Datasheet

UNISONIC TECHNOLOGIES CO., LTD
LC1126
Preliminary
LINEAR INTEGRATED CIRCUIT
ULTRA LOW OUTPUT
VOLTAGE LINEAR N-FET
CONTROLLER
„
5
6
DESCRIPTION
The UTC LC1126 is an ultra low output voltage linear N-FET
controller designed to provide well supply voltage for
front-side-bus termination on motherboards and NB applications.
The UTC LC1126 integrates many functions. A Power-On-Reset
(POR) circuit monitors supply voltages to prevent wrong
operations. A POK indicates the output status with time delay
which is set internally. It can control other converter for power
sequence. It can available for SC-59-6 package.
The UTC LC1126 can be enabled by other power system. A
0.5V reference voltage with 2% accuracy providing tight
regulation of the output voltage, enable control, open drain power
good signal, under-voltage protection and soft start.
„
4
1
2
3
SOT-26
FEATURES
* MLCC and POSCAP Stable
* 0.5V±2% Reference Voltage
* Internal soft-start
* Enable control
* Fast transient response
* Under-Voltage short circuit protection
* Power OK output with a delay time
* Adjustable output voltage down to 0.5V
* Drive N-Channel MOSFETs
„
ORDERING INFORMATION
Ordering Number
Lead Free
Halogen Free
LC1126L-AG6-R
LC1126G-AG6-R
Package
Packing
SOT-26
Tape Reel
LC1126L-AG6-R
(1)Packing Type
(1) R: Tape Reel
(2)Package Type
(2) AG6: SOT-26
(3)Halogen Free
(3) L: Lead Free, G: Halogen Free
www.unisonic.com.tw
Copyright © 2013 Unisonic Technologies Co., Ltd
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LC1126
Preliminary
„
MARKING INFORMATION
„
PIN CONFIGURATION
„
PIN DESCRIPTION
PIN NO.
1
2
3
4
5
6
PIN NAME
VCC
GND
POK
EN
FB
DRV
LINEAR INTEGRATED CIRCUIT
DESCRIPTION
Input Voltage
Ground
Power ok Output Pin
H: Normal Operation, L: Shutdown
Feedback Pin
Gate Drive to N-FET
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LC1126
„
Preliminary
LINEAR INTEGRATED CIRCUIT
BLOCK DIAGRAM
DRV
VCC
EN
Power-ON
Reset
Enable
Thermal
Shutdown
Error
Amp
Soft-Start
And
Control Logic
+
UV
-
Vref=0.5V
FB
0.25V
+
GND
92%
VREF
UNISONIC TECHNOLOGIES CO., LTD
www.unisonic.com.tw
+
Delay
-
POK
POK
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LC1126
„
Preliminary
LINEAR INTEGRATED CIRCUIT
ABSOLUTE MAXIMUM RATING (TA=25°C, unless otherwise specified)
PARAMETER
SYMBOL
RATINGS
UNIT
Supply Voltage
VCC
-0.3~7
V
DRV to GND
-0.3~VCC+0.3
V
Power Dissipation
PD
0.4
W
Junction Temperature
TJ
-40~+125
°C
Operating Temperature
TOPR
-40~+85
°C
Storage Temperature
TSTG
-65~+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.
„
ELECTRICAL CHARACTERISTICS
(VIN=1.5V, VSHDN=VIN, TA=25°C, CIN=COUT=1µF, unless otherwise noted.)
PARAMETER
SYMBOL
TEST CONDITIONS
Supply Voltage Range
VCC
Input Voltage UVLO Threshold
VUVLO
VCC Rising
Input Voltage UVLO Hysteresis
VHYST
VCC Falling
Supply Current
ICC
EN=VCC
Shutdown Current
ISD
EN=0V
Feedback Voltage
VFB
Feedback Pin Input Current
IFB
VFB=0.5V
Soft Start Time
TSS
Enable
VENH
EN Pin Logic High Threshold Voltage
VENL
Disable
EN Pin Input Current
IEN
IOUT=0mA, VIN=5V
Output Voltage UVLO Threshold
VTH(UV)
VFB Falling
Ton Duty
TON
VFB<0.25V
IDRV(SRC) Sourcing, VFB=0.48V
DRV Output Current
IDRV(SINK) Sinking, VFB=0.52V
DRV Pin Output Voltage
VDRV
VFB=0.48V, VCC=5V, No Load
POK Threshold Voltage for Power OK
VPOK
VFB Rising
POK Threshold Voltage for Power Not OK
VPNOK
VFB Falling
POK Low Voltage
POK Sinks 1mA
POK Delay Time
TDELAY
Thermal Shutdown Temperature
TSD
Thermal Shutdown Hysteresis
UNISONIC TECHNOLOGIES CO., LTD
www.unisonic.com.tw
MIN
4.5
TYP
3.75
0.25
0.4
-1
0.49
-100
0.5
1
1.3
-1
0.2
4.9
90%
82%
0.8
0.25
30
20
20
93%
85%
50
2
150
50
MAX UNIT
5.5
V
V
V
0.8
mA
1
µA
0.51
V
100
nA
ms
V
0.5
V
+1
µA
0.3
V
%
mA
mA
5.0
V
96% VFB
88% VFB
100
mV
10
ms
°C
°C
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LC1126
„
Preliminary
LINEAR INTEGRATED CIRCUIT
FUNCTION DESCRIPTIONS
Power-On-Reset
A Power-On-Reset (POR) circuit monitors the VCC pin voltage (VCC) for power-on-reset function to prevent
wrong operation. The built-in POR circuit keeps the output shutting off until internal circuit is operating properly..
Internal Soft-Start
An internal soft-start provides an internal soft-start circuitry to control rise rate of the output voltage and limit the
current surge during start-up. The typical soft-start interval is about 1ms.
Output Voltage Regulation
An error amplifier working with a temperature compensated 0.5V reference and an output NMOS regulates output
to the preset voltage. The error amplifier designed with high bandwidth and DC gain provides very fast transient
response and less load regulation.
Under-Voltage Protection (UVP)
UTC LC1126 monitors the voltage on FB pin after soft-start process is finished. Therefore the UVP is disabling
during soft-start. When the voltage on FB pin falls below the under-voltage threshold, the UVP circuit shuts off the
output immediately. After a while (~70% Duty), UTC LC1126 starts a new soft-start to regulate output.
Thermal Shutdown
A thermal shutdown circuit limits the junction temperature of UTC LC1126. When the junction temperature
exceeds +150°C, a thermal sensor turns off the output NMOS, allowing the device to cool down. The regulator
regulates the output again through initiation of new soft-start cycle after the junction temperature cools by 50°C,
resulting in a pulsed output during continuous thermal overload conditions.
„
TYPICAL APPLICATION CIRCUIT
VIN=1.5V
C1
VCC=5V
4.7µF
U1
1
C3
2
0.1µF
3
VCC
GND
POK
DRV
FB
EN
Q1
MOSFET N
6
5
C4
56pF
4
R1
43K
C2
UTC LC1126
VOUT=0.5V* (1+
VOUT=1.05V
R2
39K
10µF
R1
)
R2
10K
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www.unisonic.com.tw
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LC1126
Preliminary
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.
UNISONIC TECHNOLOGIES CO., LTD
www.unisonic.com.tw
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