EP3001-TW12B

EP3001 EOREX | Alldatasheet

Document overview

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• PDF pages: 10

Technical content

Features

• High Efficiency: Up to 96%
• 1.5MHz Constant Switching Frequency
• 600mA Output Current at V IN = 3V
• Integrated Main Switch and Synchronous Rectifier
• No Schottky Diode Required
• 2.5V to 5.5V Input Voltage Range
• Output Voltage as Low as 0.6V
• 100% Duty Cycle in Low Dropout Operation
• Low Quiescent Current: 300µA
• Slope Compensated Current Mode Control for Excellent Line and Load Transient Response
• Short Circuit Protection
• Thermal Fault Protection, <1uA Shutdown Current
• Space Saving 5-Pin Thin SOT23 package

Applications

• Cellular and Smart Phones
• Microprocessors and DSP Core Supplies
• Wireless and DSL Modems
• PDAs
• MP3 Players
• Digital Still and Video Cameras
• Portable Instruments

Description

The EP3001 is a 1.5MHz, constant frequency, slope compensated current mode PWM step-down converter. The device integrates a main switch and a synchronous rectifier for high efficiency without an external Schottky diode. It is ideal for powering portable equipment that runs from a single cell lithium-Ion (Li+) battery. The EP3001 can supply 600mA of load current from a 2.5V to 5.5V input voltage. The output voltage can be regulated as low as 0.6V. The EP3001 can also run at 100% duty cycle for low dropout operation, extending battery life in portable system. Idle mode operation at light loads provides very low output ripple voltage for noise sensitive applications. The EP3001is offered in a low profile (1mm) 5-pin, thin SOT package, and is available in an adjustable version and fixed output voltage of 1.2V, 1.5V and 1.8V. Typical Application VIN 10μF VOUT SW GND VIN VOUT 1.2V EN 4.7μF EP3001 2.2μH 100.00% 90.00% 80.00% 70.00% 60.00% 50.00% 40.00% 30.00% 20.00% 10.00% 0.00% 0.1 1 10 100 1000 Efficiency vs Output Current Figure 1-Basic application circuit with EP3001 fixed output version

Jul. 2006 www.eorex.com Pin Assignment Adjustable Output Version EN GND SW V IN FB TSOT23-5 EN GND SW V IN VOUT TSOT23-5 Top ViewTop View Fixed Output Version * Fixed 1.5V Marking A2YW * Fixed 1.8V Marking A3YW * Fixed 1.2V Marking A4YW

Ordering Information

1 EN Regulator Enable control input. Drive EN above 1.5V to turn on the part. Drive EN below 0.3V to turn it off. In shutdown, all functions are disabled drawing <1µA supply current. Do not leave EN floating.

2 GND Ground

3 SW Power Switch Output. It is the Switch note connection to Inductor. This pin connects to the drains of the internal P-Ch and N-Ch MOSFET switches. 4 V IN Supply Input Pin. Must be closely decou pled to GND, Pin 2, with a 2.2µF or greater ceramic capacitor.

5 FB/V OUT FB(EP3001-Adj):

Feedback Input Pin. Connect FB to the center point of the external resistor divider. The feedback threshold voltage is 0.6V. VOUT(EP3001-1.2/EP3001-1.5/EP3001-1.8): Output Voltage Feedback Pin. An internal resistive divider divides the output voltage down for comparison to the internal reference voltage.

Jul. 2006 www.eorex.com Thermal Resistance (Note 1) Package θJA θJC TSOT23-5 220°C/W 110°C/W Absolute Maximum Rating (Note 2) Symbol Item Rating Units VIN Input Supply Voltage -0.3 ~ +6 V VEN,FB EN, FB Voltages -0.3 ~ V IN V VSW SW Voltages -0.3 ~ V IN+0.3 V P-Channel Switch Source Current(DC) 800 mA N-Channel Switch Sink Current(DC) 800 mA Peak SW Sink and Source Current 1.3 A TOP Operating Temperature Range -40 ~+85 °C TJ Junction Temperature (Note 3) +125 °C TSTG Storage Temperature Range -65 ~ +150 °C TL Lead Temperature (Soldering, 10s) +300 °C Note 1:Thermal Resistance is specified with approximately 1 square of 1 oz copper. Note 2:Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 3:TJ is calculated from the ambient temperature TA and power dissipation PD according to the following formula: TJ = TA + (PD) × (220°C/W)

Jul. 2006 www.eorex.com Electrical Characteristics (Note 4) (VIN=VEN=3.6V, TA=25, unless otherwise noted.) Symbol Parameter Conditions Min. Typ. Max. Units VIN Input Voltage Range 2.5 5.5 V IS Input DC Supply Current Active Mode Shutdown Mode VFB=0.5V or VOUT=90% VFB=0V, VIN=4.2V 300 0.1 400 1.0 µA µA TA=+25°C 0.5880 0.6000 0.6120 V TA=0°C≤TA≤85°C 0.5865 0.6000 0.6135 V VFB Regulated Feedback Voltage TA=-40°C≤TA≤85°C 0.5820 0.6000 0.6180 V ∆VFB Reference Voltage Line Regulation V IN=2.5V to 5.5V 0.04 0.4 %/V IFB Feedback Input Bias Current V FB=0.65V ±30 nA EP3001-1.2, -40°C≤TA≤ 85°C 1.164 1.200 1.236 V EP3001-1.5, -40°C≤TA≤ 85°C 1.455 1.500 1.546 V VOUT Regulated Output Voltage EP3001-1.8, -40°C≤TA≤ 85°C 1.746 1.800 1.854 V ∆ VOUT Output Voltage Line Regulation V IN=2.5V to 5.5V 0.04 0.40 % VLOADREG Output Voltage Load Regulation 0.5 % IPK Peak Inductor Current VIN=3V, VFB=0.5V or VOUT=90% Duty Cycle < 35% 0.75 1.00 1.25 A fOSC Oscillator Frequency VFB=0.6V or VOUT=100% 1.2 1.5 1.8 MHz RPFET R DS(ON) of P-CH MOSFET I SW=300mA 0.40 0.50 Ω RNFET R DS(ON) of N-CH MOSFET I SW=-300mA 0.35 0.45 Ω ILSW SW Leakage VEN=0V, VSW=0V or 5V, VIN=5V ±0.01 ±1 µA VEN EN Threshold -40°C≤TA ≤ 85°C 0.3 1.0 1.30 V IEN EN Leakage Current ±0.01 ±1 µA Note 4:100% production test at +25°C. Specifications over the temperature range are guaranteed by design and characterization.

Jul. 2006 www.eorex.com Typical Performance Characteristics (Test circuitry is as Figure 2, unless otherwise specified.) Dynamic Supply Current vs Supply Voltage 400 380 360 340 320 300 280 260 240 220 200 32 645 Output Voltage vs Supply Voltage 1.210 1.208 1.206 1.204 1.202 1.198 1.196 1.194 1.192 1.190 32 645 1.200 100.00% 90.00% 80.00% 70.00% 60.00% 50.00% 40.00% 30.00% 20.00% 10.00% 0.00% 0.1 1 10 100 1000 Efficiency vs Output Current 100.00% 90.00% 80.00% 70.00% 60.00% 50.00% 40.00% 30.00% 20.00% 10.00% 0.00% 0.1 1 10 100 1000 Efficiency vs Output Current 100.00% 90.00% 80.00% 70.00% 60.00% 50.00% 40.00% 30.00% 20.00% 10.00% 0.00% 0.1 1 10 100 1000 Efficiency vs Output Current 100.00% 90.00% 80.00% 70.00% 60.00% 50.00% 40.00% 30.00% 20.00% 10.00% 0.00% 1 10 100 1000 Efficiency vs Output Current

Jul. 2006 www.eorex.com Functional Block Diagram *For Adjustable Output, R1+R2 Is External. Operation The EP3001 is a monolithic switching mode Step-Down DC-DC converter. It utilizes internal MOSFETs to achieve high efficiency and can generate very low output voltage by using internal reference at 0.6V. It operates at a fixed switching frequency, and uses the slope compensated current mode architecture. Current Mode PWM Control Slope compensated current mode PWM control provi des stable switching and cycle-by-cycle current limit for excellent load and line responses and protection of the internal main switch (P-Ch MOSFET) and synchronous rectifier (N-Ch MOSFET). During nor mal operation, the internal P-Ch MOSFET is turned on for a certain time to ramp the inductor current at each rising edge of the internal oscillator, and switched off when the peak inductor current is above the error voltage. The current comparator, I COMP, limits the peak inductor current. When the main switch is off, the synchronous rectifier will be turned on immediately and stay on until either the inductor current starts to reverse, as indicated by the current reversal comparator, I ZERO, or the beginning of the next clock cy cle. The OVDET comparator controls output transient overshoots by turning the main switch off and keeping it off until the fault is no longer present.

Jul. 2006 www.eorex.com Idle Mode Operation At very light loads, the EP3001 autom atically enters Idle Mode. In t he Idle Mode, the inductor current may reach zero or reverse on each pulse. The PWM control loop will automatically skip pulses to maintain output regulation. The bottom MOSFET is turned off by the current reversal comparator, I ZERO, and the switch voltage will ring. This is discontin uous mode operation, and is normal behavior for the switching regulator. Dropout Operation When the input voltage decreases toward the value of the output voltage, the EP3001 allows the main switch to remain on for more than one switching cycle and increases the duty cycle (Note 5) until it reaches 100%. The output voltage then is the input voltage minus the voltage drop across the main switch and the inductor. At low input supply voltage, the RDS(ON) of the P-Ch MOSFET increases, and the efficiency of the converter decre ases. Caution must be exercised to ensure the heat dissipated not to exceed the maximum junction temperature of the IC. Note 5: The duty cycle D of a step-down converter is defined as: D = TON × fOSC × 100%≈ IN OUT V V × 100% where TON is the main switch on time, and fOSC is the oscillator frequency (1.5MHz). Maximum Load Current The EP3001 will operate with input supply voltage as low as 2.5V, however, the maximum load current decreases at lower input due to large IR drop on the main switch and synchronous rectifier. The slope compensation signal reduces the peak inductor curr ent as a function of t he duty cycle to prevent sub-harmonic oscillations at duty cycles greater than 50%. Conversely the current limit increases as the duty cycle decreases. Short-Circuit Protection A current limit (1A) circuit is equipped in the EP300 1, to protect the EP3001 when the output pin is shorted to GND pin. This current limit will suppress the output current so that the inductor current has enough time to decay.

Jul. 2006 www.eorex.com Output Capacitor Selection The output capacitor is required to keep the output voltage ripple small and to ensure regulation loop stability. The output capacitor must have low impedance at the switching frequency. Ceramic capacitors with X5R or X7R dielectrics are recommended due to their low ESR and high ripple current. The output ripple V OUT is determined by: ∆VOUT ≤ ( ) C3f8 1ESR LfV VVV OSCOSCIN OUTINOUT Inductor Selection For most designs, the EP3001 operates with inductor s of 1µH to 4.7µH. Low inductance values are physically smaller but require faster switching, which results in some efficiency loss. The inductor value can be derived from the following equation: L = ( ) OSCLIN OUTINOUT V VVV fI ×Δ× Where ∆IL inductor Ripple Current. Large value inductors lower ripple current and small value inductors result in high ripple currents. Choose inductor ripple current approximately 35% of the maximum load current 600mA or 210mA. For output voltages above 2.0V, when light-load efficiency is important, the minimum recommended inductor is 2.2µH. For optimum voltage-positioning load transients, choose an inductor with DC series resistance in the 50mΩ to 150mΩ range. For higher efficiency at heavy loads (above 200mA), or minimal load regulation (but some transient overshoot ), the resistance should be kept below 100m Ω. The DC current rating of the inductor should be at least equal to the maximum load current plus half the ripple current to prevent core saturation (600mA+105mA). Table 1 lists some typical surface mount inductors that meet target applications for the EP3001. Part # L (µH) Max DCR (mΩ) Rated D.C. Current (A) Size W×L×H (mm) Sumida CR43 1.4 2.2 3.3 4.7 56.2 71.2 86.2 108.7 2.52 1.75 1.44 1.15 4.5×4.0×3.5 Sumida CDRH4D18 1.5 2.2 3.3 4.7 110 162 1.32 1.04 0.84 4.7×4.7×2.0 Toko D312C 1.5 2.2 3.3 4.7 120 140 180 240 1.29 1.14 0.98 0.79 3.6×3.6×1.2

Jul. 2006 www.eorex.com Package Description 5pin TSOT-23 Package Outline Dimensions MILLIMETERS INCHES DIM A 0.90 − 1.10 0.035 − 0.043 A1 0.01 − 0.13 0.0004 − 0.005 B 0.30 − 0.50 0.012 − 0.020 C 0.09 − 0.20 0.004 − 0.008 D 2.80 − 3.00 0.110 − 0.118 H 2.50 − 3.10 0.098 − 0.122 E 1.50 − 1.70 0.059 − 0.067 e 0.95 REF. 0.037 REF. e1 1.90 REF. 0.075 REF. L1 0.20 − 0.55 0.008 − 0.022 L 0.35 − 0.80 0.014 − 0.031 * Package outline exclusive of mold flash and metal burr.