P1885 [UTC]
PWM CONTROL 2A STEP-DOWN CONVERTER; PWM控制2A降压转换器型号: | P1885 |
厂家: | Unisonic Technologies |
描述: | PWM CONTROL 2A STEP-DOWN CONVERTER |
文件: | 总9页 (文件大小:262K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
UNISONIC TECHNOLOGIES CO., LTD
P1885
LINEAR INTEGRATED CIRCUIT
PWM CONTROL 2A
STEP-DOWN CONVERTER
DESCRIPTION
UTC P1885 consists of 2A step-down switching regulator
control which includes a reference voltage source, oscillation
circuit, error amplifier, internal PMOS and etc with PWM.
UTC P1885 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.
SOP-8
Lead-free:
Halogen-free: P1885G
P1885L
These ICs 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. They provide 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.
FEATURES
* Soft-start, Current Limit, Enable function
* Thermal Shutdown function
* Built-in internal SW P-channel MOS
* Input voltage: 3.6V to 23V.
* Output voltage: 0.8V to VCC
.
* Duty ratio: 0% to 100% PWM control
* Oscillation frequency: 300KHz typ.
ORDERING INFORMATION
Ordering Number
Package
SOP-8
Packing
Normal
Lead Free
Halogen Free
P1885G-S08-R
P1885-S08-R
P1885L-S08-R
Tape Reel
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LINEAR INTEGRATED CIRCUIT
PIN CONNECTIONS
PIN DESCRIPTIONS
PIN #
NAME
VCC
DESCRIPTION
2
IC power supply pin
Switch Pin. Connect external inductor/diode here. Minimize trace area at this pin to
reduce EMI.
3
Output
4
5
VSS
FB
GND
Feedback pin.
Power-off pin H: Normal operation (Step-down operation) L: Step-down operation
stopped (All circuits deactivated)
7
EN
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P1885
LINEAR INTEGRATED CIRCUIT
BLOCK DIAGRAM
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P1885
LINEAR INTEGRATED CIRCUIT
ABSOLUTE MAXIMUM RATINGS
PARAMETER
SYMBOL
VCC
RATING
UNIT
V
VCC Pin Voltage
VSS-0.3 ~ VSS+25
VSS-0.3 ~ VCC
VSS-0.3 ~ VIN+0.3
VSS-0.3 ~ VIN+0.3
Internally limited
-20 ~ +125
Feedback Pin Voltage
EN Pin Voltage
VFB
V
VEN
V
Switch Pin Voltage
Power Dissipation
VOUTPUT
PD
V
mW
℃
℃
Operating Temperature
Storage Temperature
TOPR
TSTG
-40 ~ +150
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
SYMBOL
MIN
TYP
65
MAX
UNIT
°C/W
Junction-to-Ambient
θJA
ELECTRICAL CHARACTERISTICS (VIN = 12V, Ta=25°C, unless otherwise specified)
PARAMETER
Input Voltage
Feedback Voltage
Feedback Bias Current
Switch Current
SYMBOL
VIN
CONDITIONS
MIN. TYP. MAX. UNIT
3.6
23
V
V
VFB
IOUT=0.1A
0.784 0.8 0.816
IFB(BIAS) IOUT=0.1A
ISW
0.1
0.5
μA
A
2.15
Standby Current
Line Regulation
Load Regulation
Oscillation Frequency
Frequency of Current Limit or Short
Circuit Protect
ISTN-BY VEN=0V
ΔVOUT/VOUT VIN=5V~23V, IOUT=0.2A
ΔVOUT/VOUT IOUT=0.1~2A
10
1
0.2
300
μA
%
%
2.1
0.5
360
fOSC
Measure waveform at SW pin
240
10
KHz
fOSC1
Measure waveform at SW pin
KHz
V
VSH
VSL
ISH
Evaluate oscillation at SW pin
Evaluate oscillation stop at SW pin
0.79
0.72
20
-10
2
EN Pin Input Voltage
μA
μA
ms
EN Pin Input Leakage Current
Soft-Start Time
ISL
TSS
0.3
5
VIN=5V, VFB=0V
VIN=12V, VFB=0V
VIN=12V, VOUT=5V, IOUT=2A
110
70
91
150
100
Internal MOSFET RDS(ON)
Efficiency
RDS(ON)
mΩ
η
%
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P1885
LINEAR INTEGRATED CIRCUIT
FUNCTION DESCRIPTION
PWM Control
The UTC P1885 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.
Under Voltage Lockout
The under voltage lockout circuit makes sure that the outputs of high-side MOSFET driver remain in the off state
after the supply voltage drops below 3.3V. When VCC rises above 3.5V normal operation resumes.
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P1885
LINEAR INTEGRATED CIRCUIT
TEST CIRCUITS
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P1885
LINEAR INTEGRATED CIRCUIT
TYPICAL APPLICATION CIRCUIT
VIN=12V, IMAX=2A
2.5V
15uH
VOUT
3.3V
18uH
5V
L1 Value
22uH
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P1885
LINEAR INTEGRATED CIRCUIT
TYPICAL CHARACTERISTICS
Input Voltage vs. Frequency
VOUT=5V, IOUT=0.2A
Input Voltage vs. Feedback Voltage
VOUT=5V, IOUT=0.2A
320
315
310
305
300
295
290
285
280
275
0.84
0.83
0.82
0.81
0.80
0.79
0.78
0.77
0.76
0.75
0.74
270
0
5
10
15
20
25
0
5
10
15
20
25
Input Voltage, VIN (V)
Input Voltage, VIN (V)
Line Regulation
Load Regulation
5.00
4.95
4.90
4.85
4.80
4.75
4.70
4.99
4.98
VOUT=5V, IOUT=0.2A
VIN=12V
4.97
4.96
4.95
4.94
4.93
4.92
4.91
4.90
4.89
1.0
1.5
0
0
5
10
15
20
25
0.5
2.0
Input Voltage, VIN (V)
Output Current, IOUT (A)
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P1885
LINEAR INTEGRATED CIRCUIT
UTC 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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