.7F 0.05 0.02 0.01 10 100 1K 10K 100K 1M FREQUENCY (Hz) MIC2950/2951 Line Transient Response 400 mV 200 mV 0 -50 mV C L= 4.7 8V V OUT= 5V L 6V 4V 200 16 20 7 6 5 4 3 2 1 0 2 0 600 800 -2 L IN C L= 10 F VOUT= 5V -100 0 100 200 300 400 500 600 700 TIME (mS) Ripple Rejection Ripple Rejection 90 80 70 IL = 0 60 50 C L = 1.5 40 I L = 100 A IN 30 20 400 C L = 1.5 F TIME (mS) R I P P L E R E J E C T I O N ( dB ) O U T P U T I MP E D A N C E ( O H MS ) I 0 = 1 mA 0.2 0.1 12 90 I 0 = 100 A 2 1 8 4 1.0 MIC2951 Enable Transient 100 mA 100 A 0 0.5 TIME (S) C L= 15 V OUT= 5V Output Impedance 5 TA = -55C -250 -2.0 -1.5 -1.0 -0.5 0 Load Transient Response 80 60 40 20 0 -20 -40 -60 TIME (mS) 10 TA = 25C -200 0 OUTPUT V O L T AG E (V ) OUTPUT VOLTAGE C H A N G E ( mV ) C L= 4.7 V OUT= 5V LOAD C UR R E NT OUTPUT VOLTAGE C H A N G E ( mV ) LOAD CURRENT 100 mA 100 A -150 OUTPUT LOW VOLTAGE (V) Load Transient Response 125 100 75 50 25 0 -25 -50 TA = 125C -100 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 SHUTDOWN P IN V O L T A G E (V ) 1 OUTPUT VOLTAGE C HANG E 4 TA = 125C 2.0 INPUT VOLTAGE S I N K C U R R E N T ( mA ) C O MP A R A T O R O U T P U T ( V ) VOUT = 5V 0 -50 OPEN LOOP) FEEDBACK VOLTAGE (V) MIC2951 Comparator Sink Current 2.5 6 -2 0 TEMPERATURE (C) MIC2951 Error Comparator Output 8 MIC2951 Feedback Pin Current 50 F E E D B A C K C U R R E N T ( A ) 2.1 MIC2951 Feedback Bias Current R I P P L E R E J E C T I O N ( dB ) 2.2 B I A S C U R R E N T ( nA ) MI N I MU M O P E R A T I N G V O L T A G E ( V ) MIC2950/2951 VOUT= 5V 1 10 10 2 10 3 10 4 FREQUENCY (Hz) 8 10 6 10 80 70 C L = 1.5 I L = 1 mA IN VOUT= 5V 60 50 40 30 20 I L = 10 mA 1 10 10 2 10 3 104 105 106 FREQUENCY (Hz) July 2005 I L = 50A 60 I L = 100 mA 50 40 C L = 1.5 30 IN VOUT= 5V 20 101 10 2 10 3 104 105 C L = 4.7 F 2.5 C L = 220F 2.0 L 1.5 3.3 F 1.0 0.01 0.5 0.0 10 6 IL = 100 mA 3.0 PIN 7 10 2 Shutdown Threshold Voltage 1.8 1.6 1.4 1.2 1.0 0.8 0.6 -75 -50 -25 0 25 50 75 100 125 150 30 25 20 15 T J = 150C 10 5 0 = 125C MAX TA= 25C 40 T = 85C 20 0 5 10 5 -2 POWER 60 C H A N G E ( mV ) TJ 80 0 15 20 INPUT VOLTAGE (V) July 2005 OUTPUT VOLTAGE TO PC BOARD 100 200 100 0 -75 -50 -25 0 25 50 75 100 125 150 TEMPERATURE (C) MIC2951 Maximum Rated Output Current 150 I L = 100 A I L = 1 mA 10 5 T J = 125C 0 -5 -10 5 10 15 D IS S IP A T IO N (W ) O U T P U T C U R R E N T ( mA ) 140 120 300 I L = 100 A 140 TO PC BOARD TJ 130 T A = 25C 100 80 60 T A = 50C 40 T A = 85C 20 0 20 25 30 0 5 25 30 2 0 1.25W 0 0 10 20 30 TIME (S) 9 40 15 20 25 30 Fold-Back Current Limiting 600 4 -1 10 INPUT VOLTAGE (V) Thermal Response 1 = 125C MAX VOUT= 5V 120 INPUT VOLTAGE (V) MIC2950 Maximum Rated Output 130 10 5 Line Regulation TEMPERATURE (C) 150 10 4 MIC2951 Divider Resistance 400 FREQUENCY (Hz) O U T P U T V O L T A G E C H A N G E ( mV ) S H U T DO W N T H R E S H O L D V O L T AG E (V ) FREQUENCY (Hz) 10 3 O U T P U T C U R R E N T ( mA ) 70 Output Noise 3.5 O U T P U T C U R R E N T ( mA ) R I P P L E R E J E C T I O N ( dB ) S P E C T R A L D E N S I T Y ( V / H z ) Ripple Rejection 80 10 Micrel, Inc. P IN 2 T O P IN 4 R E S IS T A N C E (k) MIC2950/2951 50 500 400 300 200 100 0 1 2 3 4 5 OUTPUT VOLTAGE (V) MIC2950/2951 MIC2950/2951 Micrel, Inc. Applications Information Automotive Applications age. (Refer to the block diagram on Page 1). This trip level remains "5% below normal" regardless of the programmed output voltage of the MIC2951. 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, current limiting, thermal limiting, or overvoltage on input (over 40V). The MIC2950/2951 are ideally suited for automotive applications for a variety of reasons. They will operate over a wide range of input voltages, have very low dropout voltages (40mV at light loads), and very low quiescent currents. These features are necessary for use in battery powered systems, such as automobiles. They are also "bulletproof" devices; 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. Figure 1 is a timing diagram depicting the ERROR signal and the regulated output voltage as the MIC2951 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--for 5.0V applications). Since the MIC2951'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 does not vary with load. External Capacitors A 1.5 F (or greater) capacitor is required between the MIC2950/MIC2951 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 -30C, so solid tantalums are recommended for operation below -25C. The important parameters of the capacitor are an effective series resistance of about 5 or less and a resonant frequency above 500kHz. The value of this capacitor may be increased without limit. The error comparator has an open-collector output which requires an external pull-up resistor. Depending on system requirements, this resistor may be returned to the output or some other supply voltage. In determining a value for this resistor, note that while the output is rated to sink 200A, this sink current adds to battery drain in a low battery condition. Suggested values range from 100k to 1M. 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 0.5F for current below 10mA or 0.15F for currents below 1 mA. Using the 8-pin versions at voltages below 5V runs the error amplifier at lower gains so that more output capacitance is needed. For the worst-case situation of a 150mA load at 1.23V output (Output shorted to Feedback) a 5F (or greater) capacitor should be used. Programming the Output Voltage (MIC2951) The MIC2951 may be pin-strapped for 5V (or 3.3V or 4.85V) using its internal voltage divider by tying Pin 1 (output) to Pin 2 (sense) and Pin 7 (feedback) to Pin 6 (5V Tap). Alternatively, it may be programmed for any output voltage between its 1.235V reference and its 30V maximum rating. An external pair of resistors is required, as shown in Figure 2. The MIC2950 will remain stable and in regulation with no load in addition to the internal voltage divider, unlike many other voltage regulators. This is especially important in CMOS RAM keep-alive applications. When setting the output voltage of the MIC2951 version with external resistors, a minimum load of 1A is recommended. 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 feedback pin bias current, nominally -20nA. The minimum recommended load current of 1 A forces an upper limit of 1.2M 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 12 A. A 0.1F capacitor should be placed from the MIC2950/MIC2951 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. Stray capacitance to the MIC2951 Feedback terminal (pin 7) can cause instability. This may especially be a problem when using high value external resistors to set the output voltage. Adding a 100pF capacitor between Output and Feedback and increasing the output capacitor to at least 3.3F will remedy this. Reducing Output Noise In some 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 the only method by which noise can be reduced on the 3 lead MIC2950 and is relatively inefficient, as increasing the capacitor from 1F to 220F only decreases the noise from 430V to 160V rms for a 100kHz bandwidth at 5V output. Error Detection Comparator Output A logic low output will be produced by the comparator whenever the MIC2951 output falls out of regulation by more than approximately 5%. This figure is the comparator's built-in offset of about 60mV divided by the 1.235V reference voltMIC2950/2951 10 July 2005 MIC2950/2951 Micrel, Inc. Noise can be reduced fourfold by a bypass capacitor across R1, since it reduces the high frequency gain from 4 to unity. Pick: C BYPASS or about 0.01 F. When doing this, the output capacitor must be increased to 3.3 F to maintain stability. These changes reduce the output noise from 430 V to 100 V rms 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. 1 2 R 1 * 200 Hz +VIN 4.75V OUTPUT VOLTAGE 100k ERROR 8 VIN 5 ERROR ERROR O UTPUT NOT * VALID NOT * VALID VOUT = V R E F R1 x (1 + ) R2 VOUT 1.2 30V VOUT 1 MIC2951 SHUTDOWN 3 SD INPUT OFF 5V INPUT VOLTAGE ON GND 4 FB 7 1.3V R1 100 pF 1.23V R2 VR E F * SEE APPLICATIONS INFORMATION *SEE APPLICATIONS INFORMATION NOTE: PINS 2 AND 6 ARE LEFT OPEN Figure 1. ERROR Output Timing 3.3F Figure 2. Adjustable Regulator Typical Applications +V IN *SLEEP INPUT 47k 5 ERROR 8 +VIN 470 k 8 +V IN ERROR OUTPUT +VIN C-MOS GATE MIC2951 SHUTDOWN 3 SD INPUT OFF GND ON 4 FB 200k + 2N3906 1% 100k 100pF 3.3F SHUTDOWN INPUT 3 VOUT 1 *VOUT VIN ON OFF SD GND 4 FB 7 7 1% 100k *MINIMUM INPUT-OUTPUT VOLTAGE RANGES FROM 40mV TO 400mV, DEPENDING ON LOAD CURRENT. *HIGH INPUT LOWERS VOUT TO 2.5V Wide Input Voltage Range Current Limiter 5V Regulator with 2.5V Sleep Function July 2005 5 ERROR MIC2951 +V OUT V OUT 1 ERROR OUTPUT 11 MIC2950/2951 MIC2950/2951 Micrel, Inc. +V = 2 IL 30V 5V BUS 1.23V IL= R LOAD +VIN V O UT 8 VIN VOUT MIC2950Z 1 *V = 5V O UT + MIC2951 SHUTDOWN 3 S D INPUT OFF ON G ND 0.1F GND 1F FB 870 27 7 4 R 1% 5-Volt Current Limiter 1F * MINIMUM INPUT-OUTPUT VOLTAGE RANGES FROM 40mV TO 400mV, DEPENDING ON LOAD CURRENT. Low Drift Current Source +VIN D1 2 SENSE 8 +VIN VOUT D2 1 MIC2951 #1 5 ERROR 1F MEMORY V+ 20 3.6V NICAD GND 4 D3 D4 2.7M Q1 27k 8 +VIN 870 29 RESET 2 SENSE VOUT 3 EARLY WARNING 1 MIC2951 #2 5 SD ERROR 330k MAIN OUTPUT + P VDO 1f GND 4 Regulator with Early Warning and Auxiliary Output * EARLY WARNING FLAG ON LOW INPUT VOLTAGE * MAIN OUTPUT LATCHES OFF AT LOWER INPUT VOLTAGES * BATTERY BACKUP ON AUXILIARY OUTPUT OPERATION: REG. #1'S VOUT IS PROGRAMMED ONE DIODE DROP ABOVE 5 V. ITS ERROR FLAG BECOMES ACTIVE WHEN VIN 5.7 V. WHEN VIN DROPS BELOW 5.3 V, THE ERROR FLAG OF REG. #2 BECOMES ACTIVE AND VIA Q1 LATCHES THE MAIN OUTPUT OFF. WHEN VIN AGAIN EXCEEDS 5.7 V REG. #1 IS BACK IN REGULATION AND THE EARLY WARNING SIGNAL RISES, UNLATCHING REG. #2 VIA D3. MIC2950/2951 12 July 2005 MIC2950/2951 Micrel, Inc. +V IN 8 470k 5 470k 3 RESET +5V 4.7mA 20mA 4 8 +V IN VOUT ER R OR MIC2951 FB SD 1N 4001 R1 7 + 0.1F 1F V OUT MIC2951 FB R2 GND 1 7 4 2 G ND 4 OUTPUT* 5 1 V IN VOUT 1 4 1N457 360 * HIGH FOR IL < 3.5mA MIN. VOLTAGE 4V Latch Off When Error Flag Occurs Open Circuit Detector for 4mA to 20mA Current Loop 8 +VIN 39k 5 RE S E T - 3 C4 + 39k + 6V 1% LEADACID BATTERY 1% C1-C4 LP339 1% R3 1% 100 k 1 k 1 k 2 SENSE ERROR VOUT 1 MIC2951 FB SD GND 4 +VOUT = 5V + 1F 7 TAP 6 100k - C1 + <5.8V** 100k - C2 + <6.0V** 100k - C3 + <6.2V** 10k 20k C1 TO C4 ARE COMPARATORS (LP339 OR EQUIVALENT) *OPTIONAL LATCH OFF WHEN DROP OUT OCCURS. ADJUST R3 FOR C2 SWITCHING WHEN VIN IS 6.0V **OUTPUTS GO LOW WHEN VIN DROPS BELOW DESIGNATED THRESHOLDS. Regulator with State-of-Charge Indicator July 2005 13 MIC2950/2951 MIC2950/2951 Micrel, Inc. + 6V 1.5k** 120k SEALED 1N457 LEADACID BATTERY FB LM385 SOURCE 8 +V IN - 400k* FOR 5.5V VOUT 1 MAIN V+ MIC2951 3 100k SENSE SD 2 + 1F GND 4 * Sets disconnect voltage ** Sets disconnect hysteresis MEMORY V+ 20 + NI-CAD BACKUP BATTERY Low-Battery Disconnect For values shown, Regulator shuts down when VIN < 5.5 V and turns on again at 6.0 V. Current drain in disconnected mode is 150A. +VIN 3 AUX. SHUTDOWN INPUT 8 +VIN 10k 5 PRE-SHUTDO WN FL AG 5 ERROR SD MIC2951 OFF VOUT 1 ON + EXTERNAL CIRCUIT PROTECTED FROM OR OVER TEMPERATURE ( V+ GOES OFF W HEN TEMP.> 125) FB 7 GND 4 T EM P. LM34 OR S E N S O R LM35 - 8.2k LM34 for 125F Shutdown LM35 for 125C Shutdown RELAY System Overtemperature Protection Circuit Schematic Diagram FEEDBACK IN R18 20k Q15A Q15B Q24 Q25 Q9 Q3 R11 18 k Q6 Q4 Q5 C1 20 pF Q40 Q8 R11 20.6 k Q16 Q17 R27 182k R17 12k Q14 5V TAP R28 60k Q20 R6 140 k R5 180 k Q13 Q21 Q23 C2 40 pF R9 27.8k Q12 Q22 R10 150 k R8 31.4 k Q41 R12 110 k Q11 R13 100 k R15 100k R14 350 k R16 30 k Q29 R30 30 k OUT SEN SE Q2 R1 20 k R2 50k Q26 Q7 Q1 10 Q42 100 x Q18 R3 50k R17 10 Q19 Q28 R4 13k R21 8 50 k Q30 Q31 Q37 10 k R22 150k Q36 R23 60k SHDN ERROR Q38 Q34 R26 60 k DENOTES CONNECTION ON MIC2950 ONLY R25 2.8 k GND Q39 MIC2950/2951 R24 50k 14 July 2005 MIC2950/2951 Micrel, Inc. Package Information MAX ) PIN 1 INCHES (MM) 0.150 (3.81) 0.013 (0.33) 45 TYP 0.0040 (0.102) 0.010 (0.25) 0.007 (0.18) 0-8 0.189 (4.8) 0.016 (0.40) PLANE 0.045 (1.14) 0.228 (5.79) 8-Pin SOIC (M) PIN 1 INCH (MM) 0.370 (9.40) 0.245 (6.22) 0.125 (3.18) 0.300 (7.62) 0.013 (0.330) 0.010 (0.254) 0.018 (0.57) 0.100 (2.54) 0.130 (3.30) 0.0375 (0.952) 8-Pin Plastic DIP (N) July 2005 15 MIC2950/2951 MIC2950/2951 Micrel, Inc. 0.187 (4.74) 0.112 (2.84) INCH (MM) 0.116 (2.95) 0.032 (0.81) 0.038 (0.97) 0.007 (0.18) 0.005 (0.13) 0.012 (0.30) R 0.012 (0.03) 5 0 MIN 0.004 (0.10) 0.0256 (0.65) TYP 0.012 (0.03) R 0.035 (0.89) 0.021 (0.53) 8-Lead MSOP (MM) 0.090 (2.286) Radius, typ. 2 3 1 0.145 (3.683) 0.135 (3.429) 0.055 (1.397) 0.045 (1.143) 10 typ. BOTTOM VIEW 0.085 (2.159) Diam. 0.185 (4.699) 0.175 (4.445) 5 typ. 0.185 (4.699) 0.175 (4.445) 0.090 (2.286) typ. 5 typ. Seating Plane 0.025 (0.635) Max Uncontrolled Lead Diameter 0.500 (12.70) Min. 0.016 (0.406) 0.014 (0.356) 0.0155 (0.3937) 0.0145 (0.3683) 0.055 (1.397) 0.045 (1.143) 0.105 (2.667) 0.095 (2.413) TO-92 (Z) 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. (c) 1999 Micrel, Inc. MIC2950/2951 16 July 2005