AS1336A-BQFT

Data sheet AS1336 D u a l , L o w Vo l ta g e , M i c r o p o w e r D C - D C St e p - U p C o n v e r t e r s 1 General Description 2 Key Features The AS1336 is a dual synchronous, fixed frequency, very high-efficiency DC-DC boost converter capable of supplying guaranteed 75mA at 3.3V on each output from a 0.8V supply only. Compact size and minimum external parts requirements make this device perfect for modern portable devices. High-speed switching frequency (1.2MHz) and internally compensated PWM current mode design provide highlyreliable DC-DC conversion, especially when driving white LEDs. MODE pins allow to enable automatic powersave mode for each regulator independently. The AS1336 can supervise the battery voltage and generate a low battery error flag. A hysteresis ensures valid operation especially during start-up and end of life. The device contains two internal MOSFET switches: one NMOS switch and one PMOS synchronous rectifier. Anti-ringing control circuitry reduces EMI by damping the inductor in discontinuous mode, and the device exhibits extremely low current (< 2µA) in shutdown. The AS1336A offers shutdown disconnect while in the AS1336B the battery is connected directly to the output during shutdown enabling the supply of real-time-clocks. The AS1336 is available in a TQFN 3x3mm 16-pin package. ! 96% Efficiency ! Operating Voltage from 0.8V to 3.6V ! Output Range: 1.8V to 3.6V ! Delivers 145mA @ 3.3V (from 1.5V) ! Low Start-Up Voltage: 0.8V ! High-Speed Fixed-Frequency: 1.2MHz ! Internal PMOS Synchronous Rectifier ! Automatic Powersave Operation ! Anti-Ringing Control Minimizes EMI ! Logic Controlled Shutdown (< 2µA) ! TQFN 3x3mm 16-pin Package 3 Applications The AS1336 is ideal for low-power applications where ultra-small size is critical as in medical diagnostic equipment, mice, pagers, digital cameras, remote wireless transmitters, MP3 players, LCD bias supplies, cordless phones, GPS receivers, and PC cards. Figure 1. Typical Application Diagram – Single Cell to 1.8V & 3.3V Synchronous Boost Converter 11 AA Battery 16 VIN CIN 10µF 15 L1 / L2 LX1 10µH 13 LX2 8 R1 R2 On Off On Off LBI 4 VOUT1 3 560kΩ FB1 5 180kΩ MODE1 10 AS1336 LBO 6 EN1 7 MODE2 12 EN2 1 VOUT2 9 GND FB2 2 GND www.austriamicrosystems.com/DC-DC_Step-Up/AS1336 COUT1 10µF VOUT1 3.3V 145mA 14 PGND Revision 1.01 150kΩ COUT2 10µF VOUT2 1.8V 260mA 120kΩ 1 - 18 AS1336 Datasheet - P i n A s s i g n m e n t s 4 Pin Assignments LX2 PGND LX1 VOUT1 Figure 2. Pin Assignments (Top View) 16 15 14 13 GND 1 GND 2 12 VOUT2 AS1336 FB1 3 11 VIN 10 LBO 6 MODE1 MODE2 7 8 LBI 5 EN2 PGND 17 EN1 4 9 FB2 Pin Descriptions Table 1. Pin Descriptions Pin Name GND Pin Number 1, 2 FB1 3 EN1 4 MODE1 5 MODE2 6 EN2 7 LBI 8 FB2 9 LBO 10 VIN 11 VOUT2 12 Description Signal Ground. These pins are used as a ground reference. Feedback Pin. Feedback input to the gm error amplifier. Connect a resistor divider tap to this pin. The output voltage can be adjusted from 1.8V to 3.6V by: VOUT = 0.8V[1 + (R1/R2)] Enable Pin. Logic controlled shutdown input. 1 = Normal operation, 1.2MHz typical operating frequency. 0 = Shutdown; quiescent current = 50µA 43 ILOAD = 5µA to 100mA 50 0.25 V 2 µA % mVpkpk 1. IQPWS is measured at VOUT. Multiply this value by VOUT/VIN to get the equivalent input (battery) current. 2. Guaranteed by design and verified in lab characterisation. Note: All limits are guaranteed. The parameters with min and max values are guaranteed with production tests or SQC (Statistical Quality Control) methods. www.austriamicrosystems.com/DC-DC_Step-Up/AS1336 Revision 1.01 5 - 18 AS1336 Datasheet - Ty p i c a l O p e r a t i n g C h a r a c t e r i s t i c s 7 Typical Operating Characteristics VIN = 1.2V, VOUT = 3.0V, L1 = L2 = 10µH, COUT1 = COUT2 = 10µF, TAMB = +25ºC (unless otherwise specified); Figure 4. Efficiency vs. Input Voltage, VOUT = 2.5V 100 100 90 90 80 80 Efficiency (%) Efficiency (%) Figure 3. Efficiency vs. Input Voltage, VOUT = 1.8V 70 60 50 70 60 50 Iout Iout Iout Iout 40 = 0.1mA = 1mA = 10mA = 100mA Iout Iout Iout Iout 40 30 30 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 0.3 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9 2.1 2.3 2.5 Input Voltage (V) Input Voltage (V) Figure 6. Efficiency vs. Input Voltage, VOUT = 3.3V 100 100 90 90 80 80 Efficiency (%) Efficiency (%) Figure 5. Efficiency vs. Input Voltage, VOUT = 3.0V 70 60 50 70 60 50 Iout Iout Iout Iout 40 = 0.1mA = 1mA = 10mA = 100mA Iout Iout Iout Iout 40 30 = 0.1mA = 1mA = 10mA = 100mA 30 0.3 0.6 0.9 1.2 1.5 1.8 2.1 2.4 2.7 3.0 0.3 0.6 0.9 1.2 1.5 Input Voltage (V) 1.8 2.1 2.4 2.7 3.0 Input Voltage (V) Figure 7. Efficiency vs. Output Current, VOUT = 1.8V Figure 8. Efficiency vs. Output Current, VOUT = 2.5V 100 100 90 90 80 80 Efficiency (%) Efficiency (%) = 0.1mA = 1mA = 10mA = 100mA 70 60 50 70 60 Vin = 0.8V 50 Vin = 0.8V Vin = 1.0V Vin = 1.0V 40 Vin = 1.2V 40 Vin = 1.2V Vin = 1.5V Vin = 1.5V Vin = 2.0V 30 30 0.1 1 10 100 1000 0.1 Output Current (mA) www.austriamicrosystems.com/DC-DC_Step-Up/AS1336 1 10 100 1000 Output Current (mA) Revision 1.01 6 - 18 AS1336 Datasheet - Ty p i c a l O p e r a t i n g C h a r a c t e r i s t i c s Figure 10. Efficiency vs. Output Current, VOUT = 3.3V 100 100 90 90 80 80 Efficiency (%) Efficiency (%) Figure 9. Efficiency vs. Output Current, VOUT = 3.0V 70 60 Vin = 0.8V 50 70 60 Vin = 0.8V 50 Vin = 1.2V Vin = 1.0V Vin = 1.5V 40 Vin = 1.5V 40 Vin = 2.0V Vin = 2.0V Vin = 2.5V Vin = 2.5V 30 30 0.1 1 10 100 1000 0.1 1 Output Current (mA) 100 100 90 90 80 80 70 60 Aut omat ic Powersave 60 Aut omat ic Powersave 50 Fixed Frequency 40 aut omat ic Powersave, Vout2 on 30 aut omat ic Powersave, Vout2 on 30 0.1 1 10 100 1000 0.1 1 Output Current (mA) 90 90 80 80 70 60 Aut omat ic Powersave Efficiency (%) 100 1000 70 60 Aut omat ic Powersave 50 Fixed Frequency 40 100 Figure 14. Efficiency vs. IOUT - Mode, VIN = 3.0V 100 50 10 Output Current (mA) Figure 13. Efficiency vs. IOUT - Mode, VIN = 2.5V Efficiency (%) 1000 70 Fixed Frequency 40 100 Figure 12. Efficiency vs. IOUT - Mode, VIN = 1.5V Efficiency (%) Efficiency (%) Figure 11. Efficiency vs. IOUT - Mode, VIN = 0.8V 50 10 Output Current (mA) Fixed Frequency aut omat ic Powersave, Vout2 on 30 40 aut omat ic Powersave, Vout2 on 30 0.1 1 10 100 1000 0.1 Output Current (mA) www.austriamicrosystems.com/DC-DC_Step-Up/AS1336 1 10 100 1000 Output Current (mA) Revision 1.01 7 - 18 AS1336 Datasheet - Ty p i c a l O p e r a t i n g C h a r a c t e r i s t i c s Figure 16. IOUT max vs. VIN, VOUT = 3.3V 400 800 350 700 Output Current (mA) Output Current (mA) Figure 15. IOUT max vs. VIN, VOUT = 1.8V 300 250 200 150 100 50 600 500 400 300 200 100 0 0 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 0.9 1.3 Input Voltage (V) 2.1 2.5 2.9 3.3 Input Voltage (V) Figure 17. Startup Voltage vs. Output Current Figure 18. VOUT vs. VIN, IOUT = 10mA 2 3.5 3.25 Output Voltage (V) 1.75 Input Voltage (V) 1.7 1.5 1.25 1 3 2.75 2.5 2.25 Vout = 1.8V 2 Vout = 2.5V 0.75 1.75 Vout = 1.8V Vout = 3.0V Vout = 3.3V Vout = 3.0V 0.5 1.5 0 20 40 60 80 100 0.3 0.6 0.9 1.2 1.5 1.8 2.1 2.4 2.7 3.0 3.3 Output Current (mA) Input Voltage (V) Figure 19. Input Current vs. Input Voltage Figure 20. Powersave Threshold vs. Input Voltage 10 160 Vout 1 = 3.3V, Vout2 = of f Vout = 3.0V Output Current (mA) Input Current (mA) Vout = 1.8V 140 Vout 1 = Vout2 = 3.3V 1 0.1 120 100 80 60 40 20 0.01 0 0.8 1.3 1.8 2.3 2.8 3.3 0.8 Input Voltage (V) www.austriamicrosystems.com/DC-DC_Step-Up/AS1336 1.3 1.8 2.3 2.8 3.3 Input Voltage (V) Revision 1.01 8 - 18 AS1336 Datasheet - Ty p i c a l O p e r a t i n g C h a r a c t e r i s t i c s 10ms/Div VLX 1V/Div Figure 24. Coil Voltage, IOUT = 100mA 1V/Div Figure 23. Coil Voltage, IOUT = 1mA VLX 1V/Div EN VOUT 200µs/Div 1V/Div 1V/Div Figure 22. Shutdown Voltage, IOUT = 1mA 1V/Div VOUT EN Figure 21. Startup Voltage, IOUT = 1mA 100ns/Div 200ns/Div VVOUT OUT 20mV/Div 1V/Div IOUT 50mV/Div Figure 25. Load Transient 100ns/Div www.austriamicrosystems.com/DC-DC_Step-Up/AS1336 Revision 1.01 9 - 18 AS1336 Datasheet - D e t a i l e d D e s c r i p t i o n 8 Detailed Description The AS1336 is a dual synchronous boost converter and can operate from a single-cell input voltage (VIN) below 0.8V, and features fixed frequency (1.2MHz) and current mode PWM control for exceptional line- and load-regulation. With low RDS(ON) and gate charge internal NMOS and PMOS switches, the device maintains high-efficiency from light to heavy loads. Figure 26. AS1336 - Block Diagram 15 LX1 Start Up1 OSC2 A B PWM Control Sync Drive Control SLP1 4 EN1 Σ Slope Compensator + PWM – Comp – 0.25Ω 2.3V 12 VOUT1 0.35Ω Current Sense 3 – gm Error Amp REF1 + Loop Filter Shutdown Control Powersave – VOUT Good + A/B MUX FB1 5 MODE1 Powersave Operation Control 1 Converter 1 GND 13 LX2 Start Up2 OSC2 A B PWM Control Sync Drive Control SLP2 7 EN2 Loop Filter Shutdown Control Powersave 0.25Ω 2.3V 12 VOUT2 0.35Ω Current Sense – gm Error Amp REF2 + 9 FB2 6 MODE2 Powersave Operation Control 8 SLP1 LBI 1.2MHz Ramp Generator 11 Σ Slope Compensator + PWM – Comp – – VOUT Good + A/B MUX SLP2 OSC1 OSC2 VIN www.austriamicrosystems.com/DC-DC_Step-Up/AS1336 2 Converter 2 Start Up OSC 1.23V Ref AS1336 Revision 1.01 GND Start Up1 10 Start Up2 LBO REF1 REF2 14 shared PGND 10 - 18 AS1336 Datasheet - D e t a i l e d D e s c r i p t i o n Modern portable devices frequently spend extended time in low-power or standby modes, switching to high powerdrain only when certain functions are enabled. The AS1336 is ideal for portable devices since it maintain high-power conversion efficiency over a wide output power range, thus increasing battery life in these types of devices. In addition to high-efficiency at moderate and heavy loads, the AS1336 includes an automatic powersave mode that improves efficiency of the power converter at light loads. The powersave mode is initiated if the output load current falls below a factory programmed threshold. Low-Voltage Start-Up The AS1336 requires VIN of only 0.8V or higher to start up. With a VOUT > 1.6V, the start-up circuitry is disabled and normal fixed-frequency PWM operation is initiated. In this mode, the AS1336 operates independent of VIN, allowing extended operating time as the battery can drop to several tenths of a volt without affecting output regulation. The limiting factor for the application is the ability of the battery to supply sufficient energy to the output. Low-Noise Fixed-Frequency Operation Oscillator The AS1336 switching frequency is internally fixed at 1.2MHz allowing the use of very small external components. Error Amplifier The integrated error amplifier is an internally compensated trans-conductance (gm) type (current output). The internal 0.8V reference voltage is compared to the voltage at pin FB to generate an error signal at the output of the error amplifier. For the adjustable output voltage version, a voltage divider from VOUT to GND programs the output voltage from 1.8 to 3.6V via pin FB as: VOUT = 0.8V(1 + (R1/R2)) (EQ 1) Current Sensing A signal representing the internal NMOS-switch current is summed with the slope compensator. The summed signal is compared to the error amplifier output to provide a peak current control command for the PWM. Peak switch current is limited to approximately 500mA independent of VIN or VOUT. Zero Current Comparator The zero current comparator monitors the inductor current to the output and shuts off the PMOS synchronous rectifier once this current drops to 20mA (approx.). This prevents the inductor current from reversing polarity and results in improved converter efficiency at light loads. Anti-Ringing Control Anti-ringing control circuitry prevents high-frequency ringing on pin SW as the inductor current approaches zero. This is accomplished by damping the resonant circuit formed by the inductor and the capacitance on pin SW (CSW). Powersave Operation Powersave operation is enabled for one boost converter if the correspondent MODE pin is set to GND. This setting applies to both boost converters integrated on the chip. Each boost converter will then switch into powersave mode independently on the other if a low output current is below the powersave operation current threshold. In light load conditions, the integrated powersave feature removes power from all circuitry not required to monitor VOUT. When VOUT has dropped approximately 1% from nominal, the AS1336 powers up and begins normal PWM operation. COUT (see Figure 26 on page 10) recharges, causing the AS1336 to re-enter powersave mode as long as the output load remains below the powersave threshold. The frequency of this intermittent PWM is proportional to load current; i.e., as the load current drops further below the powersave threshold, the AS1336 turns on less frequently. When the load current increases above the powersave threshold, the AS1336 will resume continuous, seamless PWM operation. www.austriamicrosystems.com/DC-DC_Step-Up/AS1336 Revision 1.01 11 - 18 AS1336 Datasheet - D e t a i l e d D e s c r i p t i o n Notes: 1. An optional capacitor (CFF) between pins VOUT and FB in some applications can reduce VOUTp-p ripple and input quiescent current during powersave mode. Typical values for CFF range from 15 to 220pF. 2. In powersave mode the AS1336 draws only 14µA (one chanel on) from the output capacitor(s), greatly improving converter efficiency. Shutdown Both boost converters can be enabled independently from the other. EN1 will enable boost converter 1 and EN2 enables boost converter 2. When pin EN1 or EN2 is low the AS1336 the corresponding boost converter is switched off and