NCP1410 Product Preview 250 mA Sync-Rect PFM Step-Up DC-DC Converter with Low-Battery Detector NCP1410 is a monolithic micropower high frequency step–up voltage switching converter IC specially designed for battery operated hand–held electronic products up to 250 mA loading. It integrates Synchronous Rectifier for improving efficiency as well as eliminating the external Schottky Diode. High switching frequency (up to 600 kHz) allows low profile inductor and output capacitor being used. Low–Battery Detector, Logic–Controlled Shutdown and Cycle–by–Cycle Current Limit provide value–added features for various battery–operated applications. With all these functions ON, the quiescent supply current is only 9.0 A typical. This device is available in a compact Micro8 package. http://onsemi.com MARKING DIAGRAM 8 Micro8 DM SUFFIX CASE 846A 8 1 1 A1 = Device Marking A = Assembly Location Y = Year W = Work Week Features • High Efficiency 92% Typical • Very Low Quiescent Supply Current of 9.0 A Typical • Built–in Synchronous Rectifier (PFET) Eliminates One External Schottky Diode PIN CONNECTIONS • High Switching Frequency (up to 600 kHz) Allows Small Size • • • • • • • • • Inductor High Accuracy Reference Output, 1.19 V ± 0.6% @ 25°C, can supply more than 2.5 mA when VOUT ≥ 3.3 V 1.0 V Startup Output Voltage from 1.5 V to 5.5 V Output Current up to 250 mA @ Vin = 2.5 V, Vout = 3.3 V Logic–Controlled Shutdown, 0.05 A Typical Low–Battery Detector 1.0 A Cycle–by–Cycle Current Limit Low Profile and Minimum External Parts Compact Micro8 Package • • • • FB 1 8 OUT LBI 2 7 LX LBO 3 6 GND REF 4 5 SHDN (Top View) ORDERING INFORMATION Device NCP1410DMR2 Typical Applications A1 AYW Package Shipping Micro8 2500 Tape & Reel Personal Digital Assistant (PDA) Camcorder and Digital Still Camera Hand–held Instrument Conversion from One or Two NiMH or NiCd, or One Li–ion Cell to 3.3 V/5.0 V This document contains information on a product under development. ON Semiconductor reserves the right to change or discontinue this product without notice. Semiconductor Components Industries, LLC, 2001 May, 2001 – Rev. 0 1 Publication Order Number: NCP1410/D NCP1410 Input 1 V to VOUT 10 µ 500 k 150 p 15 µ 360 k 200 k VOUT FB Low Battery Sense Input LBI Low Battery Open Drain Output 33 µ LX NCP1410 LBO GND REF SHDN 150 n Output 1.5 V to 5.5 V IOUT typical up to 250 mA at 3.3 V Output and 2.5 V Input 56 n Shutdown Open Drain Input Figure 1. Typical Operating Circuit MAXIMUM RATINGS (Note 1.) Symbol Value Unit VOUT –0.3 to 6.0 V Input/Output Pins Pin 1–5, Pin 7 VIO –0.3 to 6.0 V Thermal Characteristics Micro8 Plastic Package Thermal Resistance Junction to Air RθJA 245 °C/W Operating Junction Temperature Range TJ –40 to +150 °C Operating Ambient Temperature Range TA –40 to +85 °C Storage Temperature Range Tstg –55 to +150 °C Rating Power Supply (Pin 8) 1. This device series contains ESD protection and exceeds the following tests: Human Body Model 2.0 kV per MIL–STD–883, Method 3015. Machine Model Method 200 V. http://onsemi.com 2 NCP1410 ELECTRICAL CHARACTERISTICS (VOUT = 3.3 V, TA = 25°C for typical value, –40°C ≤ TA ≤ 85°C for min/max values unless otherwise noted.) Characteristics Operating Voltage Output Voltage Range Reference Voltage (Under no loading, TA = 25°C) Symbol Min Typ Max Unit VIN 1.0 – 5.5 V VOUT 1.5 – VIN V VREF_NL 1.183 1.190 1.197 V VREF_NL_A 1.178 – 1.202 V TCVREF – 0.03 – mV/°C Reference Voltage Load Current (VOUT = 3.3 V, VREF = VREF_NL ±1.5%, CREF = 1.0 F) (Note 2.) IREF 2.5 – – mA Reference Voltage Load Regulation (VOUT = 3.3 V, IREF = 0 to 100 A, CREF = 1.0 F) VREF_LOAD – 0.015 1.0 mV Reference Voltage Line Regulation (VOUT from 1.5 V to 5.5 V, CREF = 1.0 F) VREF_LINE – 0.03 1.0 mV/V FB, LBI Input Threshold VFB, VLBI 1.174 1.190 1.200 V ILIM – 1.0 – A Operating Current into OUT (VFB = 1.4 V, i.e. No switching, VOUT = 3.3 V) IQ – 9.0 14 A Shutdown Current into OUT (SHDN = GND) ISD – 0.05 1.0 A Reference Voltage (Under no loading, –40°C ≤ TA ≤ 85°C) Reference Voltage Temperature Coefficient LX Switch Current Limit (NFET) LX Switch MAX. ON–Time (VFB = 1.0 V, VOUT = 3.3 V) tON 1.2 1.4 1.8 S LX Switch MIN. OFF–Time (VFB = 1.0 V, VOUT = 3.3 V) tOFF 0.25 0.31 0.37 S FB Input Current IFB – 1.5 9.0 nA LBI Input Current ILBI – 1.5 8.0 nA ISHDN – 1.5 8.0 nA VLBO_L – – 0.05 V SHDN Input Current LBO Low Output Voltage (VLBI = 0, ISINK = 1.0 mA) SHDN Input Threshold, Low VSHDN_L – – 0.4 V SHDN Input Threshold, High VSHDN_H 0.6 – – V 2. Loading capability decreases with VOUT. http://onsemi.com 3 NCP1410 PIN FUNCTION DESCRIPTIONS Pin # Symbol Pin Description 1 FB Output Voltage Feedback Input. 2 LBI Low–Battery Detector Input. 3 LBO Open–Drain Low–Battery Detector Output. Output is LOW when VLBI is < 1.178 V. LBO is high impedance during shutdown. 4 REF 1.190 V Reference Voltage Output, bypass with 150 nF capacitor if this pin is not loaded, bypass with 1.0 F if this pin is loaded. 5 SHDN 6 GND 7 LX 8 OUT Shutdown Input. HIGH (> 0.6 V) = operating; LOW (< 0.4 V) = shutdown. Ground. N–Channel and P–Channel Power MOSFET Drain. Power Output. OUT provides bootstrap power to the IC. Vbat L ZLC + – Vbat LX + RSHDN SHDN _ZCUR _PWGONCE REF CREF PFM + – Voltage Reference VOUT OUT M2 Chip Enable CSHDN FB VDD VDD CF2 SENSEFET _MAINSW2ON _CEN COUT M1 GND _PFM RF1 VDD _MAINSWOFD Control Logic GND _SYNSW2ON GND _VREFOK _SYNSWOFD _ILIM + – + ILIM LBO GND LBI + – GND Figure 2. Simplified Functional Diagram http://onsemi.com 4 RF2 NCP1410 350 250 VIN = 3.0 V VIN = 2.4 V 80 EFFICIENCY (%) 300 100 VOUT = 3.3 V COUT = 33 µF L = 15 µH TA = 25°C 200 150 100 VIN = 1.8 V 60 VIN = 1.0 V 40 VOUT = 3.3 V L = 15 µH TA = 25°C 20 50 0 0.5 1.0 1.5 2.0 2.5 0 3.0 0 50 100 150 200 250 VIN, INPUT VOLTAGE (V) IO, LOAD CURRENT (mA) Figure 3. Maximum Output Current vs. Input Voltage (VOUT = 3.3 V) Figure 4. Efficiency vs. Load Current (VOUT = 3.3 V) 100 ISTBY, STANDBY CURRENT (µA) IO(max), MAXIMUM OUTPUT CURRENT (mA) TYPICAL OPERATING CHARACTERISTICS 80 60 40 20 0 0.5 VOUT = 3.3 V L = 15 µH TA = 25°C 1.0 1.5 2.0 2.5 3.0 VIN, INPUT VOLTAGE (V) Figure 5. Standby Current from VBAT vs. Input Voltage (VOUT = 3.3 V) http://onsemi.com 5 300 NCP1410 DETAILED OPERATION DESCRIPTIONS time is introduced to make sure M1 is completely OFF before M2 is being turned ON. When the main regulator is operating in CCM, as M2 is being turned OFF, and M1 is just turned ON with M2 not being completed OFF, the above mentioned situation will occur. So dead time is introduced to make sure M2 is completed OFF before M1 is being turned ON. When the regulator is operating in DCM, as coil current is dropped to zero, M2 is supposed to be OFF. Fail to do so, reverse current will flow from the output bulk capacitor through M2 and then the inductor to the battery input. It causes damage to the battery. So the ZLC comparator comes with fixed offset voltage to switch M2 OFF before any reverse current builds up. However, if M2 is switch OFF too early, large residue coil current flows through the body diode of M2 and increases conduction loss. Therefore, determination on the offset voltage is essential for optimum performance. With the implementation of synchronous rectification, efficiency can be as high as 92%. For single cell input voltage, use an external schottky diode such as MBRM120 connected from pin 7 to pin 8 to ensure start–up. NCP1410 is a monolithic micropower high frequency step–up voltage switching converter IC specially designed for battery operated hand–held electronic products up to 250 mA loading. It integrates Synchronous Rectifier for improving efficiency as well as eliminating the external Schottky Diode. High switching frequency (up to 600 kHz) allows low profile inductor and output capacitor being used. Low–Battery Detector, Logic–Controlled Shutdown and Cycle–by–Cycle Current Limit provide value–added features for various battery–operated application. With all these functions ON, the quiescent supply current is only 9.0 A typical. This device is available in a compact Micro8 package. PFM Regulation Scheme From the simplified Functional Diagram (Figure 2), the output voltage is divided down and fed back to pin 1 (FB). This voltage goes to the non–inverting input of the PFM comparator whereas the comparator’s inverting input is connected to REF. A switching cycle is initiated by the falling edge of the comparator, at the moment, the main switch (M1) is turned ON. After the maximum ON–time (typical 1.4 S) elapses or the current limit is reached, M1 is turned OFF, and the synchronous switch (M2) is turned ON. The M1 OFF time is not less than the minimum OFF–time (typical 0.31 S), this is to ensure energy transfer from the inductor to the output capacitor. If the regulator is operating at continuous conduction mode (CCM), M2 is turned OFF just before M1 is supposed to be ON again. If the regulator is operating at discontinuous conduction mode (DCM), which means the coil current will decrease to zero before the next cycle, M1 is turned OFF as the coil current is almost reaching zero. The comparator (ZLC) with fixed offset is dedicated to sense the voltage drop across M2 as it is conducting, when the voltage drop is below the offset, the ZLC comparator output goes HIGH, and M2 is turned OFF. Negative feedback of closed loop operation regulates voltage at pin 1 (FB) equal to the internal voltage reference (1.190 V). Therefore, the feedback resistors RF1 and RF2 determines the output voltage: Cycle–by–Cycle Current Limit From Figure 2, SENSEFET is applied to sample the coil current as M1 is ON. With that sample current flowing through a sense resistor, sense–voltage is developed. Threshold detector (ILIM) detects whether the sense–voltage is higher than preset level. If it happens, detector output signifies the CONTROL LOGIC to switch OFF M1, and M1 can only be switched ON as next cycle starts after the minimum OFF–time (typical 0.31 S). With properly sizing of SENSEFET and sense resistor, the peak coil current limit is set at 1.0 A typically. Voltage Reference The voltage at REF is set typically at +1.190 V. It can output up to 2.5 mA with load regulation ±1.5%, at VOUT equal to 3.3 V. If VOUT is increased, the REF load capability can also be increased. A bypass capacitor of 0.15 F is required for proper operation when REF is not loaded. If REF is loaded, 1.0 F capacitor at REF is needed. R VOUT 1.190 V 1 F2 RF1 Synchronous Rectification Shutdown The IC is shutdown when the voltage at pin 5 (SHDN) is pulled lower than 0.4 V. During shutdown, M1 and M2 are both switched OFF, however, the body diode of M2 allows current flow from battery to the output, the IC internal circuit will consume less than 0.05 A current typically. If the pin 5 voltage is pull higher than 0.6 V, for example, by a resistor connected to VIN, the IC is enabled, and the internal circuit will only consume 9.0 A current typically from the OUT pin. Refer to Figure 2, the product of RSHDN and CSHDN must be larger than (500 k • 56 n). This is to provide reset pulse for startup as battery is plugged in. Synchronous Rectifier is used to replace Schottky Diode for eliminating the conduction loss contributed by forward voltage of the latter. Synchronous Rectifier is normally realized by powerFET with gate control circuitry which, however, involved relative complicated timing concerns. As main switch M1 is being turned OFF, if the synchronous switch M2 is just turned ON with M1 not being completed turned OFF, current will be shunt from the output bulk capacitor through M2 and M1 to ground. This power loss lowers overall efficiency. So a certain amount of dead http://onsemi.com 6 NCP1410 Low–Battery Detection pin 3 (LBO) which has a hundreds kilo–Ohm of pull–high resistance. If the pin 2 voltage is higher than 1.190 V + 30 mV, the comparator output will cause the 50 Ohm low side switch to be turned OFF, pin 3 will become high impedance, and its voltage will be pulled high by the external resistor. A comparator with 30 mV hysteresis is applied to perform the low–battery detection function. When pin 2 (LBI) is at a voltage, which can be defined by a resistor divider from the battery voltage, lower than the internal reference voltage, 1.190 V, the comparator output will cause a 50 Ohm low side switch to be turned ON. It will pull down the voltage at http://onsemi.com 7 NCP1410 PACKAGE DIMENSIONS Micro8 DM SUFFIX CASE 846A–02 ISSUE E NOTES: 1. DIMENSIONING AND TOLERANCING PER ANSI Y14.5M, 1982. 2. CONTROLLING DIMENSION: MILLIMETER. 3. DIMENSION A DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.15 (0.006) PER SIDE. 4. DIMENSION B DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSION. INTERLEAD FLASH OR PROTRUSION SHALL NOT EXCEED 0.25 (0.010) PER SIDE. –A– –B– K PIN 1 ID G D 8 PL 0.08 (0.003) –T– M T B A S S SEATING PLANE 0.038 (0.0015) C H DIM A B C D G H J K L MILLIMETERS MIN MAX 2.90 3.10 2.90 3.10 --1.10 0.25 0.40 0.65 BSC 0.05 0.15 0.13 0.23 4.75 5.05 0.40 0.70 INCHES MIN MAX 0.114 0.122 0.114 0.122 --0.043 0.010 0.016 0.026 BSC 0.002 0.006 0.005 0.009 0.187 0.199 0.016 0.028 L J Micro8 is a trademark of International Rectifier. SENSEFET is a trademark of Semiconductor Components Industries, LLC. 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. 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