MIC2800 Digital Power Management IC 2MHz, 600mA DC/DC w/Dual 300mA/300mA Low VIN LDOs General Description The MIC2800 is a high performance power management IC, giving three output voltages with maximum efficiency. Integrating a 2MHz DC/DC converter with an LDO post regulator, the MIC2800 gives two high efficiency outputs with a second, 300mA LDO for maximum flexibility. The MIC2800 features a LOWQ® mode, reducing the total current draw while in this mode to less than 30µA. In LOWQ® mode, the output noise of the DC to DC converter is 75µVRMS, significantly lower than other converters which use a PFM light load mode that can interfere with sensitive RF circuitry. The DC to DC converter uses small values of L and C to reduce board space but still retains efficiencies over 90% at load currents up to 600mA. The MIC2800 is a µCap design, operating with very small ceramic output capacitors and inductors for stability, reducing required board space and component cost and it is available in fixed output voltages in the 16-pin 3mm x 3mm MLF® leadless package. Data sheets and support documentation can be found on Micrel’s web site at: www.micrel.com. Features • 2.7V to 5.5V input voltage range • 2MHz DC/DC converter and two stand-alone LDOs – LDO1: Low input voltage is powered directly from DC/DC converter for highest efficiency • Integrated power-on reset (OR function for all outputs) – Adjustable delay time • LOWQ® mode – 30µA Total IQ when in LOWQ® mode • Tiny 16-pin 3mm x 3mm MLF® package DC to DC Converter • Output current to 600mA in PWM mode • LOWQ® Mode: NO NOISE Light load mode – 75µVRMS output noise in LOWQ® mode • 2MHz PWM operation in normal mode • >90% efficiency LDOs • LDO1 input voltage directly connected to DC/DC converter output voltage for maximum efficiency – Ideal for 1.8V to 1.5V conversion – 300mA output current from 1.8V input – Output voltage down to 0.8V • LDO2 – 300mA output current capable • Thermal Shutdown Protection • Current Limit Protection Applications • • • • • Mobile phones PDAs GPS receivers Digital still cameras Portable media players Typical Application DC/DC 1.8VOUT Efficiency 100 95 3.6V 3V 90 85 4.2V 80 75 70 65 60 L = 2.2µH COUT = 2.2µF 55 /LowQ = VIN 50 0 100 200 300 400 500 600 OUTPUT CURRENT (mA) MIC2800-xxxYML VIN 2.7V to 5.5V 4.7µF/ 6.3V CBYP 0.01µF VIN VIN EN1 LOWQ EN2 CBYP CBIAS PGND CBIAS 0.1µF LDO SW FB LDO1 LDO2 POR CSET SGND CSET 0.01µF VOUT 2.2µH Memory/DSP 2.2µF ceramic Baseband COUT2 2.2µF ceramic COUT1 2.2µF ceramic GND GND LOWQ is a registered trademark of Micrel, Inc. MLF and MicroLeadFrame are registered trademarks of Amkor Technology, Inc. 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 M9999-090507-C Micrel, Inc. MIC2800 Ordering Information Part number Manufacturing Part Number Voltage Junction Temperature Range Package MIC2800-1.8/1.2/2.5YML MIC2800-1.8/1.2/2.6YML MIC2800-1.8/1.2/2.8YML MIC2800-1.8/1.2/3.3YML MIC2800-1.8/1.58/3.3YML MIC2800-1.87/1.2/2.8YML MIC2800-1.8/1.5/2.8YML MIC2800-Adj/1.2/3.3YML MIC2800-G4JYML MIC2800-G4KYML MIC2800-G4MYML MIC2800-G4SYML MIC2800-G7SYML MIC2800-D24MYML MIC2800-GFMYML MIC2800-A4SYML 1.8V/1.2V/2.5V 1.8V/1.2V/2.6V 1.8V/1.2V/2.8V 1.8V/1.2V/3.3V 1.8V/1.58V/3.3V 1.87V/1.2V/2.8V 1.8V/1.5V/2.8V Adj/1.2V/3.3V –40°C to +125°C –40°C to +125°C –40°C to +125°C –40°C to +125°C –40°C to +125°C –40°C to +125°C –40°C to +125°C –40°C to +125°C 16-Pin 3x3 MLF® 16-Pin 3x3 MLF® 16-Pin 3x3 MLF® 16-Pin 3x3 MLF® 16-Pin 3x3 MLF® 16-Pin 3x3 MLF® 16-Pin 3x3 MLF® 16-Pin 3x3 MLF® Notes: ® Other voltage options available. Please contact Micrel for details. MLF is a GREEN RoHS compliant package. Lead finish is NiPdAu. Mold compound is Halogen Free. DC/DC – Fixed Output Voltages (Range of 1.0V to 2.0V). Adjustable output voltage is available upon request. LDO1 – Output Voltage Range of 0.8V to VDC/DC - VDO. LDO2 – Output Voltage Range of 0.8V to 3.6V. September 2007 2 M9999-090507-C Micrel, Inc. MIC2800 Pin Configuration ® 3mm x 3mm MLF (ML) Fixed DC/DC Converter Output Voltage Pin Description Pin Number 1 Pin Name _____ LOWQ 2 BIAS 3 4 5 6 7 8 SGND PGND SW VIN VIN LDO2 9 FB 10 11 LDO LDO1 12 POR 13 CSET 14 CBYP 15 EN1 16 EN2 September 2007 Pin Function LOWQ Mode. Active Low Input. Logic High = Full Power Mode; Logic Low = LOWQ Mode; Do not leave floating. Internal circuit bias supply. It must be de-coupled to signal ground with a 0.1µF capacitor and should not be loaded. Signal ground. Power ground. Switch (Output): Internal power MOSFET output switches. Supply Input – DC/DC. Must be tied to PIN7 externally. Supply Input – LDO2. Must be tied to PIN6 externally. Output of regulator 2 Feedback. Input to the error amplifier for DC to DC converter. adjust version, co For fixed output voltages connect to VOUT and an internal resistor network sets the output voltage LDO Output: Connect to VOUT of the DC/DC for LOWQ mode operation. Output of regulator 1 Power-On Reset Output: Open-drain output. Active low indicates an output undervoltage condition on either one of the three regulated outputs. Delay Set Input: Connect external capacitor to GND to set the internal delay for the POR output. When left open, there is minimum delay. This pin cannot be grounded. Reference Bypass: Connect external 0.1µF to GND to reduce output noise. May be left open. Enable Input (DC/DC and LDO1). Active High Input. Logic High = On; Logic Low = Off; Do not leave floating. Enable Input (LDO 2). Active High Input. Logic High = On; Logic Low = Off; Do not leave floating 3 M9999-090507-C Micrel, Inc. MIC2800 Absolute Maximum Ratings(1) Operating Ratings(2) Supply Voltage (VIN) ............................................. 0V to +6V Enable Input Voltage (VEN)................................... 0V to +6V LOWQ Mode (VLOWQ). .......................................... 0V to +6V Power Dissipation, Internally Limited(3) Lead Temperature (soldering, 10 sec.)...................... 260°C Storage Temperature (Ts) .........................–65°C to +150°C EDS Rating(4) .................................................................. 2kV Supply voltage (VIN) ..................................... +2.7V to +5.5V Enable Input Voltage (VEN)..................................... 0V to VIN LOWQ Mode (VLOWQ). ............................................ 0V to VIN Junction Temperature (TJ) ........................ –40°C to +125°C Junction Thermal Resistance MLF-16 (θJA) ......................................................45°C/W Electrical Characteristics(5) VIN = EN1 = EN2 = LOWQ = VOUT(6) + 1V; COUTDC/DC = 2.2µF, COUT1 = COUT2 = 2.2µF; IOUTDC/DC = 100mA; IOUTLDO1 = IOUTLDO2 = 100µA; TJ = 25°C, bold values indicate –40°C < TJ < +125°C; unless noted. Parameter UVLO Threshold UVLO Hysteresis Ground Pin Current Ground Pin Current in Shutdown Ground Pin Current (LOWQ mode) Conditions Rising input voltage during turn-on VFB = GND (not switching); Typ 2.55 100 800 LDO2 Only (EN1 = LOW) 55 All EN = 0V 0.2 IDC/DC < ILDO1 < ILDO2 < 10mA 30 DC/DC and LDO1 OFF; ILDO2 < 10mA Over-temperature Shutdown Over-temperature Shutdown Hysteresis Enable Inputs (EN1; EN2; /LOWQ ) Enable Input Voltage Logic Low Logic High Enable Input Current VIL < 0.2V VIH > 1.0V Turn-on Time (See Timing Diagram) Turn-on Time EN2=VIN (LDO1 and LDO2) EN1=VIN Turn-on Time (DC/DC) EN2=VIN; ILOAD = 300mA; CBYP = 0.1µF POR Output VTH Low Threshold, % of nominal (VDC/DC or VLDO1 or VLDO2) (Flag ON) High Threshold, % of nominal (VDC/DC AND VLDO1 AND VLDO2) (Flag OFF) VOL POR Output Logic Low Voltage; IL = 250µA IPOR Flag Leakage Current, Flag OFF SET INPUT SET Pin Current Source VSET = 0V SET Pin Threshold Voltage POR = High September 2007 Min 2.45 4 20 160 23 Max 2.65 1100 Units V mV µA 85 95 5 µA µA µA 60 80 70 µA µA µA °C °C 0.2 0.1 0.1 1 1 V V µA µA 240 120 83 500 350 350 µs µs µs 1.0 90 0.75 91 % 96 99 % 10 0.01 100 1 mV µA 1.25 1.25 1.75 µA V M9999-090507-C Micrel, Inc. MIC2800 Electrical Characteristics - DC/DC Converter VIN = VOUTDC/DC + 1; EN1 = VIN; EN2 = GND; IOUTDC/DC = 100mA ;L = 2.2µH; COUTDC/DC = 2.2µF; TJ = 25°C, bold values indicate –40°C to + 125°C; unless noted. Parameter Conditions Min Nominal VOUT tolerance -2 -3 0.75 Typ Max Units +2 +3 1.6 5 % % A nA %/V %/V % % Ω Ω MHz LOWQ = High (Full Power Mode) Fixed Output Voltages Current Limit in PWM Mode FB pin input current (ADJ only) Output Voltage Line Regulation Output Voltage Load Regulation Maximum Duty Cycle PWM Switch ON-Resistance VFB = 0.9*VNOM VOUT > 2.4V; VIN = VOUT + 300mV to 5.5V, ILOAD= 100mA VOUT < 2.4V; VIN = 2.7V to 5.5V, ILOAD= 100mA 20mA < ILOAD < 300mA VFB ≤ 0.4V ISW = 150mA VFB = 0.7VFB_NOM ISW = -150mA VFB = 1.1VFB_NOM Oscillator Frequency Output Voltage Noise Load Regulation Ripple Rejection COUT = 2.2µF; CBYP = 0.1µF; 10Hz to 100KHz Current Limit September 2007 IOUT = 100µA to 50mA f = up to 1kHz; COUT = 2.2µF; CBYP = 0.1µF f = 20kHz; COUT = 2.2µF; CBYP = 0.1µF VOUT = 0V 5 0.2 1.5 0.6 0.8 2 2.2 100 1.8 LOWQ = Low (Light Load Mode) Output Voltage Accuracy Variation from nominal VOUT Variation from nominal VOUT; -40°C to +125°C Output Voltage Temp. Coefficient Line Regulation VIN = VOUT + 1V to 5.5V; IOUT = 100µA 1 1 0.2 60 -2.0 -3.0 µVRMS +2.0 +3.0 % % ppm/C 0.3 0.6 1.5 %/V %/V % dB dB mA 40 0.02 80 0.2 55 45 120 190 M9999-090507-C Micrel, Inc. MIC2800 Electrical Characteristics - LDO1 VIN = VOUTDC/DC; EN1 = VIN; EN2 = GND; COUT1 = 2.2µF, IOUT1 = 100µA; TJ = 25°C, bold values indicate –40°C< TJ < +125°C; unless noted. Parameter Conditions Min LOWQ = High (Full Power Mode) Output Voltage Accuracy Variation from nominal VOUT Variation from nominal VOUT; -40°C to +125°C Output Current Capability VIN > 1.8V VIN > 1.5V Load Regulation IOUT = 100µA to 150mA IOUT = 100µA to 300mA Current Limit VOUT = 0V Ripple Rejection f = up to 1kHz; COUT = 2.2µF; CBYP = 0.1µF f = 20kHz; COUT = 2.2µF; CBYP = 0.1µF Output Voltage Noise COUT = 2.2µF; CBYP = 0.1µF; 10Hz to 100KHz LOWQ = Low (Light Load Mode) Output Voltage Accuracy Variation from nominal VOUT Variation from nominal VOUT; -40°C to +125°C Load Regulation IOUT = 100µA to 10mA Current Limit Ripple Rejection September 2007 VOUT = 0V f = up to 1kHz; COUT = 2.2µF; CBYP = 0.1µF f = 20kHz; COUT = 2.2µF; CBYP = 0.1µF 6 Typ -2.0 -3.0 300 120 350 0.17 0.3 500 70 44 30 -3.0 -4.0 0.2 50 85 70 42 Max Units +2.0 +3.0 % % mA mA % % mA dB dB µVRMS 1.5 700 +3.0 +4.0 0.5 1.0 125 % % % % mA dB dB M9999-090507-C Micrel, Inc. MIC2800 Electrical Characteristics - LDO2 VIN = VOUTLDO2 + 1.0V; EN1 = GND; EN2 = VIN; COUT2 = 2.2µF; IOUTLDO2 = 100µA; TJ = 25°C, bold values indicate –40°C< TJ < +125°C; unless noted. Parameter Conditions Min LOWQ = High (Full Power Mode) Output Voltage Accuracy Variation from nominal VOUT Variation from nominal VOUT; -40°C to +125°C Line Regulation VIN = VOUT +1V to 5.5V; IOUT = 100µA -2.0 -3.0 Load Regulation Dropout Voltage Ripple Rejection Current Limit Output Voltage Noise IOUT = 100µA to 150mA IOUT = 100µA to 200mA IOUT = 100µA to 300mA IOUT = 150mA IOUT = 200mA IOUT = 300mA f = up to 1kHz; COUT = 2.2µF; CBYP = 0.1µF f = 20kHz; COUT = 2.2µF; CBYP = 0.1µF VOUT = 0V COUT = 2.2µF, CBYP =0.1µF, 10Hz to 100kHz LOWQ = Low (Light Load Mode) Output Voltage Accuracy Variation from nominal VOUT Variation from nominal VOUT; -40°C to +125°C Line Regulation VIN = VOUT +1V to 5.5V Typ 0.02 400 0.20 0.25 0.40 70 94 142 75 40 550 25 -3.0 -4.0 0.02 Load Regulation Dropout Voltage IOUT = 100µA to 10mA IOUT = 10mA 0.2 22 Ripple Rejection f = up to 1kHz; COUT = 2.2µF; CBYP = 0.1µF f = 20kHz; COUT = 2.2µF; CBYP = 0.1µF VIN = 2.7V; VOUT = 0V 75 55 85 Current Limit 50 Max Units +2.0 +3.0 0.3 0.6 % % %/V 1.5 300 850 +3.0 +4.0 0.3 0.6 1.0 35 50 125 % % % mV mV mV dB dB mA µVRMS % % %/V % mV mV dB dB mA Notes: 1. Exceeding the absolute maximum rating may damage the device. 2. The device is not guaranteed to function outside its operating rating. 3. The maximum allowable power dissipation of any TA (ambient temperature) is PD(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. 4. Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5k in series with 100pF. 5. Specification for packaged product only. 6. VOUT denotes the highest of the three output voltage plus one volt. September 2007 7 M9999-090507-C Micrel, Inc. MIC2800 Typical Characteristics (DC/DC PWM Mode) DC/DC 1.8VOUT Efficiency DC/DC 1.87VOUT Efficiency 100 95 100 95 90 85 3V 3.6V 90 85 4.2V 80 75 80 3.6V 1200 1000 4.2V 800 75 70 70 600 65 65 60 L = 2.2µH COUT = 2.2µF /LowQ = VIN 55 50 0 1000 1400 3V 100 200 300 400 500 600 OUTPUT CURRENT (mA) DC/DC Enable Threshold vs. Supply Voltage 950 ON 800 750 700 OFF 650 600 500 2.7 100 L = 2.2µH COUT = 2.2µF /LowQ = VIN 100 200 300 400 500 600 OUTPUT CURRENT (mA) 200 0 COUT = 2.2µF CBYP = 0.1µF /LowQ = VIN EN1 = EN2 = VIN 20 40 60 80 TEMPERATURE (°C) DC/DC Turn-On Delay vs. Supply Voltage 95 900 850 550 400 60 55 50 0 DC/DC Current Limit vs. Temperature 90 85 80 75 70 65 60 COUT = 2.2µF /LowQ = VIN 3.4 4.1 4.8 5.5 SUPPLY VOLTAGE (V) September 2007 COUT = 2.2µF /LowQ = VIN 55 50 2.7 3.2 3.7 4.2 4.7 5.2 SUPPLY VOLTAGE (V) 8 M9999-090507-C Micrel, Inc. MIC2800 Typical Characteristics (DC/DC LowQ Mode) Power Supply Rejection Ratio (Input Voltage) 60 4.2V 80 0µA 70 50 40 Power Supply Rejection Ratio (Output Current) 3.6V 80 60 100µA 50 30 40 40 IOUT = 50mA 10 VOUT = 1.8V COUT = 2.2µF /LowQ = GND 0 0.01 0.1 1 10 100 1,000 FREQUENCY (kHz) 20 VIN = 3.6V VOUT = 1.8V 10 COUT = 2.2µF /LowQ = GND 0 0.01 0.1 1 10 100 1,000 FREQUENCY (kHz) LDO Output Voltage vs. Output Current DC/DC LowQ Mode Output Noise Spectral Density 1.90 60 50mA 30 20 100 LDO Current Limit vs. Supply Voltage 20 0 2.7 COUT = 2.2µF /LowQ = GND 3.4 4.1 4.8 5.5 SUPPLY VOLTAGE (V) 10 1.89 1 1.88 1.87 0.1 1.86 1.85 1.84 VIN = 3.6V VOUT = 1.87V COUT = 2.2µF /LowQ = GND 10 20 30 40 50 60 70 80 90 OUTPUT CURRENT (mA) September 2007 0.01 VIN = 4.2V VOUT = 1.87V COUT = 2.2µF /LowQ = GND 0.001 0.01 0.1 1 10 100 1,000 10,000 FREQUENCY (kHz) 9 M9999-090507-C Micrel, Inc. MIC2800 Typical Characteristics (LDO1, LDO2) Power Supply Rejection Ratio (LDO1 LowQ Mode) Power Supply Rejection Ratio (LDO1 Normal Mode) Power Supply Rejection Ratio (LDO2 LowQ Mode) 100 80 -90 90 70 -80 60 -70 80 70 50mA 100µA 60 50 50mA 100µA 150mA 30 VIN = 4.2V VOUT = 1.2V 20 COUT = 2.2µF 10 /LowQ = GND CBYP = 0.1µF 0 0.01 0.1 1 10 100 1,000 FREQUENCY (kHz) Power Supply Rejection Ratio (LDO2 Normal Mode) 100 100µA 90 300mA VIN = 4.2V 20 VOUT = 1.2V COUT = 2.2µF 10 /LowQ = VIN CBYP = 0.1µF 0 0.01 0.1 1 10 100 1,000 FREQUENCY (kHz) (LDO2) Output Voltage vs. Temperature 2.95 80 70 150mA 50 50mA 40 30 VIN = 4.2V VOUT = 1.2V 20 COUT = 2.2µF 10 /LowQ = VIN CBYP = 0.01µF 0 0.01 0.1 1 10 100 1,000 FREQUENCY (kHz) Ground Current vs. Output Current 70 2.65 2.60 2.55 2.50 140 50 VIN = VOUT + 1V VOUT = 2.8V COUT = 2.2µF CBYP = 0.1µF EN1 = GND EN2 = VIN 20 40 60 80 TEMPERATURE (°C) (LDO2) Dropout Voltage vs. Output Current 100 80 50 60 40 VIN = 2.8V VOUT = 2.8V COUT = 2.2µF CBYP = 0.1µF 40 30 0 20 50 100 150 200 250 300 OUTPUT CURRENT (mA) 0 0 Dropout Chararcteristics 3.0 10 COUT = 2.2µF CBYP = 0.1µF /LowQ = VIN 100µA 55 120 60 70 Ground Current vs. Temperature 60 2.80 2.75 2.70 -30 VIN = 4.2V V = 2.8V -20 COUT = 2.2µF OUT -10 /LowQ = VIN CBYP = 0.01µF 0 0.01 0.1 1 10 100 1,000 FREQUENCY (kHz) 65 2.90 2.85 60 100µA -40 30 3.00 10mA -50 40 50 40 -60 50mA VOUT = 2.8V COUT = 2.2µF CBYP = 0.1µF /LowQ = VIN 50 100 150 200 250 300 OUTPUT CURRENT (mA) LDO1 Output Noise Spectral Density 45 40 35 30 300mA VIN = VOUT + 1V 100mA VOUT = 2.8V COUT = 2.2µF CBYP = 0.1µF /LowQ = VIN EN1 = GND EN2 = VIN 20 40 60 80 TEMPERATURE (°C) (LDO2) Dropout Voltage vs. Temperature 0.20 VOUT = 2.8V 0.18 COUT = 2.2µF C 0.16 BYP = 0.1µF /LowQ = VIN 0.14 0.12 0.10 0.08 0.06 0.04 0.02 0.00 10 1 1 0.1 0.1 300mA 150mA 100mA 50mA 20mA 20 40 60 80 TEMPERATURE (°C) LDO2 Output Noise Spectral Density 100mA 150mA 2.5 300mA 2.0 1.5 2.0 2.5 3.0 SUPPLY VOLTAGE (V) September 2007 3.5 VIN = 4.2V 0.01 VOUT = 1.2V COUT = 2.2µF CBYP = 0.1µF /LowQ = VIN 0.001 0.01 0.1 1 10 100 1,000 10,000 FREQUENCY (kHz) 10 VIN = 4.2V 0.01 VOUT = 2.8V COUT = 2.2µF CBYP = 0.1µF /LowQ = VIN 0.001 0.01 0.1 1 10 100 1,000 10,000 FREQUENCY (kHz) M9999-090507-C Micrel, Inc. MIC2800 Functional Characteristics DC/DC Load Transient PWM Mode DC/DC Line Transient PWM Mode VIN = VOUT + 1V Input Voltage (1V/div) VOUT = 1.8V CBYP = 0.01µF /LowQ = VIN VIN = VOUT + 1V VOUT = 1.87V COUT = 2.2µF CBYP = 0.01µF Output Voltage AC Coupled (100mV/div) Output Current (100mA/div) Output Voltage AC Coupled (100mV/div) COUT = 2.2µF 400mA 10mA /LowQ = VIN IOUT = 100mA Time (20µs/div) Time (20µs/div) Output Voltage (500mV/div) Enable Voltage (500mV/div) Enable Transient PWM Mode VIN = 3.6V VOUT = 1.8V COUT = 2.2µF CBYP = 0.01µF /LowQ = VIN IOUT = 300mA Time (40µs/div) September 2007 11 M9999-090507-C Micrel, Inc. MIC2800 Functional Characteristics DC/DC Load Transient LowQ Mode DC/DC Line Transient LowQ Mode VIN = VOUT + 1V Input Voltage (1V/div) Output Current (20mA/div) 50mA VOUT = 1.8V COUT = 2.2µF CBYP = 0.01µF /LowQ = GND VIN = VOUT + 1V VOUT = 1.87V COUT = 2.2µF 100µA CBYP = 0.01µF Output Voltage AC Coupled (20mV/div) Output Voltage AC Coupled (50mV/div) /LowQ = GND IOUT = 10mA Time (20µs/div) Time (10µs/div) Output Voltage (500mV/div) Supply Voltage & Enable Voltage (2V/div) Enable Transient LowQ Mode VIN = EN1 = 3.8V VOUT = 1.8V COUT = 2.2µF CBYP = 0.01µF /LowQ = GND IOUT = 100µA Time (20µs/div) September 2007 12 M9999-090507-C Micrel, Inc. MIC2800 Functional Characteristics LDO2 Load Transient LowQ Mode Output Voltage AC Coupled (50mV/div) Output Voltage AC Coupled (100mV/div) LDO2 Load Transient Normal Mode VIN = 3.6V VOUT = 2.8V Output Current (100mA/div) 300mA VIN = VOUT + 1V VOUT = 2.8V COUT = 2.2µF COUT = 2.2µF CBYP = 0.01µF 50mA /LowQ = GND CBYP = 0.01µF Output Current (25mA/div) /LowQ = VIN 100µA 100µA Time (200µs/div) Time (4µs/div) Input Voltage (1V/div) LDO2 Line Transient LowQ Mode 5.5V VIN = VOUT + 1V 4V VOUT = 1.87V 4V VIN = VOUT + 1V VOUT = 1.87V COUT = 2.2µF CBYP = 0.01µF CBYP = 0.01µF /LowQ = VIN /LowQ = GND IOUT = 100mA IOUT = 10mA Time (40µs/div) Time (20µs/div) September 2007 5.5V COUT = 2.2µF Output Voltage AC Coupled (50mV/div) Output Voltage AC Coupled (50mV/div) Input Voltage (1V/div) LDO2 Line Transient Normal Mode 13 M9999-090507-C Micrel, Inc. MIC2800 Functional Characteristics DC/DC LowQ Mode to PWM Mode Transition LowQ Voltage (1V/div) LowQ Voltage (1V/div) DC/DC PWM Mode to LowQ Mode Transition VIN = VOUT + 1V VOUT = 1.8V VOUT = 1.8V COUT = 2.2µF COUT = 2.2µF CBYP = 0.01µF Output Voltage AC Coupled (50mV/div) Output Voltage AC Coupled (50mV/div) VIN = VOUT + 1V CBYP = 0.01µF IOUT = 100µA IOUT = 50mA Time (100µs/div) Time (100µs/div) VIN = 4V VOUT = 1.8V COUT = 2.2µF CBYP = 0.01µF /LowQ = VIN L = 2.2µH Output Voltage AC Coupled (10mV/div) LowQ Voltage (2V/div) DC/DC PWM Waveform Time (400µs/div) September 2007 14 M9999-090507-C Micrel, Inc. MIC2800 Functional Characteristics 100 ESR vs. Load LDO 100 10 10 STABLE AREA STABLE AREA 1 1 0.1 0 100 ESR vs. Load LDO1 0.1 0 50 100 150 OUTPUT CURRENT (mA) 50 100 150 OUTPUT CURRENT (mA) ESR vs. Load LDO2 10 STABLE AREA 1 0.1 0 September 2007 50 100 150 OUTPUT CURRENT (mA) 15 M9999-090507-C Micrel, Inc. MIC2800 Functional Diagram VIN VIN CBIAS LDO DC to DC SW EN1 _____ LOWQ FB EN2 CBYP LDO1 VOUT1 LDO2 VOUT2 Reference and Quick Start PGND POR SGND POR CSET MIC2800 Fixed Block Diagram September 2007 16 M9999-090507-C Micrel, Inc. MIC2800 LDO2 Regulated output voltage of LDO2. Power is provided by VIN. Recommended output capacitance is 2.2µF. Application Notes The MIC2800 is a digital power management IC with a single integrated buck regulator and two independent low dropout regulators. LDO1 is a 300mA low dropout regulator that is using power supplied by the on board buck regulator. LDO2 is a 300mA low dropout regulator using the supply from the input pin. The buck regulator is a 600mA PWM power supply that utilizes a /LOWQ light load mode to maximize battery efficiency in light load conditions. This is achieved with a /LOWQ control pin that when pulled low, shuts down all the biasing and drive current for the PWM regulator, drawing only 20µA of operating current. This allows the output to be regulated through the LDO output, capable of providing 60mA of output current. This method has the advantage of producing a clean, low current, ultra low noise output in /LOWQ mode. During /LOWQ mode, the SW node becomes high impedance, blocking current flow. Other methods of reducing quiescent current, such as pulse frequency modulation (PFM) or bursting techniques create large amplitude, low frequency ripple voltages that can be detrimental to system operation. When more than 60mA is required, the /LOWQ pin can be forced high, causing the MIC2800 to enter PWM mode. In this case, the LDO output makes a "hand-off" to the PWM regulator with virtually no variation in output voltage. The LDO output then turns off allowing up to 600mA of current to be efficiently supplied through the PWM output to the load. EN Both enable inputs are active high, requiring 1.0V for guaranteed operation. EN1 provides logic control of both the DCDC regulator and LDO1. EN2 provides logic control for LDO2 only. The enable inputs are CMOS logic and cannot be left floating. The enable pins provide logic level control of the specified outputs. When both enable pins are in the off state, supply current of the device is greatly reduced (typically <1µA). When the DCDC regulator is in the off state, the output drive is placed in a "tri-stated" condition, where both the high side P-channel MOSFET and the low-side N-channel are in an “off” or non-conducting state. Do not drive either of the enable pins above the supply voltage. Power-On Reset (POR) The power-on reset output is an open-drain N-Channel device, requiring a pull-up resistor to either the input voltage or output voltage for proper voltage levels. The POR output has a delay time that is programmable with a capacitor from the CSET pin to ground. The delay time can be programmed to be as long as 1 second. /LOWQ The /LOWQ pin provides a logic level control between the internal PWM mode and the low noise linear regulator mode. With /LOWQ pulled low (<0.2V), quiescent current of the device is greatly reduced by switching to a low noise linear regulator mode that has a typical IQ of 20µA. In linear (LDO) mode the output can deliver 60mA of current to the output. By placing /LOWQ high (>1V), the device transitions into a constant frequency PWM buck regulator mode. This allows the device the ability to efficiently deliver up to 600mA of output current at the same output voltage. /LOWQ mode also limits the output load of both LDO1 and LDO2 to 10mA. VIN Two input voltage pins provide power to the switch mode regular and LDO2 separately. The LDO1 input voltage is provided by the DC/DC LDO pin. VIN provides power to the LDO section and the bias through an internal 6Ω resistor. Both VIN pins must be tied together. For the switch mode regulator VIN provides power to the MOSFET along with current limiting sensing. Due to the high switching speeds, a 4.7µF capacitor is recommended close to VIN and the power ground (PGND) pin for bypassing. Please refer to layout recommendations. BIAS The BIAS pin supplies the power to the internal control and reference circuitry. The bias is powered from AVIN through an internal 6Ω resistor. A small 0.1µF capacitor is recommended for bypassing. LDO The LDO pin is the output of the linear regulator and should be connected to the output. In /LOWQ mode (/LOWQ <0.2V), the LDO provides the output voltage. In PWM mode (/LOWQ >1V) the LDO pin provides power to LDO1. FB Connect the feedback pin to VOUT. LDO1 Regulated output voltage of LDO1. Power is provided by the DCDC switching regulator. Recommended output capacitance is 2.2µF. September 2007 17 M9999-090507-C Micrel, Inc. MIC2800 transient response, but performance has been optimized for a 2.2µF ceramic on the LDOs and the DC/DC. 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 much as 50% to 60% respectively over their operating temperature ranges. SW The switch (SW) pin connects directly to the inductor and provides the switching current necessary to operate in PWM mode. Due to the high speed switching on this pin, the switch node should be routed away from sensitive nodes. PGND Power ground (PGND) is the ground path for the high current PWM mode. The current loop for the power ground should be as small as possible. Refer to the layout considerations for more details. Input Capacitor A minimum 1µF ceramic is recommended on the VIN pin for bypassing. X5R or X7R dielectrics are recommended for the input capacitor. Y5V dielectrics lose most of their capacitance over temperature and are therefore, not recommended. A minimum 1µF is recommended close to the VIN and PGND pins for high frequency filtering. Smaller case size capacitors are recommended due to their lower ESR and ESL. Please refer to layout recommendations for proper layout of the input capacitor. SGND Signal ground (SGND) is the ground path for the biasing and control circuitry. The current loop for the signal ground should be as small as possible. Refer to the layout considerations for more details. CSET The SET pin is a current source output that charges a capacitor that sets the delay time for the power-on reset output from low to high. The delay for POR high to low (detecting an undervoltage on any of the outputs) is always minimal. The current source of 1.25µA charges a capacitor up from 0V. When the capacitor reaches 1.25V, the output of the POR is allowed to go high. The delay time in micro seconds is equal to the Cset in picofarads. Inductor Selection The MIC2800 is designed for use with a 2.2µH inductor. Proper selection should ensure the inductor can handle the maximum average and peak currents required by the load. Maximum current ratings of the inductor are generally given in two methods; permissible DC current and saturation current. Permissible DC current can be rated either for a 40°C temperature rise or a 10% to 20% loss in inductance. Ensure that the inductor selected can handle the maximum operating current. When saturation current is specified, make sure that there is enough margin that the peak current will not saturate the inductor. Peak inductor current can be calculated as follows: POR Delay (µs) = CSET (pF) CBYP The internal reference voltage can be bypassed with a capacitor to ground to reduce output noise and increase power supply rejection (PSRR). A quick-start feature allows for quick turn-on of the output voltage. The recommended nominal bypass capacitor is 0.1µF, but it can be increased, which will also result in an increase to the start-up time. IPK = IOUT ⎛ V VOUT ⎜⎜1 − OUT VIN ⎝ + 2× f ×L ⎞ ⎟⎟ ⎠ Output Capacitor LDO1 and LDO2 outputs require a 2.2µF ceramic output capacitor for stability. The DC/DC switch mode regulator requires a 2.2µF ceramic output capacitor to be stable. All output capacitor values can be increased to improve September 2007 18 M9999-090507-C Micrel, Inc. MIC2800 PCB Layout Top Layer Bottom Layer September 2007 19 M9999-090507-C Micrel, Inc. MIC2800 Package Information 16-Pin 3mm x 3mm MLF® (ML) 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. © 2006 Micrel, Incorporated. September 2007 20 M9999-090507-C