SEMTECH SC4215J

SC4215J
Very Low Input /Very Low Dropout
2 Amp Regulator With Soft-Start
POWER MANAGEMENT
Features










Description
Input Voltage as Low as 1.4V
400mV Dropout @ 2A
Adjustable Output from 0.5V
1ms Internal Soft-Start Minimizes Inrush Current
Over Current and Over Temperature Protection
Enable Function Option
10µA Quiescent Current in Shutdown
Reverse Blocking from Output to Input
Full Industrial Temperature Range
Fully WEEE and RoHS Compliant
Applications
The SC4215J 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
amperes. It operates with a Vin as low as 1.4V, with output
voltage programmable as low as 0.5V. The SC4215J features ultra low dropout, ideal for applications where Vout
is very close to Vin. Additionally, the SC4215J has an enable
pin to further reduce power dissipation while shut down.
The SC4215J provides excellent regulation over variations
in line, load and temperature.
The SC4215J is available in the SOIC-8-EDP (Exposed Die
Pad) package. The output voltage can be set via an external divider or to a fixed setting of 0.5V depending upon
how the FB pin is configured.
Telecom and Networking Cards
Motherboards and Peripheral Cards
 Industrial Applications
 Wireless Infrastructure
 Medical Equipment


Typical Application Circuit
SC4215J
SC4215J
0 .5 R 1
R2
R1
0 .5 V
C1
C2
R2
C2
C1
R2
Rev. 2.0
© 2012 Semtech Corporation
SC4215J
Pin Configuration
Ordering Information
Device
Package
SC4215JSETRT(1)(2)
SOIC-8-EDP
SC4215JEVB
Evaluation Board
Notes:
(1) Available in tape and reel only. A reel contains 2,500 devices.
(2) Available in lead-free package only. Device is WEEE and RoHS
compliant and halogen free.
Marking Information
S C 4 2 1 5J
SC4215J
Absolute Maximum Ratings
Recommended Operating Conditions
VIN, EN, VO, FB to GND (V) . . . . . . . . . . . . . . . . . . -0.3 to +7.0
VIN (V). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.4 < VIN < 6.0
Power Dissipation. . . . . . . . . . . . . . . . . . . . . . Internally Limited
Junction Temperature Range (°C). . . . . . . . . . -40 < TJ < +125
ESD Protection Level (kV) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Maximum Output Current (A). . . . . . . . . . . . . . . . . . . . . . . . . 2
(1)
Thermal Information
Thermal Resistance, Junction to Ambient(2) (°C/W) . . . . 36
Thermal Resistance, Junc to Case(2) (°C/W). . . . . . . . . . . . 5.5
Maximum Junction Temperature (°C). . . . . . . . . . . . . . +150
Storage Temperature Range (°C) . . . . . . . . . . . . -65 to +150
Peak IR Reflow Temperature (10s to 30s) (°C) . . . . . . . +260
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) Tested according to JEDEC standard JESD22-A114-B.
(2) Calculated from package in still air, mounted to 3” x 4.5”, 4 layer FR4 PCB with thermal vias under the exposed pad per JESD51 standards.
Electrical Characteristics
Unless specified: VEN = VIN, VFB = VO, VIN = 1.40V to 6.0V, IO = 10µA to 2A, TJ = 25° C.
Values in bold apply over the full operating temperature range.
Parameter
Symbol
Conditions
Max
Units
6.0
V
3
mA
10
50
µA
90
400
VIN = 3.3V, IO = 0A
IQ
VIN = 6.0V, VEN =0V
IO =1A
Dropout Voltage(2)(3)
Typ
1.4
VIN Operating Range (1)
Quiescent Current
Min
VDO
IO =1.5A
IO = 2A
Minimum Load Current(4)
IO
Current Limit
ICL
1.4V ≤ VIN < 1.6V
200
1.6V ≤ VIN ≤ 6.0V
1.4V ≤ VIN < 1.6V
200
500
mV
300
1.6V ≤ VIN ≤ 6.0V
1.4V ≤ VIN < 1.6V
300
600
400
1.6V ≤ VIN ≤ 6.0V
2.1
3
10
µA
4.4
A
SC4215J
Electrical Characteristics (continued)
Parameter
Symbol
Conditions
Min
Typ
Max
Units
Feedback
0.495
Reference Voltage(2)
VREF
Line Regulation
Load Regulation (5)
Feedback Pin Current
VIN = 3.3V, IO =10mA
0.505
0.500
0.490
0.510
0.485
0.515
V
IO = 10mA
0.2
%/V
IO = 10mA to 2A
0.3
%
VFB = VREF
80
200
nA
VEN = 0V, VIN =3.3V
1.5
10
µA
EN
Enable Pin Current
Enable Pin Threshold
IEN
VIH
VIL
1.6
VIN=3.3V
V
0.4
Over Temperature Protection
High Trip Level
Hysteresis
THI
160
O
C
THYST
10
O
C
Soft-Start
Soft-Start Time (6)
tSS
0.7
1
ms
Notes:
(1) Minimum VIN = VOUT + VDO or 1.4V, whichever is greater.
(2) Low duty cycle pulse testing with Kelvin connections required.
(3) VDO = VIN -VO when VO decreases by 1.5% of its nominal output voltage with VIN = VO +0.8V.
(4) Required to maintain regulation. Voltage set resistors R1 and R2 are usually utilized to meet this requirement.
(5) Where the power dissipation does not exceed the maximum rating of the package. Refer to Figure 1 on page 8.
(6) Time taken for the output to rise from 0% to 95% of the programmed output voltage.
SC4215J
Typical Characteristics
Dropout Voltage at VO = 1.5V
0 .4
0 .4
0.3
0.3
Dropout Voltage (V)
Dropout Voltage (V)
Dropout Voltage at VO = 3.3V
0.2
2 5 °C
1 2 5 °C
0.1
0.2
0.1
-4 0 °C
-4 0 °C
0 .0
0 .0
0 .5
1.0
Load Current (A)
1.5
0 .0
2 .0
0 .0
3 .5
1200
3 .0
1000
2 .5
1 .0
Load Current (A)
1 .5
2 .0
800
Tss (us)
ILIM (A)
0 .5
Startup Time vs Temperature
Current Limit vs Temperature
2 .0
1 .5
600
400
1 .0
200
0 .5
0
0 .0
-5 0
0
50
100
-5 0
150
0
50
100
150
o
o
Temperature ( C)
Temperature ( C)
EN Threshold vs VIN
Power-Supply Ripple Rejection vs Frequency
VIN = 5.0V, VOUT = 3.3V
70
2 .0
Io= 2A
60
1 .6
50
-40 o C
PSRR(dB)
Enable On Threshold (V)
2 5 °C
1 2 5 °C
1 .2
0 .8
125 o C
25 o C
40
Io= 0.1A
30
20
0 .4
10
0 .0
1 .0
2 .0
3 .0
4 .0
Input Voltage VIN (V)
5 .0
6 .0
0
1 0 0 .0 E+0
1 .0 E+3
1 0 .0 E+3
1 0 0 .0 E+3
1 .0 E +6
1 0 .0 E+6
Frequency (Hz)
SC4215J
Pin Descriptions
Pin #
Pin Name
2
EN
Enable input. Driving this pin high turns on the regulator. Driving this pin low shuts off the regulator. If not driven from a control circuit, tie this pin to the VIN pin.
3
VIN
Input supply pin. A large bulk capacitance should be placed close to this pin to ensure that the
input supply does not sag below the minimum VIN. Also a minimum of 4.7uF ceramic capacitor
should be placed directly at this pin.
6
VO
Regulator output pin. Refer to the Applications Information section for output capacitor selection.
7
FB
Inverting input of the error amplifier. This pin is used to set the output voltage (See typical Application Circuits on page 1).
8
GND
1, 4, 5
NC
THERMAL PAD
Pin Function
Ground pin.
No connection.
The exposed pad enhances thermal performance and is not electrically connected to GND inside
the package. It is recommended to connect the exposed pad to the ground plane.
Block Diagram
SS
SC4215J
Applications Information
Introduction
The SC4215J is intended for applications where high
current capability and very low dropout voltage are
required. It provides a very simple, low cost solution that
uses very little PCB area. Additional features include an
enable pin to allow for a very low power consumption in
standby mode, and a fully adjustable output.
device being some distance from any bulk capacitance on
the rail. Additionally, the input droop due to load transients is reduced, improving load transient response.
Additional capacitance may be added if required by the
application.
Output Capacitor
By connecting the FB pin directly to the VO pin, the output
voltage will be regulated to the 0.5V internal reference.
A minimum bulk capacitance of 10µF/A (output load),
along with a 0.1µF ceramic decoupling capacitor is recommended. For VO less than 0.6V, a minimum bulk capacitance of 40µF, along with a 0.1µF ceramic decoupling
capacitor is recommended. 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
SC4215J is extremely tolerant of output capacitor ESR
values and thus will also work comfortably with tantalum
output capacitors.
VO Setting with External Resistors
Soft-Start
The use of 1% resistors, and designing for a current flow ≥
10µA is recommended to ensure a well regulated output
(thus R2 ≤50kΩ). A suitable value for R2 can be chosen in
the range of 1kΩ to 50kΩ. R1 can then be calculated from.
The soft-start is achieved by using a voltage ramp as the
voltage reference for the internal error amplifier during
startup. This voltage ramp is created by an internal current
source charging an internal soft-start capacitor. When the
voltage ramp reaches 500mV, the voltage reference for
the internal error amplifier switches to the fixed 500mV
VREF. Thus, during soft-start, the output tracks the internal
voltage ramp, which limits the input inrush current and
provides a programmed soft-start profile for a wide range
of applications.
Noise Immunity
In very electrically noisy environments, it is recommended
that 0.1µF ceramic capacitors be placed from VIN to GND
and VO to GND as close to the device pins as possible.
VO Setting: VO=VREF
5 =5 ⋅
(92 − 95() )
95()
Enable
Pulling this pin below 0.4V turns the regulator off, reducing the quiescent current to a fraction of its operating
value. Driving this pin high enables the regulator. A pull
up resistor up to 400kOhms should be connected from
this pin to the VIN pin in applications where the Enable
pin is not driven from a control circuit.
Input Capacitor
A large bulk capacitance ≥ 10µF/A (output load) should be
placed close to the input supply pin of the SC4215J to
ensure that VIN does not drop below the minimum VIN. Also
a minimum of 4.7µF ceramic capacitor is recommended to
be placed directly next to the VIN pin. This allows for the
Over-Current and Thermal Shutdown
The over-current protection and thermal shutdown functions protect the regulator against damage due to excessive power dissipation. The SC4215J is designed to current
limit when the output current reashes 3A (typical). When
the load exceeds 3A, the output voltage is reduced to
maintain a constant current limit.
The thermal shutdown function limits the junction temperature to a maximum of 160OC (typical). Thermal shutdown turns off the regulator as the junction temperature
begins to exceed 160OC. When the junction temperature
SC4215J
Applications Information (Cont.)
drops below 150OC (typical), the regulator is turned on
again.
Thermal Considerations
The power dissipation in the SC4215J is given by the following equation:
PD ≈ IO(VIN - VO)
The allowable power dissipation will be dependant upon
the thermal impedance achieved in the application. The
derating curve below is valid for the thermal impedance
specified in the Thermal Information section on page 3.
Figure 1. Power Derating Curve
SC4215J
Outline Drawing — SOIC-8-EDP-2
SC4215J
Land Pattern — SOIC-8-EDP-2
10
SC4215J
© Semtech 2012
All rights reserved. Reproduction in whole or in part is prohibited without the prior written consent of the copyright
owner. The information presented in this document does not form part of any quotation or contract, is believed to be
accurate and reliable and may be changed without notice. No liability will be accepted by the publisher for any consequence of its use. Publication thereof does not convey nor imply any license under patent or other industrial or intellectual property rights. Semtech assumes no responsibility or liability whatsoever for any failure or unexpected operation
resulting from misuse, neglect improper installation, repair or improper handling or unusual physical or electrical stress
including, but not limited to, exposure to parameters beyond the specified maximum ratings or operation outside the
specified range.
SEMTECH PRODUCTS ARE NOT DESIGNED, INTENDED, AUTHORIZED OR WARRANTED TO BE SUITABLE FOR USE IN LIFESUPPORT APPLICATIONS, DEVICES OR SYSTEMS OR OTHER CRITICAL APPLICATIONS. INCLUSION OF SEMTECH PRODUCTS
IN SUCH APPLICATIONS IS UNDERSTOOD TO BE UNDERTAKEN SOLELY AT THE CUSTOMER’S OWN RISK. Should a customer
purchase or use Semtech products for any such unauthorized application, the customer shall indemnify and hold
Semtech and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs damages
and attorney fees which could arise.
Notice: All referenced brands, product names, service names and trademarks are the property of their respective
owners.
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
11