SC1566IM-2.5T [SEMTECH]
Fixed Positive LDO Regulator, 2.5V, 0.6V Dropout, PSSO3, TO-263, 3 PIN;
| 型号： | SC1566IM-2.5T |
| 厂家： | 
SEMTECH CORPORATION |
| 描述： | Fixed Positive LDO Regulator, 2.5V, 0.6V Dropout, PSSO3, TO-263, 3 PIN 线性稳压器IC 调节器 电源电路 输出元件 |
| 文件： | 总9页 (文件大小：224K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
SC1566
Very Low Dropout
3.0 Amp Regulator With Enable
POWER MANAGEMENT
Description
Features
The SC1566 is a high performance positive voltage
regulator designed for use in applications requiring very
low dropout voltage at up to 3 Amps. Since it has
superior dropout characteristics compared to regular
LDOs, it can be used to supply 2.5V on motherboards or
2.8V on peripheral cards from the 3.3V supply thus
allowing heat sink size reduction or elimination.
Additionally, the five pin versions of SC1566 have an
enable pin, to further reduce power dissipation while shut
down. The SC1566 provides excellent regulation over
variations in line, load and temperature.
u 350mV dropout @ 3A
u Adjustable output from 1.2V to 4.8V
u 2.5V and 1.8V options (5 pin parts also adjustable
externally using resistors)
u Over current and over temperature protection
u Enable pin
u 10µA quiescent current in shutdown
u Low reverse leakage (output to input)
u Full industrial temperature range
u TO-220 and TO-263 packages
Applications
The SC1566 is available as three terminal fixed output
voltage and five terminal fixed or adjustable output
voltage devices with enable. Two package options are
available: TO-263 and TO-220.
u Battery powered systems
u Motherboards and notebook computers
u Peripheral cards
u Network cards
u Set top boxes
u Medical equipment
Typical Application Circuits(1)(2)
U1
SC1566I5T-2.5
1
2
5
4
VIN
VIN
EN
VO
VO = See equation below
ENABLE
ADJ
GND
3
R1
1.200(R1+ R2)
VO=
Volts
R2
C1
C2
R2
U1
SC1566I5T-2.5
1
5
VIN
VO = 2.5V
VIN
EN
VO
2
4
ENABLE
ADJ
GND
3
C1
C2
U1
SC1566IT-1.8
1
3
VIN
VO = 1.8V
VIN
VO
GND
2
Notes:
C1
C2
(1) Maximum VO setpoint for 1.8V parts = 5.4V
(2) This device is designed to operate with
ceramic input and output capacitors
Revision 1, January 2001
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SC1566
POWER MANAGEMENT
Absolute Maximum Ratings
Parameter
Symbol
VIN
Max
Units
Input Voltage
5.5
V
Power Dissipation
PD
Internally Limited
W
Thermal Resistance Junction to Ambient
SC1566IM (TO-263)
SC1566IT (TO-220)
60
50
°C/W
qJA
Thermal Resistance Junction to Case
SC1566IM (TO-263)
SC1566IT (TO-220)
qJC
3
3
°C/W
Operating Ambient Temperature Range
Operating Junction Temperature Range
Storage Temperature Range
TA
TJ
-40 to +85
-40 to +150
-65 to +150
300
°C
°C
°C
°C
kV
TSTG
TLEAD
VESD
Lead Temperature (Soldering) 10 Sec.
ESD Rating (Human Body Model)
2
Electrical Characteristics
Unless specified: VEN = VIN. Adjustable Option (VADJ > VTH(ADJ)): VIN = 2.2V to 5.5V and IO = 10µA to 3A.
Fixed Options (VADJ = GND): VIN = (VO + 0.7V) to 5.5V and IO = 0A to 3A. Values in bold apply over the full operating temperature range.
Parameter
Symbol
Test Conditions
Min
2.2
Typ
Max
Units
VIN
Supply Voltage Range
Quiescent Current
VIN
IQ
5.5
1.75
35
V
VIN = 3.3V
0.75
10
mA
µA
VIN = 5.5V, VEN = 0V
VO
Output Voltage(1)
(Internal Fixed Voltage)
Line Regulation(1)
Load Regulation(1)
Dropout Voltage(1)(2)
VO
VIN = VO + 0.7V, IO = 10mA
-1%
VO
+1%
+2%
0.3
0.4
5
V
-2%
REG(LINE)
REG(LOAD)
VD
VIN = (VO + 0.25V) to 5.5V, IOUT = 10mA
VIN = VO + 0.7V
0.035
0.2
1
%
%
IO = 10mA
mV
10
IO = 500mA
75
100
150
mV
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SC1566
POWER MANAGEMENT
Electrical Characteristics (Cont.)
Unless specified: VEN = VIN. Adjustable Option (VADJ > VTH(ADJ)): VIN = 2.2V to 5.5V and IO = 10µA to 3A.
Fixed Options (VADJ = GND): VIN = (VO + 0.7V) to 5.5V and IO = 0A to 3A. Values in bold apply over the full operating temperature range.
Parameter
Symbol
Test Conditions
Min
Typ
Max
Units
VO (Cont.)
Dropout Voltage(1)(2)
IO = 1.5A
200
350
300
mV
mV
400
IO = 3A
450
600
10
Minimum Load Current(3)
Current Limit
IO
VIN = VO + 0.7V
1
µA
A
ICL
3.0
4.5
6.5
ADJ
Reference Voltage(1)
VREF
VIN = 2.2V, VADJ = VOUT, IO = 10mA
1.188
1.200
1.212
1.224
50
V
1.176
Adjust Pin Current(4)
Adjust Pin Threshold(5)
EN
IADJ
VADJ = VREF
10
nA
V
VTH(ADJ)
0.10
1.8
0.20
0.40
Enable Pin Current
Enable Pin Threshold
IEN
VIH
VIL
VEN = 0V, VIN = 3.3V
VIN = 3.3V
1.5
10
µA
V
VIN = 3.3V
0.4
Over Temperature Protection
High Trip level
THI
THYST
175
10
°C
°C
Hysteresis
Notes:
(1) Low duty cycle pulse testing with Kelvin connections required.
(2) Defined as the input to output differential at which the output voltage drops to 1% below the value
measured at a differential of 0.7V.
(3) Required to maintain regulation. Voltage set resistors R1 and R2 are usually utilized to meet this
requirement. Adjustable versions only.
(4) Guaranteed by design.
(5) When VADJ exceeds this threshold, the Sense Select switch disconnects the internal feedback chain from
the error amplifier and connects VADJ instead.
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SC1566
POWER MANAGEMENT
Pin Configurations
Ordering Information
Device(1)
Package
SC1566 5-PIN
SC1566IM-X.X.TR
SC1566I5M-X.X.TR(2)
SC1566IT-X.X
TO-263-3(3)
TO-263-5(3)
TO-220-3(4)
TO-220-5(4)
Versions
Pin Function
1
2
3
4
5
VIN
EN
SC1566I5T-X.X(2)
Notes:
GND
ADJ
VO
TO-263-5
(1) Where -X.X denotes voltage options. Available
voltages are: 2.5V and 1.8V.
(2) Output voltage can be adjusted using external
resistors, see Pin Descriptions below.
(3) Only available in tape and reel packaging. A reel
contains 800 devices.
TAB IS GND
TO-220-5
(6) Only available in tube packaging. A tube contains 50
devices.
SC1566 3-PIN
Versions
Block Diagram
Pin Function
1
2
3
VIN
GND
VO
TO-263-3
TAB IS GND
Note:
(1) 3-pin versions are fixed output
voltage only.
TO-220-3
* 5 lead versions only
Pin Descriptions
Pin Name Pin Desciption
ADJ
This pin, when grounded, sets the output voltage to that set by the internal feedback resistors. If external
feedback resistors are used, the output voltage will be (See Application Circuits on page 1):
1.200 (R1 + R2)
VO
=
Volts
R2
EN
Enable Input. Pulling this pin below 0.4V turns the regulator off, reducing the quiescent current to a fraction of
its operating value. The device will be enabled if this pin is left open. Connect to VIN if not being used.
GND
VIN
Reference ground. Use the tab (electrically connected to GND) for heatsinking.
Input voltage. For regulation at full load, the input to this pin must be between (VO + 0.7V) and 5.5V. Minimum
VIN = 2.2V.
VO
This pin is the power output of the device.
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SC1566
POWER MANAGEMENT
Typical Characteristics
Dropout Voltage vs. Output Current
vs. Junction Temperature
Dropout Voltage vs. Junction
Temperature vs. Output Current
500
450
400
350
300
250
200
150
100
50
500
450
400
350
300
250
200
150
100
50
150°C
25°C
IO = 3A
0°C
-40°C
IO = 1.5A
IO = 0.5A
0
0
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
-50
-25
0
25
50
75
100
125
150
IO (A)
TJ (°C)
Output Voltage (2.5V) vs. Junction
Temperature vs. Output Current
Output Voltage (2.5V) vs. Junction
Temperature vs. Output Current
2.550
2.540
2.530
2.520
2.510
2.500
2.490
2.480
2.470
2.460
2.450
2.550
2.540
2.530
2.520
2.510
2.500
2.490
2.480
2.470
2.460
2.450
VIN = 3.2V
VIN = 5.5V
I
O = 10mA
IO = 10mA
IO = 3A
IO = 3A
-50
-25
0
25
50
75
100
125
150
-50
-25
0
25
50
75
100
125
150
TJ (°C)
TJ (°C)
Reference Voltage vs. Junction
Temperature vs. Output Current
Reference Voltage vs. Junction
Temperature vs. Output Current
1.225
1.220
1.215
1.210
1.205
1.200
1.195
1.190
1.185
1.180
1.175
1.225
1.220
1.215
1.210
1.205
1.200
1.195
1.190
1.185
1.180
1.175
VIN = 2.2V
VIN = 5.5V
IO = 10mA
IO = 3A
IO = 3A
I
O = 10mA
-50
-25
0
25
50
75
100
125
150
-50
-25
0
25
50
75
100
125
150
T
J (°C)
TJ (°C)
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SC1566
POWER MANAGEMENT
Typical Characteristics (Cont.)
Quiescent Current vs.
Junction Temperature
Off-State Quiescent Current vs.
Junction Temperature
700
12
10
8
VIN = 5.5V
VIN = 3.3V
690
680
670
660
650
640
630
620
610
600
6
4
2
0
-50
-25
0
25
50
75
100
125
150
-50
-25
0
25
50
75
100
125
150
TJ (°C)
T
J (°C)
Applications Information
Introduction
External voltage selection resistors (5-pin parts): the
use of 1% resistors, and designing for a current flow
The SC1566 is intended for applications such as ³ 10µA is recommended to ensure a well regulated
graphics cards where high current capability and very low output (thus R2 £ 120kW).
dropout voltage are required. It provides a very simple,
low cost solution that uses very little pcb real estate and Thermal Considerations
typically does not require a heatsink. Additional features
include an enable pin to allow for a very low power The power dissipation in the SC1566 is approximately
consumption standby mode, and a fully adjustable equal to the product of the output current and the input
output (5-pin versions).
to output voltage differential:
Component Selection
PD
≈
(
VIN − VOUT • IO
)
Input capacitor: a 4.7µF or 10µF ceramic capacitor is
recommended. This allows for the device being some
distance from any bulk capacitance on the rail.
Additionally, input droop due to load transients is reduced,
improving load transient response. Additional capacitance
may be added if required by the application.
The absolute worst-case dissipation is given by:
PD(MAX )
=
VIN (MAX ) − VOUT
• IO(MAX ) + VIN (MAX ) • IQ(MAX )
(MIN )
For a typical scenario, VIN = 3.3V ± 5%, VOUT = 2.8V and
IO = 2.5A, therefore:
Output capacitor: a minimum bulk capacitance of 22µF,
along with a 0.1µF ceramic decoupling capacitor is
recommended. Increasing the bulk capacitance will
improve the overall transient response. The use of
multiple lower value ceramic capacitors in parallel to
achieve the desired bulk capacitance will not cause
stability issues. Although designed for use with ceramic
output capacitors, the SC1566 is extremely tolerant of
output capacitor ESR values and thus will also work
comfortably with tantalum output capacitors.
VIN(MAX) = 3.465V, VOUT(MIN) = 2.744V and IQ(MAX) = 1.75mA,
Thus PD(MAX) = 1.81W.
Using this figure, and assuming TA(MAX) = 85°C, we can
calculate the maximum thermal impedance allowable to
maintain TJ £ 150°C (see page 7):
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SC1566
POWER MANAGEMENT
Applications Information (Cont.)
This should be achievable for the TO-263 package using
pcb copper area to aid in conducting the heat away from
the device, such as a large (~2 squ. inch) pad connected
to the tab of the device. Internal ground/power planes
and air flow will also assist in removing heat. For higher
power dissipations it may be necessary to use a small
heatsink and the TO-220 package.
TJ(MAX ) − TA(MAX )
=
(
150 − 85
)
= 36°C / W
RTH(J−A)(MAX )
=
PD(MAX )
1.81
RTH(J−C)(MAX ) = 3°C / W and RTH(C−S) = 0°C / W,
therefore RTH(S−A)(MAX ) = 33°C / W
Outline Drawing - T0-263-3
Minimum Land Pattern - TO-263-3
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SC1566
POWER MANAGEMENT
Outline Drawing - TO-263-5
Minimum Land Pattern - TO-263-5
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SC1566
POWER MANAGEMENT
Outline Drawing - TO-220-3
Outline Drawing - TO-220-5
Contact Information
Semtech Corporation
Power Management Products Division
652 Mitchell Rd., Newbury Park, CA 91320
Phone: (805)498-2111 FAX (805)498-3804
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