UTC-IC P1885

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.
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.
„
SOP-8
Lead-free:
P1885L
Halogen-free: P1885G
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
Normal
P1885-S08-R
Ordering Number
Lead Free
P1885L-S08-R
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Copyright © 2008 Unisonic Technologies Co., Ltd
Halogen Free
P1885G-S08-R
Package
Packing
SOP-8
Tape Reel
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P1885
LINEAR INTEGRATED CIRCUIT
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PIN CONNECTIONS
„
PIN DESCRIPTIONS
PIN #
2
NAME
VCC
3
Output
4
5
VSS
FB
7
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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P1885
„
LINEAR INTEGRATED CIRCUIT
BLOCK DIAGRAM
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P1885
„
LINEAR INTEGRATED CIRCUIT
ABSOLUTE MAXIMUM RATINGS
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 Temperature
TOPR
-20 ~ +125
℃
Storage Temperature
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
Junction-to-Ambient
„
SYMBOL
θJA
MIN
TYP
65
MAX
UNIT
°C/W
ELECTRICAL CHARACTERISTICS (VIN = 12V, Ta=25°C, unless otherwise specified)
PARAMETER
SYMBOL
CONDITIONS
Input Voltage
VIN
Feedback Voltage
VFB
IOUT=0.1A
Feedback Bias Current
IFB(BIAS) IOUT=0.1A
Switch Current
ISW
Standby Current
ISTN-BY VEN=0V
Line Regulation
ΔVOUT/VOUT VIN=5V~23V, IOUT=0.2A
Load Regulation
ΔVOUT/VOUT IOUT=0.1~2A
Oscillation Frequency
fOSC
Measure waveform at SW pin
Frequency of Current Limit or Short
Measure waveform at SW pin
fOSC1
Circuit Protect
VSH
Evaluate oscillation at SW pin
EN Pin Input Voltage
Evaluate oscillation stop at SW pin
VSL
ISH
EN Pin Input Leakage Current
ISL
Soft-Start Time
TSS
VIN=5V, VFB=0V
Internal MOSFET RDS(ON)
RDS(ON)
VIN=12V, VFB=0V
Efficiency
η
VIN=12V, VOUT=5V, IOUT=2A
UNISONIC TECHNOLOGIES CO., LTD
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MIN. TYP. MAX. UNIT
3.6
23
V
0.784 0.8 0.816
V
0.1
0.5
μA
2.15
A
10
μA
1
2.1
%
0.2
0.5
%
240
300
360
KHz
10
0.3
KHz
0.79
0.72
20
-10
2
110
70
91
V
5
150
100
μA
μA
ms
mΩ
%
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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
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LINEAR INTEGRATED CIRCUIT
TEST CIRCUITS
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+
-
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P1885
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LINEAR INTEGRATED CIRCUIT
TYPICAL APPLICATION CIRCUIT
VOUT
L1 Value
VIN=12V, IMAX=2A
2.5V
3.3V
15uH
18uH
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5V
22uH
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LINEAR INTEGRATED CIRCUIT
TYPICAL CHARACTERISTICS
Input Voltage vs. Frequency
320
Input Voltage vs. Feedback Voltage
0.84
VOUT=5V, IOUT=0.2A
315
310
0.82
305
0.81
300
0.80
295
0.79
290
0.78
285
0.77
280
0.76
275
0.75
270
0
5
10
15
20
Input Voltage, VIN (V)
25
0.74
0
Line Regulation
5.00
VOUT=5V, IOUT=0.2A
0.83
5
10
15
20
Input Voltage, VIN (V)
25
Load Regulation
4.99
VOUT=5V, IOUT=0.2A
VIN=12V
4.98
4.95
4.97
4.96
4.90
4.95
4.85
4.94
4.93
4.80
4.92
4.91
4.75
4.90
4.70
0
5
10
15
20
Input Voltage, VIN (V)
25
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4.89
0
1.0
1.5
0.5
Output Current, IOUT (A)
2.0
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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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