NCP1521AMUTBG

NCP1521 1.5 MHz, 600 mA, High−Efficiency, Low Quiescent Current, Adjustable Output Voltage Step−Down Converter The NCP1521 step−down PWM DC−DC converter is optimized for portable applications powered from one cell Li−ion or three cell Alkaline/NiCd/NiMH batteries. The device is available in an adjustable output voltage from 0.9 V to 3.3 V. It uses synchronous rectification to increase efficiency and reduce external part count. The device also has a built−in 1.5 MHz (nominal) oscillator which reduces component size by allowing a small inductor and capacitors. Automatic switching PWM/PFM mode offers improved system efficiency. Finally, it includes an integrated soft−start, cycle−by−cycle current limiting, and thermal shutdown protection. The NCP1521 is available in space saving, low profile TSOP5 and UDFN6 packages. Features http://onsemi.com MARKING DIAGRAM 5 5 1 TSOP−5 SN SUFFIX CASE 483 DBPAYWG G 1 • 95.3% of Efficiency for 3.3 V Output and 4.2 V Input and 80 mA • • • • • • • • • • • • • • • • Load−Current Sources up to 600 mA 1.5 MHz Switching Frequency Adjustable Output Voltage from 0.9 V to 3.3 V 30 mA Quiescent Current Synchronous Rectification for Higher Efficiency 2.7 V to 5.5 V Input Voltage Range Thermal Limit Protection Shutdown Current Consumption of 0.3 mA Short Circuit Protection This is a Pb−Free Device Cellular Phones, Smart Phones and PDAs Digital Still/Video Cameras MP3 Players and Portable Audio Systems Wireless and DSL Modems Portable Equipment USB Powered Devices VIN CIN 2 OFF ON 3 GND EN FB 4 R2 VIN L 1 VIN LX 5 COUT R1 Cff VOUT OFF ON DBP = Specific Device Code A = Assembly Location Y = Year W = Work Week G = Pb−Free Package (Note: Microdot may be in either location) UDFN6 MU SUFFIX CASE 517AB 1 6 2 ZCMG 5 G 3 4 ZC = Specific Device Code M = Date Code G = Pb−Free Package (Note: Microdot may be in either location) ORDERING INFORMATION Device NCP1521ASNT1G NCP1521AMUTBG Package Shipping Typical Applications TSOP−5 3000/T ape & Reel (Pb−Free) UDFN6 3000/T ape & Reel (Pb−Free) †For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging Specification Brochure, BRD8011/D. R2 1 EN FB 6 2.2 mH R1 5 4 18 pF VOUT 10 mF 2 GND LX 3 VIN GND 4.7 mF Figure 1. Typical Application − TSOP−5 Figure 2. Typical Application − UDFN6 © Semiconductor Components Industries, LLC, 2006 1 July, 2006 − Rev. 4 Publication Order Number: NCP1521/D NCP1521 100 90 Eff (%) 80 70 Vout = 3.3 V Vin = 4.2 V TA = 25°C 60 50 0 100 200 300 Iout (mA) 400 500 600 Figure 3. Efficiency vs. Output Current Q1 Vbattery Q2 VIN 1 PWM/PFM CONTROL LX 5 2.2 mH 10 mF 4.7 mF GND 2 ILIMIT R1 18 pF Enable EN 3 LOGIC CONTROL & THERMAL SHUTDOWN REFERENCE VOLTAGE FB 4 R2 Figure 4. Simplified Block Diagram http://onsemi.com 2 NCP1521 PIN FUNCTION DESCRIPTION Pin No. TSOP5 1 2 3 4 5 Pin No. UDFN6 3 2, 4 1 6 5 Symbol VIN GND EN FB LX Function Analog Input Analog/Power Ground Digital Input Analog Input Analog Output Description Power Supply Input for Analog VCC. Ground connection for the NFET Power Stage and the Analog Sections of the IC. Enable for Switching Regulator. This pin is active high. Do not float this pin. Feedback voltage from the output of the power supply. This is the input to the error amplifier. Connection from Power MOSFETs to the Inductor. For one option, an output discharge circuit sinks current from this pin. PIN CONNECTIONS VIN GND EN 1 2 3 (Top View) 4 FB 5 LX EN GND VIN 1 2 3 6 5 4 FB LX GND Figure 5. Pin Connections − TSOP5 Figure 6. Pin Connections − UDFN6 MAXIMUM RATINGS Rating Minimum Voltage All Pins Maximum Voltage All Pins (Note 2) Maximum Voltage Enable, FB, LX Thermal Resistance, Junction −to−Air Operating Ambient Temperature Range Storage Temperature Range Junction Operating Temperature Latch−up Current Maximum Rating (TA = 85°C) (Note 4) ESD Withstand Voltage (Note 3) Human Body Model Machine Model TSOP5 UDFN6 Symbol Vmin Vmax Vmax RqJA TA Tstg Tj Lu Vesd 2.0 200 kV V Value −0.3 7.0 VIN + 0.3 200 TBD −40 to 85 −55 to 150 −40 to 125 +/−100 Unit V V V _C/W _C _C _C mA Maximum ratings are those values beyond which device damage can occur. Maximum ratings applied to the device are individual stress limit values (not normal operating conditions) and are not valid simultaneously. If these limits are exceeded, device functional operation is not implied, damage may occur and reliability may be affected. 1. Maximum electrical ratings are defined as those values beyond which damage to the device may occur at TA = 25°C. 2. According to JEDEC standard JESD22−A108B. 3. This device series contains ESD protection and exceeds the following tests: Human Body Model (HBM) per JEDEC standard: JESD22−A114. Machine Model (MM) per JEDEC standard: JESD22−A115. 4. Latchup current maximum rating per JEDEC standard: JESD78. http://onsemi.com 3 NCP1521 ELECTRICAL CHARACTERISTICS (Typical values are referenced to TA = +25°C, Min and Max values are referenced −40°C to +85°C ambient temperature, unless otherwise noted, operating conditions VIN = 3.6 V, VOUT = 1.8 V, unless otherwise noted.) Characteristic Input Voltage Range Undervoltage Lockout (VIN Falling) Quiescent Current PFM No Load Standby Current, EN Low Oscillator Frequency Peak Inductor Current Feedback Reference Voltage FB Pin Tolerance Overtemp @ Iout = 100 mA Reference Voltage Line Regulation Output Voltage Accuracy @ Iout = 100 mA (Note 5) Minimum Output Voltage Maximum Output Voltage Output Voltage Line Regulation (Vin = 2.7–5.5) Io = 100 mA Voltage Load Regulation (IO = 100 mA to 300 mA) (IO = 100 mA to 600 mA) Load Transient Response (300 mA to 600 mA Load Step, Trise 10 ms) Duty Cycle P−Ch On−Resistance N−Ch On−Resistance P−Ch Leakage Current N−Ch Leakage Current Enable Pin High Enable Pin Low EN > Input Current, EN = 3.6 V Soft−Start Time Thermal Shutdown Threshold Thermal Shutdown Hysteresis Symbol VIN VUVLO Iq Istb Fosc ILIM Vref VFBtol DVFB VOUT VOUT VOUT DVOUT VLOADREG − − VOUT − RLxH RLxL ILeakH ILeakL VENH VENL IENH Tstart TSD TSDH − − − − − − 1.2 − − − − − 0.0005 0.001 50 − 300 300 0.05 0.01 − − 2.0 350 160 25 − − − 100 − − − − − 0.4 − 500 − − %/mA %/mA mV % mW mW mA mA V V mA ms °C °C Min 2.7 2.3 − − 1.3 − − −3.0 − −3% − − − Typ − 2.5 30 0.3 1.5 1200 0.6 − 0.1 Vnom 0.9 3.3 0.1 Max 5.5 2.6 45 1.2 1.8 − − 3.0 − +3% − − − Unit V V mA mA MHz mA V % % V V V % 5. The overall output voltage tolerance depends upon the accuracy of the external resistor (R1, R2). http://onsemi.com 4 NCP1521 100 90 QUIESCENT CURRENT (mA) 80 70 60 50 40 30 20 10 0 2.7 3.2 3.7 4.2 4.7 EN = VIN IOUT = 0 mA 5.2 5.7 QUIESCENT CURRENT (mA) 100 90 80 70 60 50 40 30 20 10 0 −40 −20 0 20 40 60 80 100 VIN = 2.7 V VIN = 5.5 V VIN, INPUT VOLTAGE (V) TEMPERATURE (°C) Figure 7. Quiescent Current vs. Supply Voltage Figure 8. Quiescent Current vs. Temperature 1.0 EN = VIN SHUTDOWN CURRENT (mA) 0.8 IOUT = 0 mA EFFICIENCY (%) 100 95 TA = −40°C 90 85 80 75 70 3.2 3.7 4.2 4.7 0 100 200 300 400 500 600 VIN, INPUT VOLTAGE (V) IOUT, OUTPUT CURRENT (mA) TA = 85°C TA = 25°C 0.6 0.4 0.2 0 2.7 Figure 9. Shutdown Current vs. Supply Voltage Figure 10. Efficiency vs. Output Current (VOUT = 1.8 V, VIN = 3.6 V) 100 TA = −40°C 100 95 TA = 25°C EFFICIENCY (%) 90 TA = 25°C 85 80 75 70 0 100 200 300 400 500 600 0 100 200 300 400 500 600 IOUT, OUTPUT CURRENT (mA) IOUT, OUTPUT CURRENT (mA) TA = 85°C TA = −40°C 90 EFFICIENCY (%) 80 70 TA = 85°C 60 50 Figure 11. Efficiency vs. Output Current (VOUT = 0.9 V, VIN = 3.6 V) Figure 12. Efficiency vs. Output Current (VOUT = 3.3 V, VIN = 4.5 V) http://onsemi.com 5 NCP1521 1.8 2 V/Div FREQUENCY (MHz) EN 1.7 1.6 IOUT = 600 mA 1.5 IOUT = 300 mA 1.4 VOUT 500 mV/Div 100 ms/Div 1.3 2.7 3.2 3.7 4.2 4.7 5.2 5.7 VIN, INPUT VOLTAGE (V) Figure 13. Soft Start Time (VIN = 3.6 V) Figure 14. Frequency vs. Input Voltage 1.8 1.7 FREQUENCY (MHz) 1.6 1.5 1.4 1.3 IOUT = 300 mA 1.2 −40 −20 0 20 40 60 80 100 VIN = 3.6 V LOAD REGULATION (%) VIN = 5.5 V 3.0 2.5 2.0 1.5 1.0 0.5 0.0 −0.5 −1.0 −1.5 −2.0 −2.5 −3.0 0 VOUT = 0.9 V VOUT = 1.8 V VOUT = 3.3 V 100 200 300 400 500 600 700 TEMPERATURE (°C) IOUT, OUTPUT CURRENT (mA) Figure 15. Frequency vs. Temperature Figure 16. Load Regulation 2.0 100 90 VOUT = 1.8 V TA = 25°C 1.5 OUTPUT CURRENT (mA) 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 OUTPUT VOLTAGE (V) 80 70 60 50 40 30 20 10 1.0 0.5 0.0 VIN, ENABLE INPUT VOLTAGE (V) 0 2.7 3.2 3.7 4.2 4.7 5.2 5.7 VIN, INPUT VOLTAGE (V) Figure 17. Output Voltage vs. Enable Input Pin Voltage Figure 18. PFM/PWM Threshold vs. Input Voltage http://onsemi.com 6 NCP1521 2.0 1.5 OUTPUT VOLTAGE (%) 1.0 0.5 0.0 −0.5 −1.0 −1.5 VIN = 3.6 V −2.0 −50 0 50 TEMPERATURE (°C) 100 150 −2.0 −50 IOUT = 300 mA OUTPUT VOLTAGE (%) IOUT = 100 mA 2.0 1.5 1.0 0.5 0.0 −0.5 −1.0 −1.5 VIN = 3.6 V 0 50 TEMPERATURE (°C) 100 150 IOUT = 100 mA IOUT = 300 mA IOUT = 600 mA IOUT = 600 mA Figure 19. Output Voltage Accuracy (VOUT = 0.9 V) 2.0 1.5 OUTPUT VOLTAGE (%) 1.0 0.5 IOUT = 100 mA 0.0 −0.5 −1.0 −1.5 VIN = 4.0 V −2.0 −50 0 50 TEMPERATURE (°C) 100 150 IOUT = 600 mA IOUT = 300 mA Figure 20. Output Voltage Accuracy (VOUT = 1.8 V) VOUT 50 mV/Div IOUT 200 mA/Div 10 ms/Div Figure 21. Output Voltage Accuracy (VOUT = 3.3 V) Figure 22. Load Transient Response in PWM Operation (VIN = 3.6 V) VOUT 50 mV/Div 2.5 ms/Div ILX 500 mA/Div IOUT 200 mA/Div VOUT 10 ms/Div 500 mV/Div Figure 23. Load Transient Response in PWM Operation (VIN = 3.6 V) Figure 24. Short Circuit Protection (VIN = 3.6 V) http://onsemi.com 7 NCP1521 OPERATION DESCRIPTION Overview The NCP1521 uses a constant frequency, current mode step−down architecture. Both the main (P−Channel MOSFET) and synchronous (N−Channel MOSFET) switches are internal. It delivers a constant voltage from either a single Li−Ion or three cell NiMH/NiCd battery to portable devices such as cell phones and PDA. The output voltage is set by the external resistor divider. The NCP1521 sources at least 600 mA, depending on external components chosen. The NCP1521 works with two modes of operation; PWM/PFM depending on the current required. The device operates in PWM mode at load currents of approximately 40 mA or higher, having voltage tolerance of "3% with 90% efficiency or better. Lighter load currents cause the device to automatically switch into PFM mode for reduced current consumption (IQ = 30 mA typ) and extended battery life. Additional features include soft−start, undervoltage protection, current overload protection, and thermal shutdown protection. As shown in Figure 1, only six external components are required for implementation. The part uses an internal reference voltage of 0.6 V. It is recommended to keep the part in shutdown until the input voltage is 2.7 V or higher. PWM Operating Mode 125 ns/div Figure 25. PWM Switching Waveform (Vin = 3.6 V, Vout = 1.8 V, Iout = 300 mA) PFM Operating Mode In this mode, the output voltage of the NCP1521 is regulated by modulating the on−time pulse width of the main switch Q1 at a fixed frequency of 1.5 MHz. The switching of the PMOS Q1 is controlled by a flip−flop driven by the internal oscillator and a comparator that compares the error signal from an error amplifier with the sum of the sensed current signal and compensation ramp. At the beginning of each cycle, the main switch Q1 is turned ON by the rising edge of the internal oscillator clock. The inductor current ramps up until the sum of the current sense signal and compensation ramp becomes higher than the error voltage amplifier. Once this has occurred, the PWM comparator resets the flip−flop, Q1 is turned OFF and the synchronous switch Q2 is turned ON. Q2 replaces the external Schottky diode to reduce the conduction loss and improve the efficiency. To avoid overall power loss, a certain amount of dead time is introduced to ensure Q1 is completely turned OFF before Q2 is being turned ON. Under light load conditions (