1 www.semtech.com
SC4215A
Very Low Input /Very Low Dropout
2 Amp Regulator With Enable
POWER MANAGEMENT
POWER MANAGEMENT PRELIMINARY
Revision July 12, 2004
The SC4215A is a high performance positive voltage
regulator designed for use in applications requiring very
low Input voltage and very low dropout voltage at up to 2
amp. It operates with a Vin as low as 1.4V, with output
voltage programmable as low as 0.5V. The SC4215A fea-
tures ultra low dropout, ideal for applications where Vout
is very close to Vin. Additionally, the SC4215A has an en-
able pin to further reduce power dissipation while shut
down. The SC4215A provides excellent regulation over
variations in line, load and temperature.
The SC4215A is available in the SOIC-8EDP (Exposed Die
Pad) package. The output voltage can be set via an exter-
nal divider or to 0.5V depending on how the FB pin is con-
figured.
Input Voltage as low as 1.4V
500mV dropout @ 2A
Adjustable output from 0.5V to 3.3V
Over current and over temperature protection
Enable pin
10µA quiescent current in shutdown
Low reverse leakage (output to input)
Full industrial temperature range
Available in SOIC-8EDP package
Telecom/Networking cards
Motherboards/Peripheral cards
Industrial Applications
Wireless infrastructure
Set top boxes
Medical equipment
Notebook computers
Battery powered systems
Description Features
Applications
Typical Application Circuits
C2
U1
4
3
2
81
5
6
7
NC
VIN
EN
GNDNC
NC
VO
FB
VO = 0.5VVIN
C1
ENABLE
ENABLE
C1
R2
VIN
R1
U1
4
3
2
81
5
6
7
NC
VIN
EN
GNDNC
NC
VO
FB
VO
C2
Volts
R2
R2)(R10.5
VO +
=
SC4215A
SC4215A
22004 Semtech Corp. www.semtech.com
SC4215A
POWER MANAGEMENT PRELIMINARY
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Note: (1) 2 square inch of FR-4, double sided, 1 oz. minimum copper weight.
Absolute Maximum Ratings
Electrical Characteristics
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.
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Unless specified: VEN = VIN, VFB = VO, VIN = 1.40V to 5.5V, VIN = (VO + 0.5V) to 5.5V and IO = 1mA to 1A.
Values in bold apply over the full operating temperature range.
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 0.5V.
(3) Required to maintain regulation. Voltage set resistors R1 and R2 are usually utilized to meet this requirement.
(4) Guaranteed by design.
32004 Semtech Corp. www.semtech.com
SC4215A
POWER MANAGEMENT PRELIMINARY
Electrical Characteristics (Cont.)
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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 0.5V.
(3) Required to maintain regulation. Voltage set resistors R1 and R2 are usually utilized to meet this requirement.
(4) Guaranteed by design.
Unless specified: VEN = VIN, VFB = VO, VIN = 1.40V to 5.5V, VIN = (VO + 0.5V) to 5.5V and IO = 1mA to 1A.
Values in bold apply over the full operating temperature range.
42004 Semtech Corp. www.semtech.com
SC4215A
POWER MANAGEMENT PRELIMINARY
Volts
R2
R2)(R10.5
VO +
=
Pin Descriptions
Pin Configuration
Ordering Information
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Note:
(1) Available voltage is : 0.5V or Output voltage can be adjusted using
external resistors, see Pin Descriptions.
(2) Only available in tape and reel packaging 2500 devices for the
SOIC-8EDP package.
(3) Lead free product.
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Top View
SOIC-8EDP
VIN
NC
NC NC
EN
VO
FB
GND 1
2
3
4
EN
NC
5
6
7
8
NC
FB
VO VIN
NC
GND
GND
Exposed
Die Pad
Bottom View
SOIC-8EDP
52004 Semtech Corp. www.semtech.com
SC4215A
POWER MANAGEMENT PRELIMINARY
Block Diagram
Rsense
Vin
VIN
Vout
GND
Vpump
FB
Reverse Voltage
Shutdown
0.5V Ref
Vdd
VOUT
EN
Thermal
Shutdown
+-
+
-
+
-
UVLO
62004 Semtech Corp. www.semtech.com
SC4215A
POWER MANAGEMENT PRELIMINARY
Introduction
The SC4215A is intended for applications where high cur-
rent capability and very low dropout voltage are required.
It provides a very simple, low cost solution that uses very
little PCB real estate. Additional features include an en-
able pin to allow for a very low power consumption standby
mode, and a fully adjustable output.
Component Selection
Input capacitor: A large bulk capacitance of about 100uF
should be closely placed to the input supply pin of the
SC4215A to ensure that Vin does not sag below 1.4V. Also
a minimum of 4.7µF ceramic capacitor is
recommended to be placed directly next to the Vin pin.
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.
Output capacitor: a minimum bulk capacitance of 10µF,
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 SC4215A is extremely tolerant of
output capacitor ESR values and thus will also work
comfortably with tantalum output capacitors.
Noise immunity: in very electrically noisy environments, it
is recommended that 0.1µF ceramic capacitors be placed
from IN to GND and OUT to GND as close to the device pins
as possible.
External voltage selection resistors: the use of 1%
resistors, and designing for a current flow ≥ 10µA is
recommended to ensure a well regulated output (thus R2
≤ 120kΩ).
Applications Information
Thermal Considerations
The power dissipation in the SC4215A is approximately
equal to the product of the output current and the input to
output voltage differential:
()
OD IVOUTVINP •−≈
The absolute worst-case dissipation is given by:
()
)()()()()()( MAXQMAXMAXOMINMAXMAXD IVINIVOUTVINP •+•−=
For a typical scenario, VIN = 3.3V ± 5%, VOUT = 2.8V and
IO = 1A, therefore:
VIN(MAX) = 3.465V, VOUT(MIN) = 2.744V and IQ(MAX) = 1.75mA,
Thus PD(MAX) = .722W.
Using this figure, and assuming TA(MAX) = 70°C, we can cal-
culate the maximum thermal impedance allowable to main-
tain TJ ≤ 150°C:
()
()
WC
P
TT
R
MAXD
MAXAMAXJ
MAXAJTH /110
722.
70150
)(
)()(
))(( °=
−
=
−
=
−
This should be achievable for the SOIC-8EDP package us-
ing PCB copper area to aid in conducting the heat away,
such as one square inch of copper connected to the ground
pins of the device. Internal ground/power planes and air
flow will also assist in removing heat. For higher ambient
temperatures it may be necessary to use additional cop-
per area.
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SC4215A
POWER MANAGEMENT PRELIMINARY
Outline Drawing - SOIC-8EDP
Land Pattern - SOIC-8EDP
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SC4215A
POWER MANAGEMENT PRELIMINARY
Semtech Corporation
Power Management Products Division
200 Flynn Road, Camarillo, CA 93012
Phone: (805)498-2111 FAX (805)498-3804
Contact Information