SC4217 Datasheet

SC4217
Very Low Input /Very Low Dropout
3 Amp Regulator With Enable
POWER MANAGEMENT
Features
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Description
Input voltage range from 1.8V to 5.5V
Typical 300mV dropout @ 3A
Adjustable output from 1.24V
Over-current and over-temperature protection
Enable pin
10µA shutdown current
Full industrial temperature range
TO263-5 package, fully WEEE and RoHS compliant
Applications
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The SC4217 is a 3A, high performance LDO designed for
use in applications requiring very low input voltage and
very low dropout voltage. It operates with an input voltage as low as 1.8V and a programmable output voltage
from 1.24V. The SC4217 features ultra- low dropout, ideal
for applications where VOUT is very close to V IN . Additionally, the SC4217 has an enable pin to further reduce
power dissipation while shut down. The SC4217 provides
excellent regulation over line, load and temperature.
The SC4217 is available in a TO263-5 package and is fully
WEEE and RoHS compliant.
Telecom/networking equipment
Motherboards/peripheral cards
Industrial equipment
Wireless infrastructure
Set-top boxes
Medical equipment
Typical Application Circuit
EN
1
SC4217
EN
2
VIN
VO
VIN
3
GND
ADJ
VO
4
5
R1
C2
C1
R2
0
Nov. 17, 2011
0
SC4217
Pin Configuration
Ordering Information
TOP VIEW
2
3
Package
SC4217MTRT(1)(2)
TO263-5
SC4217EVB
Evaluation Board
Notes:
) Available in tape and reel only. A reel contains 800 devices.
2) Device is WEEE and RoHS compliant.
TAB
1
Device
4
5
(TO263-5L)
Marking Information
SC4217
Recommended Operating Conditions
Absolute Maximum Ratings
VIN Range……………………………………………
1.8V to 5.5V
VIN, VO, ADJ to GND ………………………………………………6V
Maximum Output Current……………………………………… 3A
EN ………………………………………………… -0.3V to VIN+0.3V
Operating Ambient Temperature Range ……………… -40 to +85°C
Lead Temperature (Soldering) 10s …………………………… 300°C
Operating Junction Temperature Range…………… -40 to +125°C
ESD Protection Level …………………………………………… 2kV
Storage Temperature Range ………………………… -65 to +150°C
Thermal Information
Thermal Resistance, junction to case Jθ(1)JC……………… 3°C/W
Thermal Resistance, junction to ambient JθJA…………… 30°C/W
Other Notes:
Tested according to JEDEC standard JESD22-A114-B.
1) 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.
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.
Electrical Characteristics
) Unless otherwise noted, VEN = VIN. VIN = 1.8V to 5.5V, VIN = VO+0.5V, and IO = 10µA to 3A.
2) Values in bold apply over the full operating temperature range.
Parameter
Symbol
Conditions
Min
Typ
Max
Units
VIN = 3.3V
0.75
1.75
mA
VIN = 5.5V, VEN = 0V
10
50
µA
VIN
Quiescent Current
IQ
VO
VIN = VO + 0.5V
-2%
+2%
-3%
+3%
Output Voltage(1)
VO
Line Regulation(1)
REG(LINE)
IO = 10mA
0.2
0.4
%/V
Load Regulation(1)
REG(LOAD)
IO = 10mA to 3A
0.5
1.0
%
90
300
IO = 1A
Dropout Voltage(1, 2)
400
VD
200
IO = 1.5A
Dropout Voltage(1, 2)
VD
Minimum Load Current(3)
IO
Current Limit
ICL
400
V
mV
500
IO = 3A, VIN = VO + 0.5V
300
500
600
VIN = VO +0.5V
3.3
mV
1
10
μA
4.5
6.75
A
SC4217
Electrical Characteristics (continued)
Parameter
Symbol
Conditions
Min
VIN = 3.3V, VADJ = VOUT, IO = 10mA
1.227
Typ
Max
Units
ADJ
Reference Voltage(1)
VREF
Adjust Pin Current(4)
IADJ
Adjust Pin Threshold
(5)
1.215
VADJ = VREF
0.05
V TH(ADJ)
1.24
1.252
V
1.265
80
200
nA
0.16
0.40
V
1.5
10
µA
EN
Enable Pin Current
Enable Pin Theshold
IEN
VEN = 0V, VIN = 3.3V
VIH
VIN = 3.3V
VIL
VIN = 3.3V
1.6
V
0.4
Over Temperature Protection
High Trip Level
Hysteresis
THI
160
THYST
10
°C
Notes:
) Low duty cycle pulse testing with Kelvin connections required.
2) Defined as the input to output differential at which the output voltage drops to 1.5% below the value measured at a differential of 0.8V.
3) Required to maintain regulation. Voltage set resistors R1 and R2 are usually utilized to meet this requirement. Adjustable versions only.
4) Guaranteed by design.
5) When VADJ exceeds this threshold, the “Sense Select” switch disconnects the internal feedback chain from the error amplifier and connects VADJ instead.
SC4217
Pin Descriptions
Pin #
Pin Name
Pin Function
1
EN
Enable input. Pulling this pin below 0.4V turns off the regulator reducing the quiescent current to a franction
of its operating value. The device will be enabled if this pin is left open. Connect to VIN if not being used.
2
VIN
Input voltage. For regulation at full load, the input to this pin must be between (VO+0.5V) and 5.5V. Minimum
VIN = 1.8V. A large bulk capacitance should be placed closey to this pin to ensure that the input supply does
not sag below 1.8V. A minimum of 4.7µF ceramic capacitors should be placed directly at this pin.
3
GND
Reference ground. The GND pin and the exposed die pad must be connected together at the IC pin.
4
VO
The pin is the power output of the device. A minimum of 10µF capactor should be placed directly at this pin.
5
ADJ
Use external feedback resistors to program the output voltage. See application circuit on page 1.
VO= [(R2+R1)*1.24V]/R2. The ADJ pin cannot be tied directly either to VO pin or to GND pin.
T
THERMAL
PAD
Thermal pad should be connected to PCB ground plane for thermal and electrical purposes.
Block Diagram
RSense
VO
VIN
VPump
Current Limit
Reference
VDD
ADJ
1.5uA
EN
1.24V
REF
Thermal
Shutdown
GND
VOUT
VIN
Reverse Voltage
Shutdown
SC4217
Typical Characteristics
) Unless otherwise noted, typical values are taken under the conditions: TAMBIENT=25°C, VIN=3.3V, VO=2.5V, IO=2A, CIN=COUT=0.1mF(Ceramic)+10mF(Tantalum)
Dropout Voltage vs Temperature
Dropout Voltage vs Output Current
350
400
300
350
250
300
200
250
150
200
100
IOUT =3A
150
25°C
50
IOUT =1A
100
0
50
0
1
2
3
-50
4
-25
0
25
50
75
100
Output Current (A)
Temperature ( °C )
ADJ Pin Leakage Current vs Temperature
Quiescent Current vs Input Voltage
90
2.0
VADJ =1.24V
88
1.5
TAMBIENT = 85 °C
86
1.0
TAMBIENT = 25 °C
84
0.5
82
80
0.0
-50
-25
0
25
50
75
100
3
3.5
Temperature ( °C )
4
4.5
5
5.5
6
6.5
Input Voltage ( V )
Enable Voltage Low vs Temperature
Enable Voltage High vs Temperature
1.50
1.75
V IN =5.5V
V IN =5.5V
1.50
1.25
1.25
V IN =3.3V
V IN =3.3V
1.00
1.00
V IN =1.8V
0.75
0.50
-50
-25
0
25
50
Temperature ( °C )
V IN =1.8V
0.75
75
100
0.50
-50
-25
0
25
50
75
100
Temperature ( °C )
SC4217
Typical Characteristics
) Unless otherwise noted, typical values are taken under the conditions: TAMBIENT=25°C, VIN=3.3V, VO=2.5V, IO=2A, CIN=COUT=0.1mF(Ceramic)+10mF(Tantalum)
Soft start performance
Load transient test
Input voltage
Output Voltage
Output voltage
EN pin voltage
Output Current
SC4217
Applications Information
Introduction
The SC4217 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 real estate. Additional features include an
enable pin to allow for a very low power consumption
standby mode, and a fully adjustable output.
Component Selection
Input Capacitor
A minimum of 4.7µF ceramic or tantalum 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, bulk capacitance of about ≥ 10µF may be added closely to the input
supply pin of the SC4217 to ensure that Vin does not sag,
improving load transient response.
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
SC4217 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.
Thermal Considerations
The power dissipation in the SC4217 is approximately
equal to the product of the output current and the
input to output voltage differential:
PD | (VIN VOUT) u IO
The absolute worst-case dissipation is given by:
PD | (VIN(MAX) VOUT(MIN)) u IO(MAX) VIN(MAX) u IQ(MAX)
For a typical scenario, VIN = 3.3V ± 5%, VOUT = 2.8V and
IO = 1.5A, therefore:
VIN(MAX) = 3.465V, VOUT(MIN) = 2.744V and IQ(MAX) = 1.75mA,
Thus PD(MAX) = 1.09W.
Using this figure, and assuming TA(MAX) = 70°C, we can
calculate the maximum thermal impedance allowable
to maintain TJ ≤150°C:
RTH(J A)(MAX)
(TJ(MAX) TA(MAX))
PD(MAX)
(150 70)
1.09
73.4qC/W
This should be achievable for the TO263-5 package using pcb copper area to aid in conducting the heat away,
such as one square inch of copper connected to the
exposed die pad 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 copper area.
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 ≤ 50kΩ).
Enable
Pulling this pin below 0.4V turns the regulator off, reducing the quiescent current to a fraction of its operating
value.
SC4217
Typical Application Circuits
C1
1uF
R1
1
VIN=3.3V
2
3
GND
C5
10uF (Tantalum)
VO=2.5V
SC4217
10k
EN
VO
VIN
GND
ADJ
4
R2
10.2k
5
C4
C2
C3
0.1uF(Ceramic)
10uF (Tantalum)
R3
10k
0.1uF(Ceramic)
0
AGND
PGND
GND
0
0
Figure 1: Application circuit with 3.3V input and 2.5V output
SC4217
Outline Drawing — TO263-5
A
E
E/2
DIM
0
L1
D
H
1 2 3 4 5
e
bXN
aaa
B A
A
A1
b
c
c1
D
D1
E
E1
H
e
L
L1
N
0
01
aaa
DIMENSIONS
INCHES
MILLIMETERS
MIN NOM MAX MIN NOM MAX
.190 4.06
4.83
.010 0.00
0.25
.039 0.51
0.99
.029 0.38
0.74
.065 1.14
1.65
.380 8.28
9.65
6.86
.420 9.65
10.67
6.22
.625 14.61
15.88
.067 BSC
1.70 BSC
.070
.110 1.78
2.79
.066
1.68
5
5
15°
15°
0°
8°
0°
8°
.010
0.25
.160
.000
.020
.015
.045
.326
.270
.380
.245
.575
A
SEATING
PLANE
A1
B
c1
SIDE VIEW
SEE DETAIL A
PLATED COPPER
HEAT SPREADER
D1
(L1)
c
E1
NOTES:
1.
CONTROLLING DIMENSIONS ARE IN INCHES (ANGLES IN DEGREES).
2.
DIMENSIONS "D" AND "E" DO NOT INCLUDE MOLD FLASH, PROTRUSIONS
L
DETAIL
A
01
OR GATE BURRS.
10
SC4217
Land Pattern — TO263-5
H
DIM
K
Z
G
H
K
P
X
Y
Z
DIMENSIONS
INCHES
MILLIMETERS
.125
.420
.350
.067
.042
.140
.615
3.17
10.67
8.89
1.70
1.07
3.56
15.62
G
Y
P
X
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
www.semtech.com
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