ILC6376 FAIRCHILD | Alldatasheet

Document overview

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Technical content

Features

  • ±2.5% accurate output voltages
  • Guaranteed 500mA output current
  • 95% efficiency
  • 55µA no load battery input current (ILC6377)
  • 1.5µA shutdown current
  • Built in short circuit and overcurrent protection
  • Undervoltage lockout and soft-start
  • External transistor drive available for higher IOUT
  • 300kHz operation
  • Automatic switchover to PFM mode at low currents for longest battery life (ILC6377)
  • Fixed 3.3V or 5V or adjustable output
  • SO-8 package

Applications

  • Cellular Phones
  • Palmtops and PDAs
  • Portable Instrumentation
  • Buck Converter for Industrial / Networking Applications

Description

The ILC6376/77 is a 95% efficient, 300kHz step-down DC- DC converter in an SO-8 package; capable of delivering 500mA output current. The device is also capable of driving an external FET for higher output current applications. The ILC6376/77 uses a unique p-channel architecture with built-in charge pump to maintain low on-resistance, even at low input voltages. The ILC6376 operates in PWM mode with 300kHz switching frequency. The ILC6377 does the same at high and medium load currents. When the load current drops and the device hits approximately 25% duty cycle, ILC6377 automatically switches over to PFM or pulse skipping mode. PFM (pulse frequency modulation) mode of operation extends efficiency at light loads. Start-up is controlled via an external soft-start capacitor. The device will automatically re-enter start-up mode when an output current overload condition is sensed; thus providing automatic short-circuit protection. Voltage lockout prevents faulty operation below the minimum operating voltage level. In shutdown, the ILC6376/77 consumes only 1.5µA current. The ILC6376/77SOXX offers fixed 3.3V or 5V output while ILC6376/77SOADJ allows adjustable output. Both versions of ILC6376/77 are available in an SO-8 surface mount package. Typical Applications VOUT ILC6376/77 (TOP VIEW) + CL VIN S/D CSS SD1 L *CIN Fig 1. Typical step-down DC-DC converter application 22µH 47µF 10µF ILC6376/77 0.5A, 300kHz, SO-8 PWM/PFM Step Down Converter with Shutdown ©2001 Fairchild Semiconductor Corporation SD1: SS12 Schottky Diode (FAIRCHILD) CL: 10V/47µF Tantalum Capacitor (NICHICON, F93) CSS: 4700pF Ceramic Capacitor CIN: 16V / 10µF Tantalum Capacitor (NICHICON, F93)

External gate drive pin (low when P-Ch FET is ON) P-BST P-Ch gate boost S/D, Softstart, VREF Shutdown, also soft-start capacitor pin and VREFoutput VOUT / FB Output voltage sense pin for ILC6376/77SO-XX; 1V feedback pin for ILC6376/77SO-ADJ GND Ground connection EXT1 External gate drive pin (low when P-Ch FET is ON) LX Inductor Switch Pin ILC6376/77 (TOP VIEW) 8 LX FB EXT1 S/D, GND P_BST EXT2 VIN CSS ILC6376/77 SOXX ILC6376/77 (TOP VIEW) LX VOUT EXT1 S/D, GND P_BST EXT2 VIN CSS ILC6376/77 SOADJ PWM/PFM Protection LX GND EXT1 RAMP WAVE VIN VOUT P_BST GATE DRIVER GENERATOR, OSCILLATOR CONTROLLER PWM Comp EXT2 Error Amp S/D, Softstart, Vref S/D, Vref with Soft- start ILC6376/77 ©2001 Fairchild Semiconductor Corporation

Absolute Maximum Ratings (TA=25°C) VOUT = 3.3V, VIN = 4V, FOSC=300kHz, IOUT = 130mA, TA = 25°C, unless otherwise specified. Circuit configuration figure 1. Parameter Symbol Ratings Units VIN Input Voltage Pin VIN -0.3 to +12 V VOUT Pin (ILC6376/77SOXX) FB Pin (ILC6376/77SOADJ) VOUT VFB -0.3 to +12 -0.3 to VIN +0.3 V Voltage on LX pin VLX VIN - VLX = -0.3 to +12 V Peak Switch Current on LX pin ILX 700 mA Voltage on P_BST pin VDP_BST VIN - VP_BST = -0.3 to +12 V Current EXT1, EXT2 pins IEXT1, IEXT2 ±50 mA Voltage on all other pins -0.3 to VIN + 0.3 V Continuous Total Power Dissipation PD 300 mW Operating Ambient Temperature TOPR -30~+80 Storage Temperature TSTG -40~+125 Parameter Symbol Conditions Min. Typ. Max. Units Output Voltage VOUT 3.218 3.300 3.383 V Input Voltage VIN V Output Maximum Current IOUT(MAX) 500 600 mA Input Current Supply IIN VIN 3.5V, No Loads ILC6376 1480 2190 µA ILC6377 Shutdown Current IS/D VS/D = 0V 1.5 2.5 µA LX Switch On - Resistance Rds(on) Open Loop Measurement, VS/D = VIN, VLX = VIN - 0.2V, VOUT = 3V 0.64 0.85 Ω LX Switch Leakage Current ILXL Open Loop Measurement, VOUT = VIN, VLX = 0V 2.0 µA Oscillator Frequency FOSC Measurement Waveform at EXT pin VIN = 3.6V IOUT = 20mA 255 300 345 kHz Max Duty Cycle MAXDTY 100 PFM Duty Cycle PFMDTY No Load (ILC6377) Efficiency EFFI Undervoltage Lockout VUVLO Minimum VIN when Vref does not start up 0.9 1.8 V Soft-Start Time TSS VREF rises to 0V from 0.9V 6.0 10.0 16.0 msec Shutdown Input Voltage VSD High = Regulator “ON” Low = Regulator “OFF” 0.65 0.2 V EXT1, EXT2 Hi On- Resistance REXtHI 3V applied to VOUT with no external components Ω EXT1, EXT2 Low On- Resistance REXtLOW 3.6V applied to VOUT with no external components Ω ILC6376/77 ©2001 Fairchild Semiconductor Corporation

Min. Typ. Max. Units Output Voltage VOUT 4.875 5.000 5.125 V Input Voltage VIN V Output Maximum Current IOUT(MAX) 500 600 mA Input Supply Current IIN VIN 5.25V, No Load ILC6376 2540 3740 µA ILC6377 110 Shutdown Current IS/D VS/D = 0V 1.5 2.5 µA LX Switch On-Resistance Rds(on) Open Loop Measurement, VS/D = VIN, VLX =VIN - 0.2V, VOUT = 4.5V 0.44 0.58 Ω LX Switch Leakage Current ILXL Open Loop Measurement, VOUT = VIN, VLX = 0V 2.0 µA Oscillator Frequency FOSC Measure Waveform at EXT pin VIN = 5.3V IOUT = 20mA 255 300 345 kHz Max Duty Cycle MAXDTY 100 PFM Duty Cycle PFMDTY No Load (ILC6377) Efficiency EFFI Undervoltage Lockout VUVLO Minimum VIN when VREF does not start up 0.9 1.8 V Soft-Start Time TSS VREF rises to 0V from 0.9V 6.0 10.0 msec Shutdown Input Voltage VS/D High = Regulator “ON” Low = Regulator “OFF” 0.65 0.2 V EXT1, EXT2 Hi On- Resistance REXtHI Open Loop Measurement Ω EXT1, EXT2 Low On- Resistance REXtLOW Open Loop Measurement Ω Unless Otherwise specified all limits are at VOUT = 5.0V, VIN = 6V, FOSC=300kHz, IOUT = 200mA, TA = 25°C. Circuit config- uration figure 1. ILC6376/77 ©2001 Fairchild Semiconductor Corporation

Unless Otherwise specified all limits are at VOUT programmed to 5.0V, VIN = 6V, FOSC=300kHz, IOUT = 200mA, TA = 25°C. Circuit configuration figure 1. Parameter Symbol Conditions Min. Typ. Max. Units Feedback Voltage (pin 5) VFB .995 1.000 1.015 V Output Voltage VOUT RFB1 + RFB2 < 2MΩ 1.5 V Output Maximum Current IOUT(MAX) 500 600 mA Input Supply Current IIN VIN 5.25V, No Load 110 µA Shutdown Current IS/D VS/D = 0V 1.5 2.5 µA LX Switch On-Resistance Rds(on) Open Loop Measurement, VS/D = VIN, VLX = VIN - 0.2V, VOUT = 4.5V 0.44 0.58 Ω LX Leak Current ILXL Open Loop Measurement, VOUT = VIN, VLX = 0V 2.0 µA Oscillator Frequency FOSC Measure Waveform at EXT pin VIN = 5.3V IOUT = 20mA 255 300 345 kHz Max Duty Cycle MAXDTY 100 PFM Duty Cycle PFMDTY No Load (ILC6377) Efficiency EFFI Undervoltage Lockout VUVLO Minimum VIN when VREF does not start up 0.9 1.8 V Soft-Start Time TSS VREF rises to 0V from 0.9V 6.0 10.0 16.0 msec Shutdown Input Voltage VS/D High = Regulator “ON” Low = Regulator “OFF” 0.65 0.2 V EXT1, EXT2 Hi On- Resistance REXtHI Open Loop Measurement Ω EXT1, EXT2 Low On- Resistance REXtLOW Open Loop Measurement Ω ©2001 Fairchild Semiconductor Corporation ILC6376/77

External component selection Proper selection of external components is important for achieving high performance. The output inductor selected should have low DC resistance on the order of 0.2Ω or less and saturation current rating of 1A or higher. Recommended inductors are Sumida CD54 (22µH, 0.18Ω max DC resis- tance) or Coilcraft DO3308P-223 (22µH, 0.18Ω max DC resistance) or equivalent. The catch diode should be a schottky diode with low forward drop and rated at 1A or greater current, SS12 or it’s equiva- lent is recommended. Input and output capacitors should be tantalum capacitors with low equivalent series resistance (ESR) and voltage rat- ing higher than the actual application. Soft-start Pin 4 of ILC6376/77 functions as the soft-start pin as well as the shutdown pin. A soft-start capacitor (from pin 4 to ground) controls the rate at which the power supply starts up; thus preventing large overshoots at the output as well as large in-rush current. The value for CSS should be 100pF or greater. Shutdown The ILC6376/77 is placed in shutdown mode by taking pin 4 to ground. In shutdown, the quiescent current of the device is under 2µA. When using the shutdown feature, pin 4 must be driven from an open collector or open drain output without employing an external pull-up resistor, as shown in figure 2. Over-current and short-circuit protection In the event of an over-current or short-circuit condition, the ILC6376/77 cycles the soft-start pin in a hiccup mode to pro- vide fault protection. When the output voltage decreases due to overload, the ILC6376/77 will operate continuously at the maximum duty cycle. If the period of maximum duty cycle operation exceeds TPRO (typically 5 msec), pin 4 will be pulled low; thus discharging the external soft-start capacitor CSS. This action inhibits the regulator’s PWM action. Next, the ILC6376/77’s soft-start circuitry starts recharging CSS and initiates a controlled start-up. If the overload condition continues to exist, the above sequence of events will repeat; thus continuing to cycle the soft-start function. Note that very little power is dissipated with this method of fault protection versus constant current limit protection. Even though the internal power MOSFET is pulsed on and off at high peak current, the DC current is low; thus leading to low power dissipation even under short-circuit conditions. Keep in mind that the duration of maximum duty cycle condition is used to trigger the ILC6376/77’s fault protec- tion circuit. As such, a small input-output (VIN - VOUT) differential voltage may trigger the device’s fault protec- tion circuitry even at low output current. Undervoltage Lockout The undervoltage lockout feature prevents faulty operation by disabling the operation of the regulator when input volt- age is below the minimum operating voltage, VUVLO. When the input voltage is lower than VUVLO the device disables the internal P-channel MOSFET and provides “high” output at both EXT1 and EXT2 outputs. VOUT ILC6376/77 (TOP VIEW) + CL VIN S/D CSS SD1 L *CIN Fig 1. Typical step-down DC-DC converter application SD1: SS12 Schottky Diode (FAIRCHILD) CL: 10V/47µF Tantalum Capacitor (NICHICON, F93) CSS: 4700pF Ceramic Capacitor CIN: 16V / 10µF Tantalum Capacitor (NICHICON, F93) 22µH 47µF 10µF Figure 1 shows a typical fixed output voltage step-down DC-DC converter application circuit for ILC6376/77SOXX. ILC6376/77 ©2001 Fairchild Semiconductor Corporation

external P-channel MOSFET is shown in figure 2. efficiency at low input voltages and high output currents. is clamped to a safe negative voltage. output capacitor (CL) values chosen. and the vicinity of inductive flux.

6 CFB

Figure 3. P-Channel Negative P_BST must be less than 10V.

Typical Performance Characteristics General conditions for all curves: Circuit 1; L = 20µH (Sumida, CD54), CIN = 47µF (tantalum) with 0.1µF (ceramic), CL = 47µH (tantalum) SS12 schottky diode, CSS = 4700pF (ceramic), TA = 25°C unless otherwise noted. OUTPUT CURRENT: IOUT(mA) Output Voltage vs. Output Current 3.5 3.4 3.3 3.2 3.1 3.0 0.1 100 1000 ILC6377SO33 OUTPUT VOLTAGE: VOUT(V) L = 22µH (CD54) VIN = 3.96 5.0V 8.0V Output Voltage vs. Output Current 5.4 5.2 5.0 4.8 4.6 4.4 0.1 100 1000 ILC6377SO50 OUTPUT VOLTAGE: VOUT(V) OUTPUT CURRENT: IOUT(mA) L = 22µH (CD54) 10.0V 6.0V 8.0V Output Voltage vs. Output Current 3.5 3.4 3.3 3.2 3.1 3.0 0.1 100 1000 ILC6377SO33 OUTPUT VOLTAGE: VOUT(V) OUTPUT CURRENT: IOUT(mA) L = 10µH (CD54) VIN = 3.96 5.0V 8.0V Output Voltage vs. Output Current 3.5 3.4 3.3 3.2 3.1 3.0 0.1 100 1000 ILC6376SO33 OUTPUT VOLTAGE: VOUT(V) OUTPUT CURRENT: IOUT(mA) L = 22µH (CD54) VIN = 3.96V, 5.0V,8.0V 10.0V Output Voltage vs. Output Current 3.5 3.4 3.3 3.2 3.1 3.0 0.1 100 1000 ILC6377SO-33 OUTPUT VOLTAGE: VOUT(V) OUTPUT CURRENT: IOUT(mA) L = 47µH (CD105) VIN = 4.0V 5.0V 8.0V Output Voltage vs. Output Current 5.4 5.2 5.0 4.8 4.6 4.4 0.1 100 1000 ILC6376SO50 OUTPUT VOLTAGE: VOUT(V) OUTPUT CURRENT: IOUT(mA) L =22µH (CD54) 10.0V 6.0V 8.0V ILC6376/77 ©2001 Fairchild Semiconductor Corporation

Typical Performance Characteristics General conditions for all curves: Circuit 1; L = 20µH (Sumida, CD54), CIN = 47µF (tantalum) with 0.1µF (ceramic), CL = 47µH (tantalum) SS12 schottky diode, CSS = 4700pF (ceramic), TA = 25°C unless otherwise noted. Efficiency vs. Output Current 100 0.1 100 1000 ILC6377SO33 EFFICIENCY: EFFI(%) OUTPUT CURRENT: IOUT(mA) L = 22µH (CD54) VIN = 4.0V 5.0V 8.0V Efficiency vs. Output Current 100 0.1 100 1000 ILC6377SO33 EFFICIENCY: EFFI(%) OUTPUT CURRENT: IOUT(mA) L = 10µH (CD54) VIN = 3.96V 5.0V 8.0V Efficiency vs. Output Current 100 0.1 100 1000 ILC6377SO33 EFFICIENCY: EFFI(%) OUTPUT CURRENT: IOUT(mA) L = 47µH (CD105) VIN = 4.0V 5.0V 8.0V Efficiency vs. Output Current 100 0.1 100 1000 ILC6376SO33 EFFICIENCY: EFFI(%) OUTPUT CURRENT: IOUT(mA) L = 22µH (CD54) VIN = 4.0V 5.0V 10.0V 8.0V Efficiency vs. Output Current 100 0.1 100 1000 ILC6376SO50 EFFICIENCY: EFFI(%) OUTPUT CURRENT: IOUT(mA) L = 22µH (CD54) VIN = 3.96V 10.0V 8.0V 5.0V Efficiency vs. Output Current 100 0.1 100 1000 ILC6377SO50 EFFICIENCY: EFFI(%) OUTPUT CURRENT: IOUT(mA) L = 22µH (CD54) VIN = 6.0V 10.0 8.0V ILC6376/77 ©2001 Fairchild Semiconductor Corporation

Typical Performance Characteristics General conditions for all curves: Circuit 1; L = 20µH (Sumida, CD54), CIN = 47µF (tantalum) with 0.1µF (ceramic), CL = 47µH (tantalum) SS12 schottky diode, CSS = 4700pF (ceramic), TA = 25°C unless otherwise noted. -40 -20 ILC6377SO33 Output Voltage vs. Ambient Temperature STAND-BY CURRENT (µA) AMBIENT TEMP.: TA (˚C) 3.40 3.35 3.20 3.25 3.30 400 350 300 250 200 -40 -20 ILC6377SO33 Oscillation Frequency vs. Ambient Temperature OSCILLATION FREQUENCY: FOSC(kHz) AMBIENT TEMP.: TA (˚C) 100 -40 -20 ILC6377SO33 Stand-by Current vs. Ambient Temperature SUPPLY CURRENT: IIN(µA) AMBIENT TEMP.: TA (˚C) 1.2 -40 -20 ILC6377SO33 On Resistance vs. Ambient Temperature SWITCH RESISTANCE: RDS(ON)(Ω) AMBIENT TEMP.: TA (˚C) 1.0 0.8 0.6 0.4 0.2 -40 -20 ILC6377SO33 PFM Duty Ration vs. Ambient Temperature PFM DUTY RATIO: PFMDTY(%) AMBIENT TEMP.: TA (˚C) 3.40 3.35 3.20 3.25 3.30 3.40 3.35 3.30 3.26 3.20 -40 -20 ILC6377SO33 Output vs. Ambient Temperature OUTPUT VOLTAGE (V) AMBIENT TEMP.: TA (˚C) ILC6376/77 ©2001 Fairchild Semiconductor Corporation

Typical Performance Characteristics General conditions for all curves: Circuit 1; L = 20µH (Sumida, CD54), CIN = 47µF (tantalum) with 0.1µF (ceramic), CL = 47µH (tantalum) SS12 schottky diode, CSS = 4700pF (ceramic), TA = 25°C unless otherwise noted. -40 -20 ILC6377SO33 Soft-Start Time vs. Ambient Temperature SOFT-START TIME: TSS(ms) AMBIENT TEMP.: TA (˚C) -40 -20 ILC6377SO33 CE "H" Voltage vs. Ambient Temperature CE "H" VOLTAGE: VCEL(V) AMBIENT TEMP.: TA (˚C) 0.8 0.6 0.4 0.2 1.0 -40 -20 ILC6377SO33 Minimum Operating Voltage vs. Ambient Temperature MIN. OPERATING VOLTAGE: VOUT(V) AMBIENT TEMP.: TA (˚C) 1.6 1.4 1.2 1.0 0.8 1.8 -40 -20 ILC6377SO33 CE "L" Voltage vs. Ambient Temperature CE "L" VOLTAGE: VCEL(V) AMBIENT TEMP.: TA (˚C) 0.8 0.6 0.4 0.2 0.8 1.0 100 -40 -20 ILC6377SO33 Efficiency vs. Ambient Temperature EFFICIENCY: EFFI(%) AMBIENT TEMP.: TA (˚C) ILC6376/77 ©2001 Fairchild Semiconductor Corporation

11/21/01 0.0m 001 Stock#DSxxxxxxxx 2001 Fairchild Semiconductor Corporation LIFE SUPPORT POLICY FAIRCHILD’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD SEMICONDUCTOR CORPORATION. As used herein: 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and (c) 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 of the user. 2. A critical component in any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. www.fairchildsemi.com DISCLAIMER FAIRCHILD SEMICONDUCTOR RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY PRODUCTS HEREIN TO IMPROVE RELIABILITY, FUNCTION OR DESIGN. FAIRCHILD DOES NOT ASSUME ANY LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCT OR CIRCUIT DESCRIBED HEREIN; NEITHER DOES IT CONVEY ANY LICENSE UNDER ITS PATENT RIGHTS, NOR THE RIGHTS OF OTHERS.

Ordering Information

3.3V, 300kHz step-down PWM converter ILC6376SO50 5V, 300kHz step-down PWM converter ILC6376ADJ Adjustable, 300kHz step-down PWM converter ILC6377SO33 3.3V, 300kHz step-down PWM/PFM converter ILC6377SO50 5V, 300kHz step-down PWM/PFM converter ILC6377SOADJ Adjustable, 300kHz step-down PWM/PFM converter ILC6376/77