Cherry CS52015-3 1.5a, 3.3v fixed linear regulator Datasheet

CS52015-3
CS52015-3
1.5A, 3.3V Fixed Linear Regulator
Description
The CS52015-3 linear regulator provides 1.5A at 3.3V with an output
voltage accuracy of ±1.5%.
The regulator is intended for use as
a post regulator and microprocessor
supply. The fast loop response and
low dropout voltage make this regulator ideal for applications where
low voltage operation and good
transient response are important.
The circuit is designed to operate
with dropout voltages less than
Features
1.4V at 1.5A output current. The
maximum quiescent current is only
10mA at full load. Device protection includes overcurrent and thermal shutdown.
The CS52015-3 is pin compatible
with the LT1086 family of linear
regulators but has lower dropout
voltage.
The regulator is available in TO220, surface mount D2, and SOT-223
packages.
■ Output Current to 1.5A
■ Output Accuracy to ±1.5%
Over Temperature
■ Dropout Voltage (typical)
1.05V @ 1.5A
■ Fast Transient Response
■ Fault Protection
Current Limit
Thermal Shutdown
Application Diagram
Package Options
VOUT
VIN
3.3V
@ 1.5A
3L TO-220
3L D2PAK
Tab (VOUT)
Tab (VOUT)
CS52015-3
Gnd
10 mF
5V
1
22mF
5V
3L SOT-223
1
Tab (VOUT)
CS52015 -3
1 Gnd
2 VOUT (tab)
3 VIN
1
Consult factory for other fixed output voltage
options.
Cherry Semiconductor Corporation
2000 South County Trail, East Greenwich, RI 02818
Tel: (401)885-3600 Fax: (401)885-5786
Email: [email protected]
Web Site: www.cherry-semi.com
Rev. 2/17/98
1
A
¨
Company
CS52015-3
Absolute Maximum Ratings
Supply Voltage, VIN .....................................................................................................................................................................7V
Operating Temperature Range................................................................................................................................-40¡C to 70¡C
Junction Temperature ............................................................................................................................................................150¡C
Storage Temperature Range ..................................................................................................................................-60¡C to 150¡C
Lead Temperature Soldering
Wave Solder (through hole styles only) .....................................................................................10 sec. max, 260¡C peak
Reflow (SMD styles only) ......................................................................................60 sec. max above 183¡C, 230¡C peak
ESD Damage Threshold............................................................................................................................................................2kV
Electrical Characteristics: CIN = 10µF, COUT = 22µF Tantalum, VOUT + VDROPOUT < VIN < 7V, 0¡C ² TA ² 70¡C, TJ ² +150¡C,
unless otherwise specified, Ifull load = 1.5A.
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
3.250
(-1.5%)
3.300
3.350
(+1.5%)
V
■ Fixed Output Voltage
Output Voltage
(Notes 1 and 2)
VINÐVOUT=1.5V
0²IOUT²1.5A
Line Regulation
2V²VINÐVOUT²3.7V; IOUT=10mA
0.02
0.20
%
Load Regulation
(Notes 1 and 2)
VINÐVOUT=2V; 10mA ²IOUT²1.5A
0.04
0.4
%
Dropout Voltage (Note 3)
IOUT=1.5A
1.05
1.4
V
Current Limit
VINÐVOUT=3V
1.6
3.1
A
Quiescent Current
IOUT=10mA
5.0
10.0
mA
Thermal Regulation (Note 4)
30ms pulse; TA=25¡C
0.002
0.020
%/W
Ripple Rejection
(Note 4)
f=120Hz; IOUT=1.5A; VINÐVOUT=3V;
VRIPPLE=1VP-P
80
Thermal Shutdown (Note 5)
150
180
Thermal Shutdown Hysteresis
(Note 5)
25
dB
210
¡C
¡C
Note 1: Load regulation and output voltage are measured at a constant junction temperature by low duty cycle pulse testing. Changes in output voltage due to temperature changes must be taken into account separately.
Note 2: Specifications apply for an external Kelvin sense connection at a point on the output pin 1/4Ó from the bottom of the package.
Note 3: Dropout voltage is a measurement of the minimum input/output differential at full load.
Note 4: Guaranteed by design, not tested in production.
Note 5: Thermal shutdown is 100% functionally tested in production.
Package Pin Description
PACKAGE PIN #
PIN SYMBOL
FUNCTION
D2PAK
TO-220
SOT-223
1
1
1
Gnd
Ground connection
2
2
2
VOUT
Regulated output voltage (case).
3
3
3
VIN
Input voltage
2
CS52015-3
Block Diagram
V OUT
V IN
Output
Current
Limit
Thermal
Shutdown
-
+
Error
Amplifier
Bandgap
Gnd
Typical Performance Characteristics
1.05
0.10
0.08
TCASE 0ûC
Output Voltage Deviation (%)
V Drop Out (V)
1.00
0.95
TCASE 25ûC
0.90
0.85
0.80
TCASE 125ûC
0.06
0.04
0.02
0.00
-0.02
-0.04
-0.06
-0.08
-0.10
-0.12
0
0.75
0
300
600
900
1200
10
20
30
40
50
60
70
80
90 100 110 120 130
TJ (°C)
1500
IOUT (mA)
Dropout Voltage vs Output Current
Output Voltage vs. Temperature
3.5
85
3.3
3.1
65
2.9
55
2.7
ISC(A)
Ripple Rejection (dB)
75
TCASE = 25°C
IOUT = 1.5A
(VIN Ð VOUT) = 3V
VRIPPLE = 1.0VPP
45
35
2.5
2.3
2.1
1.9
25
1.7
15
101
102
103
104
105
1.5
106
1.0 1.5
Frequency (Hz)
Ripple Rejection vs. Frequency
2.0
2.5
3.0
3.5 4.0 4.5
VIN - VOUT (V)
Short Circuit Current vs VIN-VOUT
3
5.0
5.5
6.0
6.5
7.0
0.100
Output Voltage Deviation (%)
200
100
0
COUT =CIN =22mF Tantalum
-100
-200
Load Step (mA)
CS52015-3
Voltage Deviation (mV)
Typical Performance Characteristics
1500
0.075
0.050
TCASE = 125°C
TCASE = 25°C
0.025
750
TCASE = 0°C
0.000
0
0
1
2
3
4
5
6
7
8
9
0
10
1
Output Current (A)
Time mS
Transient Response
2
Load Regulation vs. Output Current
Applications Information
The CS52015-3 linear regulator provides a 3.3V output
voltage at currents up to 1.5A. The regulator is protected
against overcurrent conditions and includes thermal
shutdown.
The CS52015-3 has a composite PNP-NPN output transistor
and requires an output capacitor for stability. A detailed
procedure for selecting this capacitor is included in the
Stability Considerations section.
Protection Diodes
When large external capacitors are used with a linear regulator it is sometimes necessary to add protection diodes. If
the input voltage of the regulator gets shorted, the output
capacitor will discharge into the output of the regulator.
The discharge current depends on the value of the capacitor, the output voltage and the rate at which VIN drops. In
the CS52015-3 linear regulator, the discharge path is
through a large junction and protection diodes are not usually needed. If the regulator is used with large values of
output capacitance and the input voltage is instantaneously shorted to ground, damage can occur. In this case, a
diode connected as shown in Figure 1 is recommended.
Stability Considerations
The output or compensation capacitor helps determine
three main characteristics of a linear regulator: start-up
delay, load transient response and loop stability.
The capacitor value and type are based on cost, availability, size and temperature constraints. A tantalum or aluminum electrolytic capacitor is best, since a film or ceramic
capacitor with almost zero ESR can cause instability. The
aluminum electrolytic capacitor is the least expensive solution. However, when the circuit operates at low temperatures, both the value and ESR of the capacitor will vary
considerably. The capacitor manufacturersÕ data sheet provides this information.
A 22µF tantalum capacitor will work for most applications,
but with high current regulators such as the CS52015-3 the
transient response and stability improve with higher values of capacitance. The majority of applications for this
regulator involve large changes in load current so the output capacitor must supply the instantaneous load current.
The ESR of the output capacitor causes an immediate drop
in output voltage given by:
IN4002
VIN
VOUT
VIN
C1
(optional)
VOUT
CS52015-3
C2
Gnd
Figure 1: Protection diode scheme for large output capacitors.
ÆV = ÆI ´ ESR
Output Voltage Sensing
For microprocessor applications it is customary to use an
output capacitor network consisting of several tantalum and
ceramic capacitors in parallel. This reduces the overall ESR
and reduces the instantaneous output voltage drop under
load transient conditions. The output capacitor network
should be as close as possible to the load for the best results.
Since the CS52015-3 is a three terminal regulator, it is not
possible to provide true remote load sensing. Load regulation is limited by the resistance of the conductors connecting the regulator to the load. For best results the regulator
should be connected as shown in Figure 2.
4
IOUT(max) is the maximum output current, for the application
RC
VIN
IQ is the maximum quiescent current at IOUT(max).
conductor
parasitic resistance
A heat sink effectively increases the surface area of the
package to improve the flow of heat away from the IC and
into the surrounding air.
VOUT
VIN
CS52015-3
RLOAD
Each material in the heat flow path between the IC and the
outside environment has a thermal resistance. Like series
electrical resistances, these resistances are summed to
determine RQJA, the total thermal resistance between the
junction and the surrounding air.
1. Thermal Resistance of the junction to case, RQJC (¡C/W)
2. Thermal Resistance of the case to Heat Sink, RQCS (¡C/W)
Figure 2: Conductor parasitic resistance effects can be minimized with
the above grounding scheme for fixed output regulators.
3. Thermal Resistance of the Heat Sink to the ambient air,
RQSA (¡C/W)
Calculating Power Dissipation and Heat Sink Requirements
The CS52015-3 linear regulator includes thermal shutdown
and current limit circuitry to protect the device. High
power regulators such as these usually operate at high
junction temperatures so it is important to calculate the
power dissipation and junction temperatures accurately to
ensure that an adequate heat sink is used.
These are connected by the equation:
RQJA = RQJC + RQCS + RQSA
The value for RQJA is calculated using equation (3) and the
result can be substituted in equation (1).
The case is connected to VOUT on the CS52015-3, and electrical isolation may be required for some applications.
Thermal compound should always be used with high current regulators such as these.
The value for RQJC is 3.5ûC/W. For a high current regulator
such as the CS52015-3 the majority of the heat is generated
in the power transistor section. The value for RQSA
depends on the heat sink type, while RQCS depends on factors such as package type, heat sink interface (is an insulator and thermal grease used?), and the contact area
between the heat sink and the package. Once these calculations are complete, the maximum permissible value of
RQJA can be calculated and the proper heat sink selected.
For further discussion on heat sink selection, see application note ÒThermal Management for Linear Regulators.Ó
The thermal characteristics of an IC depend on the following four factors:
1. Maximum Ambient Temperature TA (¡C)
2. Power dissipation PD (Watts)
3. Maximum junction temperature TJ (¡C)
4. Thermal resistance junction to ambient RQJA (C/W)
These four are related by the equation
TJ = TA + PD ´ RQJA
(1)
The maximum ambient temperature and the power dissipation are determined by the design while the maximum
junction temperature and the thermal resistance depend on
the manufacturer and the package type.
The maximum power dissipation for a regulator is:
PD(max)={VIN(max)ÐVOUT(min)}IOUT(max)+VIN(max)IQ
(3)
(2)
where
VIN(max) is the maximum input voltage,
VOUT(min) is the minimum output voltage,
5
CS52015-3
Applications Information: continued
PACKAGE DIMENSIONS IN mm (INCHES)
PACKAGE THERMAL DATA
3L
3L
3L
Thermal Data
TO-220 D2PAK
SOT-223
RQJC
typ
3.5
3.5
15
ûC/W
RQJA
typ
50
10 - 50*
156
ûC/W
*Depending on thermal properties of substrate. RQJA = RQJC + RQCA
3 Lead TO-220 (T) Straight
4.83 (.190)
4.06 (.160)
10.54 (.415)
9.78 (.385)
6.55 (.258)
5.94 (.234)
1.40 (.055)
1.14 (.045)
3.96 (.156)
3.71 (.146)
2.87 (.113)
2.62 (.103)
3 Lead SOT-223 (ST)
6.70 (.264)
6.30 (.248)
14.99 (.590)
14.22 (.560)
7.30 (.287)
6.70 (.264)
1.52 (.060)
1.14 (.045)
14.22 (.560)
13.72 (.540)
3.15 (.124)
2.95 (.116)
6.17 (.243) REF
3.70 (.146)
3.30 (.130)
1.40 (.055)
1.14 (.045)
1.02 (.040)
0.63 (.025)
2.30 (.090)
1.05 (.041)
0.85 (.033)
0.56 (.022)
0.38 (.014)
2.79 (.110)
2.29 (.090)
0.35 (.014)
0.25 (.010)
1.70 (.067)
1.50 (.060)
5.33 (.210)
4.83 (.190)
2.92 (.115)
2.29 (.090)
0.10 (.004)
0.02 (.001)
0.85 (.033)
0.65 (.026)
1.30 (.051)
1.10 (.043)
10° MAX
4.60 (.181)
3 Lead D2PAK (DP)
10.31 (.406)
10.05 (.396)
1.40 (.055)
1.14 (.045)
1.68 (.066)
1.40 (.055)
8.53 (.336)
8.28 (.326)
15.75 (.620)
14.73 (.580)
2.74(.108)
2.49(.098)
1.40 (.055)
1.14 (.045)
2.79 (.110)
2.29 (.090)
0.91 (.036)
0.66 (.026)
2.54 (.100) REF
4.57 (.180)
4.31 (.170)
.254 (.010) REF
0.10 (.004)
0.00 (.000)
Ordering Information
Part Number
CS52015-3GT3
CS52015-3GDP3
CS52015-3GDPR3
CS52015-3GST3
CS52015-3GSTR3
Rev. 2/17/98
Type
1.5A, 3.3V output
1.5A,3.3V output
1.5A, 3.3V output
Description
3 L TO-220 Straight
3 L D2PAK
3 L D2PAK
(tape & reel)
1.5A, 3.3V output 3 Lead SOT-223
1.5A, 3.3V output 3 Lead SOT-223
(tape & reel)
Cherry Semiconductor Corporation reserves the
right to make changes to the specifications without
notice. Please contact Cherry Semiconductor
Corporation for the latest available information.
6
© 1999 Cherry Semiconductor Corporation
CS52015-3
Package Specification
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