AIC1899 1.0MHz Current-Mode Step-Up DC/DC Converter FEATURES DESCRIPTION Fixed Frequency 1.0MHz Current-Mode PWM The current-mode pulse-width modulation, AIC1899, Operation. step up converter is designed for MP3 player. The Adjustable Output Voltage up to 24V. built-in high voltage N-channel MOSFET allows 2.5V to 5.5V Input Range. AIC1899 for step-up applications with up to 24V Maximum 0.1µA Shutdown Current. output voltage, and other low-side switching DC/DC Programmable Soft-Start. converter. Tiny Inductor and Capacitors are allowed. Space-Saving TSOT-23-6 and SOT-23-6 The high switching frequency allows the use of Package. small external components. The Soft-Start function is programmable with an external capacitor, which APPLICATIONS sets the input current ramp rate. OLED Driver for MP3 Player White LED Backlight The AIC1899 is available in a space-saving TSOT-23-6 and SOT-23-6 package. TYPICAL APPLICATION CIRCUIT L1 Vin=3V U1 AIC1899 IN Cin 33uF/6.3V + 22uH SHDN FB Fig. 1 15V/15mA SS0540 R1 11k SS GND R2 1k C2 33nF Analog Integrations Corporation D1 LX Cout 10uF/25V + Co 0.1uF CF 1nF Typical Step up Application Circuit Si-Soft Research Center 3A1, No.1, Li-Hsin Rd. I, Science Park, Hsinchu 300, Taiwan, R.O.C. TEL: 886-3-5772500 FAX: 886-3-5772510 www.analog.com.tw DS-1899G-01 121208 1 AIC1899 ORDERING INFORMATION AIC1899XXXX PIN CONFIGURATION PACKING TYPE TR: TAPE & REEL BG: BAG PACKAGE TYPE G: SOT-23-6 K: TSOT-23-6 P: LEAD FREE COMMERCIAL G: GREEN PACKAGE Example: AIC1899PGTR in Lead Free SOT-23-6 Package & Tape SOT-23-6 / TSOT-23-6 FRONT VIEW 6 5 1: LX 2: GND 1899G 3: FB 4: SHDN 5: SS 2 1 6: IN 4 3 Note: Pin1 is determined by orienting the package marking as shown. & Reel Packing Type AIC1899PKTR in Lead Free TSOT-23-6 Package & Tape & Reel Packing Type TSOT-23-6 Marking Part No. Marking Part No. Marking AIC1899PK 899PK AIC1899GK 899GK Part No. Marking Part No. Marking AIC1899PG 1899P AIC1899GG 1899G SOT-23-6 Marking ABSOLUTE MAXIMUM RATINGS IN, SHDN , FB, SS to GND LX to GND LX Pin RMS Current Operating Temperature Range Junction Temperature Storage Temperature Range Lead Temperature (soldering, 10s) -0.3V to +6V -0.3V to +27V 0.14A -40°C to 85°C 125°C -65°C to 150°C 260°C Thermal Resistance Junction to Case 130°C /W Thermal Resistance Junction to Ambient 220°C /W (Assume no ambient airflow, no heatsink) Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. 2 AIC1899 ELECTRICAL CHARACTERISTICS (VIN=V SHDN =3V, FB=GND, SS=Open, TA=25°°C, unless otherwise specified) (Note 1) PARAMETER Input Supply Range SYMBOL CONDITIONS VIN VOUT VIN Undervoltage Lockout UVLO VIN rising, 50mV hysteresis IIN Output Current Iout Shutdown Supply Current TYP 2.5 Output Voltage Adjust Range Quiescent Current MIN MAX UNITS 5.5 V 24 V 2.2 VFB = 1.3V, not switching V 0.1 0.2 VFB = 1.0V, switching 1 5 Vin = 3V, Vout = 15V 15 Vin = 3.3V, Vout = 15V 17 mA mA V SHDN = 0, TA = +25°C 0.01 0.5 µA V SHDN = 0 0.01 10 µA 1.23 1.255 V 21 80 nA 0.05 0.20 %/V 1700 KHz ERROR AMPLIFIER Feedback Regulation Set Point VFB FB Input Bias Current IFB Line Regulation 1.205 VFB = 1.24V 2.6V < VIN < 5.5V OSCILLATOR Frequency fOSC 800 1000 Maximum Duty Cycle DC 80 82 % POWER SWITCH On-Resistance RDS(ON) Vin = 5V Leakage Current ILX(OFF) VLX = 24V, TA = +25°C 1.2 1.6 0.1 1 Ω µA VLX = 24V 10 Reset Switch Resistance Guaranteed By Design 100 Ω Charge Current VSS = 1.2V 7.0 µA 0.3 V SOFT-START 1.5 4 CONTROL INPUT Input Low Voltage VIL V SHDN , VIN = 2.5V to 5.5V Input High Voltage VIH V SHDN , VIN = 2.5V to 5.5V SHDN Input Current I SHDN V SHDN = 1.8V V SHDN = 0 1.0 V 25 50 0.01 0.1 µA Note 1: Specifications are production tested at TA=25°C. Specifications over the -40°C to 85°C operating temperature range are assured by design, characterization and correlation with Statistical Quality Controls (SQC). 3 AIC1899 TYPICAL PERFORMANCE CHARACTERISTICS 1.25 1.05 Feedback Voltage (V) Switching Frequency (MHz) 1.15 VIN=3.6V 1.00 0.95 0.90 0.85 -40 -20 0 20 40 60 80 1.24 VIN=3.6V 1.23 1.22 1.21 1.20 -50 0.80 100 -25 0 VIN=4.2V 90 VIN=3.6V VIN=3.3V VIN=2.7V VIN=2.5V 80 75 100 Feedback Pin Voltage VIN=5.0V VIN=4.2V 85 75 70 VOUT=5.0V L1: 10uH, GTSK-51-100M 65 50 90 Efficiency (%) Efficiency (%) Fig. 3 Switching Frequency vs. Temperature 85 25 Temperature (°C) Temperature (°C) Fig. 2 80 VIN=3.6V VIN=3.3V 75 70 VOUT=15V L1: 22uH, SLF6025-220MR 65 60 60 0 15 Fig. 4 30 45 60 75 90 0 15 Output Current (mA) Efficiency vs. Output Current Fig. 5 30 45 60 Output Current (mA) Efficiency vs. output current 15.5 5.50 VIN=3.3V VIN=3.6V 5.25 Output Voltage (V) Output Voltage (V) 5.00 4.75 15.0 14.5 14.0 13.5 4.50 1 10 Output Current (mA) Fig. 6 100 μH) Load Regulation (L1=10 1 10 100 Output Current (mA) Fig. 7 Load Regulation (L1=22 μH) 4 AIC1899 TYPICAL PERFORMANCE CHARACTERISTICS (Continued) 1.9 1.10 TA=25oC 1.8 1.7 1.6 RDSON (Ω) FREQUENCY(MHz) 1.05 1.00 0.95 1.5 1.4 1.3 1.2 1.1 1.0 0.90 2.5 3.0 3.5 4.0 4.5 5.0 5.5 2.5 3.0 SUPPLY VOLTAGE(V) 3.5 4.0 4.5 5.0 5.5 SUPPLY VOLTAGE (V) Fig. 8 Frequency vs. Supply Voltage Fig. 9 RDS-ON vs. Supply Voltage 1.4 85 SUPPLY CURRENT (µA) SUPPLY CURRENT (mA) FB=1.0V 1.2 SHDN=1.0V 1.0 0.8 80 FB=1.3V 75 SHDN=1.0V 70 0.6 2.5 3.0 3.5 4.0 4.5 5.0 5.5 65 2.5 3.0 SUPPLY VOLTAGE (V) 4.0 4.5 5.0 5.5 SUPPLY VOLTAGE (V) Fig. 10 Switching Current VOUT 3.5 Fig. 11 Non-Switching Current VSHDN VLX VOUT VLX IL Fig. 12 Operation Waveform (VIN=3V; VOUT=15V, IOUT=15mA, Test circuit as Fig.1) Fig. 13 Start-up Waveform (VIN=3V; VOUT=15V, IOUT=15mA, Test circuit as Fig.1) 5 AIC1899 BLOCK DIAGRAM VIN Control PWM/PFM I9 R3 Soft Start R4 Error Amp - + - + Q1 Q2 FB 1 8 R1 Control Logic SHDN Driver RC CC 1.0MHz Oscillator R2 LX x1 Slope Compensation Current AMP x 5 + x20 RS - SS 4µA PWM Comparator GND PIN DESCRIPTIONS PIN 1: LX - Power Switching Connection. Connect LX to inductor and output rectifier. Keep the distance between the components as close to LX as possible. PIN 2: GND - Ground. PIN 3: FB Feedback Input. Connect a resistive voltage-divider from the output to FB to set the output voltage. - PIN 4: SHDN - Shutdown Input. Drive SHDN low to turn off the converter. To automatically start the converter, connect SHDN to IN. Drive SHDN with a slew rate of 0.1V/µs or greater. Do not leave SHDN unconnected. SHDN draws up to 50µA. PIN 5: SS - Soft-Start Input. Connect a soft-start capacitor from SS to GND in order to soft-start the converter. Leave SS open to disable the soft-start function. PIN 6: IN - Internal Bias Voltage Input. Connect IN to the input voltage source. Bypass IN to GND with a capacitor sitting as close to IN as possible. 6 AIC1899 APPLICATION INFORMATION The AIC1899 operates well with a variety of K= external components. The components in Figure 1 ∆iL : Ratio of the inductor peak-to-peak IL are suitable for most applications. See the following sections to optimize AC current to average DC external components for a particular application. inductor current The inductance value is then given by: 2 Inductor Selection L= A 22µH inductor is recommended for most AIC1899 applications. Although small size and Vi (min) ⋅ η ⋅ D K ⋅ f ⋅ Vo ⋅ I o (max) where: high efficiency are major concerns, the inductor D = Duty cycle = should have low core losses at 1.0MHz and low DCR (copper wire resistance). Vi (min) − (V f + Vo ) I i (max) ⋅ R ds (on ) − (V f + Vo ) V f : Catch diode forward drop f : Switching frequency Inductor selection depends on input voltage, output voltage, maximum current, size, and availability of inductor values. Other factors can include efficiency and ripple voltage. Inductors are specified by their inductance (L), peak current (IL(PK)), and resistance (DCR). The following step-up circuit equations are useful in choosing the inductor values based on the application. They allow the trading of peak current and inductor value while considering component availability and cost. The equation used here assumes a constant K, which is the ratio of the inductor peak-to-peak AC current to average DC inductor current. A good compromise between the size of the inductor versus loss and output ripple is to choose a K of 0.3 to 0.5. The peak inductor current is then given by: Capacitor Selection The AIC1899 operates with both tantalum and ceramic output capacitors. When using tantalum capacitors, the zero caused by the ESR of the tantalum is used to ensure stability. When using ceramic capacitors, the zero due to the ESR will be at too high a frequency to be useful in stabilizing the control loop. When using ceramic capacitors, increase add the a feedforward phase margin, capacitor improving to the control-loop stability. Diode Selection Schottky diodes, with their low forward voltage drop and fast reverse recovery, are the ideal i L ( pk ) I o (max) ⋅ Vo K = ⋅ 1 + η ⋅ Vi (min) 2 where: IO(max): Maximum output current, (A) Vi(min): Minimum input voltage, (V) η : Conversion efficiency, 0.8 choices for AIC1899 applications. The forward voltage drop of an Schottky diode represents the conduction losses in the diode, while the diode capacitance (CT or CD) represents the switching losses. For diode selection, both forward voltage drop and diode capacitance need to be considered. Schottky diodes with higher current ratings usually have lower forward voltage drop 7 AIC1899 and larger diode capacitance, which can cause significant switching losses at the Calculate 1.0MHz R1 and R2 using the equation: R 1 Vo = − 1 R 2 VFB switching frequency of AIC1899. VFB , the step-up regulator feedback set Setting the Output Voltage where The AIC1899 operates with an adjustable output point, is 1.23V. Connect the resistive-divider as close to the IC as possible. from Vin to 24V. Connect a resistive voltage divider from the output to FB (see Fig.1). APPLICATION EXAMPLES L1 Vin=3V~4.2V U1 AIC1899 IN Cin 33uF + D1 15V/15mA SS0540 LX SHDN FB R1 11k SS GND C2 33nF Fig. 14 22uH R2 1k Cout 10uF + Co 0.1uF CF 1nF 1-Cell Li-Ion boost converter for OLED Application 8 AIC1899 PHYSICAL DIMENSIONS (unit: mm) TSOT-23-6 S Y M B O L A A E E1 D e e1 SEE VIEW B WITH PLATING c A A2 b BASE METAL SECTION A-A 0.25 A1 GAUGE PLANE SEATING PLANE L θ L1 VIEW B TSOT-23-6 MILLIMETERS MIN. MAX. A - 1.00 A1 0 0.10 A2 0.70 0.90 b 0.30 0.50 c 0.08 0.22 D 2.80 3.00 E 2.60 3.00 E1 1.50 1.70 e 0.95 BSC e1 1.90 BSC L 0.60 0.30 L1 θ 0.60 REF 0° 8° Note : 1. Refer to JEDEC MO-193AA. 2. Dimension "D" does not include mold flash, protrusions or gate burrs. Mold flash, protrusion or gate burrs shall not exceed 6 mil per side. 3. Dimension "E1" does not include inter-lead flash or protrusions. 4. Controlling dimension is millimeter, converted inch dimensions are not necessarily exact. 9 AIC1899 SOT-23-6 D 1 E A A e1 S Y M B O L E e SEE VIEW B b WITH PLATING 2 A c A BASE METAL 1 A SECTION A-A 5 .2 0 L L1 VIEW B GAUGE PLANE SEATING PLANE θ SOT-23-6 MILLIMETERS MIN. MAX. A 0.95 1.45 A1 0.05 0.15 A2 0.90 1.30 b 0.30 0.50 c 0.08 0.22 D 2.80 3.00 E 2.60 3.00 E1 1.50 1.70 e 0.95 BSC e1 1.90 BSC L 0.30 0.42 REF L1 θ 0.60 0° 8° Note : 1. Refer to JEDEC MO-178AB. 2. Dimension "D" does not include mold flash, protrusions or gate burrs. Mold flash, protrusion or gate burrs shall not exceed 10 mil per side. 3. Dimension "E1" does not include inter-lead flash or protrusions. 4. Controlling dimension is millimeter, converted inch dimensions are not necessarily exact. Note: Information provided by AIC is believed to be accurate and reliable. However, we cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in an AIC product; nor for any infringement of patents or other rights of third parties that may result from its use. We reserve the right to change the circuitry and specifications without notice. Life Support Policy: AIC does not authorize any AIC product for use in life support devices and/or systems. Life support devices or systems are devices or systems which, (I) are intended for surgical implant into the body or (ii) support or sustain life, and whose failure to perform, when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury to the user. 10