SC8863-250CSKT [SEMTECH]
Fixed/Adjustable Positive LDO Regulator, 2.4125V Min, 2.5875V Max, 0.24V Dropout, PDSO5, SOT-23, 5 PIN;
| 型号： | SC8863-250CSKT |
| 厂家： | 
SEMTECH CORPORATION |
| 描述： | Fixed/Adjustable Positive LDO Regulator, 2.4125V Min, 2.5875V Max, 0.24V Dropout, PDSO5, SOT-23, 5 PIN 线性稳压器IC 调节器 电源电路 光电二极管 输出元件 |
| 文件： | 总9页 (文件大小：95K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
150mA ULTRA LOW DROPOUT,
LOW NOISE REGULATOR
SC8863
March 1, 2000
TEL:805-498-2111 FAX:805-498-3804 WEB:http://www.semtech.com
DESCRIPTION
FEATURES
•
•
•
•
•
•
•
•
•
•
Guaranteed 150 mA output current
Fixed or adjustable output
Very small external components
Low 75µVRMS output noise
Very low supply current
Thermal overload protection
Reverse battery protection
Low power shutdown
Surface mount packaging (5 pin SOT-23)
Full industrial temperature range
The SC8863 is a low dropout linear regulator that
operates from a +2.5V to +5.5V input range and
delivers up to 150mA. A PMOS pass transistor allows
the low 110µA supply current to remain independent of
load, making these devices ideal for battery operated
portable equipment such as cellular phones, cordless
phones and personal digital assistants.
The SC8863 output voltage can be preset or adjusted
with an external resistor divider. Other features include
low powered shutdown, short circuit protection, thermal
shutdown protection and reverse battery protection.
The SC8863 comes in the tiny 5 lead SOT-23
package.
APPLICATIONS
•
•
•
•
•
•
•
Battery Powered Systems
Cellular Telephones
Cordless Telephones
Personal Digital Assistants
Portable Instrumentation
Modems
PCMCIA cards
ORDERING INFORMATION
Part Number
SC8863-XXXCSK(1)(2)
Package
BLOCK DIAGRAM
SOT-23-5
Notes:
(1) Where -XXX denotes voltage options. Available
voltages are: 2.50V (-250), 2.80V (-280), 3.00V (-300),
and 3.30 (-330)V.
(2) Add suffix ‘TR’ for tape and reel.
ABSOLUTE MAXIMUM RATINGS
Parameter
Symbol
Maximum Units
Input Supply Voltage
VIN
-0.6 to +7
571
V
Power Dissipation
TA = 70°C
PD
mW
Thermal Resistance
256
81
°C/W
°C/W
°C
θJA
θJC
TA
Operating Ambient
Temperature Range
-40 to +85
PIN CONFIGURATION
Operating Junction
Temperature Range
TJ
-40 to +150
-65 to +150
+300
°C
°C
°C
Storage Temperature
Range
TSTG
TLEAD
ESD
Lead Temperature
(Soldering) 10 Sec
ESD Rating
1.25
kV
1
© 2000 SEMTECH CORP.
652 MITCHELL ROAD NEWBURY PARK CA 91320
150mA ULTRA LOW DROPOUT,
LOW NOISE REGULATOR
SC8863
March 1, 2000
PIN DESCRIPTIONS
Pin #
Pin Name
EN
Description
1
2
3
4
5
Active high enable pin. Connect to VIN if not being used.
Ground pin. Can be used for heatsinking if needed.
Input pin.
GND
IN
OUT
SET
Regulator output, sourcing up to 150mA
Connecting this pin to ground results in the internally preset value for
VOUT. Connecting to an external resistor divider changes VOUT to:
R1
VOUT = 1.250 • 1+
R2
TYPICAL APPLICATION - INTERNALLY PRESET OUTPUT VOLTAGE
U1
SC8863
VO
3
1
4
5
VIN > VOUT + VD(MAX)
VOUT @ IOUT up to 150mA
VIN
EN
SET
GND
2
C1
C2
1uF Ceramic
1uF Ceramic
TYPICAL APPLICATION - EXTERNALLY SET OUTPUT VOLTAGE(1)
U1
SC8863
VO
3
1
4
5
VIN > VOUT + VD(MAX)
VOUT @ IOUT up to 150mA
VIN
R1
EN
SET
GND
2
R2
C1
10k
C2
2.2uF Ceramic
1uF Ceramic
NOTES:
(1) Select R1 and R2 such that the current flowing through them is ≥ 10µA (i.e. R2 ≤ 120kΩ). A value of 10kΩ is
recommended for R2. Please see Component Selection - Externally Set Output.
2
© 2000 SEMTECH CORP.
652 MITCHELL ROAD NEWBURY PARK CA 91320
150mA ULTRA LOW DROPOUT,
LOW NOISE REGULATOR
SC8863
March 1, 2000
ELECTRICAL CHARACTERISTICS
Unless specified: VIN = 3.6V, VSET = GND, VEN = VIN, TA = 25°C. Values in bold apply over full operating ambient temperature range.
Parameter
Symbol
Conditions
Min
Typ
Max Units
IN
Supply Voltage Range
Supply Current
VIN
IQ
V
2.5
5.5
130
160
160
IOUT = 0mA
100
110
µA
µA
µA
50mA ≤ IOUT ≤ 150mA
200
1
VEN = 0V
0.0001
2
OUT
Output Voltage (1)
VOUT
IOUT = 1mA
-2.0% VOUT +2.0%
V
-3.5%
+3.5%
1mA ≤ IOUT ≤ 150mA, VOUT+1V ≤ VIN ≤ 5.5V
2.5V ≤ VIN ≤ 5.5V, SET = OUT, IOUT = 1mA
Line Regulation(1)
Load Regulation(1)
REG(LINE)
REG(LOAD)
5
10
mV
mV
mV
mV
mV
12
-15
IOUT = 0mA to 50mA
-10
-15
-2.5
-5
-20
IOUT = 0mA to 100mA
-20
-25
I
OUT = 0mA to 50mA, SET = OUT
-7.5
-15.0
-15
I
OUT = 0mA to 100mA, SET = OUT
-30
Dropout Voltage(1)(2)
VD
IOUT = 1mA
1.1
55
mV
mV
IOUT = 50mA
90
120
180
240
350
I
OUT = 100mA
110
mV
Current Limit
ILIM
en
240
90
mA
150
Output Voltage Noise
10Hz to 99kHz, IOUT = 50mA, COUT = 1µF
µVRMS
COUT = 100µF
75
Power Supply Rejection
Ratio
PSRR
55
dB
f ≤ 1kHz
3
652 MITCHELL ROAD NEWBURY PARK CA 91320
© 2000 SEMTECH CORP.
150mA ULTRA LOW DROPOUT,
LOW NOISE REGULATOR
SC8863
March 1, 2000
ELECTRICAL CHARACTERISTICS (Cont.)
Unless specified: VIN = 3.6V, VSET = GND, VEN = VIN, TA = 25°C. Values in bold apply over full operating ambient temperature range.
Parameter
EN
Symbol
Conditions
Min
Typ
Max Units
EN Input Threshold
VIH
VIL
IEN
V
1.8
0.4
EN Input Bias Current(3)
EN = VIN
0
100
nA
200
SET
Sense/Select Threshold
SET Reference Voltage(1)
VTH
55
mV
V
20
80
VSET
IOUT = 1mA
1.225 1.250 1.275
1.206 1.294
1mA ≤ IOUT ≤ 150mA, 2.5V ≤ VIN ≤ 5.5V
SET Input Leakage Current(3)
ISET
SET = 1.3V
0.015 2.500 nA
5.000
OVER TEMPERATURE PROTECTION
High Trip Level
Hysteresis
THI
170
10
°C
°C
THYST
NOTE:
(1) Low duty cycle pulse resting with Kelvin corrections required.
(2) Defined as the input to output differential at which the output voltage drops 100mV below the value measured at
a differential of 2V.
(3) Guaranteed by design.
4
© 2000 SEMTECH CORP.
652 MITCHELL ROAD NEWBURY PARK CA 91320
150mA ULTRA LOW DROPOUT,
LOW NOISE REGULATOR
SC8863
March 1, 2000
TYPICAL CHARACTERISTICS
Output Voltage vs. Output Current
Output Voltage vs. Junction
Temperature vs. Output Current
2.86
2.85
2.84
2.83
2.82
2.81
2.80
2.79
2.78
2.77
2.76
2.75
2.74
2.86
2.85
2.84
2.83
2.82
2.81
2.80
2.79
2.78
2.77
2.76
2.75
2.74
VIN = 3.6V
TJ = 25°C
VIN = 3.6V
IO = 1mA
IO = 50mA
IO = 100mA
IO = 150mA
0
25
50
75
100
125
150
-50
-25
0
25
50
75
100
125
I
OUT (mA)
TJ (°C)
SET Reference Voltage vs.
Output Current
SET Reference Voltage vs. Junction
Temperature vs. Output Current
1.275
1.270
1.265
1.260
1.255
1.250
1.245
1.240
1.235
1.230
1.225
1.290
1.280
1.270
1.260
1.250
1.240
1.230
1.220
1.210
VIN = 3.6V
TJ = 25°C
VIN = 3.6V
IO = 1mA
IO = 50mA
IO = 100mA
IO = 150mA
0
25
50
75
100
125
150
-50
-25
0
25
50
75
100
125
IOUT (mA)
TJ (°C)
Dropout Voltage vs. Output Current
vs. Junction Temperature
Line Regulation vs.
Junction Temperature
250
225
200
175
150
125
100
75
12
SET = GND
VIN = 2.5V to 5.5V
SET = OUT
IOUT = 1mA
10
8
-40°C
25°C
6
125°C
4
50
2
25
0
0
0
25
50
75
100
125
150
-50
-25
0
25
50
75
100
125
IOUT (mA)
TJ (°C)
5
© 2000 SEMTECH CORP.
652 MITCHELL ROAD NEWBURY PARK CA 91320
150mA ULTRA LOW DROPOUT,
LOW NOISE REGULATOR
SC8863
March 1, 2000
TYPICAL CHARACTERISTICS (Cont.)
Load Regulation (SET = OUT)
vs. Junction Temperature
Load Regulation (SET = GND)
vs. Junction Temperature
50
20.0
17.5
15.0
12.5
10.0
7.5
VIN = 3.6V
SET = GND
VIN = 3.6V
SET = OUT
45
40
35
30
25
20
15
10
5
IOUT = 0mA to 150mA
I
I
OUT = 0mA to 150mA
OUT = 0mA to 100mA
IOUT = 0mA to 50mA
IOUT = 0mA to 100mA
5.0
2.5
IOUT = 0mA to 50mA
0
0.0
-50
-25
0
25
50
75
100
125
150
125
-50
-25
0
25
50
75
100
125
TJ (°C)
TJ (°C)
Supply Current
vs. Output Current
Supply Current vs.
Junction Temperature
120
110
100
90
80
70
60
50
40
30
20
10
0
150
125
100
75
VIN = 3.6V
IOUT = 150mA
50
25
VIN = 3.6V
TJ = 25°C
0
0
25
50
75
100
125
-50
-25
0
25
50
75
100
125
I
OUT (mA)
TJ (°C)
Current Limit vs.
Junction Temperature
Enable Input Threshold vs.
Junction Temperature
350
300
250
200
150
100
50
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
VIN = 3.6V
VIN = 3.6V
VIH
VIL
0
-50
-25
0
25
50
75
100
-50
-25
0
25
50
75
100
125
T
J (°C)
TJ (°C)
6
© 2000 SEMTECH CORP.
652 MITCHELL ROAD NEWBURY PARK CA 91320
150mA ULTRA LOW DROPOUT,
LOW NOISE REGULATOR
SC8863
March 1, 2000
TYPICAL CHARACTERISTICS (Cont.)
Sense/Select Threshold
vs. Junction Temperature
Output Spectral Noise Density
vs. Frequency
80
10
1
VIN = 3.6V
SC8863-2.8
VIN = 3.6V
IOUT = 50mA
TJ = 25°C
70
60
50
40
30
20
COUT = 1µF
0.1
0.01
COUT = 100µF
0.1
1
10
100
-50
-25
0
25
50
75
100
125
TJ (°C)
f (kHz)
ing the bulk capacitance will further reduce output
noise and improve the overall transient response.
APPLICATIONS INFORMATION
Theory Of Operation
Input capacitor - Semtech recommends the use of a
1µF ceramic capacitor at the input. This allows for the
device being some distance from any bulk capacitance
on the rail. Additionally, input droop due to load tran-
sients is reduced, improving load transient response.
The SC8863 is intended for applications where very
low dropout voltage, low supply current and low output
noise are critical. It provides a very simple, low cost
solution that uses very little pcb real estate. Fixed out-
put voltage options require the use of only two external
capacitors for operation.
Component Selection - Externally Set Output
Please refer to Figure 1 below. The output voltage can
be externally adjusted anywhere within the range from
1.25V to (VIN(MIN) - VD(MAX)). The output voltage will be
in accordance with the following equation:
Each voltage option has both fixed and adjustable out-
put voltage modes. Grounding the SET pin (pulling it
below the Sense/Select threshold of 55mV) will con-
nect the internal resistor divider to the error amplifier
resulting with the internally preset output voltage. If
SET is pulled above this threshold, then the Sense/
Select switch will connect the SET pin to the error am-
plifier. The output will be regulated such that the volt-
age at SET will equal VSET, the SET reference voltage
(typically 1.250V).
R1
VO = 1.250 • 1+
R2
1% tolerance resistors are recommended. The values
of R1 and R2 should be selected such that the current
flow through them is ≥ 10µA (thus R2 ≤ 120kΩ).
At high input voltages and/or high output currents, sta-
An active high enable pin (EN) is provided to allow the
customer to shut down the part and enter an extremely
low power Off-state. A logic Low signal will reduce the
supply current to 0.1nA.
U1
SC8863
VO
3
1
4
5
VIN
R1
EN
SET
GND
2
Component Selection - General
R2
10k
Output capacitor - Semtech recommends a minimum
capacitance of 1µF at the output with an equivalent se-
ries resistance (ESR) of <1Ω over temperature. Ce-
ramic capacitors are ideal for this application. Increas-
C1
C2
1uF Ceramic
2.2uF Ceramic
Figure 1: Externally set output
7
© 2000 SEMTECH CORP.
652 MITCHELL ROAD NEWBURY PARK CA 91320
150mA ULTRA LOW DROPOUT,
LOW NOISE REGULATOR
SC8863
March 1, 2000
bility may be improved by increasing C2 to 2.2µF and
reducing R2 to 10kΩ. See “Component Selection -
General” for input capacitor requirements.
The junction temperature can be further reduced by
the use of larger trace widths, and connecting pcb cop-
per area to the GND pin (pin 2), which connectes di-
rectly to the device substrate. Adding approximately
one square inch of pcb copper to pin 2 will reduce
θTH(J-A) to approximately 130°C/W and TJ(MAX) to ap-
proximately 110°C, for example. Lower junction tem-
peratures improve overall output voltage accuracy. A
sample pcb layout for the Internally Preset Output Volt-
age circuit on page 2 is shown in Figure 2 below.
Thermal Considerations
The worst-case power dissipation for this part is given
by:
PD(MAX )
=
(VIN (
− VO (
)
• IO(MAX ) + VIN (MAX ) • IQ(MAX )
MAX
)
MIN
)
For all practical purposes, it can be reduced to:
Layout Considerations
PD(MAX )
=
(VIN (
− VO (
)
• IO(MAX )
MAX
)
MIN
)
Looking at a typical application:
VIN(MAX) = 4.2V
VO = 3V - 3.5% worst-case
IO = 150mA
While layout for linear devices is generally not as criti-
cal as for a switching application, careful attention to
detail will ensure reliable operation. See Figure 2 below
for a sample layout.
TA = 85°C
1) Attaching the part to a larger copper footprint will
enable better heat transfer from the device, especially
on PCBs where there are internal ground and power
planes.
PD(MAX )
=
(
4.2 − 2.895
• 0.150 = 196 mW
)
Using this figure, we can calculate the maximum ther-
2) Place the input and output capacitors (and the ca-
pacitor from OUT to SET for adjustable applications)
close to the device for optimal transient response and
device behaviour.
mal impedance allowable to maintain TJ ≤ 150°C:
(
TJ(MAX ) − TA(MAX )
)
=
150 − 85
(
)
= 332°C / W
θ(J−A )(MAX )
=
PD(MAX )
0.196
3) Connect all ground connections directly to the
ground plane. If there is no ground plane, connect to a
common local ground point before connecting to board
ground.
With the standard SOT-23-5 Land Pattern shown at
the end of this datasheet, and minimum trace widths,
the thermal impedance junction to ambient for SC8863
is 256°C/W. Thus with no additional heatsinking,
TJ(MAX) = 135°C.
Top Copper
Top Silk Screen
Figure 2: Suggested pcb layout based upon internally preset output voltage application on page 2.
NOTES:
(1) All vias go to the ground plane.
(2) Copper area on pin 2 is recommended, but not required. Connect to the ground plane with a via or vias.
8
© 2000 SEMTECH CORP.
652 MITCHELL ROAD NEWBURY PARK CA 91320
150mA ULTRA LOW DROPOUT,
LOW NOISE REGULATOR
SC8863
March 1, 2000
DEVICE OUTLINE - SOT23-5
LAND PATTERN - SOT23-5
ECN 00-915
9
© 2000 SEMTECH CORP.
652 MITCHELL ROAD NEWBURY PARK CA 91320
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