UNISONIC TECHNOLOGIES CO., LTD P1886
PWM CONTROL 3A STEP-DOWN CONVERTER
DESCRIPTION
UTC P1886 consists of 3A step-down switching regulator control which includes a reference voltage source, oscillation circuit, error amplifier, internal PMOS and etc with PWM. UTC P1886 can provide low-ripple power, high efficiency, and excellent transient characteristics and an enable function, an over current protect function and a short circuit protect function are built inside, so the operation frequency will be reduced from 300KHz to 30KHz when OCP or SCP happens. And the PWM control circuit can vary the duty ratio linearly from 100 down to 0%. This converter also includes an error amplifier circuit as well as a soft-start circuit that prevents overshoot at startup. Also, to minimum external component count an internal compensation block is built in. UTC P1886 can work as step-down switching regulators with the addition of an internal P-channel Power MOS, a coil, capacitors, and a diode connected externally. It provides such outstanding features: low current consumption. It is also suitable for the operation via an AC adapter because this converter can accommodate an input voltage up to 23V.
LINEAR INTEGRATED CIRCUIT
SOP-8
FEATURES
* Soft-start, Current Limit, Enable function * Thermal Shutdown function * Built-in internal SW P-channel MOS * Input voltage: 4V to 23V. * Output voltage: 0.8V to VCC. * Duty ratio: 0% to 100% PWM control * Oscillation frequency: 300KHz typ.
ORDERING INFORMATION
Ordering Number Lead Free Halogen Free P1886L-S08-R P1886G-S08-R Package SOP-8 Packing Tape Reel
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PIN CONNECTIONS
LINEAR INTEGRATED CIRCUIT
NC VCC Output VSS
1 2 3 4
8 7 6 5
NC EN NC FB
PIN DESCRIPTIONS
PIN NO 2 3 4 5 7 NAME VCC Output VSS FB EN DESCRIPTION IC power supply pin Switch Pin. Connect external inductor/diode here. Minimize trace area at this pin to reduce EMI. GND Feedback pin. Power-off pin H: Normal operation (Step-down operation) L: Step-down operation stopped (All circuits deactivated)
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P1886
BLOCK DIAGRAM
Output
LINEAR INTEGRATED CIRCUIT
Oscillation Circuit
Reference Voltage Source with Soft Start
+ PWM-Switched Control Circuit FB
Thermal Shutdown
VEN Vss
VCC
EN
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ABSOLUTE MAXIMUM RATINGS
LINEAR INTEGRATED CIRCUIT
PARAMETER SYMBOL RATING UNIT VCC Pin Voltage VCC VSS-0.3 ~ VSS+25 V Feedback Pin Voltage VFB VSS-0.3 ~ VCC V EN Pin Voltage VEN VSS-0.3 ~ VIN+0.3 V Switch Pin Voltage VOUTPUT VSS-0.3 ~ VIN+0.3 V Power Dissipation PD Internally limited mW Operating Ambient Temperature Ta -20 ~ +85 °C Operating Temperature TOPR -20 ~ +125 °C Storage Temperature TSTG -40 ~ +150 °C Note: Absolute maximum ratings are those values beyond which the device could be permanently damaged. Absolute maximum ratings are stress ratings only and functional device operation is not implied.
THERMAL DATA
PARAMETER Junction to Ambient Junction to Case SYMBOL θJA θJC MIN TYP MAX 134 22 UNIT °C/W °C/W
ELECTRICAL CHARACTERISTICS (Ta=25°C, VIN=12V, unless otherwise specified)
PARAMETER Input Voltage Feedback Voltage Feedback Bias Current Switch Current Standby Current Line Regulation Load Regulation Oscillation Frequency Frequency of Current Limit or Short Circuit Protect EN Pin Input Voltage EN Pin Input Leakage Current Soft-Start Time Internal MOSFET RDS(ON) Efficiency SYMBOL VIN VFB IFB(BIAS) ISW ISTN-BY ΔVOUT VOUT ΔVOUT VOUT fOSC fOSC1 VSH VSL ISH ISL TSS RDS(ON) η CONDITIONS IOUT=0.1A IOUT=0.1A VEN=0V VIN=5V~23V, IOUT=0.2A IOUT=0.1~3A Measure waveform at SW pin Measure waveform at SW pin Evaluate oscillation at SW pin Evaluate oscillation stop at SW pin 240 10 0.79 0.72 20 -10 2 110 70 88 MIN. TYP. MAX. UNIT 4 23 V 0.784 0.8 0.816 V 0.1 0.5 µA 3.5 A 10 µA 1 0.2 300 2 0.5 360 % % KHz KHz V V µA µA ms mΩ mΩ %
0.3 VIN=5V, VFB=0V VIN=12V, VFB=0V VIN=12V, VOUT=5V, IOUT=3A
5 150 100
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FUNCTION DESCRIPTION
PWM Control
LINEAR INTEGRATED CIRCUIT
The UTC P1886 consists of DC/DC converters which employ a PWM system. In this DC/DC converter, the pulse width varies in a range from 0 to 100% which is according to the load current. Cause the switching frequency remains constant the ripple voltage which produced by the switching can be removed easily through a filter. Therefore, these converters provide a low-ripple power over broad ranges of input voltage and load current.
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TEST CIRCUITS
LINEAR INTEGRATED CIRCUIT
+
-
TYPICAL APPLICATION CIRCUIT
VIN=12V, IMAX=3A VOUT L1 Value 2.5V 15µH 3.3V 18µH 5V 22µH
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TYPICAL CHARACTERISTICS
320 Oscillation frequency,Fosc (KHz) 315 310 305 300 295 290 285 280 275 270 0 5 20 15 Input Voltage,VIN (V) 10 Line Regulation 5.00 4.95 Output Voltage,VOUT (V) 4.90 4.85 4.80 4.75 4.70 0 VOUT=5V IOUT=0.2A Output Voltage,VOUT (V) 4.99 4.98 4.97 4.96 4.95 4.94 4.93 4.92 4.91 4.90 5 10 15 20 25 25 Input Voltage vs. Frequency VOUT=5V IOUT=0.2A Feedback Voltage, FB (V) 0.84 0.83 0.82 0.81 0.80 0.79 0.78 0.77 0.76 0.75 0.74
LINEAR INTEGRATED CIRCUIT
Input Voltage vs. Feedback Voltage VOUT=5V IOUT=0.2A
0
5
10 15 20 Input Voltage,VIN (V) Load Regulation
25
VIN=12V
4.89 0.0
0.5
Input Voltage,VIN (V) Output Current vs. Efficiency 100 90 80 Efficiency (%) 70 60 50 40 30 20 10 0 0.0 0.5 2.0 2.5 1.5 1.0 Output Current,IOUT(A) 3.0 VOUT=5.0V VOUT=3.3V
1.0 2.0 1.5 2.5 Ouput Current,IOUT (A)
3.0
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LINEAR INTEGRATED CIRCUIT
U TC assumes no responsibility for equipment failures that result from using products at values that exceed, even momentarily, rated values (such as maximum ratings, operating condition ranges, or other parameters) listed in products specifications of any and all UTC products described or contained herein. UTC products are not designed for use in life support appliances, devices or systems where malfunction of these products can be reasonably expected to result in personal injury. Reproduction in whole or in part is prohibited without the prior written consent of the copyright owner. The information presented in this document does not form part of any quotation or contract, is believed to be accurate and reliable and may be changed without notice.
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