MIC5245 Micrel MIC5245 150mA µCap CMOS LDO Regulator Final Information General Description Features The MIC5245 is an efficient, precise CMOS voltage regulator optimized for ultra-low-noise applications. The MIC5245 offers better than 1% initial accuracy, extremely low dropout voltage (typically 150mV at 150mA) and constant ground current over load (typically 100µA). The MIC5245 provides a very low noise output, ideal for RF applications where quiet voltage sources are required. A noise bypass pin is also available for further reduction of output noise. • • • • • • • • • • • Designed specifically for hand-held and battery-powered devices, the MIC5245 provides a TTL logic compatible enable pin. When disabled, power consumption drops nearly to zero. The MIC5245 also works with low-ESR ceramic capacitors, reducing the amount of board space necessary for power applications, critical in hand-held wireless devices. Key features include current limit, thermal shutdown, a pushpull output for faster transient response, and an active clamp to speed up device turnoff. Available in the IttyBitty™ SOT-23-5 and power MSO-8 packages, the MIC5245 also offers a range of fixed output voltages. Ultralow dropout—100mV @ 100mA Ultralow noise—30µV(rms) Stability with tantalum or ceramic capacitors Load independent, ultralow ground current 150mA output current Current limiting Thermal Shutdown Tight load and line regulation “Zero” off-mode current Fast transient response TTL-Logic-controlled enable input Applications • • • • • • • • Cellular phones and pagers Cellular accessories Battery-powered equipment Laptop, notebook, and palmtop computers PCMCIA VCC and VPP regulation/switching Consumer/personal electronics SMPS post-regulator/dc-to-dc modules High-efficiency linear power supplies Not recommended for new designs, see MIC5255. Ordering Information Part Number Marking Voltage Junction Temp. Range Package MIC5245-2.5BM5 LS25 2.5V –40°C to +125°C SOT-23-5 MIC5245-2.7BM5 LS27 2.7V –40°C to +125°C SOT-23-5 MIC5245-2.8BM5 LS28 2.8V –40°C to +125°C SOT-23-5 MIC5245-2.85BM5 LS2J 2.85V –40°C to +125°C SOT-23-5 MIC5245-3.0BM5 LS30 3.0V –40°C to +125°C SOT-23-5 MIC5245-3.1BM5 LS31 3.1V –40°C to +125°C SOT-23-5 MIC5245-3.2BM5 LS32 3.2V –40°C to +125°C SOT-23-5 MIC5245-3.3BM5 LS33 3.3V –40°C to +125°C SOT-23-5 MIC5245-3.3BMM — 3.3V –40°C to +125°C MSOP-8 Other voltages available. Contact Micrel for details. Typical Application VIN MIC5245-x.xBM5 1 5 2 3 Enable Shutdown EN EN (pin 3) may be connected directly o IN (pin 1). VOUT COUT 4 CBYP (optional) MIC5245-3.3MM ENABLE SHUTDOWN 1 8 VIN 2 7 VOUT 3 6 4 5 COUT CBYP (OPTIONAL) Ultra-Low-Noise Regulator Application Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com August 2002 1 MIC5245 MIC5245 Micrel Pin Configuration EN GND IN 3 2 1 LSxx 4 5 BYP OUT MIC5245-x.xBM5 EN 1 8 GND IN 2 7 GND OUT 3 6 GND BYP 4 5 GND 8-Pin MSOP (BMM) Pin Description Pin Number Power MOS-8 Pin Number SOT-23 Pin Name Pin Function 2 1 IN Supply Input 5–8 2 GND 1 3 EN Enable/Shutdown (Input): CMOS compatible input. Logic high = enable; logic low = shutdown. Do not leave open. 4 4 BYP Reference Bypass: Connect external 0.01µF capacitor to GND to reduce output noise. May be left open. 3 5 OUT Regulator Output Ground Absolute Maximum Ratings (Note 1) Operating Ratings (Note 2) Supply Input Voltage (VIN) .................................. 0V to +7V Enable Input Voltage (VEN) ................................. 0V to +7V Junction Temperature (TJ) ...................................... +150°C Storage Temperature ............................... –65°C to +150°C Lead Temperature (soldering, 5 sec.) ....................... 260°C ESD, Note 3 Input Voltage (VIN) ......................................... +2.7V to +6V Enable Input Voltage (VEN) .................................. 0V to VIN Junction Temperature (TJ) ....................... –40°C to +125°C Thermal Resistance SOT-23 (θJA) .....................................................235°C/W MSOP-8 (θJA) ......................................................80°C/W MIC5245 2 August 2002 MIC5245 Micrel Electrical Characteristics (Note 7) VIN = VOUT + 1V, VEN = VIN; IOUT = 100µA; TJ = 25°C, bold values indicate –40°C ≤ TJ ≤ +125°C; unless noted. Symbol Parameter Conditions Min VO Output Voltage Accuracy IOUT = 0mA –1 –2 ∆VLNR Line Regulation VIN = VOUT + 0.1V to 6V Max Units 1 2 % % 0 0.3 %/V ∆VLDR Load Regulation IOUT = 0.1mA to 150mA, Note 4 2.0 3.0 % VIN – VOUT Dropout Voltage, Note 5 IOUT = 100µA 1.5 5 mV IOUT = 50mA 50 85 mV IOUT = 100mA 100 150 mV IOUT = 150mA 150 200 250 mV mV –0.3 Typical IQ Quiescent Current VEN ≤ 0.4V (shutdown) 0.2 1 µA IGND Ground Pin Current, Note 6 IOUT = 0mA 100 150 µA IOUT = 150mA 100 µA 50 dB 300 mA µV(rms) PSRR Power Supply Rejection f = 120Hz, COUT = 10µF, CBYP = 0.01µF ILIM Current Limit VOUT = 0V en Output Voltage Noise COUT = 10µF, CBYP = 0.01µF, f = 10Hz to 100kHz 30 VIL Enable Input Logic-Low Voltage VIN = 2.7V to 5.5V, regulator shutdown 0.8 VIH Enable Input Logic-High Voltage VIN = 2.7V to 5.5V, regulator enabled IEN Enable Input Current 160 Enable Input V 1 V VIL ≤ 0.4V 0.17 µA VIH ≥ 2.0V 1.5 µA 500 Ω Thermal Shutdown Temperature 150 °C Thermal Shutdown Hysteresis 10 °C Shutdown Resistance Discharge 2.0 0.4 Thermal Protection 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 recommended. Note 4. Regulation is measured at constant junction temperature using low duty cycle pulse testing. Parts are tested for load regulation in the load range from 0.1mA to 150mA. Changes in output voltage due to heating effects are covered by the thermal regulation specification. Dropout Voltage is defined as the input to output differential at which the output voltage drops 2% below its nominal value measured at 1V differential. For outputs below 2.7V, dropout voltage is the input-to-output voltage differential with the minimum input voltage 2.7V. Minimum input operating voltage is 2.7V. Ground pin current is the regulator quiescent current. The total current drawn from the supply is the sum of the load current plus the ground pin current. Specification for packaged product only. Note 5. Note 6. Note 7. August 2002 3 MIC5245 MIC5245 Micrel Typical Characteristics Power Supply Rejection Ratio Power Supply Rejection Ratio 100 60 40 VIN = 4V VOUT = 3V IOUT = 100mA 80 COUT = 1µF tant PSRR (dB) IOUT = 10mA 80 COUT = 1µF tant PSRR (dB) 60 40 VIN = 4V VOUT = 3V 60 40 20 20 20 0 1E+1 1k 1E+4 10k 1E+5 1M 1E+7 10M 10 1E+2 100k 1E+6 100 1E+3 FREQUENCY (Hz) 0 1E+1 1k 1E+4 10k 1E+5 1M 1E+7 10M 10 1E+2 100k 1E+6 100 1E+3 FREQUENCY (Hz) 0 1E+1 1k 1E+4 10k 1E+5 1M 1E+7 10M 10 1E+2 100k 1E+6 100 1E+3 FREQUENCY (Hz) Power Supply Rejection Ratio Power Supply Rejection Ratio Power Supply Rejection Ratio 100 80 80 60 40 PSRR (dB) 100 VIN = 4V VOUT = 3V PSRR (dB) IOUT = 150mA 80 COUT = 1µF tant 60 40 IOUT = 100µA COUT = 10µF cer. CBYP = 0.01µF 0 1E+1 1k 1E+4 10k 1E+5 1M 1E+7 10M 10 1E+2 100k 1E+6 100 1E+3 FREQUENCY (Hz) 20 V = 4V IN VOUT = 3V 0 1E+1 100 1E+3 1k 1E+4 10k 1E+5 100k 1E+6 1M 1E+7 10M 10 1E+2 FREQUENCY (Hz) Power Supply Rejection Ratio Power Supply Rejection Ratio 100 100 60 40 IOUT = 100mA COUT = 10µF cer. CBYP = 0.01µF 20 60 40 IOUT = 150mA COUT = 10µF cer. CBYP = 0.01 20 Power Supply Ripple Rejection vs. Voltage Drop 10mA 30 20 10 0 0 MIC5245 100µA COUT = 10µF cer. CBYP = 0.01µF 200 400 600 800 1000 VOLTAGE DROP (mV) 70 100µA 10mA 60 50 40 30 150mA 20 IOUT = 100mA 10 0 0 COUT = 1µF 200 400 600 800 1000 VOLTAGE DROP (mV) Noise Performance 10 IL = 100µA IL = 100µA IOUT = 100mA NOISE (µV/√Hz) RIPPLE REJECTION (dB) 100mA 50 40 Power Supply Ripple Rejection vs. Voltage Drop 10 70 60 0 1E+1 100 1E+3 1k 1E+4 10k 1E+5 100k 1E+6 1M 1E+7 10M 10 1E+2 FREQUENCY (Hz) Noise Performance 80 IOUT = 10mA COUT = 10µF cer. CBYP = 0.01µF 20 0 1E+1 1E+7 100 1E+3 1k 1E+4 10k 1E+5 100k 1E+6 1M 10M 10 1E+2 FREQUENCY (Hz) 0 1E+1 100 1E+3 1k 1E+4 10k 1E+5 100k 1E+6 1M 1E+7 10M 10 1E+2 FREQUENCY (Hz) 40 80 VIN = 4V VOUT = 3V 80 PSRR (dB) 80 VIN = 4V VOUT = 3V VIN = 4V VOUT = 3V 60 RIPPLE REJECTION (dB) 20 1 VIN = 4V 0.1 V OUT = 3V COUT = 1µF cer. CBYP = 0.01µF 0.01 10 1E+2 100 1E+3 1k 1E+4 10k 100k 1M 1E+1 1E+5 1E+6 FREQUENCY (Hz) 4 NOISE (µV/√Hz) PSRR (dB) VIN = 4V VOUT = 3V 100 PSRR (dB) 100 100 IOUT = 100µA 80 COUT = 1µF tant PSRR (dB) Power Supply Rejection Ratio 1 VIN = 4V 0.1 VOUT = 3V COUT = 10µF cer. CBYP = 0.01µF 0.01 1k 1E+4 10 1E+2 1M 10k 1E+5 100 1E+3 100k 1E+6 1E+1 FREQUENCY (Hz) August 2002 MIC5245 Micrel Ground Pin Current Ground Pin Current 200 QUIESCENT CURRENT (µA) QUIESCENT CURRENT (µA) 95 VIN = 4V VOUT = 3V 90 85 0.1 1 10 100 LOAD CURRENT (mA) Ground Pin Current 100 IOUT = 150mA QUIESCENT CURRENT (µA) QUIESCENT CURRENT (µA) VOUT = 3V 75 50 25 IOUT = 100µA 0 Dropout Characteristics 0 1 2 3 4 INPUT VOLTAGE (V) RL = 30kΩ RL = 30Ω 1.5 1.0 0.5 0 0 1 2 3 4 INPUT VOLTAGE (V) ILOAD = 100µA 6 4 2 Dropout Voltage TA = 25°C 100 50 0 0 August 2002 TA = -40°C 25 50 75 100 125 150 OUTPUT CURRENT (mA) 250 1 2 3 4 INPUT VOLTAGE (V) 5 150 100 50 Output Voltage vs. Temperature 3.05 500 400 300 200 IL = 150mA 200 Short Circuit Current OUTPUT CURRENT (mA) TA = 125°C IOUT = 150mA 0 -40 -20 0 20 40 60 80 100120140 TEMPERATURE (°C) 600 250 150 25 Dropout Voltage 0 -40 -20 0 20 40 60 80 100120140 TEMPERATURE (°C) 5 300 200 50 300 DROPOUT VOLTAGE (mV) DROPOUT VOLTAGE (mV) VOUT = 3V 2.0 75 Dropout Voltage 8 3.5 2.5 VOUT = 3V 0 0 5 VIN = 3.5V VEN = 3V 100 0 -40 -20 0 20 40 60 80 100120140 TEMPERATURE (°C) 5 OUTPUT VOLTAGE (V) QUIESCENT CURRENT (µA) VIN = 4V VOUT = 3V 75 OUTPUT VOLTAGE (V) IOUT = 100µA 0 -40 -20 0 20 40 60 80 100 TEMPERATURE (°C) Ground Pin Current 50 -40 -20 0 20 40 60 80 100 TEMPERATURE (°C) DROPOUT VOLTAGE (mV) 50 100 100 3.0 100 500 Ground Pin Current 150 125 150 VIN = 4V VOUT = 3V VIN = 4V TYPICAL 3V DEVICE 3.00 2.95 2.90 ILOAD = 100µA 2.85 -50 0 50 100 TEMPERATURE (°C) 150 MIC5245 MIC5245 Micrel Enable Pin Bias Current 4 THRESHOLD VOLTAGE (V) ENABLE PIN CURRENT (µA) 2.0 1.5 VIN = 4.0V 1.0 0.5 VEN = 100mV Enable Threshold Voltage 3 2 VIN = 4.0V 1 0 -40 -20 0 20 40 60 80 100 TEMPERATURE (°C) 0 -40 -20 0 20 40 60 80 100120140 TEMPERATURE (°C) Functional Characteristics Load Transient Response ∆ OUTPUT VOLTAGE (100mV/div.) OUTPUT CURRENT 6V VOUT = 3V COUT = 10µF CBYP = 0.01µF IOUT = 100µA 4V VIN = 4V VOUT = 3V COUT = 10µF cer. CBYP = 0.01µF Enable Pin Delay Shutdown Delay 100µA OUTPUT VOLTAGE (1V/div.) OUTPUT VOLTAGE (1V/div.) ENABLE VOLTAGE (2V/div.) TIME (100µs/div.) VIN = 4V VOUT = 3V COUT = 10µF CBYP = 0.01µF IOUT = no load TIME (20µs/div.) MIC5245 150mA TIME (10ms/div.) ENABLE VOLTAGE (1V/div.) INPUT VOLTAGE (2V/div.) ∆ OUTPUT VOLTAGE (50mV/div.) Line Transient Response VOUT = 3V COUT = 10µF CBYP = 0.01µF IOUT = no load TIME (1ms/div.) 6 August 2002 MIC5245 Micrel Block Diagrams IN Reference Voltage Startup/ Shutdown Control Quickstart/ Noise Cancellation EN BYP PULL UP Thermal Sensor FAULT Error Amplifier Undervoltage Lockout Current Amplifier ACTIVE SHUTDOWN OUT PULL DOWN GND August 2002 7 MIC5245 MIC5245 Micrel Active Shutdown The MIC5245 also features an active shutdown clamp, which is an N-channel MOSFET that turns on when the device is disabled. This allows the output capacitor and load to discharge, de-energizing the load. Applications Information Enable/Shutdown The MIC5245 comes with an active-high enable pin that allows the regulator to be disabled. Forcing the enable pin low disables the regulator and sends it into a “zero” off-modecurrent state. In this state, current consumed by the regulator goes nearly to zero. Forcing the enable pin high enables the output voltage. This part is CMOS and the enable pin cannot be left floating; a floating enable pin may cause an indeterminate state on the output. Input Capacitor An input capacitor is not required for stability. A 1µF input capacitor is recommended when the bulk ac supply capacitance is more than 10 inches away from the device, or when the supply is a battery. Thermal Considerations The MIC5245 is designed to provide 150mA of continuous current in a very small package. Maximum power dissipation can be calculated based on the output current and the voltage drop across the part. To determine the maximum power dissipation of the package, use the junction-to-ambient thermal resistance of the device and the following basic equation: TJ(max) − TA PD(max) = θ JA Output Capacitor The MIC5245 requires an output capacitor for stability. The design requires 1µF or greater on the output to maintain stability. The capacitor can be a low-ESR ceramic chip capacitor. The MIC5245 has been designed to work specifically with the low-cost, small chip capacitors. Tantalum capacitors can also be used for improved capacitance over temperature. The value of the capacitor can be increased without bound. TJ(max) is the maximum junction temperature of the die, 125°C, and TA is the ambient operating temperature. θJA is layout dependent; Table 1 shows examples of junction-toambient thermal resistance for the MIC5245. X7R dielectric 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 much 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 or a tantalum capacitor to ensure the same minimum capacitance value over the operating temperature range. Tantalum capacitors have a very stable dielectric (10% over their operating temperature range) and can also be used with this device. Bypass Capacitor A capacitor can be placed from the noise bypass pin to ground to reduce output voltage noise. The capacitor bypasses the internal reference. A 0.01µF capacitor is recommended for applications that require low-noise outputs. The actual power dissipation of the regulator circuit can be determined using the equation: PD = (VIN – VOUT) IOUT + VIN IGND Package SOT-23-5 (M5) 235°C/W 185°C/W θJC 145°C/W Table 1. SOT-23-5 Thermal Resistance Substituting PD(max) for PD and solving for the operating conditions that are critical to the application will give the maximum operating conditions for the regulator circuit. For example, when operating the MIC5245-3.3BM5 at 50°C with a minimum footprint layout, the maximum input voltage for a set output current can be determined as follows: 125°C − 50°C PD(max) = 235°C/W PD(max) = 315mW The junction-to-ambient thermal resistance for the minimum footprint is 235°C/W, from Table 1. The maximum power dissipation must not be exceeded for proper operation. Using the output voltage of 3.3V and an output current of 150mA, the maximum input voltage can be determined. Because this device is CMOS and the ground current is typically 87µA over the load range, the power dissipation contributed by the ground current is < 1% and can be ignored for this calculation. 315mW = (VIN – 3.3V) 150mA Transient Response The MIC5245 implements a unique output stage to dramatically improve transient response recovery time. The output is a totem-pole configuration with a P-channel MOSFET pass device and an N-channel MOSFET clamp. The N-channel clamp is a significantly smaller device that prevents the output voltage from overshooting when a heavy load is removed. This feature helps to speed up the transient response by significantly decreasing transient response recovery time during the transition from heavy load (100mA) to light load (100µA). MIC5245 θJA Recommended θJA 1" Square Minimum Footprint Copper Clad 315mW = VIN × 150mA – 495mW 810mW = VIN × 150mA VIN(max) = 5.4V Therefore, a 3.3V application at 150mA of output current can accept a maximum input voltage of 5.4V in a SOT-23-5 package. For a full discussion of heat sinking and thermal 8 August 2002 MIC5245 Micrel effects on voltage regulators, refer to the Regulator Thermals section of Micrel’s Designing with Low-Dropout Voltage Regulators handbook. Fixed Regulator Applications VIN MIC5245-x.xBM5 1 5 2 3 VIN 1 5 2 3 Enable Shutdown 1.0µF 4 EN VOUT Figure 2. Low-Noise Fixed Voltage Application 1µF 4 Figure 2 is an example of a low-noise configuration where CBYP is not required. COUT = 1µF minimum. 0.01µF Dual-Supply Operation 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. Figure 1. Ultra-Low-Noise Fixed Voltage Application Figure 1 includes a 0.01µF capacitor for low-noise operation and shows EN (pin 3) connected to IN (pin 1) for an application where enable/shutdown is not required. COUT = 1µF minimum. August 2002 MIC5245-x.xBM5 V OUT 9 MIC5245 MIC5245 Micrel Package Information 1.90 (0.075) REF 0.95 (0.037) REF 1.75 (0.069) 1.50 (0.059) 3.00 (0.118) 2.60 (0.102) DIMENSIONS: MM (INCH) 3.02 (0.119) 2.80 (0.110) 0.50 (0.020) 0.35 (0.014) 1.30 (0.051) 0.90 (0.035) 0.20 (0.008) 0.09 (0.004) 10° 0° 0.15 (0.006) 0.00 (0.000) 0.60 (0.024) 0.10 (0.004) SOT-23-5 (M) MIC5245 10 August 2002 MIC5245 August 2002 Micrel 11 MIC5245 MIC5245 Micrel MICREL, INC. 1849 FORTUNE DRIVE TEL + 1 (408) 944-0800 FAX SAN JOSE, CA 95131 + 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. © 2002 Micrel, Incorporated MIC5245 12 August 2002