NCP1400A Micropower Fixed Frequency PWM Step-Up DC-DC Converter Features http://onsemi.com 5 1 THIN SOT–23–5 SN SUFFIX CASE 483 PIN CONNECTIONS AND MARKING DIAGRAM CE 1 OUT 2 NC 3 • Extremely Low Start–Up Voltage of 0.8 V • Operation Down to Less than 0.2 V • Only Four External Components for Simple Highly Efficient • • • • Converters Up to 100 mA Output Current Capability Fixed Frequency Pulse Width Modulation Operation Phase Compensated Error Amplifier for Stable Converter Operation Chip Enable Power Down Capability for Extended Battery Life LX 4 GND xxx = Marking Y = Year W = Work Week (Top View) ORDERING INFORMATION See detailed ordering and shipping information in the ordering information section on page 2 of this data sheet. Typical Applications • • • • • • • 5 xxxYW The NCP1400A series are micropower step–up DC to DC converters that are specifically designed for powering portable equipment from one or two cell battery packs. These devices are designed to start–up with a cell voltage of 0.8 V and operate down to less than 0.2 V. With only four external components, this series allows a simple means to implement highly efficient converters that are capable of up to 100 mA of output current. Each device consists of an on–chip fixed frequency oscillator, pulse width modulation controller, phase compensated error amplifier that ensures converter stability with discontinuous mode operation, soft–start, voltage reference, driver, and power MOSFET switch with current limit protection. Additionally, a chip enable feature is provided to power down the converter for extended battery life. The NCP1400A device series are available in the Thin SOT–23–5 package with six standard regulated output voltages. Additional voltages that range from 1.8 V to 4.9 V in 100 mV steps can be manufactured. Cellular Telephones Pagers Personal Digital Assistants Electronic Games Digital Cameras Camcorders Handheld Instruments Vin Vout CE 1 NC 3 NCP1400A OUT 2 LX 5 GND 4 Figure 1. Typical Step–Up Converter Application Semiconductor Components Industries, LLC, 2001 June, 2001 – Rev. 3 1 Publication Order Number: NCP1400A/D NCP1400A ORDERING INFORMATION Device Output Voltage Switching Frequency Marking NCP1400ASN19T1 1.9 V NCP1400ASN25T1 2.5 V DAV NCP1400ASN27T1 2.7 V DAA NCP1400ASN30T1 3.0 V NCP1400ASN33T1 3.3 V DAJ NCP1400ASN50T1 5.0 V DAD Package Shipping Thin SOT–23–5 SOT 23 5 3000 Units on 7 Inch Reel DAI 180 KHz DAB NOTE: The ordering information lists six standard output voltage device options. Additional devices with output voltage ranging from 1.8 V to 5.0 V in 100 mV increments can be manufactured. Contact your ON Semiconductor representative for availability. ABSOLUTE MAXIMUM RATINGS ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁ Rating Power Supply Voltage (Pin 2) Symbol Value Unit VOUT –0.3 to 6.0 V Input/Output Pins LX (Pin 5) LX Peak Sink Current VLX ILX –0.3 to 6.0 400 V mA CE (Pin 1) Input Voltage Range Input Current Range VCE ICE –0.3 to 6.0 –150 to 150 V mA Thermal Resistance Junction to Air RθJA 250 °C/W Operating Ambient Temperature Range (Note 2.) TA –40 to +85 °C Operating Junction Temperature Range TJ –40 to +125 °C Storage Temperature Range Tstg –55 to +150 °C NOTES: 1. This device series contains ESD protection and exceeds the following tests: Human Body Model (HBM) 2.0 kV per JEDEC standard: JESD22–A114. Machine Model (MM) 200 V per JEDEC standard: JESD22–A115. 2. The maximum package power dissipation limit must not be exceeded. TJ(max) TA PD RJA 3. Latch–up Current Maximum Rating: 150 mA per JEDEC standard: JESD78. 4. Moisture Sensitivity Level (MSL): 1 per IPC/JEDEC standard: J–STD–020A. http://onsemi.com 2 NCP1400A ELECTRICAL CHARACTERISTICS (For all values TA = 25°C, unless otherwise noted.) Characteristic Symbol Min Typ Max fOSC f Unit 144 180 216 kHz – 0.11 – %/°C DMAX 68 75 82 % OSCILLATOR Frequency (VOUT = VSET x 0.96, Note 5.) Frequency Temperature Coefficient (TA = –40°C to 85°C) Maximum PWM Duty Cycle (VOUT = VSET x 0.96) Minimum Start–up Voltage (IO = 0 mA) Minimum Start–up Voltage Temperature Coefficient (TA = –40°C to 85°C) Minimum Operation Hold Voltage (IO = 0 mA) Soft–Start Time (VOUT 0.8 V) Vstart – 0.8 0.95 V Vstart – –1.6 – mV/°C Vhold 0.3 – – V tSS 0.5 2.0 – ms LX (PIN 5) LX Pin On–State Sink Current (VLX = 0.4 V) Device Suffix: 19T1 25T1 27T1 30T1 33T1 50T1 ILX mA 80 80 100 100 100 100 90 120 125 130 135 160 – – – – – – VLXLIM 0.65 0.8 1.0 V ILKG – 0.5 1.0 µA CE Input Voltage (VOUT = VSET x 0.96) High State, Device Enabled Low State, Device Disabled VCE(high) VCE(low) 0.9 – – – – 0.3 CE Input Current (Note 6.) High State, Device Enabled (VOUT = VCE = 5.0 V) Low State, Device Disabled (VOUT = 5.0 V, VCE = 0 V) ICE(high) ICE(low) –0.5 –0.5 0 0.15 0.5 0.5 Voltage Limit (VOUT = VCE = VSET x 0.96, VLX “L’’ Side) Off–State Leakage Current (VLX = 5.0 V, TA = –40°C to 85°C) CE (PIN 1) V µA TOTAL DEVICE Output Voltage (Vin 0.8 V, IO = 4.0 mA) Device Suffix: 19T1 25T1 27T1 30T1 33T1 50T1 VOUT V 1.853 2.438 2.633 2.925 3.218 4.875 1.9 2.5 2.7 3.0 3.3 5.0 1.948 2.563 2.768 3.075 3.383 5.125 VOUT Output Voltage Temperature Coefficient (TA = –40°C to +85°C) Device Suffix: 19T1 25T1 27T1 30T1 33T1 50T1 ppm/°C – – – – – – 100 100 100 100 100 150 – – – – – – Operating Current 2 (VOUT = VCE = VSET +0.5 V, Note 5.) IDD2 – 7.0 15 µA Off–State Current (VOUT = 5.0 V, VCE = 0 V, TA = –40°C to +85°C, Note 6.) IOFF – 0.6 1.5 µA Operating Current 1 (VOUT = VCE = VSET x 0.96, fOSC = 180 kHz) Device Suffix: 19T1 25T1 27T1 30T1 33T1 50T1 IDD1 µA – – – – – – 5. VSET means setting of output voltage. 6. CE pin is integrated with an internal 10 MΩ pull–up resistor. http://onsemi.com 3 23 32 32 37 37 70 50 60 60 60 60 100 NCP1400A 3.4 Vin= 1.5 V 1.9 Vin= 0.9 V Vin= 1.2 V 1.8 NCP1400ASN19T1 L = 22 µH TA = 25°C 1.7 1.6 VOUT, OUTPUT VOLTAGE (V) VOUT, OUTPUT VOLTAGE (V) 2.0 3.2 Vin= 2.0 V 3.0 Vin= 1.5 V NCP1400ASN30T1 L = 22 µH TA = 25°C 2.6 20 40 60 80 0 100 60 80 Figure 2. NCP1400ASN19T1 Output Voltage vs. Output Current Figure 3. NCP1400ASN30T1 Output Voltage vs. Output Current 5.5 80 Vin= 3.0 V 5.0 Vin= 0.9 V Vin= 2.0 V Vin= 1.5 V 4.5 NCP1400ASN50T1 L = 22 µH TA = 25°C 0 40 IO, OUTPUT CURRENT (mA) 100 4.0 20 IO, OUTPUT CURRENT (mA) 6.0 3.5 Vin= 1.2 V Vin= 0.9 V 2.8 2.4 0 EFFICIENCY (%) VOUT, OUTPUT VOLTAGE (V) 2.1 20 Vin= 1.5 V 60 Vin= 1.2 V Vin= 0.9 V 40 NCP1400ASN19T1 L = 22 µH TA = 25°C 20 40 60 80 0 100 0 20 40 60 80 IO, OUTPUT CURRENT (mA) IO, OUTPUT CURRENT (mA) Figure 4. NCP1400ASN50T1 Output Voltage vs. Output Current Figure 5. NCP1400ASN19T1 Efficiency vs. Output Current 100 100 100 Vin= 2.5 V Vin= 3.0 V 80 EFFICIENCY (%) 80 EFFICIENCY (%) 100 Vin= 2.0 V Vin= 0.9 V 60 Vin= 1.2 V Vin= 1.5 V 40 NCP1400ASN30T1 L = 22 µH TA = 25°C 20 Vin= 0.9 V Vin= 1.5 V Vin= 2.0 V 60 40 NCP1400ASN50T1 L = 22 µH TA = 25°C 20 0 0 0 20 40 60 80 100 0 20 40 60 80 IO, OUTPUT CURRENT (mA) IO, OUTPUT CURRENT (mA) Figure 6. NCP1400ASN30T1 Efficiency vs. Output Current Figure 7. NCP1400ASN50T1 Efficiency vs. Output Current http://onsemi.com 4 100 NCP1400A 100 IDD1, OPERATING CURRENT (µA) IDD1, OPERATING CURRENT (µA) 80 NCP1400ASNXXT1 L = 10 µH TA = 25°C 70 60 50 40 30 20 10 0 1.5 2.5 2.0 3.0 3.5 4.0 4.5 5.0 40 NCP1400ASN30T1 VOUT = 3.0 V x 0.96 Open–loop Test 20 –25 0 25 50 75 VOUT, OUTPUT VOLTAGE (V) TA, AMBIENT TEMPERATURE (°C) Figure 8. NCP1400ASNXXT1 Operating Current (IDD1) vs. Output Voltage Figure 9. NCP1400ASN30T1 Current Consumption vs. Temperature 100 1.0 VLXLIM, VLX, VOLTAGE LIMIT (V) IDD1, OPERATING CURRENT (µA) 60 0 –50 5.5 100 80 60 40 NCP1400ASN50T1 VOUT = 5.0 V x 0.96 Open–loop Test 20 0 –50 –25 0 25 50 75 0.8 0.6 0.4 0.2 NCP1400ASN19T1 VOUT = 1.9 V x 0.96 0 –50 100 –25 0 25 50 75 100 TA, AMBIENT TEMPERATURE (°C) TA, AMBIENT TEMPERATURE (°C) Figure 10. NCP1400ASN50T1 Current Consumption vs. Temperature Figure 11. NCP1400ASN19T1 VLX Voltage Limit vs. Temperature 1.0 VLXLIM, VLX, VOLTAGE LIMIT (V) 1.0 VLXLIM, VLX, VOLTAGE LIMIT (V) 80 0.8 0.6 0.4 NCP1400ASN30T1 VOUT = 3.0 V x 0.96 0.2 0 –50 –25 0 25 50 75 100 0.8 0.6 0.4 NCP1400ASN50T1 VOUT = 5.0 V x 0.96 0.2 0 –50 –25 0 25 50 75 100 TA, AMBIENT TEMPERATURE (°C) TA, AMBIENT TEMPERATURE (°C) Figure 12. NCP1400ASN30T1 VLX Voltage Limit vs. Temperature Figure 13. NCP1400ASN50T1 VLX Voltage Limit vs. Temperature http://onsemi.com 5 NCP1400A VOUT, OUTPUT VOLTAGE (V) 3.1 3.0 2.9 2.8 2.7 –50 fOSC, OSCILLATOR FREQUENCY (kHz) 5.1 NCP1400ASN30T1 L = 10 µH IO = 4.0 mA Vin = 1.2 V –25 0 25 50 75 100 NCP1400ASN30T1 VOUT = 3.0 V x 0.96 Open–loop Test –25 0 25 50 75 –25 0 25 50 75 100 300 250 200 150 100 NCP1400ASN50T1 VOUT = 5.0 V x 0.96 Open–loop Test 50 0 –50 100 –25 0 25 50 75 TA, AMBIENT TEMPERATURE (°C) TA, AMBIENT TEMPERATURE (°C) Figure 16. NCP1400ASN30T1 Oscillator Frequency vs. Temperature Figure 17. NCP1400ASN50T1 Oscillator Frequency vs. Temperature 100 100 DMAX, MAXIMUM DUTY CYCLE (%) 100 DMAX, MAXIMUM DUTY CYCLE (%) 4.7 Figure 15. NCP1400ASN50T1 Output Voltage vs. Temperature 150 90 80 70 60 40 –50 NCP1400ASN50T1 L = 10 µH IO = 4.0 mA Vin = 1.2 V Figure 14. NCP1400ASN30T1 Output Voltage vs. Temperature 200 50 4.8 TA, AMBIENT TEMPERATURE (°C) 250 0 –50 4.9 TA, AMBIENT TEMPERATURE (°C) 300 50 5.0 4.6 –50 100 fOSC, OSCILLATOR FREQUENCY (kHz) VOUT, OUTPUT VOLTAGE (V) 3.2 NCP1400ASN30T1 VOUT = 3.0 V x 0.96 Open–loop Test –25 0 25 50 75 90 80 70 60 50 40 –50 100 NCP1400ASN50T1 VOUT = 5.0 V x 0.96 Open–loop Test –25 0 25 50 75 100 TA, AMBIENT TEMPERATURE (°C) TA, AMBIENT TEMPERATURE (°C) Figure 18. NCP1400ASN30T1 Maximum Duty Cycle vs. Temperature Figure 19. NCP1400ASN50T1 Maximum Duty Cycle vs. Temperature http://onsemi.com 6 Vstart 0.8 NCP1400ASN30T1 L = 22 µH COUT = 10 µF IO = 0 mA 0.6 0.4 0.2 Vhold 0.0 –50 –25 0 25 50 75 100 1.0 Vstart 0.8 NCP1400ASN50T1 L = 22 µH COUT = 10 µF IO = 0 mA 0.6 0.4 Vhold 0.2 0.0 –50 –25 0 25 50 75 TA, AMBIENT TEMPERATURE (°C) TA, AMBIENT TEMPERATURE (°C) Figure 20. NCP1400ASN30T1 Startup/Hold Voltage vs. Temperature Figure 21. NCP1400ASN50T1 Startup/Hold Voltage vs. Temperature ILX, LX PIN ON–STATE CURRENT (mA) 200 160 120 80 NCP1400ASN30T1 VLX = 0.4 V 40 –50 Vstart, Vhold, STARTUP AND HOLD VOLTAGE (V) 1.0 –25 0 25 50 75 100 100 260 220 180 140 NCP1400ASN50T1 VLX = 0.4 V 100 –50 –25 0 25 50 75 100 TA, AMBIENT TEMPERATURE (°C) TA, AMBIENT TEMPERATURE (°C) Figure 22. NCP1400ASN30T1 LX Pin On–State Current vs. Temperature Figure 23. NCP1400ASN50T1 LX Pin On–State Current vs. Temperature RDS(on), LX SWITCH ON–RESISTANCE (Ω) ILX, LX PIN ON–STATE CURRENT (mA) ILX, LX PIN ON–STATE CURRENT (mA) Vstart, Vhold, STARTUP AND HOLD VOLTAGE (V) NCP1400A 5.0 180 NCP1400ASNXXT1 VLX = 0.4 V TA = 25°C 160 4.0 140 3.0 120 2.0 100 1.0 80 60 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 0 1.5 NCP1400ASNXXT1 VLX = 0.4 V TA = 25°C 2.0 2.5 3.0 3.5 4.0 4.5 5.0 VOUT, OUTPUT VOLTAGE (V) VOUT, OUTPUT VOLTAGE (V) Figure 24. NCP1400ASNXXT1 LX Pin On–State Current vs. Output Voltage Figure 25. NCP1400ASNXXT1 LX Switch On–Resistance vs. Output Voltage http://onsemi.com 7 5.5 1.4 Vstart 1.2 1.0 Vhold 0.8 0.6 NCP1400ASN19T1 L = 22 µH COUT = 68 µF TA = 25°C 0.4 0.2 0 0 Vstart/Vhold, STARTUP/HOLD VOLTAGE (V) Vstart/Vhold, STARTUP/HOLD VOLTAGE (V) 1.6 5.0 10 15 20 25 30 1.0 Vhold 0.8 0.6 NCP1400ASN30T1 L = 22 µH COUT = 68 µF TA = 25°C 0.4 0.2 0 0 5.0 10 15 20 25 Figure 27. NCP1400ASN30T1 Operation Startup/Hold Voltage vs. Output Current 30 80.0 Vstart 1.2 1.0 Vhold 0.8 0.6 NCP1400ASN50T1 L = 22 µH COUT = 68 µF TA = 25°C 0.4 0.2 0 5.0 10 20 15 25 NCP1400ASN19T1 L = 22 µH COUT = 68 µF TA = 25°C 60.0 40.0 Vin= 1.2 V Vin= 1.5 V Vin= 0.9 V 20.0 0 30 0 20 40 60 80 IO, OUTPUT CURRENT (mA) IO, OUTPUT CURRENT (mA) Figure 28. NCP1400ASN50T1 Operation Startup/Hold Voltage vs. Output Current Figure 29. NCP1400ASN19T1 Ripple Voltage vs. Output Current 80 100 80 Vin= 2.0 V Vripple, RIPPLE VOLTAGE (mV) Vripple, RIPPLE VOLTAGE (mV) Vstart 1.2 Figure 26. NCP1400ASN19T1 Operation Startup/Hold Voltage vs. Output Current 1.4 Vin= 1.5 V 60 Vin= 1.5 V 40 NCP1400ASN30T1 L = 22 µH COUT = 68 µF TA = 25°C Vin= 0.9 V 20 0 1.4 IO, OUTPUT CURRENT (mA) 1.6 0 1.6 IO, OUTPUT CURRENT (mA) Vripple, RIPPLE VOLTAGE (mV) Vstart/Vhold, STARTUP/HOLD VOLTAGE (V) NCP1400A 0 20 40 60 80 60 Vin= 2.0 V Vin= 0.9 V 40 Vin= 3.0 V Vin= 1.5 V 20 0 100 NCP1400ASN50T1 L = 22 µH COUT = 68 µF TA = 25°C 0 20 40 60 80 IO, OUTPUT CURRENT (mA) IO, OUTPUT CURRENT (mA) Figure 30. NCP1400ASN30T1 Ripple Voltage vs. Output Current Figure 31. NCP1400ASN50T1 Ripple Voltage vs. Output Current http://onsemi.com 8 100 NCP1400A 2 s/div 2 s/div VOUT = 3.0 V, Vin = 1.2 V, IO = 10 mA., L = 22 H, COUT = 68 F 1. VLX, 2.0 V/div 2. VOUT, 20 mV/div, AC coupled 3. IL, 100 mA/div VOUT = 3.0 V, Vin = 1.2 V, IO = 25 mA., L = 22 H, COUT = 68 F 1. VLX, 2.0 V/div 2. VOUT, 20 mV/div, AC coupled 3. IL, 100 mA/div Figure 32. Operating Waveforms (Medium Load) Figure 33. Operating Waveforms (Heavy Load) Vin = 1.2 V, L = 22 H 1. VOUT = 1.9 V (AC coupled), 50 mV/div 2. IO = 3.0 mA to 30 mA Vin = 1.2 V, L = 22 H 1. VOUT = 1.9 V (AC coupled), 50 mV/div 2. IO = 30 mA to 3.0 mA Figure 34. NCP1400ASN19T1 Load Transient Response Figure 35. NCP1400ASN19T1 Load Transient Response Vin = 1.5 V, L = 22 H 1. VOUT = 3.0 V (AC coupled), 50 mV/div 2. IO = 3.0 mA to 30 mA Vin = 1.5 V, L = 22 H 1. VOUT = 3.0 V (AC coupled), 50 mV/div 2. IO = 30 mA to 3.0 mA Figure 36. NCP1400ASN30T1 Load Transient Response Figure 37. NCP1400ASN30T1 Load Transient Response http://onsemi.com 9 NCP1400A Vin = 1.5 V, L = 22 H 1. VOUT = 5.0 V (AC coupled), 50 mV/div 2. IO = 3.0 mA to 30 mA Vin = 1.5 V, L = 22 H 1. VOUT = 5.0 V (AC coupled), 50 mV/div 2. IO = 30 mA to 3.0 mA Figure 38. NCP1400ASN50T1 Load Transient Response Figure 39. NCP1400ASN50T1 Load Transient Response OUT 2 LX 5 VLX LIMITER + ERROR AMP DRIVER NC 3 PHASE COMPENSATION PWM CONTROLLER SOFT–START 180 kHz OSCILLATOR VOLTAGE REFERENCE POWER SWITCH GND 4 1 CE Figure 40. Representative Block Diagram PIN FUNCTION DESCRIPTION ÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ Pin # Symbol 1 CE 2 OUT 3 NC 4 GND 5 LX Pin Description Chip Enable Pin (1) The chip is enabled if a voltage equal to or greater than 0.9 V is applied. (2) The chip is disabled if a voltage less than 0.3 V is applied. (3) The chip is enabled if this pin is left floating. Output voltage monitor pin and also the power supply pin for the device. No internal connection to this pin. Ground pin. External inductor connection pin to power switch drain. http://onsemi.com 10 NCP1400A DETAILED OPERATING DESCRIPTION Operation Compensation The NCP1400A series are monolithic power switching regulators optimized for applications where power drain must be minimized. These devices operate as fixed frequency, voltage mode boost regulator and is designed to operate in the discontinuous conduction mode. Potential applications include low powered consumer products and battery powered portable products. The NCP1400A series are low noise fixed frequency voltage–mode PWM DC–DC converters, and consist of soft–start circuit, feedback resistor, reference voltage, oscillator, loop compensation network, PWM control circuit, current limit circuit and power switch. Due to the on–chip feedback resistor and loop compensation network, the system designer can get the regulated output voltage from 1.8 V to 5.0 V with a small number of external components. The quiescent current is typically 32 µA (VOUT = 2.7 V), and can be further reduced to about 1.5 µA when the chip is disabled (VCE 0.3 V). The device is designed to operate in discontinuous conduction mode. An internal compensation circuit was designed to guarantee stability over the full input/output voltage and full output load range. Stability cannot be guaranteed in continuous conduction mode. Current Limit The NCP1400A series utilizes cycle–by–cycle current limiting as a means of protecting the output switch MOSFET from overstress and preventing the small value inductor from saturation. Current limiting is implemented by monitoring the output MOSFET current build–up during conduction, and upon sensing an overcurrent conduction immediately turning off the switch for the duration of the oscillator cycle. The voltage across the output MOSFET is monitored and compared against a reference by the VLX limiter. When the threshold is reached, a signal is sent to the PWM controller block to terminate the output switch conduction. The current limit threshold is typically set at 350 mA. Soft Start There is a soft start circuit in NCP1400A. When power is applied to the device, the soft start circuit pumps up the output voltage to approximately 1.5 V at a fixed duty cycle, the level at which the converter can operate normally. What is more, the start–up capability with heavy loads is also improved. Enable/Disable Operation The NCP1400A series offer IC shutdown mode by chip enable pin (CE pin) to reduce current consumption. An internal pull–up resistor tied the CE pin to OUT pin by default, i.e., user can float the pin CE for permanent “On’’. When voltage at pin CE is equal or greater than 0.9 V, the chip will be enabled, which means the regulator is in normal operation. When voltage at pin CE is less than 0.3 V, the chip is disabled, which means IC is shutdown. Important: DO NOT apply a voltage between 0.3 V to 0.9 V to pin CE as this voltage will place the IC into an undefined state and the IC may drain excessive current from the supply. Oscillator The oscillator frequency is internally set to 180 kHz at an accuracy of 20% and with low temperature coefficient of 0.11%/°C. Figures 16 and 17 illustrate oscillator frequency versus temperature. Regulated Converter Voltage (VOUT) The VOUT is set by an internal feedback resistor network. This is trimmed to a selected voltage from 1.8 V to 5.0 V range in 100 mV steps with an accuracy of 2.5%. http://onsemi.com 11 NCP1400A APPLICATION CIRCUIT INFORMATION L1 C1 10 µF CE 1 22 µH OUT 2 NC 3 NCP1400A Vin D1 Vout LX 5 C2 68 µF GND 4 Figure 41. Typical Step–Up Converter Application Step–up Converter Design Equations Diode General step–up DC–DC converter designed to operate in discontinuous conduction mode can be defined by: The diode is the largest source of loss in DC–DC converters. The most importance parameters which affect their efficiency are the forward voltage drop, VF , and the reverse recovery time, trr. The forward voltage drop creates a loss just by having a voltage across the device while a current flowing through it. The reverse recovery time generates a loss when the diode is reverse biased, and the current appears to actually flow backwards through the diode due to the minority carriers being swept from the P–N junction. A schottky diode with the following characteristics is recommended: Small forward voltage, VF 0.3 V Small reverse leakage current Fast reverse recovery time/switching speed Rated current larger than peak inductor current, Irated IPK Reverse voltage larger than output voltage, Vreverse Vout ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁ Calculation Equation D t on T IPK V int on L IO (V in) 2(t on) 2f 2L(V out V F V in) NOTES: D – Duty cycle IPK – Peak inductor current IO – Desired dc output current Vin – Nominal operating dc input voltage Vout – Desired dc output voltage VF – Diode forward voltage Assume saturation voltage of the internal FET switch is negligible. External Component Selection Input Capacitor The input capacitor can stabilize the input voltage and minimize peak current ripple from the source. The value of the capacitor depends on the impedance of the input source used. Small ESR (Equivalent Series Resistance) Tantalum or ceramic capacitor with value of 10 µF should be suitable. Inductor Inductance values between 18 µH and 27 µH are the best suitable values for NCP1400A. In general, smaller inductance values can provide larger peak inductor current and output current capability, and lower conversion efficiency, and vice versa. Select an inductor with smallest possible DCR, usually less than 1.0 Ω, to minimize loss. It is necessary to choose an inductor with saturation current greater than the peak current which the inductor will encounter in the application. Output Capacitor The output capacitor is used for sustaining the output voltage when the internal MOSFET is switched on and smoothing the ripple voltage. Low ESR capacitor should be used to reduce output ripple voltage. In general, a 47 µF to 68 µF low ESR (0.15 Ω to 0.30 Ω) Tantalum capacitor should be appropriate. http://onsemi.com 12 NCP1400A An evaluation board of NCP1400A has been made in the small size of 23 mm x 20 mm and is shown in Figures 42 and 43. Please contact your ON Semiconductor representative for availability. The evaluation board schematic diagram, the artwork and the silkscreen of the surface mount PCB are shown below: 20 mm 1 23 mm Figure 42. NCP1400A PWM Step–up DC–DC Converter Evaluation Board Silkscreen 20 mm 23 mm Figure 43. NCP1400A PWM Step–up DC–DC Converter Evaluation Board Artwork (Component Side) http://onsemi.com 13 NCP1400A Components Supplier ÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁ Á ÁÁÁÁÁÁÁ Á ÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁ Parts Supplier Part Number Description Phone Inductor, L1 Sumida Electric Co. Ltd. CD54–220MC Inductor 22 µH/1.11 A (852) 2880–6688 Schottky Diode, D1 ON Semiconductor Corp. MBR0520LT1 Schottky Power Rectifier (852) 2689–0088 Output Capacitor, C2 KEMET Electronics Corp. T494D686K010AS Low ESR Tantalum Capacitor 68 µF/10 V (852) 2305–1168 Input Capacitor, C1 KEMET Electronics Corp. T491C106K016AS Low Profile Tantalum Capacitor 10 µF/16 V (852) 2305–1168 PCB Layout Hints Grounding efficiency (short and thick traces for connecting the inductor L can also reduce stray inductance), e.g.: short and thick traces listed below are used in the evaluation board: 1. Trace from TP1 to L1 2. Trace from L1 to Lx pin of U1 3. Trace from L1 to anode pin of D1 4. Trace from cathode pin of D1 to TP2 One point grounding should be used for the output power return ground, the input power return ground, and the device switch ground to reduce noise as shown in Figure 44, e.g.: C2 GND, C1 GND, and U1 GND are connected at one point in the evaluation board. The input ground and output ground traces must be thick enough for current to flow through and for reducing ground bounce. Output Capacitor Power Signal Traces The output capacitor should be placed close to the output terminals to obtain better smoothing effect on the output ripple. Low resistance conducting paths should be used for the power carrying traces to reduce power loss so as to improve D1 MBR0520LT1 TP2 L1 22 µH VOUT C2 68 µF/10 V TP3 JP1 Enable On Off CE LX 1 OUT GND TP1 2 C1 10 µF/16 V 5 NCP1400A U1 NC 4 Figure 44. NCP1400A Evaluation Board Schematic Diagram http://onsemi.com 14 TP4 GND Gnd 3 Vin NCP1400A PACKAGE DIMENSIONS THIN SOT–23–5 SN SUFFIX CASE 483–01 ISSUE B NOTES: 1. DIMENSIONING AND TOLERANCING PER ANSI Y14.5M, 1982. 2. CONTROLLING DIMENSION: MILLIMETER. 3. MAXIMUM LEAD THICKNESS INCLUDES LEAD FINISH THICKNESS. MINIMUM LEAD THICKNESS IS THE MINIMUM THICKNESS OF BASE MATERIAL. D S 5 4 1 2 3 B L G A J C 0.05 (0.002) H M K http://onsemi.com 15 DIM A B C D G H J K L M S MILLIMETERS MIN MAX 2.90 3.10 1.30 1.70 0.90 1.10 0.25 0.50 0.85 1.05 0.013 0.100 0.10 0.26 0.20 0.60 1.25 1.55 0 10 2.50 3.00 INCHES MIN MAX 0.1142 0.1220 0.0512 0.0669 0.0354 0.0433 0.0098 0.0197 0.0335 0.0413 0.0005 0.0040 0.0040 0.0102 0.0079 0.0236 0.0493 0.0610 0 10 0.0985 0.1181 NCP1400A ON Semiconductor and are trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC reserves the right to make changes without further notice to any products herein. SCILLC makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does SCILLC assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages. “Typical” parameters which may be provided in SCILLC data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including “Typicals” must be validated for each customer application by customer’s technical experts. SCILLC does not convey any license under its patent rights nor the rights of others. SCILLC products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other applications intended to support or sustain life, or for any other application in which the failure of the SCILLC product could create a situation where personal injury or death may occur. Should Buyer purchase or use SCILLC products for any such unintended or unauthorized application, Buyer shall indemnify and hold SCILLC and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that SCILLC was negligent regarding the design or manufacture of the part. SCILLC is an Equal Opportunity/Affirmative Action Employer. PUBLICATION ORDERING INFORMATION Literature Fulfillment: Literature Distribution Center for ON Semiconductor P.O. Box 5163, Denver, Colorado 80217 USA Phone: 303–675–2175 or 800–344–3860 Toll Free USA/Canada Fax: 303–675–2176 or 800–344–3867 Toll Free USA/Canada Email: [email protected] JAPAN: ON Semiconductor, Japan Customer Focus Center 4–32–1 Nishi–Gotanda, Shinagawa–ku, Tokyo, Japan 141–0031 Phone: 81–3–5740–2700 Email: [email protected] ON Semiconductor Website: http://onsemi.com For additional information, please contact your local Sales Representative. N. American Technical Support: 800–282–9855 Toll Free USA/Canada http://onsemi.com 16 NCP1400A/D