MIC23099 Single AA/AAA Cell Step-Up/Step-Down Regulators with Battery Monitoring General Description Features • • • • • • • • • • • • • • • The MIC23099 is a high-efficiency, low-noise, dual-output, integrated power-management solution for single-cell alkaline or NiMH battery applications. The synchronous boost output voltage (VOUT1) is enabled first and is powered from the battery. Next the synchronous buck output (VOUT2), which is powered from the boost output voltage, is enabled. This configuration allows VOUT2 to be independent of battery voltage, thereby allowing the buck output voltage to be higher or lower than the battery voltage. VIN range from 0.85V to 1.6V VOUT1 (step-up) adjustable from 1.8V to 3.3V VOUT2 (step-down) adjustable from 1.0V to VOUT1 VOUT1/400mW and VOUT2/30mA from a single cell Minimizes switching noise in the audio band Step-up regulator with output disconnect in shutdown VOUT1, above 90% efficiency for 5mA to 200mA Anti-ringing control circuit to minimize EMI Turn-on inrush current limiting and soft-start Automatic output discharge Low-battery indicator Power Good (PG) output Low output ripple < 10mV Short-circuit and thermal protection 14-pin 2.5mm × 2.5mm × 0.55mm thin QFN (TQFN) package • −40°C to +125°C junction temperature range To minimize switching artifacts in the audio band, both the converters are design to operate with a minimum switching frequency of 80kHz for the buck and 100kHz for the boost. The high current boost has a maximum switching frequency of 1MHz, minimizing the solution footprint. The MIC23099 incorporates both battery-management functions and fault protection. The low-battery level is indicated by an external LED connected to the LED pin. In addition, a supervisory circuit monitors each output and asserts a power-good (PG) signal when the sequencing is done or de-asserted when a fault condition occurs. Applications Datasheets and support documentation are available on Micrel’s web site at: www.micrel.com. • Audio headsets • Portable applications Typical Application Efficiency (VIN = 1.2V) vs. Output Current 6.8µH 2 (0.9V – 1.6V) 6 10uF VOUT1 SW1 OUT1 VIN PGND1 FB1 100k 5 PG 4 47µF EP EN VOUT1 1.8V/111mA 13 NC BOOST VOUT1 = 1.8V 90 3 R2 PG 100 R1 1 33pF MIC23099 OUT2 10 4.7µH SW2 VOUT2 1.0V/30mA 12 VOUT1 AGND ON (VIN >= 1.2V) Blinking (VIN < 1.2V) 0.25Hz/25%DC 82Ω PGND2 7 LED FB2 8 11 10µF R3 EFFICIENCY (%) 14 80 BUCK VOUT2 = 1.0V 70 60 50 LED Pin = OPEN L1 = IFSC1515AHER6R8M01M L2 = SPM4012T-4R7M 9 40 0.001 0.01 0.1 0.2 R4 OUTPUT CURRENT (A) Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com August 6, 2014 Revision 1.3 Micrel, Inc. MIC23099 Ordering Information Part Number Output Voltages Marking MIC23099YFT Adjustable 23099 (1) Junction Temperature Range –40°C to +125°C Package Lead Finish (2) 14-Pin 2.5mm × 2.5mm × 0.55mm Thin QFN Pb-Free Notes: 1. Pin 1 identifier = “▲”. 2. Thin QFN is a Green RoHs-compliant package. Lead finish is NiPdAu. Mold compound is Halogen Free. Pin Configuration 14-Pin 2.5mm × 2.5mm QFN (FT) (Top View) Pin Description Pin Number Pin Name 1 PGND1 Pin Function Power Ground 1: The power ground for the synchronous boost DC/DC converter power stage. 2 VIN Battery Voltage Supply (Input): The internal circuitry operates from the battery voltage during start up. Once VOUT1 exceeds VIN, the bias current comes from VOUT1. The start-up sequence is initiated once the battery voltage is above 0.9V. The boost output (VOUT1) is power-up first, then the buck output (VOUT2) follows. If the battery voltage falls below 0.85V for more than 15 cool-off cycles, both outputs are simultaneously turned off and an internal resistor discharges the output capacitors to 0V. 3 FB1 Feedback 1 (Input): Connect a resistor divider network to this pin to set the output voltage for the synchronous boost regulator. Resistors should be selected based on a nominal VFB1 = 0.6V. 4 NC No Connect Pin (NC): Leave open, do not connect to ground. 5 PG Power Good (Output): This is an open drain, active high output. When VIN, VFB1 or VFB2 are below their nominal voltages the Power Good output gets pulled low after a de-glitch period. The PG pin will be pulled low without delay when the enable is set low. EN Enable (input): A logic level control of both outputs. The EN pin is CMOS-compatible. Logic high = enable, logic low = shutdown. In the off state, supply current of the device is greatly reduced (typically 1µA). When the EN pin goes high, the start-up sequence is initiated. The boost output (VOUT1) is powered up first then the buck output (VOUT2) follows. When EN goes low, both outputs are immediately turned off and the boost output (VOUT1) is completely disconnected from the input voltage. Then both converters output capacitors are discharged to ground through an internal pull down circuit. The EN pin has a 4MΩ resistance to AGND. 6 August 6, 2014 2 Revision 1.3 Micrel, Inc. MIC23099 Pin Description (Continued) Pin Number Pin Name 7 LED 8 AGND 9 FB2 10 OUT2 11 PGND2 Pin Function LED (Output): This is an open drain output that is used for a low battery indicator. Under normal conditions, the LED is always ON. If the battery voltage is between 1.2V to 0.85V, the external LED will blink with a duty cycle of 25% at 0.25Hz. The LED will be OFF if the battery voltage falls below 0.85V for more than 15 cool-off cycles or the EN pin is low. Analog Ground: The analog ground for both regulator control loops. Feedback 2 (Input): Connect a resistor divider network to this pin to set the output voltage for the synchronous buck regulator. Resistors should be selected based on a nominal VFB2 = 0.6V. Output Voltage 2 (Input): If the EN is low or the power good output is pulled low, an internal resistor discharges VOUT2 output capacitance to 0V. Also, if the inductor current falls to zero an internal antiringing switch is connected between the SW2 and OUT2 pins to minimize the switch node ringing. Power Ground 2: The power ground for the synchronous buck DC/DC converter power stage. SW2 Switch Pin 2 (Input): Inductor connection for the synchronous step-down regulator. Connect the inductor between VOUT2 and the SW2 pin. Due to the high-speed switching on this pin, the SW2 pin should be routed away from sensitive nodes and trace length should be kept as short and wide as possible to reduce EMI. If the inductor current falls to zero or EN is low, then an internal anti-ringing switch is connected between the SW2 and VOUT2 pins to minimize the switch node ringing. OUT1 Output 1 (Output): Output of the synchronous boost regulator and is the bias supply once VOUT1 is greater than VIN. The boost output also serves as the supply input for the buck converter (VOUT2). If the EN is low or the power good output is pulled low, an internal resistor discharges VOUT1 output capacitance to 0V. 14 SW1 Switch Pin 1 (Input): Inductor connection for the synchronous boost regulator. Connect the inductor between VIN and SW1. Due to the high-speed switching on this pin, the SW1 pin should be routed away from sensitive nodes and trace length should be kept as short and wide as possible to reduce EMI. If the inductor current falls to zero, an internal anti-ringing switch is connected between the SW1 and VIN pins to minimize the switch node ringing. EP GND Exposed Pad (Power): Must make a full connection to a GND plane. 12 13 August 6, 2014 3 Revision 1.3 Micrel, Inc. MIC23099 Absolute Maximum Ratings(3) Operating Ratings(4) Supply Voltage (VIN) ..................................... −0.3V to +6.0V Switch Voltage (VSW1)................................... −0.3V to +6.0V Switch Voltage (VSW2)................................... −0.8V to +6.0V Enable Voltage (VEN) ......................................... −0.3V to VIN Feedback Voltage (VFB) ............................... −0.3V to +6.0V LED Output (VLED) ........................................ −0.3V to +6.0V Power Good (VPG) ........................................ −0.3V to +6.0V AGND to PGND1, PGND2 ........................... −0.3V to +0.3V Ambient Storage Temperature (Ts) .......... −65°C to +150°C (6) ESD HBM Rating ......................................................... 2kV ESD MM Rating............................................................ 200V Input Voltage after Start-Up (VIN) ............. +0.875V to +1.6V Enable Voltage (VEN) .............................................. 0V to VIN LED Output (VLED) .............................................. 0V to VOUT1 Output Voltage Range (VOUT1) ..................... +1.8V to +3.3V Output Voltage Range (VOUT2) ...................... +1.0V to VOUT1 (5) Junction Temperature (TJ) ..................... –40°C to +125°C Junction Thermal Resistance 2.5mm × 2.5mm Thin QFN-14 (θJA) ................. +70°C/W 2.5mm × 2.5mm Thin QFN-14 (θJC) ................ +25°C/W Electrical Characteristics(7) VIN = VEN = +1.25V; VOUT1 = +1.8V; VOUT2 = 1.0V; LOUT1 = 6.8µH; LOUT2 = 4.7µH; COUT1 = 47µF; COUT2 = 10µF TA = 25°C, unless otherwise noted. Bold values indicate –40°C ≤ TJ ≤ +125°C. Parameter Test Conditions Min. Typ. Max. Units Input Supply (VIN) Minimum Start Up Voltage VIN Rising; RLOAD ≥ 500Ω, IOUT2 = 0mA 0.75 0.9 V Quiescent Current - PFM Mode IOUT1 , IOUT2 = 0mA (Switching, Closed Loop) Measured at VIN with LED pin open 200 270 μA Quiescent Current - PFM Mode IOUT1 , = 2mA; IOUT2 = 10mA (Switching, Closed Loop) Measured at VIN 12.6 Shutdown Current VEN = 0V; VIN = 1.6V 0.02 Measured at VIN mA 2 μA Enable Input (EN) 0.8 EN Logic Level High to Start Up VEN Rising, Regulator Enabled EN Logic Level Low VEN Falling, Regulator Shutdown 0.5 0.2 V EN Bias Current VEN = 0V (Regulator Shutdown) 0.3 1 µA EN Pull-Down Resistance IEN = 0.5µA into Pin 4.0 5.0 MΩ 3.0 0.58 V Solution Efficiency System Efficiency VIN = 1.25V; VOUT1 = 1.8V; VOUT2 = 1.0V POUT1 = 8mW; POUT2 = 20mW 88 % System Efficiency VIN = 1.25V; VOUT1 = 1.8V; VOUT2 = 1.0V POUT1 = 80mW; POUT2 = 20mW 92 % Notes: 3. Absolute maximum ratings indicate limits beyond which damage to the component may occur. 4. The device is not guaranteed to function outside its operating ratings. 5. 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 will result in excessive die temperature, and the regulator will go into thermal shutdown. 6. Devices are ESD sensitive. Handling precautions are recommended. Human body model, 1.5kΩ in series with 100pF. 7. Specification for packaged product only. 8. Guaranteed by design. August 6, 2014 4 Revision 1.3 Micrel, Inc. MIC23099 Electrical Characteristics(7) (Continued) VIN = VEN = +1.25V; VOUT1 = +1.8V; VOUT2 = 1.0V; LOUT1 = 6.8µH; LOUT2 = 4.7µH; COUT1 = 47µF; COUT2 = 10µF; TA = 25°C, unless otherwise noted. Bold values indicate –40°C ≤ TJ ≤ +125°C. Parameter Test Conditions Min. Typ. Max. Units 0.825 0.85 0.875 V Fault Conditions VIN and VOUT1, 2 Fault Conditions VIN Turn Off Threshold Voltage VIN Falling; after Start Up PG Deglitch Delay, VIN Fault VIN Falling below 0.85V to VPG = LOW 120 180 ms PG Deglitch Delay, VOUT1, 2 Fault VOUT1 or VOUT2 falling below 90% of target value to VPG = LOW 60 120 ms 2250 ms Cool OFF Delay Time VPG = Low to VOUT1 Enabled COUT1 = 47µF; COUT2 = 10µF 750 1300 Hiccup Cycles before Latch OFF Counts Cool OFF cycles 15 Cycles OUT1 Active Discharge Resistance VEN = 0V 500 700 Ω OUT2 Active Discharge Resistance VEN = 0V 500 700 Ω Power Good Output (PG) PG Threshold Voltage VREF1 Rising or Falling 90 92.5 95 %VREF1 PG Threshold Voltage VREF2 Rising or Falling 90 92.5 95 %VREF2 PG Output Low Voltage IPG = 1mA (sinking), VEN = 0V 0.1 0.5 V PG Leakage Current VPG = 1.8V; VEN = 1.8V 0.01 1 μA 50 ms 1.25 V 31 mV PG Turn-On Delay −1 10 LED Low-Battery Indicator Output (LED) 1.15 Low-Battery Threshold VIN Falling 1.2 Low-Battery Hysteresis VIN Rising LED Flash Frequency VIN = 1.15V; VEN = 1.15V 0.125 0.25 0.5 Hz LED Flash Duty Cycle VIN = 1.15V; VEN = 1.15V 22.5 25 27.5 % LED Output Leakage Current VLED = 4.0V; VEN = 0V 0.01 1 μA LED Switch On-Resistance VIN = VEN = 1.25V; ILED = 1.0mA 25 Ω Thermal Protection Thermal Shutdown TJ Rising 150 °C Thermal Hysteresis Temperature Decreasing 20 °C August 6, 2014 5 Revision 1.3 Micrel, Inc. MIC23099 Electrical Characteristics(7) (Continued) VIN = VEN = +1.25V; VOUT1 = +1.8V; VOUT2 = 1.0V; LOUT1 = 6.8µH; LOUT2 = 4.7µH; COUT1 = 47µF; COUT2 = 10µF; TA = 25°C, unless otherwise noted. Bold values indicate –40°C ≤ TJ ≤ +125°C. Parameter Test Conditions Min. Typ. Max. Units 0.579 0.6 0.621 V 1 500 nA Boost Boost Reference (FB1) Feedback Regulation Voltage VIN = 0.9V to 1.5V PWM Mode FB Bias Current VFB1 = 0.6V VOUT1: 10% to 90% of target value Soft-Start Time RLOAD = 500Ω; COUT1 = 47µF 5 ms Boost Internal MOSFETs High-Side On-Resistance ISW1 = 100mA; VIN = 1.25V 200 mΩ Low-Side On-Resistance ISW1 = -100mA; VIN = 1.25V 140 mΩ Leakage Current into SW1 VSW = 4.0V, VOUT1 = 0V, VEN = 0V, VIN = 4.0V 0.01 2 µA 80 140 Ω 1.0 1.1 MHz Anti-Ringing Resistance Boost Switching Frequency Switching Frequency PWM Mode 0.9 Minimum Switching Frequency POUT1 = 20mW (PFM Mode) 100 Minimum Duty Cycle VFB1 = 0.7V 15 % Maximum Duty Cycle VFB1 = 0.5V 85 % Maximum Output Power VOUT1>1.8V; IOUT2 = 0mA 450 mW Current-Limit Threshold (NMOS) VFB1 = 0.5V 1.0 1.5 2.0 A Current-Limit Threshold (PMOS) VFB1 = 0.5V 1.5 2.5 3.0 A Linear Mode Current Limit (PMOS) VIN=1.25V, VOUT1 = 0V 56 80 180 mA (8) kHz Boost Current Limit Boost Power Supply Rejection PSRR (ΔVIN/ΔVOUT1) ΔVIN = 200mVp-p, f = 217Hz, IOUT1 = PFM 50 dB PSRR (ΔVIN/ΔVOUT1) ΔVIN = 200mVp-p, f = 1.0kHz, IOUT1 = PFM 50 dB PSRR (ΔVIN/ΔVOUT1) ΔVIN = 200mVp-p, f = 20kHz, IOUT1 = PFM 42 dB August 6, 2014 6 Revision 1.3 Micrel, Inc. MIC23099 Electrical Characteristics(7) (Continued) VIN = VEN = +1.25V; VOUT1 = +1.8V; VOUT2 = 1.0V; LOUT1 = 6.8µH; LOUT2 = 4.7µH; COUT1 = 47µF; COUT2 = 10µF; TA = 25°C, unless otherwise noted. Bold values indicate –40°C ≤ TJ ≤ +125°C. Parameter Test Conditions Min. Typ. Max. Units 0.579 0.6 0.621 V 1 500 nA Buck Buck Reference (FB2) Feedback Regulation Voltage Vout1 = 1.8V to 3.3V IOUT2 = 6mA to 30mA; (±3.5%) FB Bias Current VFB2 = 0.6V VOUT2: 10% to 90% of target value Soft-Start Time IOUT2 = 0mA; COUT2 = 10µF 0.1 ms Buck Internal MOSFETs High-Side On-Resistance ISW2 = 100mA; VOUT1 = 1.8V 560 mΩ Low-Side On-Resistance ISW2 = -100mA; VOUT1 = 1.8V 380 mΩ Leakage Current into SW2 VOUT1 = 3.3V, VSW2 = 3.3V, VEN = 0V, VOUT2 = 3.3V 0.01 2 µA Leakage Current out of SW2 VOUT1 = 3.3V, VSW2 = 0V, VEN = 0V, VOUT2=0V 0.01 0.5 µA 80 140 Ω Anti-Ringing Resistance Buck Switching Frequency (8) Minimum Switching Frequency POUT2 = 8mW (PFM Mode) Maximum Duty Cycle VFB2 = 0.5V 80 kHz 100 % 30 mA Buck Current Limit Maximum Output Current Current-Limit Threshold (PMOS) VFB2 = 0.5V 80 120 mA PSRR (ΔVOUT1/ΔVOUT2) ΔVOUT1 = 200mVp-p, f = 217Hz, IOUT2 = 10mA 50 dB PSRR (ΔVOUT1/ΔVOUT2) ΔVOUT1 = 200mVp-p, f = 1.0kHz, IOUT2 = 10mA 50 dB PSRR (ΔVOUT1/ΔVOUT2) ΔVOUT1 = 200mVp-p, f = 20kHz, IOUT2 = 10mA 42 dB Buck Power Supply Rejection August 6, 2014 7 Revision 1.3 Micrel, Inc. MIC23099 Block Diagram August 6, 2014 8 Revision 1.3 Micrel, Inc. MIC23099 Typical Characteristics Buck Efficiency (VIN = 1.8V) vs. Output Current Efficiency (VIN = 1.2V) vs. Output Current 100 100 1.03 BOOST VOUT1 = 1.8V L2 = SPM4012T-4R7M BUCK VOUT2 = 1.0V 80 70 60 LED Pin = OPEN L1 = IFSC1515AHER6R8M01M L2 = SPM4012T-4R7M 50 40 0.001 0.01 80 L2 = CIG2MW4R7NNE 70 60 VIN = 1.8V VOUT2 = 1.0V TA = 25⁰C 50 OUTPUT CURRENT (A) VIN = 1.8V VOUT2 = 1.0V TA = 25⁰C 0.98 0 0.03 0.01 0.01 PFM -0.5% VIN = 1.8V VOUT2 = 1.0V TA = 25⁰C 2.0% 0.612 PFM IOUT1 = 100uA 0.610 0.608 0.606 VIN = 1.2V TA = 25⁰C 0.604 PWM IOUT1 = 100mA 0.602 PFM -2.0% VIN = 1.2V VOUT1 = 1.8V TA = 25⁰C -4.0% 0.03 0 0.598 -50 -25 0 25 50 75 TEMPERATURE (°C) OUTPUT CURRENT (A) PWM 0.0% 0.600 -1.0% 0.02 0.03 Boost Output Voltage vs. Output Current LOAD REGULATION (%) FEEDBACK VOLTAGE (V) 0.5% 0.02 OUTPUT CURRENT (A) 0.614 0.01 0.99 Boost Feeback Voltage vs. Temperature 1.0% 0 1 OUTPUT CURRENT (A) Buck Load Regulation vs. Output Current 0.0% PFM 1.01 0.97 40 0.001 0.2 0.1 OUTPUT VOLTAGE (V) EFFICIENCY (%) EFFICIENCY (%) 1.02 90 90 LOAD REGULATION (%) Buck Output Voltage vs. Output Current 100 0.04 0.08 0.12 0.16 0.2 125 OUTPUT CURRENT (A) Boost Output Voltage vs. Output Current 1.84 OUTPUT VOLTAGE (V) 1.83 1.82 1.81 PWM 1.80 1.79 1.78 PFM 1.77 VIN = 1.2V VOUT1 = 1.8V TA = 25⁰C 1.76 1.75 0 0.04 0.08 0.12 0.16 0.2 OUTPUT CURRENT (A) August 6, 2014 9 Revision 1.3 Micrel, Inc. MIC23099 Typical Characteristics (Continued) VIN Quiescent Current (Switching) vs. Input Voltage VIN Shutdown Current vs. Input Voltage 300 250 200 150 100 50 VEN = 0V TA = 25°C 0.4 EN THRESHOLD (V) IOUT1 = 0A IOUT2 = 0A LED = OPEN SWITCHING TA = 25°C SHUTDOWN CURRENT (µA) QUIESCENT CURRENT (µA) 0.8 0.5 350 0.3 0.2 0.1 0.7 RISING 0.6 0.5 FALLING TA = 25°C 0.0 0 0.9 1.1 1.0 1.2 1.3 1.4 1.5 0.9 1.6 1.0 INPUT VOLTAGE (V) 1.1 1.2 1.3 1.4 1.5 0.4 1.6 0.9 1.0 100 VIN = 1.2V IOUT1 = 0A IOUT2 = 0A LED = OPEN SWITCHING 0.9 VIN = 1.2V 0.8 0.8 EN THRESHOLD (V) SHUTDOWN CURRENT (µA) 150 1.5 Enable Threshold vs. Temperature 1.0 200 1.3 INPUT VOLTAGE(V) VIN Shutdown Supply Current vs. Temperature 250 50 1.1 INPUT VOLTAGE (V) VIN Quiescent Current (Switching) vs. Temperature QUIESCENT CURRENT (µA) Enable Threshold vs. Input Voltage 0.6 0.4 0.7 RISING 0.6 0.5 FALLING 0.4 0.3 0.2 0.2 0.1 0 0 25 50 75 100 125 -50 -25 0 25 50 75 100 25 50 75 100 125 TEMPERATURE (°C) FB1 BIAS Current vs. Temperature FB2 BIAS Current vs. Temperature Boost Switching Frequency (PWM) vs. Temperature 10 10 8 6 4 VIN = 1.2V 2 1,200 8 6 4 VIN = 1.2V 2 0 25 50 75 TEMPERATURE (°C) 100 125 1,100 1,000 900 VIN = 1.2V 800 0 0 August 6, 2014 0 TEMPERATURE (°C) 12 -25 -25 TEMPERATURE (°C) 12 -50 -50 125 SWITCHNG FREQUENCY (kHz) -25 FB2 BIAS CURRENT (nA) FB1 BIAS CURRENT (nA) -50 VIN = 1.2V 0.0 0.0 -50 -25 0 25 50 75 TEMPERATURE (°C) 10 100 125 -50 -25 0 25 50 75 100 125 TEMPERATURE (°C) Revision 1.3 Micrel, Inc. MIC23099 Typical Characteristics (Continued) LED Flash Duty-Cycle vs. Temperature LED Flash Duty-Cycle vs. Input Voltage Low-BatteryThreshold vs. Temperature 1.25 0.50 50 100 LOW-BATTERY THRESHOLD (V) CONSTANT ON 40 0.40 DUTY-CYCLE (%) DUTY-CYCLE (%) 75 50 FLASHING 30 0.30 0.20 20 25 VOUT1 = 1.8V IOUT1 = 0A TA = 25⁰C 0.10 10 0 1.0 1.2 1.4 0 0.00 1.6 0 25 50 75 100 TEMPERATURE (°C) LED Flash Frequency vs. Input Voltage LED Flash Frequency vs. Temperature FREQUENCY (Hz) VOUT1 = 1.8V IOUT1 = 0.A TA = 25⁰C 0.4 FREQUENCY (Hz) -25 INPUT VOLTAGE (V) 0.5 0.3 FLASHING 0.2 1.22 1.21 1.20 FALLING 1.19 1.18 1.17 IOUT = 0A 1.16 125 -50 -25 0 25 50 75 100 125 TEMPERATURE (°C) VIN Fault Delay vs. Temperature 0.5 250 0.4 200 0.3 0.2 0.1 0.1 RISING 1.23 1.15 -50 FAULT DELAY (ms) 0.8 VIN = 1.1V 1.24 150 100 VOUT1 = 1.8V IOUT1 = 0A 50 VIN = 1.1V CONSTANT ON 0.0 0.0 1.0 1.2 1.4 1.6 0 -50 -25 0 25 50 75 100 25 50 75 VOUT1 Fault Delay vs. Temperature VOUT2 Fault Delay vs. Temperature Cool OFF Delay vs. Temperature 150 100 50 100 50 VIN = 1.2V VIN = 1.2V 0 25 50 75 TEMPERATURE (°C) 100 125 125 1,500 1,000 500 VIN = 1.2V 0 0 0 100 2,000 COOL OFF DELAY (ms) 150 August 6, 2014 0 TEMPERATURE (°C) 200 -25 -25 TEMPERATURE (°C) 200 -50 -50 125 INPUT VOLTAGE (V) FAULT DELAY (ms) FAULT DELAY (ms) 0.8 -50 -25 0 25 50 75 TEMPERATURE (°C) 11 100 125 -50 -25 0 25 50 75 100 125 TEMPERATURE (°C) Revision 1.3 Micrel, Inc. MIC23099 Typical Characteristics (Continued) Buck Switching Frequency vs. Output Current Boost Ripple Rejection 90 80 300 RIPPLE REJECTION (dB) SWITCHING FREQUENCY (kHz) 350 250 PFM 200 150 100 VOUT1 = 1.8V VOUT2 = 1.0V TA = 25⁰C 50 0.01 0.02 OUTPUT CURRENT (A) 60 50 40 30 20 VIN =1.5V VOUT1 = 1.8V IOUT = 0A TA = 25°C 10 0 -10 0 0 70 0.03 -20 0.1 1 10 100 1000 FREQUENCY (kHz) Buck Ripple Rejection 90 RIPPLE REJECTION (dB) 80 70 60 50 40 30 20 10 VIN =1.5V VOUT2 = 1.0V IOUT = 0A TA = 25°C 0 -10 -20 0.1 1 10 100 1000 FREQUENCY (kHz) August 6, 2014 12 Revision 1.3 Micrel, Inc. MIC23099 Functional Characteristics August 6, 2014 13 Revision 1.3 Micrel, Inc. MIC23099 Functional Characteristics (Continued) August 6, 2014 14 Revision 1.3 Micrel, Inc. MIC23099 Functional Characteristics (Continued) August 6, 2014 15 Revision 1.3 Micrel, Inc. MIC23099 Application Information Overview The MIC23099 is a dual output voltage, powermanagement IC (PMIC) that has excellent light load efficiency that operates from a single cell battery. The PMIC has a synchronous boost regulator, a synchronous buck regulator, inrush current limiting, fault detection, a low battery monitor and warning circuitry. The synchronous boost output voltage (VOUT1) is enabled first and is powered from the battery. Next the synchronous buck output (VOUT2), which is powered from the boost output voltage, is enabled. This configuration allows VOUT2 to be independent of battery voltage, thereby allowing the buck output voltage to be higher or lower than the battery voltage. Also, an inrush current limiting feature is provided to reduce the inrush current which minimizes the voltage droop on the battery when the device is turned on. Buck Regulator The buck converter is designed to operate in PFM mode with constant peak current control. When the buck regulator high-side switch turns on, the inductor current starts to rise. When the inductor current hits the current limit threshold, a RS flip-flop is reset, turning off high-side switch and on the low-side synchronous switch. The lowside switch will remain on until the inductor current falls to zero at which time it is turned off. Both switches will remain off until the cycle repeats itself when the buck feedback voltage falls below the internal 0.6V reference and the internal comparator sets the RS flip-flop Q output high. The boost regulator is a current-mode PWM design that incorporates a high-efficiency PFM light-load mode, while the buck operates in PFM mode with constant peak current control. The boost employs adaptive pulse width control that minimizes output ripple and avoids output ripple chatter commonly found in conventional micro power boost regulators. In addition, the MIC23099 incorporates a frequency control scheme that minimizes switching noise in the audio band. Low-Battery Voltage Monitoring The internal low input voltage monitor determines when the input voltage is below the internally set 1.2V (typical) threshold. When the input voltage falls below the internally set threshold, the external LED connected to the LED pin begins to blink at a frequency of 0.25Hz with a duty cycle of 25%. The low input voltage threshold of 1.2V has a ±50mV variation. The MIC23099 has an integrated low-battery monitor function. The low-battery level is indicated by an external LED connected to the LED pin. The LED is on when the battery voltage is above the 1.2V threshold and flashes when the battery voltage falls below the threshold. In addition, a supervisor circuit monitors each output and asserts a power good signal when the sequencing is done or the power good output is pulled low when a fault condition occurs. Anti-Ringing Control Both the buck and boost converters have an anti-ringing control circuit that minimizes the ringing on the switching node caused by the inductor and the parasitic capacitance of the switch node when the synchronous MOSFET turns off. When the inductor current falls to zero an internal anti-ringing switch is connected across the inductor. This temporally shorts the inductor and eliminates the ringing on the switch node. Boost Regulator The high-efficiency, micro-power synchronous boost regulator operates from one alkaline or NiMH battery. It offers true output disconnect to achieve a shutdown quiescent current of less than 1.0µA, extending battery life. True Micro-Power Shutdown This shutdown feature disconnects the boost output from the battery. This feature eliminates power draw from the battery through the synchronous switch during shutdown. In conventional boost regulators, there is a catch diode that provides a current path from the battery through the inductor to the output of the boost regulator that can draw current even when the regulator is shutdown. The boost regulator achieves high efficiency over a wide output current range by operating in either PWM or PFM mode. PFM mode provides the best efficiency at light loads and PWM mode at heavy loads. Operating mode is automatically selected according to output load conditions. In PWM mode, the switching frequency is 1.0MHz, minimizing the solution foot-print. The current-mode PWM design is internally compensated, simplifying the design. Current mode provides excellent line and load regulation as well as cycle-by-cycle current limiting. August 6, 2014 16 Revision 1.3 Micrel, Inc. MIC23099 Power-Up Sequencing When the enable pin voltage rises above the enable threshold voltage, the MIC23099 enters its start-up sequence. Initially, the boost converter high-side PMOS switch operates in linear mode and emulates a current limited switch until the output voltage VOUT1 reaches VIN. Then a fixed duty-cycle clock controls the boost converter until VOUT1 reaches 1.6V. When VOUT1 is greater than 1.6V the boost PFM control circuitry takes over until the output reaches its regulated voltage value. The boost regulator operates in either PWM or PFM mode. To avoid PWM to PFM chatter, the PWM entry and exit points are not the same. When in PFM mode the output current needs to reach 90mA to enter into PWM mode and exits at 30mA. The boost switching frequency is greater than 100kHz with loads greater than 20mW. When VOUT1 reaches 92.5% of its nominal value, VOUT2 is enabled. The power good output goes high 10ms to 50ms after VOUT2 reaches the programmed value. Figure 1 waveforms detail the circuits operation. Figure 2. Boost Switching Frequency vs. Output Current Buck Switching Frequency The buck converter is designed to operate in PFM mode only. It has peak current control, which turns off the highside switch when the inductor current hits the current limit threshold. The cycle repeats itself when the output voltage falls below its regulated value. As a result, the switching frequency varies linearly with output current as shown in Figure 3. The buck switching frequency is greater than 80kHz with loads greater than 8mW. Figure 1. Power-Up Sequencing Power Good The power good (PG) circuitry monitors the battery voltage and feedback pin voltage of the boost and buck regulators. The PG pin output goes logic high when FB1 and FB2 pin voltages are both greater than 92.5% (typical) of the internal reference voltage and the input voltage is greater than 0.85V (typical). To minimize false triggering, the power good output has both a turn on delay and a falling deglitch delay. Boost Switching Frequency To reduce switching artifacts in the audio band, the buck and boost regulators switching frequency are controlled to minimize overlap. Figure 2 shows the boost switching frequency versus output load current and Figure 3 shows the buck. switching frequency versus output load current. Figure 3. Buck Switching Frequency vs. Output Current August 6, 2014 17 Revision 1.3 Micrel, Inc. MIC23099 Low-Battery Detection and Output Latch-Off Figure 4 shows the low-battery power cycling operation. If the battery voltage (VIN) drops below 0.85V for more than 100ms to 150ms, the PG de-asserts (goes low) and outputs VOUT1 and VOUT2 are disabled. Then the 500Ω active discharges resistors are enabled and discharges VOUT1 and VOUT2 to ground, finally the MIC23099 enters a cool off or sleep period. After a cool off period of about 1.3 sec, if the battery voltage is above the 0.85V threshold, then the outputs will power up again. This th cycle repeats itself until the end of the 15 cycle when both outputs are latched off for the last time. The outputs can be turned back on by recycling the input power or by toggling the enable pin. If the battery voltage is still low, the MIC23099 will turn itself off again after 15 power-up cycles. Figure 5. Output Fault Power Cycling Boost Short-Circuit Protection The low-side current limit protects the IC from transient overload conditions, but not from a direct short to ground. The high-side MOSFET current limit provides the protection from a short to ground. In this fault condition, the high-side PMOS switch operates in linear mode and limits the current to approximately 80mA. If the short circuit condition last for more than 30ms, the PMOS switch is latched off as shown in Figure 6. The outputs are not re-enabled until the input power is recycled or the enable pin is toggled. Figure 4. Low-Battery Power Cycling Output Fault and Power Cycling If either VOUT1 or VOUT2 outputs are out of tolerance for longer than the power good deglitch delay of between 60ms to 120ms, both outputs are disabled. The power down procedure is the same as the low-battery fault detection, as shown in Figure 5. The outputs can be turned back on by recycling the input power or by toggling the enable pin. The latch-off feature eliminates the thermal stress on the MIC23099 and the external inductors during a fault event. August 6, 2014 Figure 6. Power-Up into Short Circuit 18 Revision 1.3 Micrel, Inc. MIC23099 Figure 8 shows the buck load regulation. Boost Overcurrent Protection The boost converter has current-limit protection on both the high-side and low-side MOSFETs. The low-side MOSFET provides cycle-by-cycle current limiting. When the peak switch current exceeds the NMOS current limit threshold, the low-side switch is immediately turned off and the high-side switch is turned on. Peak switch current is limited to approximately 1.5A. The low-side switch is allowed to turn on again on the next clock cycle. If the overload condition last more than 60ms to 120ms, both outputs are disabled and the IC enters its power cycling mode. Component Selection Resistors An external resistive divider network (R1 and R2) with its center tap connected to the feedback pin sets the output voltage for each regulator. R1 is the top resistor and R2 is the bottom resistor in the divider string. The resistor values for the desired output voltage are calculated as illustrated in Equation 1. Large resistor values are recommended to reduce light load operating current, and improve efficiency. The recommended resistor value for R1 should be around, R1 ≈ 150kΩ. R2 = R1 VOUT − 1 0 . 6 V Figure 8. Buck Load Regulation Inductor Inductor selection is a balance between efficiency, cost, size, switching frequency and rated current. For most applications, inductors in the range 4.7µH to 6.8µH are recommended. Larger inductance values reduce the peak-to-peak ripple current, thereby reducing both the DC losses and AC losses for better efficiency. The inductor’s DC resistance (DCR) also plays an important role. Since the majority of the input current (minus the MIC23099 operating current) is passed through the inductor, higher DCR inductors will reduce efficiency at higher load currents. Eq. 1 The switch current limit for the MIC23099 is typically 1.5A. The saturation current rating of the selected inductor should be 20 − 30% higher than the current limit specification for the respective regulator. In the case of the boost converter, Equation 1 sets the output voltage to its PWM value as shown in Figure 7. The no-load PFM output voltage is 2% higher than the PWM value. This higher PFM output voltage value is necessary to prevent PFM to PWM mode skipping which can introduce noise into the audio band. Input Capacitor The step-up converter exhibits a triangular, or sawtooth, current waveform at its input, so an input capacitor is required to decouple this waveform and thereby reduce the input voltage ripple. A 4.7µF to 10µF ceramic capacitor should be sufficient for most applications. A minimum input capacitance of 1µF is recommended. The input capacitor should be as close as possible to the inductor, VIN pin, and PGND1 pin of the MIC23099. Short, and wide, PCB traces are good for noise performance. Output Capacitor Output capacitor selection is also a trade-off between performance, size, and cost. Increasing the output capacitor will lead to an improved transient response performance. X5R and X7R ceramic capacitors are recommended. For most applications, 10µF to 47µF should be sufficient. Figure 7. Boost Load Regulation August 6, 2014 19 Revision 1.3 Micrel, Inc. MIC23099 PCB Layout Guidelines Inductor WARNING! To minimize EMI and output noise, follow these layout recommendations. PCB Layout is critical to achieve reliable, stable and efficient performance. A ground plane is required to control EMI and minimize the inductance in power, signal and return paths. The following guidelines should be followed to insure proper operation of the MIC23099 converter. • Keep the inductor connection to the switch node (SW) short. • Do not route any digital lines underneath or close to the inductor. • Keep the switch node (SW) away from the feedback (FB) pin. • To minimize noise, place a ground plane underneath the inductor. IC • • Output Capacitor The 4.7µF ceramic capacitor, which is connected between OUT1 and PGND1, must be located as close as possible to the IC. The analog ground pin (AGND) must be connected directly to the ground planes. Do not route the AGND pin to the PGND Pad on the top layer. • Place the IC close to the point of load (POL). • Use fat traces to route the input and output power lines to minimize EMI. • Signal and power grounds should be kept separate and connected at only one location. • The exposed pad (EP) must be soldered to the ground plane (layer 2). It serves as an additional ground connection and a way to conduct heat away from the package. • Use a wide trace to connect the output capacitor ground terminal to the input capacitor ground terminal. • Phase margin will change as the output capacitor value and ESR changes. Contact the factory if the output capacitor is different from what is shown in the BOM. • The feedback trace should be separate from the power trace and connected as close as possible to the output capacitor. Sensing a long high current load trace can degrade the DC load regulation. Input Capacitor • Place the input capacitor next. • Place the input capacitors on the same side of the board and as close to the IC as possible. • Keep both the VIN and PGND connections short. • Place several vias to the ground plane close to the input capacitor ground terminal. • Use either X7R or X5R dielectric input capacitors. Do not use Y5V or Z5U type capacitors. • Do not replace the ceramic input capacitor with any other type of capacitor. Any type of capacitor can be placed in parallel with the input capacitor. • If a Tantalum input capacitor is placed in parallel with the input capacitor, it must be recommended for switching regulator applications and the operating voltage must be derated by 50%. • In “Hot-Plug” applications, a Tantalum or Electrolytic bypass capacitor must be used to limit the overvoltage spike seen on the input supply when power is suddenly applied. August 6, 2014 20 Revision 1.3 Micrel, Inc. MIC23099 Typical Application Schematic L1 6.8µH 14 2 (0.9V – 1.6V) VIN C1 10µF 6 EN SW1 OUT1 13 VOUT1 1.8V/111mA C2 4.7µF VIN PGND1 EN FB1 1 3 VOUT1 MIC23099 5 4 PG PG 12 SW2 10 OUT2 NC PGND2 Blinking (VIN < 1.2V) 0.25Hz/25%DC R6 80.6Ω 7 FB2 LED EP AGND VOUT2 1.1V/30mA C5 10µF C4 4.7µF VOUT2 R3 392kΩ 11 9 VOUT1 C7 33pF L2 4.7µH VOUT1 ON (VIN >= 1.2V) C6 47µF PGND2 R2 66.5kΩ R5 100kΩ C3 4.7µF R1 133kΩ PGND2 8 R4 576kΩ LED Note: C5 AND C6 ARE SOC BYPASS CAPACITORS August 6, 2014 21 Revision 1.3 Micrel, Inc. MIC23099 Bill of Materials Item C1, C5 C2, C3, C4 C6 C7 D1 Part Number GRM188R60J106ME47D CL10A106MQ8NNNC GRM188R60J475ME19D CL10A475MQ8NNNC GRM31CR60J476ME19L Manufacturer Murata Description Qty. (9) (10) Samsung Murata Samsung Murata 10µF/6.3V, Ceramic Capacitor, X5R, 0603, ±20% 2 4.7µF/6.3V, Ceramic Capacitor, X5R, 0603, ±20% 3 47µF/6.3V, Ceramic Capacitor, X5R, 1206, ±20% 1 CL31A476MQHNNNE Samsung CL05C330JB5NNNC Samsung 33pF/50V, Ceramic Capacitor, C0G, 0402, ±5% 1 (11) 1.7V/20mA, LED, 660NM RED WTR CLR, 1206 1 6.8µH, 1.5A Inductor, 90mΩ, 3.8mm × 3.8mm × 1.8mm 1 SML-LXT1206SRC Lumex Vishay Dale (12) L1 IFSC1515AHER6R8M01 L2 CIG2MW4R7NNE Samsung 4.7µH, 1.1A Inductor, 140mΩ, 2.0mm × 1.6mm × 1.0mm 1 R1 RC1005F1333CS Samsung 133kΩ Resistor, 0402, 1% 1 R2 RC1005F6652CS Samsung 66.5kΩ Resistor, 0402, 1% 1 R3 RC1005F3923CS Samsung 392kΩ Resistor, 0402, 1% 1 R4 RC1005F5763CS Samsung 576kΩ Resistor, 0402, 1% 1 R5 RC1005F1003CS Samsung 100kΩ Resistor, 0402, 1% 1 R6 RC1005F80R6CS Samsung 80.6Ω Resistor, 0402, 1% 1 U1 MIC23099YFT Micrel Single AA/AAA Cell Step-Up/Step-Down Regulators with Battery Monitoring 1 (13) Notes: 9. Murata: www.murata.com. 10. Samsung: www.samsung.com. 11. Lumex: www.lumex.com. 12. Vishay Dale: www.vishay.com. 13. Micrel, Inc.: www.micrel.com. August 6, 2014 22 Revision 1.3 Micrel, Inc. MIC23099 PCB Layout Recommendations Top Layer (Power Trace Layer) Layer 2 (Ground Plane) August 6, 2014 23 Revision 1.3 Micrel, Inc. MIC23099 PCB Layout Recommendations (Continued) Layer 3 ( Routing Layer) Bottom Layer (Ground Plane) August 6, 2014 24 Revision 1.3 Micrel, Inc. MIC23099 Package Information(14) 14-Pin 2.5mm × 2.5mm Thin QFN (FT) Note: 14. Package information is correct as of the publication date. For updates and most current information, go to www.micrel.com. August 6, 2014 25 Revision 1.3 Micrel, Inc. MIC23099 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 Micrel makes no representations or warranties with respect to the accuracy or completeness of the information furnished in this data sheet. This information is not intended as a warranty and Micrel does not assume responsibility for its use. Micrel reserves the right to change circuitry, specifications and descriptions at any time without notice. No license, whether express, implied, arising by estoppel or otherwise, to any intellectual property rights is granted by this document. Except as provided in Micrel’s terms and conditions of sale for such products, Micrel assumes no liability whatsoever, and Micrel disclaims any express or implied warranty relating to the sale and/or use of Micrel products including liability or warranties relating to fitness for a particular purpose, merchantability, or infringement of any patent, copyright or other intellectual property right. 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. © 2014 Micrel, Incorporated. August 6, 2014 26 Revision 1.3