View EP3001-TW12B_4257037.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

eorex
Features
* High Efficiency: Up to 96% * 1.5MHz Constant Switching Frequency * 600mA Output Current at VIN = 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: 300A * 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
EP3001
1.5MHz, 600mA Synchronous Step-down Converter
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.
Applications
* Cellular and Smart Phones * Microprocessors and DSP Core Supplies * Wireless and DSL Modems * PDAs * MP3 Players * Digital Still and Video Cameras * Portable Instruments
Typical Application
Efficiency vs Output Current
100.00%
L1 2.2H 3
90.00%
VOUT 1.2V C1 10F
VIN C1 4.7F
4
80.00% 70.00% 60.00% 50.00% 40.00% 30.00% 20.00% 10.00% 0.00% 0.1 1 10 100 1000
VIN
SW
EP3001
1 EN GND 2 VOUT 5
Figure 1-Basic application circuit with EP3001 fixed output version
Jul. 2006 1/10
www.eorex.com
eorex
Pin Assignment
Adjustable Output Version
Top View EN GND SW 1 2 3 4 VIN 5 FB EN GND SW 1 2 3 Top View
EP3001
Fixed Output Version
5
VOUT
4
VIN
TSOT23-5
TSOT23-5
* Fixed 1.5V Marking A2YW * Fixed 1.8V Marking A3YW * Fixed 1.2V Marking A4YW
Ordering Information
Pin Description
Pin 1 Name EN Function 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 <1A supply current. Do not leave EN floating. Ground 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. Supply Input Pin. Must be closely decoupled to GND, Pin 2, with a 2.2F or greater ceramic capacitor. 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.
2 3 4 5
GND SW VIN FB/VOUT
Jul. 2006 2/10
www.eorex.com
eorex
Thermal Resistance (Note 1)
Package TSOT23-5 JA 220C/W JC
EP3001
110C/W
Absolute Maximum Rating (Note 2)
Symbol VIN VEN,FB VSW EN, FB Voltages SW Voltages P-Channel Switch Source Current(DC) N-Channel Switch Sink Current(DC) Peak SW Sink and Source Current TOP TJ TSTG TL Operating Temperature Range Junction Temperature
(Note 3)
Item Input Supply Voltage
Rating -0.3 ~ +6 -0.3 ~ VIN -0.3 ~ VIN+0.3 800 800 1.3 -40 ~+85 +125 -65 ~ +150 +300
Units V V V mA mA A C C C C
Storage Temperature Range Lead Temperature (Soldering, 10s)
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) x (220C/W)
Jul. 2006 3/10
www.eorex.com
eorex
Electrical Characteristics (Note 4)
(VIN=VEN=3.6V, TA=25, unless otherwise noted.)
Symbol VIN IS VFB VFB IFB Parameter Input Voltage Range Input DC Supply Current Active Mode Shutdown Mode Regulated Feedback Voltage Reference Voltage Line Regulation Feedback Input Bias Current Conditions VFB=0.5V or VOUT=90% VFB=0V, VIN=4.2V TA=+25C TA=0CTA85C TA=-40CTA85C VIN=2.5V to 5.5V VFB=0.65V EP3001-1.2, -40CTA 85C EP3001-1.5, -40CTA 85C EP3001-1.8, -40CTA 85C VIN=2.5V to 5.5V VIN=3V, VFB=0.5V or VOUT=90% Duty Cycle < 35% VFB=0.6V or VOUT=100% ISW=300mA ISW=-300mA VEN=0V, VSW=0V or 5V, VIN=5V -40CTA 85C Min. 2.5 Typ.
EP3001
Max. 5.5 400 1.0 0.6120 0.6135 0.6180 0.4 30
Units V A A V V V %/V nA V V V % %
0.5880 0.5865 0.5820
300 0.1 0.6000 0.6000 0.6000 0.04
1.164 1.455 1.746
1.200 1.500 1.800 0.04 0.5
1.236 1.546 1.854 0.40
VOUT
Regulated Output Voltage
VOUT VLOADREG IPK fOSC RPFET RNFET ILSW VEN IEN
Output Voltage Line Regulation Output Voltage Load Regulation Peak Inductor Current Oscillator Frequency RDS(ON) of P-CH MOSFET RDS(ON) of N-CH MOSFET SW Leakage EN Threshold EN Leakage Current
0.75 1.2
1.00 1.5 0.40 0.35 0.01
1.25 1.8 0.50 0.45 1 1.30 1
A MHz A V A
0.3
1.0 0.01
Note 4:100% production test at +25C. Specifications over the temperature range are guaranteed by design and characterization.
Jul. 2006 4/10
www.eorex.com
eorex
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 2 3 4 5 6 1.210 1.208 1.206 1.204 1.202 1.200 1.198 1.196 1.194 1.192 1.190 2 3 4
EP3001
Output Voltage vs Supply Voltage
5
6
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% 0.1 100.00% 90.00% 80.00% 70.00% 60.00% 50.00% 40.00% 30.00% 20.00% 10.00% 0.00% 0.1
Efficiency vs Output Current
1
10
100
1000
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% 0.1 100.00% 90.00% 80.00% 70.00% 60.00% 50.00% 40.00% 30.00% 20.00% 10.00% 0.00%
Efficiency vs Output Current
1
10
100
1000
1
10
100
1000
Jul. 2006 5/10
www.eorex.com
eorex
Functional Block Diagram
EP3001
*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 provides 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 normal 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, ICOMP, 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, IZERO, or the beginning of the next clock cycle. 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 6/10
www.eorex.com
eorex
Idle Mode Operation Dropout Operation
EP3001
At very light loads, the EP3001 automatically enters Idle Mode. In the 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, IZERO, and the switch voltage will ring. This is discontinuous mode operation, and is normal behavior for the switching regulator.
When the input voltage decreases toward the value of the output voltage, the EP3001 allows the main (Note 5) switch to remain on for more than one switching cycle and increases the duty cycle 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 decreases. 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: V D = TON x fOSC x 100% OUT x 100% VIN 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 current as a function of the 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 EP3001, 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 7/10
www.eorex.com
eorex
Applications Information
EP3001
Figure 2-below shows the Basic Application Circuit with EP3001 adjustable versions.
Setting the Output Voltage
Figure 2 above shows the basic application circuit with EP3001 adjustable output version. The external resistor sets the output voltage according to the following equation: VOUT=0.6V 1 +
R1 R2 = 300K for all outputs; R1 = 300K for VOUT = 1.2V; R1 = 200K for VOUT = 1.5V; R1 = 150K for VOUT = 1.8V; R1 = 95.3K for VOUT = 2.5V; R1 = 67K for VOUT = 3.3V

R2
Input Capacitor Selection
The input capacitor reduces the surge current drawn from the input and switching noise from the device. The input capacitor impedance at the switching frequency shall be less than input source impedance to prevent high frequency switching current passing to the input. A low ESR input capacitor sized for maximum RMS current must be used. Ceramic capacitors with X5R or X7R dielectrics are highly recommended because of their low ESR and small temperature coefficients. A 4.7F ceramic capacitor for most applications is sufficient.
Jul. 2006 8/10
www.eorex.com
eorex
Output Capacitor Selection
VOUT
VOUT x (VIN - VOUT VIN x fOSC x L
EP3001
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 VOUT is determined by:
)
x ESR +

1 8 x fOSC
x C3
Inductor Selection
For most designs, the EP3001 operates with inductors of 1H to 4.7H. 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=
VOUT x (VIN - VOUT ) VIN x IL x fOSC
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 2.2H. For optimum voltage-positioning load transients, choose an inductor with DC series resistance in the 50m to 150m range. For higher efficiency at heavy loads (above 200mA), or minimal load regulation (but some transient overshoot), the resistance should be kept below 100m. 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 # Sumida CR43 L (H) 1.4 2.2 3.3 4.7 1.5 2.2 3.3 4.7 1.5 2.2 3.3 4.7 Max DCR (m) 56.2 71.2 86.2 108.7 75 110 162 120 140 180 240 Rated D.C. Current (A) 2.52 1.75 1.44 1.15 1.32 1.04 0.84 1.29 1.14 0.98 0.79 Size WxLxH (mm)
4.5x4.0x3.5
Sumida CDRH4D18
4.7x4.7x2.0
Toko D312C
3.6x3.6x1.2
Jul. 2006 9/10
www.eorex.com
eorex
Package Description
5pin TSOT-23 Package Outline Dimensions
EP3001
DIM A A1 B C D H E e e1 L1 L
MILLIMETERS MIN. 0.90 0.01 0.30 0.09 2.80 2.50 1.50 NOM. - - - - - - - 0.95 REF. 1.90 REF. 0.20 0.35 - - 0.55 0.80 0.008 0.014 0 MAX. 1.10 0.13 0.50 0.20 3.00 3.10 1.70 MIN. 0.035 0.0004 0.012 0.004 0.110 0.098 0.059
INCHES NOM. - - - - - - - 0.037 REF. 0.075 REF. - - - 0.022 0.031 10 MAX. 0.043 0.005 0.020 0.008 0.118 0.122 0.067
Q 0 10 - * Package outline exclusive of mold flash and metal burr.
Jul. 2006 10/10
www.eorex.com

▲Up To Search▲

Price & Availability of EP3001-TW12B

	To Download EP3001-TW12B Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .