SEMTECH SC4437SK

SC4437
Wide Input Voltage Range
Precision Voltage Reference
POWER MANAGEMENT
Features
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Description
VIN Voltage Range: VOUT + 0.9V to 28V
VOUT: Fixed 3.3V
VOUT High Accuracy ( ±1% ) over -40°C to 125°C
VOUT Low Temperature Coefficient
Output Current up to 20mA
Low (< 160µA) Quiescent Current
Stable without Compensation Capacitor
Available with Compact, Surface Mount SOT-23
Package
Pb-Free, Halogen Free, RoHS/WEEE compliant
product
Applications
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The SC4437 is a low power precision series bandgap
reference device. It accepts wide input voltage range VOUT
+ 0.9V to 28V and generates stable output voltage with
superior accuracy and low drift over operating
temperatures. The SC4437 is ideal for battery powered
systems where there can be wide variations in supply
voltage and a need to minimize power dissipation.
The SC4437 is able to supply up to 20mA output current
with excellent line and load regulation characteristics.
The output compensation capacitor is optional. It
provides user the flexibility of compact, low cost design
or further noise performance enhanced design.
The SC4437 is available in a compact 3-lead surface
mount SOT-23 package.
Bias Supplies
High Accuracy Micropower Supplies
Data Acquisition Systems
Medical Devices
Portable Battery Powered Equipment
Test Equipment
Automotive and Industrial
Typical Application Circuit
SC4437
VIN up to 28V
CIN
0.1 µF
September 21, 2009
OUT
IN
3.3V
CO
(optional)
GND
1
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SC4437
Pin Configuration
Ordering Information
Device
Package
SC4437SK-3.3TRT
3-Lead Plastic SOT-23
SC4437EVB
Evaluation Board
TOP VIEW
IN 1
3 GND
OUT 2
Notes:
(1) Available in tape and reel only. A reel contains 3,000 devices.
(2) Pb-Free, Halogen Free, RoHS/WEEE compliant product.
3-LEAD PLASTIC SOT-23
θJA = 202°C/W
Marking Information
© 2009 Semtech Corp.
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SC4437
Recommended Operating Conditions
Absolute Maximum Ratings
VIN Voltage ……………………………………………… 30V
VIN Voltage …………………… …………………… 4.2 to 28V
Reverse Voltage …………………………………………-15V
Maximum Output Current ………………………………… 20mA
Output Short Circuit Duration ………………… Indefinite(1)
Temperature Range ……………………………-40˚C to 125˚C
Lead Temperature (Soldering) 10 seconds (2) ………… 260°C
ESD Rating ……………………………………… … …… 2kV
Thermal Information
Thermal Resistance, Junction to Ambient(3) ……… 202 °C/W
Maximum Junction Temperature …………………… +150°C
Storage Temperature Range(4) ………………-65°C to +150°C
Exceeding the above specifications may result in permanent damage to the device or device malfunction. Operation outside of the parameters
specified in the Electrical Characteristics section is not recommended.
NOTES:
(1) For VIN ≤ 10 V.
(2) Compatible for Wave Soldering and IR Reflow.
(3) Calculated from package in still air, mounted to 3” x 4.5”, 4 layer FR4 PCB per JESD51 standards.
(4) If the part is stored outside of the specified temperature range, the output may drift.
Electrical Characteristics
Unless specified: VIN= VOUT + 2.5V, IOUT = 0, CIN= 0.1µF, CO = 0µF, -40°C< TA =TJ < 125°C
Parameter
Symbol
Conditions
Min
VIN
Refer to Line Regulation Spec.
4.2
Typ
Max
Units
28
V
INPUT
Input Voltage Range
Drop Out Voltage
VIN-VOUT
IOUT = 0
0.6
0.9
V
IOUT = 10mA, TA = 25°C
0.9
1.28
V
1.38
V
IOUT = 10mA
Leakage Current for Input Voltage
Reverse Connection
IREV
Quiescent Current
IQ
VIN = -15V
2
6
µΑ
TA = 25°C
110
180
µΑ
220
µΑ
OUTPUT
Output Voltage
Output Voltage Accuracy
VOUT
TJ =25°C
3.3
%
0°C≤TJ < 100°C, 0mA<IOUT ≤ 20mA,
4.2V ≤VIN ≤28V
VOUT + 0.9V ≤ VIN ≤ VOUT +2.5V
Line Regulation
dVOUT/dVIN
TA = 25°C
VOUT + 2.5V ≤ VIN ≤ 28V
© 2009 Semtech Corp.
TA = 25°C
3
-1
100
50
V
1
%
500
ppm/V
3300
ppm/V
100
ppm/V
300
ppm/V
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SC4437
Electrical Characteristics (continued)
Unless specified: VIN= VOUT + 2.5V, IOUT = 0, CIN= 0.1µF, CO = 0µF, -40°C< TA =TJ < 125°C
Parameter
Symbol
Conditions
TA = 25°C
IOUT = 100µA
Load Regulation
dVOUT/dILOAD
Min
TA = 25°C
IOUT = 10mA
TA = 25°C
IOUT = 20mA
Typ
Max
Units
3000
4000
ppm/mA
6000
ppm/mA
150
ppm/mA
250
ppm/mA
100
ppm/mA
150
ppm/mA
120
ppm/°C
100
75
Output Voltage Temperature
Coefficient
dVOUT/dT
0°C≤ TJ < 105°C
80
Output Short Circuit Current
ISC
Short VOUT to GND, TA = 25°C
55
TON
VIN > VOUT + 2.5V, VOUT settles to ±0.05% of final
value
mA
DYNAMIC
Turn-On Settling Time
3 (1)
ms
NOTES:
(1) Guaranteed by design.
© 2009 Semtech Corp.
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SC4437
Pin Descriptions
Pin #
Pin Name
1
VIN
Input supply voltage for the precision voltage reference.
2
VOUT
Output voltage.
3
GND
Ground connection for the circuit.
© 2009 Semtech Corp.
Pin Function
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SC4437
Typical Waveforms
Minimum Input - Output Voltage Differential
Supply Current vs Input Voltage
Minimum Input-Output Voltage Differential
150
140
130
120
110
100
90
80
70
60
50
Supply Current (µA)
20
Load Current (mA)
Supply Current vs Input Voltage
15
125 °C
-55 °C
10
5
25 °C
0
0
0.5
1
1.5
Input-Output Voltage (V)
2
125 °C
25 °C
-55 °C
0
Load Regulation - Sourcing
Output Voltage - 3.3V (mV)
Output Voltage - 3.3V (mV)
0
25 °C
125 °C
-20
-55 °C
-30
5
10
15
Output Current (mA)
20
Load Regulation, Sinking
Load Regulation, Sourcing
0
10
15
Input Voltage (V)
Load Regulation - Sinking
10
-10
5
180
130
80
30
25 °C
-55 °C
-20
20
Line Regulation
125 °C
0
0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8
Output Current (mA)
2
Power Supply Rejection Ratio vs Frequency
Line Regulation
Power Supply Rejection Ratio vs Frequency
100
25 °C
3.3
3.29
PSRR (dB)
Output Voltage (V)
3.31
125 °C
-55 °C
3.28
10
3.27
1
3.26
0
5
© 2009 Semtech Corp.
10
15
Input Voltage (V)
20
0.1
6
1
10
100
Frequency (KHz)
1000
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SC4437
Typical Waveforms (Continued)
Output Impedance
Start Up with Input Voltage 20 V
Output Impedance (Ohm)
Output Impedance vs Frequency
1000
100
No Output Cap
10
1 ȝF Output Cap
1
0.01
0.1
1
10
100
Frequency (KHz)
1000
Output Noise Performance 10 Hz to 100 kHz
Output Noise Waveform 0.1Hz to 10 Hz
Noise Density uV/(Hz^0.5)
Noise Density VS Frequency
1.000
0.100
0.01
0.1
1
10
100
Frequency (kHz)
1 mA Transient Response without Output Cap
© 2009 Semtech Corp.
1 mA Transient Response with 1 µF Output Cap
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SC4437
Block Diagram
VIN
VOUT
GND
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SC4437
Applications Information
Advantage Over Shunt References
The SC4437 is a low power precision series voltage
reference. The series reference has major advantages over
shunt references when the load current has variations and
the reference is powered by a battery. A shunt reference
requires a resistance to connect the input and the output.
This resistance will be designed to consume the maximum
load current. When the actual load current is smaller than
the maximum load current, the difference will be
consumed by the reference. This behavior not only reduce
efficiency but also increase the thermal stress on the
device, thus is not desirable. On the contrary, the series
reference consumes the same current as the load. When
there is no load current required, the device itself
consumes very little current (in the scale of 10s of µA).
improve the dynamic response under load transient. In
order to obtain optimum performance under load
transient, it is recommended that a 0.1 µ F ceramic
capacitor placed at the input and a 1 µF (and up) ceramic
capacitor placed at the output.
Reverse Battery Connection Protection
The SC4437 has reverse battery connection protection.
When the input and ground is reversely connected, the
leakage current from the input is very small (maximum 6
µA), protecting both the battery and the device itself.
Load Transient Responses
The following figure shows the circuit setup to test the 1
mA load transient response.
3.3V
Precision Reference Over Wide Input Voltage Range, Load
Conditions and Operating Temperatures
2.3V
SC4437
The SC4437 can maintain 1% precision regulation over
wide load range, operating temperature condition and
input voltage range. To provide 3.3V output voltage, the
load can range from 0 to 20mA; the temperature can
range from -40 °C to 125 °C; the input voltage can range
from V OUT + 0.9V to 28V, depending on the load and
temperature conditions. The input voltage range should
be selected based on the drop out voltage specification.
Although the SC4437 can maintain tight regulation over
wide operating conditions, attention should be paid to
the thermal stress of the device. For example, with the
input voltage of 28V and the load current of 20mA, the
power consumption on the device is
P = (28V-3.3V)*0.02A = 0.494W
With the thermal resistance of 202 °C/W, the power
consumption on the chip gives an ambient to junction
temperature increase of 99.8 °C. If the ambient temperature
is higher than 25 °C, then the junction temperature will be
higher than 125°C, thus should be avoided.
Input and Output Capacitances
The SC4437 is stable with or without output capacitors
under all load conditions. Adding output capacitances can
© 2009 Semtech Corp.
5.8V
OUT
IN
CIN
0.1 µF
1 kȍ
GND
3.3V
CO
(optional)
Without output capacitance, the transient response is
shown below.
The high overshoot is due to the high resistance at high
frequency without output capacitance.
With 1µF capacitance, the transient response is improved
significantly. The figure below shows the 1mA transient
response with 1 µF capacitance at the output.
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SC4437
Applications Information (continued)
Noise Density uV/(Hz^0.5)
Noise Density VS Frequency
1.000
0.100
0.01
0.1
1
10
100
Frequency (kHz)
Start Up
With the input voltage 5.8V, the device shows very small
start up overshoot, as shown by the figure below.
Low Noise Operation
The SC4437 is a low noise reference. The noise is measured
with high gain amplification and band filtering. Without
any output capacitor the noise level is measured to be
around 0.7 µV/√Hz from 0 to 100 kHz. With output capacitor
the noise level will be significantly lower. The following
figure shows the noise measurement result under room
temperature without output capacitor from 10Hz to
100kHz and the scope picture of noise measurement
result from 0.1 Hz to 10 Hz .
© 2009 Semtech Corp.
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SC4437
Outline Drawing – SOT-23 3L
D
A
DIM
e1
A
A1
A2
b
c
D
E
E1
e
e1
L
L1
N
0
aaa
bbb
3
B
E
E1
1
2
bxN
e
bbb
.035
.000
.035
.012
.003
.110
.082
.047
.015
0°
.037
-
.114
.093
.051
.075
.037
.020
.022
3
-
.044
.004
.040
.020
.007
.120
.104
.055
.024
8°
.004
.008
1.12
0.89
0.10
0.01
0.88 0.95 1.02
0.51
0.30
0.18
0.08
2.80 2.90 3.04
2.10 2.37 2.64
1.20 1.30 1.40
1.90 BSC
0.95 BSC
0.40 0.50 0.60
(0.55)
3
0°
8°
0.10
0.20
C A B
A2
A
DIMENSIONS
MILLIMETERS
INCHES
MIN NOM MAX MIN NOM MAX
aaa C
3X
SEATING PLANE
A1
C
H
GAUGE
PLANE
SEATING
PLANE
C
SIDE VIEW
0
c
0.25
L
L1
SEE DETAIL A
DETAIL A
NOTES:
1. CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES).
2. DATUMS -A- AND -B- TO BE DETERMINED AT DATUM PLANE
-H-
3. DIMENSIONS "E1" AND "D" DO NOT INCLUDE MOLD FLASH, PROTRUSIONS
OR GATE BURRS.
© 2009 Semtech Corp.
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SC4437
Land Pattern – SOT-23
Contact Information
Semtech Corporation
Power Management Products Division
200 Flynn Road, Camarillo, CA 93012
Phone: (805) 498-2111 Fax: (805) 498-3804
www.semtech.com
© 2009 Semtech Corp.
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