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Электронный компонент: CS52015-1GDPR3

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Cherry Semiconductor Corporation
2000 South County Trail, East Greenwich, RI 02818
Tel: (401)885-3600 Fax: (401)885-5786
Email: info@cherry-semi.com
Web Site: www.cherry-semi.com
1
Features
s
Output Current to 1.5A
s
Output Accuracy to 1%
Over Temperature
s
Dropout Voltage (typical)
1.05V @ 1.5A
s
Fast Transient Response
s
Fault Protection
Current Limit
Thermal Shutdown
Package Options
3L TO-220
Tab (V
OUT
)
CS52015-1
1.5A Adjustable Linear Regulator
1
CS52015-1
The CS52015-1 linear regulator pro-
vides 1.5A with an accuracy of 1%.
The device uses two external resis-
tors to set the output voltage within
a 1.25V to 5.5V range.
The regulator is intended for use as
a post regulator and microprocessor
supply. The fast loop response and
low dropout voltage make this reg-
ulator ideal for applications where
low voltage operation and good
transient response are important.
The circuit is designed to operate
with dropout voltages less than
1.4V at 1.5A output current. Device
protection includes overcurrent and
thermal shutdown.
The CS52015-1 is pin compatible
with the LT1086 family of linear
regulators but has lower dropout
voltage.
The regulator is available in TO-
220, surface mount D
2
, and SOT-223
packages.
Application Diagram
Consult factory for fixed output voltage
versions.
CS52015 -1
1
Adj
2
V
OUT (Tab)
3
V
IN
Description
3L D
2
PAK
Tab (V
OUT
)
1
A Company
5.0V
CS52015-1
V
IN
Adj
124
W
1%
200
W
1%
3.3V @ 1.5A
0.1
mF
5V
Tantalum
22
mF
5V
10
mF
5V
V
OUT
SOT-223
Tab (V
OUT
)
1
Rev. 2/17/98
2
CS52015-1
Absolute Maximum Ratings
Supply Voltage, V
CC
....................................................................................................................................................................7V
Operating Temperature Range................................................................................................................................-40C to 70C
Junction Temperature ............................................................................................................................................................150C
Storage Temperature Range ..................................................................................................................................-60C to 150C
Lead Temperature Soldering
Wave Solder (through hole styles only) .....................................................................................10 sec. max, 260C peak
Reflow (SMD styles only) ......................................................................................60 sec. max above 183C, 230C peak
ESD Damage Threshold............................................................................................................................................................2kV
PACKAGE PIN #
PIN SYMBOL
FUNCTION
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
Electrical Characteristics:
C
IN
= 10F, C
OUT
= 22F Tantalum, V
OUT
+ V
DROPOUT
< V
IN
< 7V, 0C T
A
70C, T
J
+150C,
unless otherwise specified, I
full load
= 1.5A.
Package Pin Description
s Adjustable Output Voltage (CS52015-1)
Reference Voltage
V
IN
V
OUT
=1.5V; V
Adj
= 0V
1.241
1.254
1.266
V
(Notes 1 and 2)
10mAI
OUT
1.5A
(-1%)
(+1%)
Line Regulation
1.5VV
IN
V
OUT
5.75V; I
OUT
=10mA
0.02
0.20
%
Load Regulation
V
IN
V
OUT
=1.5V; 10mAI
OUT
1.5A 0.04
0.4
%
(Notes 1 and 2)
Dropout Voltage (Note 3)
I
OUT
=1.5A
1.05
1.4
V
Current Limit
V
IN
V
OUT
=3V; T
J
25C
1.6
3.1
A
Minimum Load Current (Note 4) V
IN
=7V ; V
Adj
=0
0.6
2.0
mA
Adjust Pin Current
V
IN
V
OUT
=3V; I
OUT
=10mA
50
100
A
Thermal Regulation (Note 5)
30ms pulse; T
A
=25C
0.002
0.020
%/W
Ripple Rejection (Note 5)
f=120Hz; I
OUT
=1.5A; V
IN
V
OUT
=3V; 80
dB
V
RIPPLE
=1V
PP
Thermal Shutdown (Note 6)
150
180
210
C
Thermal Shutdown Hysteresis
25
C
(Note 6)
Note 1: Load regulation and output voltage are measured at a constant junction temperature by low duty cycle pulse testing. Changes in out-
put 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 1/4 from the bottom of the package.
Note 3: Dropout voltage is a measurement of the minimum input/output differential at full load.
Note 4: The minimum load current is the minimum current required to maintain regulation. Normally the current in the resistor divider used
to set the output voltage is selected to meet the minimum requirement.
Note 5: Guaranteed by design, not 100% tested in production.
Note 6: Thermal shutdown is 100% functionally tested in production.
D
2
PAK
TO-220
SOT-223
1
1
1
Adj
Adjust pin (low side of the internal reference.
2
2
2
V
OUT
Regulated output voltage (case).
3
3
3
V
IN
Input voltage
CS52015-1
3
Block Diagram
1500
1200
900
600
300
0
0.75
0.80
0.85
0.90
0.95
1.00
1.05
I
OUT
(mA)
V Drop Out (V)
T
CASE
0C
T
CASE
125C
T
CASE
25C
0
10
130
-0.12
0.10
Output V
oltage Deviation (%)
T
J
(
C)
20
30
40
50
60
70
80
90 100 110 120
0.08
0.06
0.04
0.02
0.00
-0.02
-0.04
-0.06
-0.08
-0.10
0.025
0.000
0.050
0.075
0.100
0
1
2
Output Current (A)
Output V
oltage Deviation (%)
T
CASE
= 0
C
T
CASE
= 125
C
T
CASE
= 25
C
Dropout Voltage vs. Output Current
Reference Voltage vs. Temperature
Load Regulation vs. Output Current
1
2
3
4
5
6
0.40
Minimum Load Current (mA)
V
IN
V
OUT
(V)
7
0.45
0.50
0.55
0.60
0.65
T
CASE
= 0
C
T
CASE
= 125
C
T
CASE
= 25
C
C
IN
=C
OUT
=22
mF Tantalum
Minimum Load Current vs V
IN
-V
OUT
Error
Amplifier
+
Output
Current
Limit
-
V
IN
V
OUT
Adj
Thermal
Shutdown
Bandgap
Typical Performance Characteristics
4
CS52015-1
Applications Information
The CS52015-1 linear regulator provides adjustable volt-
ages at currents up to 1.5A. The regulator is protected
against overcurrent conditions and includes thermal
shutdown.
The CS52015-1 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.
The 52015-1 has an output voltage range of 1.25V to 5.5V.
An external resistor divider sets the output voltage as
shown in Figure 1. The regulator maintains a fixed 1.25V
(typical) reference between the output pin and the adjust
pin.
A resistor divider network R1 and R2 causes a fixed cur-
rent to flow to ground. This current creates a voltage
across R2 that adds to the 1.25V across R1 and sets the
overall output voltage. The adjust pin current (typically
50A) also flows through R2 and adds a small error that
should be taken into account if precise adjustment of V
OUT
is necessary.
The output voltage is set according to the formula:
V
OUT
= V
REF
(
)
+ I
Adj
R2
The term I
Adj
R2 represents the error added by the adjust
pin current.
R1 is chosen so that the minimum load current is at least
2mA. R1 and R2 should be the same type, e.g. metal film
for best tracking over temperature. While not required, a
bypass capacitor from the adjust pin to ground will
improve ripple rejection and transient response. A 0.1F
tantalum capacitor is recommended for first cut design.
Type and value may be varied to obtain optimum perfor-
mance vs price.
R1 + R2
R1
Adjustable Operation
0
20
30
40
50
60
40.0
Adjust Pin Current (
m
A)
Temperature (
C)
80
45.0
50.0
55.0
60.0
65.0
70.0
90
100
10
70
110 120 130
I
O
= 10mA
15
10
1
Frequency (Hz)
Ripple Rejection (dB)
25
35
45
55
65
75
85
10
2
10
3
10
4
10
6
10
5
T
CASE
= 25
C
I
OUT
= 1.5A
(V
IN
V
OUT
) = 3V
V
RIPPLE
= 1.0V
PP
C
Adj
= 0.1
mF
Adjust Pin Current vs. Temperature
Ripple Rejection vs. Frequency
0
2
3
4
5
6
750
V
oltage Deviation (mV)
7
-100
0
100
200
Time
mS
Load Step (mA)
10
9
8
1
1500
-200
0
V
OUT
=3.3V
C
OUT
=C
IN
=22
mF Tantalum
C
Adj
=0.1mF
Transient Response
1.5
2.5
3.0
3.5
1.5
I
SC
(A)
V
IN
- V
OUT
(V)
1.7
1.9
2.1
2.3
3.1
3.3
1.0
4.0
2.5
2.7
2.9
3.5
2.0
4.5
5.0
6.0
5.5
6.5
7.0
Short Circuit Current vs V
IN
-V
OUT
Typical Performance Characteristics
5
CS52015-1
Applications Information: continued
Figure 1. Resistor divider scheme.
The CS52015-1 linear regulator has an absolute maximum
specification of 7V for the voltage difference between V
IN
and V
OUT
. However, the IC may be used to regulate volt-
ages in excess of 7V. The main considerations in such a
design are power-up and short circuit capability.
In most applications, ramp-up of the power supply to V
IN
is fairly slow, typically on the order of several tens of mil-
liseconds, while the regulator responds in less than one
microsecond. In this case, the linear regulator begins
charging the load as soon as the V
IN
to V
OUT
differential is
large enough that the pass transistor conducts current. The
load at this point is essentially at ground, and the supply
voltage is on the order of several hundred millivolts, with
the result that the pass transistor is in dropout. As the sup-
ply to V
IN
increases, the pass transistor will remain in
dropout, and current is passed to the load until V
OUT
reaches the point at which the IC is in regulation. Further
increase in the supply voltage brings the pass transistor
out of dropout. The result is that the output voltage fol-
lows the power supply ramp-up, staying in dropout until
the regulation point is reached. In this manner, any output
voltage may be regulated. There is no theoretical limit to
the regulated voltage as long as the V
IN
to V
OUT
differen-
tial of 7V is not exceeded.
However, the possibility of destroying the IC in a short
circuit condition is very real for this type of design. Short
circuit conditions will result in the immediate operation of
the pass transistor outside of its safe operating area. Over-
voltage stresses will then cause destruction of the pass
transistor before overcurrent or thermal shutdown circuit-
ry can become active. Additional circuitry may be required
to clamp the V
IN
to V
OUT
differential to less than 7V if fail-
safe operation is required. One possible clamp circuit is
illustrated in figure 2; however, the design of clamp cir-
cuitry must be done on an application by application basis.
Care must be taken to ensure the clamp actually protects
the design. Components used in the clamp design must be
able to withstand the short circuit condition indefinitely
while protecting the IC.
Figure 2: Short Circuit Protection Circuit for High Voltage Application.
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 is based on cost, availability,
size and temperature constraints. A tantalum or aluminum
electrolytic capacitor is best, since a film or ceramic capaci-
tor with almost zero ESR can cause instability. The alu-
minum electrolytic capacitor is the least expensive solu-
tion. However, when the circuit operates at low tempera-
tures, both the value and ESR of the capacitor will vary
considerably. The capacitor manufacturers data sheet pro-
vides this information.
A 22F tantalum capacitor will work for most applications,
but with high current regulators such as the CS52015-1 the
transient response and stability improve with higher val-
ues of capacitance. The majority of applications for this
regulator involve large changes in load current so the out-
put capacitor must supply the instantaneous load current.
The ESR of the output capacitor causes an immediate drop
in output voltage given by:
V = I
ESR
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 net-
work should be as close as possible to the load for the best
results.
When large external capacitors are used with a linear regu-
lator 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 capaci-
tor, the output voltage and the rate at which V
IN
drops. In
the CS52015-1 linear regulator, the discharge path is
through a large junction and protection diodes are not usu-
ally needed. If the regulator is used with large values of
output capacitance and the input voltage is instantaneous-
ly shorted to ground, damage can occur. In this case, a
diode connected as shown in Figure 2 is recommended.
Protection Diodes
Stability Considerations
V
IN
V
OUT
V
Adj
EXTERNAL SUPPLY
V
OUT
V
OUT
V
IN
CS52015-1
V
IN
Adj
R
1
R
2
C
1
C
Adj
V
OUT
C
2
V
REF
I
Adj
6
CS52015-1
Figure 3. Protection diode scheme for Large Output Capacitors.
Since the CS52015-1 is a three terminal regulator, it is not
possible to provide true remote load sensing. Load regula-
tion is limited by the resistance of the conductors connect-
ing the regulator to the load.
For the adjustable regulator, the best load regulation occurs
when R1 is connected directly to the output pin of the regu-
lator as shown in Figure 3. If R1 is connected to the load,
R
C
is multiplied by the divider ratio and the effective resis-
tance between the regulator and the load becomes
R
C
(
)
R
C
= conductor parasitic resistance
Figure 4. Grounding scheme for the adjustable output regulator to mini-
mize parasitic resistance effects.
The CS52015-1 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.
The case is connected to V
OUT
on the CS52015-1, and elec-
trical isolation may be required for some applications.
Thermal compound should always be used with high cur-
rent regulators such as these.
The thermal characteristics of an IC depend on the follow-
ing four factors:
1. Maximum Ambient Temperature T
A
(C)
2. Power dissipation P
D
(Watts)
3. Maximum junction temperature T
J
(C)
4. Thermal resistance junction to ambient R
QJA
(C/W)
These four are related by the equation
T
J
= T
A
+ P
D
R
QJA
(1)
The maximum ambient temperature and the power dissi-
pation 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:
P
D(max)
={V
IN(max)
V
OUT(min)
}I
OUT(max)
+V
IN(max)
I
Q
(2)
where
V
IN(max)
is the maximum input voltage,
V
OUT(min)
is the minimum output voltage,
I
OUT(max)
is the maximum output current, for the application
I
Q
is the maximum quiescent current at I
OUT
(max).
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.
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 R
QJA
, the total thermal resistance between the
junction and the surrounding air.
1. Thermal Resistance of the junction to case, R
QJC
(C/W)
2. Thermal Resistance of the case to Heat Sink, R
QCS
(C/W)
3. Thermal Resistance of the Heat Sink to the ambient air,
R
QSA
(C/W)
These are connected by the equation:
R
QJA
= R
QJC
+ R
QCS
+ R
QSA
(3)
The value for R
QJA
is calculated using equation (3) and the
result can be substituted in equation (1).
The value for R
QJC
is 3.5C/W. For a high current regula-
tor such as the CS52015-1 the majority of the heat is gener-
ated in the power transistor section. The value for R
QSA
depends on the heat sink type, while R
QCS
depends on fac-
tors such as package type, heat sink interface (is an insula-
tor and thermal grease used?), and the contact area
between the heat sink and the package. Once these calcula-
tions are complete, the maximum permissible value of R
QJA
can be calculated and the proper heat sink selected. For fur-
ther discussion on heat sink selection, see application note
Thermal Management for Linear Regulators.
Calculating Power Dissipation and Heat Sink Requirements
V
OUT
R
C
V
IN
conductor parasitic
resistance
CS52015-1
V
IN
Adj
R
LOAD
R
1
R
2
R1 + R2
R1
Output Voltage Sensing
V
OUT
V
IN
CS52015-1
V
IN
Adj
R
1
R
2
C
1
V
OUT
C
2
C
Adj
IN4002 (optional)
Applications Information: continued
3L
3L
3L
Thermal Data
TO-220
D
2
PAK
SOT-223
R
Q
JC
typ
3.5
3.5
15
C/W
R
Q
JA
typ
50
10 - 50*
156
C/W
*Depending on thermal properties of substrate. R
QJA
= R
QJC
+ R
QCA
7
Part Number
Type
Description
CS52015-1GT3
1.5A, adj. output
3 L TO-220 Straight
CS52015-1GDP3
1.5A, adj. output
3 L D
2
PAK
CS52015-1GDPR3 1.5A, adj. output
3 L D
2
PAK
(tape & reel)
CS52015-1GST3
1.5A, adj. output
SOT-223
CS52015-1GSTR3
1.5A, adj. output
SOT-223 (tape & reel)
Ordering Information
Rev. 2/17/98
Package Specification
PACKAGE THERMAL DATA
CS52015-1
1999 Cherry Semiconductor Corporation
Cherry Semiconductor Corporation reserves the
right to make changes to the specifications without
notice. Please contact Cherry Semiconductor
Corporation for the latest available information.
PACKAGE DIMENSIONS IN mm (INCHES)
3 Lead D
2
PAK (DP)
2.54 (.100) REF
10.31 (.406)
10.05 (.396)
8.53 (.336)
8.28 (.326)
0.91 (.036)
0.66 (.026)
1.40 (.055)
1.14 (.045)
4.57 (.180)
4.31 (.170)
1.68 (.066)
1.40 (.055)
2.74(.108)
2.49(.098)
1.40 (.055)
1.14 (.045)
0.10 (.004)
0.00 (.000)
.254 (.010) REF
15.75 (.620)
14.73 (.580)
2.79 (.110)
2.29 (.090)
3 Lead TO-220 (T) Straight
5.33 (.210)
4.83 (.190)
2.79 (.110)
2.29 (.090)
1.02 (.040)
0.63 (.025)
0.56 (.022)
0.38 (.014)
1.40 (.055)
1.14 (.045)
4.83 (.190)
4.06 (.160)
6.17 (.243) REF
1.14 (.045)
1.52 (.060)
1.14 (.045)
1.40 (.055)
2.87 (.113)
2.62 (.103)
6.55 (.258)
5.94 (.234)
14.22 (.560)
13.72 (.540)
2.92 (.115)
2.29 (.090)
9.78 (.385)
10.54 (.415)
3.71 (.146)
3.96 (.156)
14.99 (.590)
14.22 (.560)
3 Lead SOT-223 (ST)
10
MAX
1.30 (.051)
1.10 (.043)
4.60 (.181)
2.30 (.090)
1.05 (.041)
0.85 (.033)
7.30 (.287)
6.70 (.264)
3.30 (.130)
3.70 (.146)
3.15 (.124)
2.95 (.116)
6.70 (.264)
6.30 (.248)
1.70 (.067)
1.50 (.060)
0.10 (.004)
0.02 (.001)
0.85 (.033)
0.65 (.026)
0.35 (.014)
0.25 (.010)