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EUP7903
300mA High PSRR LDO Regulators
DESCRIPTION
The EUP7903 is a high current, low-dropout (LDO) linear regulator with fast transient response and high PSRR. It offers high output accuracy, extremely low dropout voltage, low quiescent current and fast start-up time. The EUP7903 is designed to work with low-ESR ceramic capacitors, reducing the amount of the PCB area necessary for power applications. Only a 1uF ceramic output capacitor can make the device stable over the whole load range. EUP7903 can be externally set either fixed output mode or adjustable output mode. Connect FB pin to GND to select the fixed output mode. Its output is one of pre-set values: 1.25V~5V (50mV per step). Operated in the adjustable mode when the FB pin is connected to an external resistors divider, its output can be adjusted from 1.25V to 5V. Other key features include over-current protection, thermal shutdown. The device is available in the small SOT23-5 package.
FEATURES
2.5V to 5.5V Input Voltage Range 180mV@300mA Dropout Voltage Excellent Transient Response Stable with 1uF Ceramic Output Capacitor 70dB PSRR at 1kHz Low 90A Quiescent Current Low Shutdown CurrentG <1A Output Current Limit Short Circuit Protection Output Voltage With High Accuracy: 2% Initial Accuracy Fixed Output VoltageG 1.25V~5V (0.05V step) Adjustable Output Voltage: 1.25V~5V Thermal Shutdown Output Auto-Discharge in Shutdown RoHS Compliant and 100% Lead (Fb)-Free
APPLICATIONS
Cellular Phones Bluetooth portable radios and Accessories Battery-Powered Equipment Laptop, Palmtops, Notebook Computer PDAs Digital still Camera and Video Recorders
Typical Application Circuit
Figure. 1 Adjustable Output
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Typical Application Circuit (continued)
Figure. 2 Fixed Output
Block Diagram
Figure. 3
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Pin Configurations
Package Type Pin Configurations
SOT23-5
Pin Description
PIN EN GND IN OUT FB SOT23-5 1 2 3 4 5 DESCRIPTION Enable Pin. Connect this pin to ground or less than 0.4V to disable the device, connect EN to 1.5V or above to enable the device. Signal Ground. Input Supply of the LDO. Output of the LDO. Feedback pin. This pin is the anode terminal of the error amplifier. The FB pin compares with internal reference voltage to regulate the output voltage. Connect to GND for fixed output voltage version.
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Ordering Information
Order Number EUP7903-15VIR1 EUP7903-18VIR1 EUP7903-25VIR1 EUP7903-28VIR1 EUP7903-33VIR1 EUP7903VIR1 EUP7903-XXVIR1 EUP7903 - 1/4
1/4 1/4 1/4 1/4
Package Type SOT23-5 SOT23-5 SOT23-5 SOT23-5 SOT23-5 SOT23-5 SOT23-5
1/4
Marking xxxxx AD1C xxxxx AD1D xxxxx AD1B xxxxx AD1E xxxxx AD1H xxxxx AD1A xxxxx xxxx
Operating Temperature Range -40 C to +85C -40 C to +85C -40 C to +85C -40 C to +85C -40 C to +85C -40 C to +85C -40 C to +85C
Lead Free Code 1: Lead Free 0: Lead Packing R: Tape & Reel Operating temperature range I: Industry Standard Package Type V: SOT-23 Output Voltage 15:1.5V 18:1.8V 25:2.5V 28:2.8V 33:3.3V XX: Voltage Options (1.25V to 5V, 0.05V per step) NoteG Every EUP7903 version can operate at adjustable mode by connecting FB pin to an external resistor divider.
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Absolute Maximum Ratings (1)
VIN,VEN --------------------------------------------------------------------------------------------0.3V to 6V VOUT -------------------------------------------------------------------------------------- -0.3V to (VIN+0.3V) Junction Temperature -------------------------------------------------------------------------------+150ae Storage Temperature Range ----------------------------------------------------------------- -65ae to +150ae Lead Temperature ----------------------------------------------------------------------------------+260ae Thermal Resistance JA (SOT23-5) --------------------------------------------------------------220ae /W ESD Rating Human Body Model ------------------------------------------------------------------------2kV
Recommend Operating Conditions (2)
VIN ------------------------------------------------------------------------------------------------ 2.5V to 5.5V VEN -----------------------------------------------------------------------------------------------0V to 5.5V Operating Temperature Range --------------------------------------------------------------- -40ae to +85ae Note (1): Stress beyond those listed under "Absolute Maximum Ratings" may damage the device. Note (2): The device is not guaranteed to function outside the recommended operating conditions.
Electrical Characteristics
TA=25ae , VIN=VOUT+1V, or VIN=2.5V for VOUT<1.5V unless otherwise specified.
Symbol
Parameter
Conditions
EUP7903 Min. Typ. Max.
2.5 5.5 130 1
Unit
V A A dB
Input Voltage VIN Input Voltage IQ Quiescent Current ISHDN Shutdown Current Power Supply Ripple PSRR Rejection VFB FB Pin Voltage Enable VENH Enable High Voltage VENL Disable Low Voltage IEN EN Input Current TST Start-up Time Output voltage VOUT VLNR VLDR VDROP Output Voltage Accuracy Output Line Regulation Output Load Regulation
VEN=3.5V, IOUT=0mA VEN=0V VIN=VNOM+1VP-P,f=100Hz, ILOAD=10mA 1.225 Over temperature range Over temperature range VIN=3.5V, VEN=3.5V or 0V VIN=3.5V, VOUT=2.5V VIN=VOUT+1V, IOUT=10mA VIN=VOUT+1V, IOUT=10mA, TA =-40ae to +85ae VOUT+0.5V90 0.1 75 1.25
1.275
V V V A s % % %/V mV mV mA mA ae ae
0.2 40
0.4 1
-2 -3 0.01 10
+2 +3 0.1 16 240
Dropout Voltage (3) 180 IOUT=300mA (Applied for VOUT2.3V) IOUTMAX Maximum Output Current 300 Protection ILIMIT Current Limit 330 500 TSD Thermal Shutdown Temperature No Load, VIN=VEN=5V 155 TSDHYS Thermal Shutdown Hysteresis No Load, VIN=VEN=5V 30 Note (3): Dropout is defined as VIN-VOUT when VOUT is 2% below the value of VOUT for VIN=VOUT+0.5V.
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Typical Characteristics
Time (40s/div)
Time (4ms/div)
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Typical Characteristics (continued)
Thermal Shutdown Cycle
Time (40ms/div)
Time (400s/div)
Time (100s/div)
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Detailed Function Description
The EUP7903 is a high output current, low dropout linear regulator with fast transient response and high PSRR. It offers high output accuracy, extremely low dropout voltage, low quiescent current and fast start-up time. It is designed to work with low-ESR ceramic capacitor, reducing the amount of the PCB area. Only a 1uF ceramic capacitor can make the device stable over the whole load range. As shown in the function block diagram, the EUP7903 is composed of the bandgap reference voltage, the error amplifier, P-channel MOSFET pass transistor, internal resistor divider and some additional protection circuits. The reference voltage, connected to the cathode terminal of the error amplifier, compares with the feedback voltage to regulate the output voltage to make it constant over the whole load range. If the feedback voltage is lower than the reference voltage, the pass transistor gate is pulled low to increase its conductivity. This allows more current to flow to the output and increases the output voltage. If the feedback voltage is higher than the reference voltage, the pass transistor allows less current to flow to the output. The feedback point is the output of the internal or external resistor divider connected to the VOUT pin. Enable/Shutdown The EUP7903 is disabled when the EN pin is connected to ground or the voltage less than 0.4V, and the quiescent current is less than 1uA. Connect EN pin to 1.5V or higher to enable the device. Output Soft stop When the regulator is disabled, an internal 400 resistor is connected between VOUT and GND. To discharge output capacitor COUT. Adjustable Output Voltage EUP7903 has a wide output voltage range. The output voltage is programmed by an external resistor divider as shown in Figure 1. The output voltage can be calculated by the following equation:
Figure. 4 Output Voltage Select Circuit Fixed Output Voltage When the FB voltage is less than 220mV, EUP7903 will operate in the fixed output mode, its output is one of pre-set values: 1.25V~5V. There is no external component needed to set the output voltage. Current Limit The EUP7903 includes a current limit circuit to monitor the gate voltage of the pass transistor to limit the output current. When the output current is higher than the over-current limit, the circuit will clamp the gate voltage of the pass transistor to limit the output current. The typical output current limit is 500mA. Thermal Shutdown The EUP7903 monitors internal temperature. When the junction temperature exceeds 155ae , the over temperature protection (OTP) circuit turn off the pass transistor until the device is cooled down by 30ae . Then the pass transistor resumes. For continue operation, do not exceed absolute maximum junctiqwk iknf on temperature. Application Information Resistor Select Choose R2=100k to optimize accuracy, power supply rejection, noise and power consumption. And the R1 can be chosen by:
R1 = R 2 (
VOUT = (1 +
R1 ) x VREF R2
VOUT - 1) VREF
(EQ.2)
(EQ.1)
Where VREF is the internal reference voltage, which is 1.25V in EUP7903.
where VREF is the internal reference voltage, which is 1.25V in EUP7903. External Capacitor The EUP7903 requires external capacitors for stability. It is specifically designed to work with low-ESR capacitors requiring minimum PCB area. Input capacitor A 1uF ceramic capacitor or higher is required between the VIN pin and the GND pin. Place it as close as possible to the device. There are no requirements for the ESR on the input capacitor, but the tolerance and temperature coefficient must be considered when selecting the capacitor to ensure the capacitance is 1uF over the whole operating temperature range.
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Output capacitor The EUP7903 is designed specifically to work with very small ceramic output capacitors. A 1uF to 10uF capacitor with 5m[ to 500m[ ESR range is suitable for the most EUP7903 applications. The ESR of a typical 1uF ceramic capacitor is around 20m, which easily meets the ESR requirement for stability. Capacitor characteristics More consideration should be taken when selecting the capacitor because its capacitance can vary with temperature. The capacitor type X7R or X5R, which operates over a temperature range of -40J to +85J , will only vary within 15%. However Z5U or T5V temperature characteristics. Their capacitance can drop by more than 50% as the temperature goes from 25J to 85J . Therefore the capacitor type X7R or X5R is recommended in applications where the ambient temperature will change significantly above or below 25J . No load Stability The EUP7903 will remain stable and in regulation with no external load. This is special important in CMOS RAM keep-alive applications. Thermal Considerations Thermal protection limits power dissipation in EUP7903.When the device junction temperature exceeds 155C, the OTP circuit starts the thermal shutdown function and turns the pass transistor off. The pass transistor turns on again after the junction temperature cools down 30C. For continuous operation, do not exceed absolute maximum junction temperature 150C. The power dissipation definition in device is:
PD ( MAX ) = (125C - 25C) / 220 = 0.445W (EQ.5)
for SOT23-5 package The maximum power dissipation depends on operating ambient temperature for fixed TJ(MAX) and thermal resistance JA. For EUP7903 packages, the Figure 5 of derating curves allows the designer to see the effect of rising ambient temperature on the maximum power allowed.
0.6
Maximum Power Dissipation(W)
0.5 0.4 0.3 0.2 0.1 0.0
SOT23-5
0
25
50
75
100
Ambient Temperature( C)
o
125
150
Figure. 5. Power Dissipation for EUP7903 Package The EUP7903 is available in the SOT23-5 package.
PD = ( VIN - VOUT ) x I OUT + VIN x I Q
(EQ.3)
The maximum power dissipation depends on the thermal resistance of IC package, PCB layout, the rate of surroundings airflow and temperature difference between junction and ambient. The maximum power dissipation can be calculated by following formula :
(EQ.4) Where TJ(MAX) is the maximum operation junction temperature 125C, TA is the ambient temperature and the JA is the junction to ambient thermal resistance. For recommended operating conditions specification of EUP7903, where TJ(MAX) is the maximum junction temperature of the die (125C) and TA is the operated ambient temperature. The junction to ambient thermal resistance JA is layout dependent. For SOT-23-5 package, the thermal resistance JA is 220C/W on the standard thermal test board. The maximum power dissipation at TA = 25C can be calculated by following formula :
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PD ( MAX) = (TJ ( MAX) - TA ) JA
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Packaging Information
SOT23-5
SYMBOLS A A1 D E1 E L b e
MILLIMETERS MIN. MAX. 1.30 0.00 0.15 2.90 1.60 2.60 3.00 0.30 0.60 0.30 0.50 0.95
INCHES MIN. 0.000 0.114 0.063 0.102 0.012 0.012 0.037 0.118 0.024 0.020 MAX. 0.052 0.006
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