SC1457ITSK-32TR [SEMTECH]
Fixed Positive LDO Regulator, 3.2V, 0.23V Dropout, CMOS, PDSO5, 1 MM HEIGHT, TSOT-23, 5 PIN;
| 型号： | SC1457ITSK-32TR |
| 厂家： | 
SEMTECH CORPORATION |
| 描述： | Fixed Positive LDO Regulator, 3.2V, 0.23V Dropout, CMOS, PDSO5, 1 MM HEIGHT, TSOT-23, 5 PIN 光电二极管 输出元件 调节器 |
| 文件： | 总13页 (文件大小：425K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
NOT RECOMMENDED FOR NEW DESIGN
SC1457
150mA Ultra Low Dropout
Regulator with Undervoltage Flag
POWER MANAGEMENT
Description
Features
The SC1457 is a low dropout linear regulator that
operates from a +2.25V to +6.5V input range and
delivers up to 150mA. A PMOS pass transistor allows
the low 75µA 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.
Guaranteed 150mA output current
Error flag indicates output undervoltage fault
2% output accuracy guaranteed over line, load and
temperature
Very small external components - designed to work
with ceramic capacitors
Low 110µVRMS output noise
Very low supply current
Thermal overload protection
Reverse battery protection
Low power shwn
Full industrial temperature range
Very low rofile packaging available (1mm max.
height)
Surface mount packaging (SOT-23-5 and
TSOT-23-5)
The SC1457 has very low dropout voltage (typically 1.1mV
at light loads and 150mV at 150mA) with better than
1.5% initial output voltage accuracy. It has a logic
compatible enable control input and an internal output
undervoltage monitor.
Designed especially for hand held, battery powered
devices, the SC1457 can be switched by a CMOS or TTL
compatible logic signal. When disabled, power
consumption drops nearly to zero. Other features include
short circuit protection, thermal shutdown protection and
reverse battery protection.
Applications
Battey Powered Systems
Clar Telephones
Cordless Telephones
Personal Digital Assistants
Portable Instrumentation
Modems
The SC1457 is available in several fixed voltages in he
tiny 5 lead SOT-23 package and the ultra low profile 5
lead TSOT-23.
PCMCIA cards
Typical Application Circuit
U1
SC1457
OUT
1
3
5
4
VIN
VO
IN
R1 100k
C1
C2
EN
FLG
GND
2
1uF
1uF
UNDERVOLTAGE FLAG
Revision: November 10, 2004
1
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NOT RECOMMENDED FOR NEW DESIGN
SC1457
POWER MANAGEMENT
Absolute Maximum Ratings
Exceeding the specifications below may result in permanent damage to the device, or device malfunction. Operation outside of the parameters specified
in the Electrical Characteristics section is not implied. Exposure to Absolute Maximum rated conditions for extended periods of time may affect device
reliability.
Parameter
Symbol
Maximum
Units
Input Supply Voltage
VIN
VEN, VFLG
θJA
-0.6 to +7
-0.6 to VIN
256
V
V
I/O Pin Voltages
Thermal Resistance Junction to Ambient
Thermal Resistance Junction to Case
Operating Ambient Temperature Range
Operating Junction Temperature Range
Storage Temperature Range
°C/W
°C/W
°C
81
θJC
TA
-40 to +85
-4+125
-60 to +150
300
TJ
°C
TSTG
TLEAD
VESD
°C
Lead Temperature (Soldering) 10 seconds
ESD Rating (Human Body Model)
°C
2
kV
Electrical Characteristics
Unless specified: VIN = VOUT + 1V, VEN = VIN, IOUT = 100µA, TA = 25°C. Values in bold aply over full operating ambient temperature range.
Parameter
Symbol
ondition
Min
Typ
Max
Units
IN
Supply Voltage Range
Supply Current
VIN
IQ
2.25
6.50
130
160
1.0
V
IOUT = 0mA to150mA
VIN = 6.5V, VEN = 0V
75
µA
0.1
µA
1.5
OUT
Output Voltage (1)
VOUT
IOUT = 1mA
-1.5%
VOUT
2.5
-3
+1.5%
+2.0%
10
V
0mA ≤ IOUT ≤ 150mA, VOUT +1V ≤ VIN ≤ 5.5V -2.0%
(VOUT(NOM) + 0.1V) ≤ VIN ≤ 5.5V, IOUT = 1mA
Line Regulation (1)(2)
Load Regulation (1)
REG(LINE)
REG(LOAD)
mV
mV
12
IOUT = 0.1mA to 150mA
-10
-20
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NOT RECOMMENDED FOR NEW DESIGN
SC1457
POWER MANAGEMENT
Electrical Characteristics (Cont.)
Unless specified: VIN = VOUT + 1V, VEN = VIN, IOUT = 100µA, TA = 25°C. Values in bold apply over full operating ambient temperature range.
Parameter
Symbol
Conditions
Min
Typ
Max Units
Out (Cont.)
Current Limit
Dropout Voltage(1)(3)
ILIM
VD
400
mA
mV
IOUT = 1mA
1
I
OUT = 50mA
50
65
75
mV
mV
mV
µVRMS
dB
IOUT = 100mA
100
150
125
155
190
230
I
OUT = 150mA
Output Voltage Noise
en
10Hz to 100kHz, IUT = 50mA, COUT = 1µF
10Hz to 100kHz, IOUT = 50mA, COUT = 100µF
f = 120Hz
135
110
60
Power Supply Rejection Ratio
EN
PSRR
Enable Input Threshold
VIH
VIL
IEN
2.25V ≤ VIN ≤ 6.5V
2.25V ≤ VIN ≤ 6.5V
0V ≤ VEN ≤ VIN
1.6
V
0.4
Enable Input Bias Current(4)
FLG
-0.5
0
+0.5
µA
%
Flag Threshold
VTH(FLG)
Under voltage condition (below nominal)
-4
-6
-8
-4
-12
0.4
+1
Output Logic Low Voltage
Flag Leakage Current
Over Temperature Protection
High Trip Level
VFLG
IFLG
IFLG = 1mA, undervoltage condition
Flag OFF, VFLG = 0V to 6.5V
V
-1
0.1
µA
THI
150
20
°C
°C
Hysteresis
THYST
NOTES:
(1) Low duty cycle pulse testing with Kelvin connections required.
(2) VIN(MIN) = 2.25V.
(3) Defined as the input to output differential at which the output voltage drops 100mV below the value measured
at a differential of 1V. Not measurable on 1.5V and 1.8V parts due to minimum VIN constraints.
(4) Guaranteed by design.
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NOT RECOMMENDED FOR NEW DESIGN
SC1457
POWER MANAGEMENT
Pin Configuration
Ordering Information
Part Number
SC1457ISK-X.XTR(1)
SC1457ISKX.XTRT(1)(4)
SC1457ITSK-XXTR(1)
SC1457ITSKXXTRT(1)(4)
SC1457EVB(3)
Package
Top View
SOT-23-5(2)
TSOT-23-5(2)
N/A
Notes:
(SOT-23-5 & TSOT-23-5)
(1) Where X.X or XX denotes voltage options. Available
voltages are: 1.5V 5 or 15), 1.8V (1.8 or 18), 2.5V
(2.5 or 25), 2.7V (2.7 or 27), 2.8V (2.8 or 28), 2.9V (2.9
or 29), 3.0V (3.0 or 30), 3.1V (3.1 or 31), 3.2V (3.2 or
32) and 3.33.3 or 33).
(2) Only available in tape and reel packaging. A reel
contains 3000 devices.
(3Evaluation board for SC1457. Specify output voltage
opion when ordering.
(4) Lead free product. This product is fully WEEE and
Block Diagram
RoHS compliant.
Pin Descriptions
Pin
Pin Name
Pin Function
1
2
3
4
5
IN
Input pin
GND
EN
Ground pin. Can be used for heatsinking if needed.
Active high enable pin. Connect VIN if not being used.
Error Flag. Open drain output. Active low indicates an output undervoltage condition.
Regulator output sourcing up to 150mA.
FLG
OUT
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NOT RECOMMENDED FOR NEW DESIGN
SC1457
POWER MANAGEMENT
Marking Information
Top Mark
Bottom Mark
x7XX
yyww
x = package (5 for SOT-23-5, T for TSOT-23-5)
7 = SC1457
yyww = Date code
(example: 0008 for week 8 of 2000)
XX = voltage option
(examples: 5731 for 3.1V option in SOT-23-5,
T728 for 2.8V option in TSOT-23-5)
The regulator has its own current limit circuitry to
ensure thae output current will not damage the
device during output short, overload or start-up. The
current limit is guaranteed to be greater than 400mA to
allow fast charging of the output capacitor and high
iniial currents for DSP initialization.
Applications Information
Theory Of Operation
The SC1457 is intended for applications where very low
dropout voltage, low supply current and output voltage
monitoring are critical. It provides a very simple, low cost
solution that uses very little pcb real estate. Only two
external capacitors and one resistor are requiror
operation.
The SC1457 includes thermal shutdown circuitry to turn
off tdevice if TJ exceeds 150°C (typical), with the
device remaining off until TJ drops by 20°C (typical).
Reverse battery protection circuitry ensures that the
device cannot be damaged if the input supply is
accidentally reversed, limiting the reverse current to less
than 1.5mA.
The SC1457 contains a bandgap reference trimmed for
optimal temperature coefficient whicfed into the
inverting input of an error amplifier. The output voltage
of the regulator is divided down internally using a
resistor divider and compared the bandgp voltage.
The error amplifier drives the gate olow RDS(ON)
P-channel MOSFET pass device.
Component Selection - General
Output capacitor - Semtech recommends a minimum
capacitance of 1µF at the output with an equivalent
series resistance (ESR) of < 1Ω over temperature. While
the SC1457 has been designed to be used with ceramic
capacitors, it does not have to be used with ceramic
capacitors, allowing the designer a choice. Increasing the
bulk capacitance will further reduce output noise and
improve the overall transient response.
An active high enable pin (EN) allows the regulator to be
shut down. Pulling this pin low causes the device to
enter a very low power shutdown mode, where it will draw
typically 0.1µA from the input supply.
An open drain flag pin (FLG) is provided to signal
whenever the output voltage is 6% (typically) below
nominal. A tap is taken from the internal resistor divider
and compared to the bandgap voltage to determine if
the output voltage is above or below this level. The flag
pin pulls low whenever the output is out of specification.
An external pullup resistor is required for a high signal
when the flag pin is not pulling low. Since this circuitry is
powered from the input supply, the FLG pin will pull low
for output voltages all the way down to zero, unlike
external devices powered from the LDO output.
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 transients
is reduced, improving overall load transient response.
Flag pullup resistor - Semtech recommends a maximum
value of 100kΩ for this resistor to ensure that this pin is
high even under worst-case flag pin leakage conditions
of 1µA when off.
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NOT RECOMMENDED FOR NEW DESIGN
SC1457
POWER MANAGEMENT
Applications Information (Cont.)
With the standard SOT-23-5/TSOT-23-5 Land Pattern
shown at the end of this datasheet, and minimum trace
widths, the thermal impedance junction to ambient for
SC1457ISK is 256°C/W. Thus no additional heatsinking
is required for this example.
Thermal Considerations
The worst-case power dissipation for this part is given
by:
(1)
P
=
VIN(MAX) − VOUT(MIN) • IOUT(MAX) + VIN(MAX) • IQ(MAX)
( )
D(MAX)
The junction temperature can be reduced further (or
higher power dissipation can be allowed) by the use of
larger trace widths and connecting PCB copper to the
GND pin (pin 2), which connects directly to the device
substrate. Adding approximately one square inch of PCB
(2) copper to pin 2 will reduce θJA to approximately
130°C/W and X) for the example above to
approximately 100°C for the SOT-23-5 package. The use
of multi layeboards with internal ground/power planes
will lower thunction temperature and improve overall
output voltage accuracy.
For all practical purposes, equation (1) can be reduced
to the following expression:
P
=
VIN(MAX) − VOUT(MIN) • IOUT(MAX)
( )
D(MAX)
Looking at a typical application, 3.3V to 2.8V at 150mA:
VIN(MAX) = 3.3 + 5% = 3.465V
VOUT(MIN) = 2.8V - 2% = 2.744V
IOUT = 150mA
TA = 85°C
Layout Considerations
Inserting these values into equation (2) gives us:
While layout for linear devices is generally not as critical
as foswitching application, careful attention to detail
will enure reliable operation.
PD(MAX)
=
3.465 − 2.744 • 0.150 = 108mW
( )
) 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.
Using this figure, we can calculate the maximum thermal
impedance allowable to maintain TJ ≤ 1°C:
(
TJ(MAX) − TA(MAX)
)
(
125 − 85
)
θJA(MAX)
=
=
= 370°CW
PD(MAX)
0.
2) Place the input, output and bypass capacitors close
to the device for optimal transient response and device
behaviour.
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.
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NOT RECOMMENDED FOR NEW DESIGN
SC1457
POWER MANAGEMENT
Typical Characteristics
Quiescent Current vs. Junction Temperature
vs. Input Voltage
Off-State Quiescent Current
vs. Junction Temperature
120
200
175
150
125
100
75
VIN = 6.5V
VEN = 0V
IOUT = 150mA
VIN = 6.5V
100
80
60
40
20
0
V
IN = 3.8V
50
25
0
-50
-25
0
25
50
75
100
125
125
125
-50
0
25
50
75
100
125
125
125
T
J (°C)
T
J (°C)
Output Voltage vs. Junction Temperature
vs. Output Current
Line Regulation vs. Junction Temperature
vs. Input Voltage Change
0.00
-0.05
-0.10
-0.15
-0.20
-0.25
-0.30
12
10
8
I
OUT = 1mA
IOUT = 1mA
IOUT = 50mA
VIN = VOUT + 1V to 6.5V
6
100mA ≤ IOUT ≤ 150mA
4
2
VIN = VOUT + 1V to 5.5V
VIN = VOUT + 1V
0
-50
-25
0
2
50
75
100
-50
-25
0
25
50
75
100
T
J (°C)
TJ (°C)
Load Regulation vs.
Junction Temperature
Current Limit vs. Junction Temperature
vs. Input Voltage
10
9
8
7
6
5
4
3
2
1
0.90
0.85
0.80
0.75
0.70
0.65
0.60
0.55
0.50
0.45
0.40
VIN = VOUT + 1V
IOUT = 0.1mA to 150mA
VIN = 6.5V
V
IN = 3.8V
0
-50
-25
0
25
50
75
100
-50
-25
0
25
50
75
100
T
J (°C)
T
J (°C)
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NOT RECOMMENDED FOR NEW DESIGN
SC1457
POWER MANAGEMENT
Typical Characteristics (Cont.)
Dropout Voltage vs. Junction Temperature
Dropout Voltage vs. Output Current
vs. Junction Temperature
vs. Output Current
200
200
175
150
125
100
75
175
150
IOUT = 150mA
125
100
75
Top to bottom:
TJ = 125°C
TJ = 25°C
50
50
IOUT = 50mA
25
0
25
TJ = -40°C
0
-50
-25
0
25
50
75
100
125
0
5
50
75
100
125
150
T
J (°C)
I
OUT (mA)
Enable Input Threshold Voltage vs. Junction
Temperature vs. Input Voltage
Flag Threshold Voltage vs. Input Voltage
vs. Output Voltage
1.6
-4.0
-4.5
-5
-5.5
-6.0
-6.5
-7.0
-7.5
-8.0
1.4
1.2
1.0
0.8
0.6
0.4
VIH @ VIN = 6.5V
VIH @ VIN = 3.8V
V
OUT = 1.5V
VIL @ VIN = 6.5V
VOUT = 3.3V
V
IL @ VIN = 3.8V
-50
-25
0
25
50
75
100
125
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
6.5
T
J (°C)
V
IN (V)
Flag Threshold Voltage vs. Junction Temperature
Flag Voltage vs. Junction Temperature
vs. Flag Current
vs. Output Voltage
-4.0
200
175
150
125
100
75
VIN = 4.3V
-4.5
-5.0
VOUT = 1.5V
IFLG = 10mA
-5.5
-6.0
VOUT = 3.3V
-6.5
-7.0
-7.5
-8.0
50
I
FLG = 1mA
25
0
-50
-25
0
25
50
75
100
125
-50
-25
0
25
50
75
100
125
T
J (°C)
TJ (°C)
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NOT RECOMMENDED FOR NEW DESIGN
SC1457
POWER MANAGEMENT
Typical Characteristics (Cont.)
Reverse Battery Protection vs.
Junction Temperature
5.0
VIN = VEN = -6.5V
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
-50
-25
0
25
50
75
100
125
T
J (°C)
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NOT RECOMMENDED FOR NEW DESIGN
SC1457
POWER MANAGEMENT
Evaluation Board Schematic
J1
RIPPLE MON
J2
IN MON
J3
U1
SC1457
OUT
J4
1
3
5
4
IN
R1
IN
OUT MON
C1
C2
R4
C3
C4
R2
R3
FLG
EN
GND
2
J5
J6
1
2
C5
J8
EN
J7
IQ MON
FLG
1
2
3
EN
J9
Q1
DRV
J10
J11
J12
J13
J14
J15
GND GND GND GND GND GND
1
2
3
4
8
7
6
5
S
S
S
G
D
D
D
D
J16
1
2
3
Si4410
LOAD RV EN
Evaluation Board Bill of Materials
Quantity
Reference
Part/escription
Not placed
1µF ceramic
BNC socket
Test pin
Vendor
Notes
3
2
1
3
1
1
1
2
1
6
1
1
1
1
1
1
C1, C4, C5
C2, C3
J1
Murata
Various
Various
Various
Various
Various
Various
Various
Various
Vishay
Various
GRM42-6X7R105K10
OUT ripple monitor
V
J2 - J4
J5
Red
Test pin
White
J6
Header, 2 pin
Test pin
J7
Yellow
J8, J16
J9
Header, 3 pin
Test pin
Orange
Black
J10 - J15
Q1
Test pin
Si4410
R1
100kΩ, 1/10W
Not placed
See next page
10kΩ, 1/10W
R2
R3
Various
Various
Semtech
R4
U1
SC1457ISK-X.X or
SC1457ITSK-XX
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NOT RECOMMENDED FOR NEW DESIGN
SC1457
POWER MANAGEMENT
Evaluation Board Gerber Plots
Top Copper
Bottom Copper
Output Voltage Option (V)
R3 Value/Size
1.5
1.8
2.5
2.7
2.8
2.9
3.0
3.1
3.2
3.3
10Ω/0.5W
12Ω/0.5W
16Ω/0.5W
18Ω/0.5W
18Ω/0.5W
18Ω/0.5W
20Ω/0.5
20ΩW
22Ω/0.5W
22Ω/0.5W
Top Silk Screen
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NOT RECOMMENDED FOR NEW DESIGN
SC1457
POWER MANAGEMENT
Outline Drawing - SOT-23-5
DIMENSIONS
INCHES MILLIMETERS
A
DIM
A
MIN NOM MAX MIN NOM MAX
e1
D
E
-
-
-
-
.035
.057 0.90
.006 0.00
1.45
0.15
A1 .000
A2 .035 .045 .051
.90
.020 0.25
.009 0.08
1.15 1.30
N
1
-
-
-
-
b
.010
.003
0.50
0.22
2X
E/2
c
EI
D
.110 .114 .118 2.80 2.90 3.00
E1 .060 .063 .069 1.50 1.60 1.75
2
E
.110 BSC
.037 BSC
.075 BSC
2.80 BSC
0.95 BSC
1.90 BSC
ccc C
2X N/2 TIPS
e
e1
L
e
.012 .018 .024 0.30 0.45 0.60
(.024)
(0.60)
L1
N
B
5
5
-
-
01
0°
10°
0°
10°
aaa
.004
.008
.008
0.10
0.20
0.20
D
bbb
ccc
aaa C
A2
A
SEATING PLANE
A1
bxN
bbb
H
C
c
GAGE
C A-B D
PLANE
0.25
L
01
(L1)
DETAIL A
DETAIL A
SIDE VIEW
NOTES:
1. CONTROLLING DIMENSIONS IN MILLIMETERS ANGLES IN DEGREES).
2. DATUMS -A- AND -B- TO BE DETERMIND ADATUM PLANE -H-
3. DIMENSIONS "E1" AND "D" DO NOT INCLUDE MOLD FLASH, PROTRUSIONS
OR GATE BURRS.
Outline Drawing - TSOT-23-5
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NOT RECOMMENDED FOR NEW DESIGN
SC1457
POWER MANAGEMENT
Land Pattern - SOT-23-5 & TSOT-23-5
X
DIMENSIONS
DIM
INCHES
MILLIMETERS
(.098)
.055
.037
.024
.043
.141
(2.50)
1.40
0.95
0.60
1.10
3.60
C
G
P
X
Y
Z
(C)
G
Z
Y
P
NOTES:
1. THIS LAND PATTERN IS FOR REFERENCE PURPOSES ONLY.
CONSULT YOUR MANUFACTURING GROUP TO ENSURE YOUR
COMPANY'S MANUFACTURING GUIDELINES ARE MET.
Contact Information
Semtech Corporation
Power Management Products Division
200 Flynn Road, Camarillo, CA 93012
Phone: (805)498-2111 FAX (805)498-3804
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SEMTECH
SC1457ITSK31TRT
Fixed Positive LDO Regulator, 3.1V, 0.23V Dropout, CMOS, PDSO5, 1 MM HEIGHT, ROHS COMPLIANT, TSOT-23, 5 PIN
SEMTECH
SC1457ITSK32TRT
Fixed Positive LDO Regulator, 3.2V, 0.23V Dropout, CMOS, PDSO5, 1 MM HEIGHT, ROHS COMPLIANT, TSOT-23, 5 PIN
SEMTECH
SC1457ITSK33TRT
Fixed Positive LDO Regulator, 3.3V, 0.23V Dropout, CMOS, PDSO5, 1 MM HEIGHT, ROHS COMPLIANT, TSOT-23, 5 PIN
SEMTECH
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