CS5207-1
7.0 A Adjustable Linear
Regulator
The CS5207–1 linear regulator provides 7.0 A adjustable voltages
with an accuracy of ±1.5 %. Two external resistors are used to set the
output voltage within a 1.25 V to 13 V range.
The regulator is intended for use as 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 as low as 1.0 V
depending on the output current. The maximum quiescent current is only
10 mA at full load.
The regulator is fully protected against overload conditions with
protection circuitry for Safe Operating Area (SOA), overcurrent and
thermal shutdown.
The regulator is available in TO–220 package. A 3.3 V, fixed version
is also available. Please consult your local sales representative for more
information.
Features
Output Current to 7.0 A
Output Trimmed to ±1.5%
Dropout Voltage 1.4 V @ 7.0 A
Fast Transient Response
Fault Protection Circuitry
– Thermal Shutdown
– Overcurrent Protection
– Safe Area Protection
•
•
•
•
•
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TO–220
THREE LEAD
T SUFFIX
CASE 221A
1
2
3
PIN CONNECTIONS AND
MARKING DIAGRAMS
CS5207–1
AWLYWW
Tab = VOUT
Pin 1. Adj
2. VOUT
3. VIN
1
VOUT
A
WL, L
YY, Y
WW, W
= Assembly Location
= Wafer Lot
= Year
= Work Week
VIN
ORDERING INFORMATION*†
Device
Output
Current
Limit
Thermal
Shutdown
– +
CS5207–1GT3
Package
Shipping
TO–220‡
50 Units/Rail
*Additional ordering information can be found on page
6 of this data sheet.
†Consult your local sales representative for fixed
output voltage versions.
‡TO–220 is 3–pin, straight leaded.
Error
Amplifier
Adj
Bandgap
Figure 1. Block Diagram
Semiconductor Components Industries, LLC, 2001
March, 2001 – Rev. 3
1
Publication Order Number:
CS5207–1/D
CS5207–1
ABSOLUTE MAXIMUM RATINGS*
Parameter
Supply Voltage, VCC
Operating Temperature Range
Junction Temperature
Storage Temperature Range
Lead Temperature Soldering:
Wave Solder (through hole styles only) Note 1.
Value
Unit
17
V
–40 to +70
°C
150
°C
–60 to +150
°C
260 Peak
°C
1. 10 second maximum.
*The maximum package power dissipation must be observed.
ELECTRICAL CHARACTERISTICS (CIN = 10 µF, COUT = 22 µF Tantalum, VIN – VOUT = 3.0 V, VIN ≤ 15 V, 0°C ≤ TA ≤ 70°C,
TJ ≤ +150°C, unless otherwise specified, Ifull load = 7.0 A)
Characteristic
Test Conditions
Min
Typ
Max
Unit
1.235
(–1.5%)
1.254
1.272
(+1.5%)
V
Adjustable Output Voltage
Reference Voltage (Notes 2. and 3.)
VIN – VOUT = 1.6 V; VAdj = 0 V
10 mA ≤ IOUT ≤ 7.0 A
Line Regulation
1.6 V ≤ VIN – VOUT ≤ 6.0 V; IOUT = 10 mA
–
0.04
0.20
%
Load Regulation (Notes 2. and 3.)
VIN – VOUT = 1.6 V; 10 mA ≤ IOUT ≤ 7.0 A
–
0.13
0.5
%
Dropout Voltage (Note 4.)
IOUT = 7.0 A
–
1.4
1.55
V
Current Limit
VIN – VOUT = 3.0 V; TJ ≥ 25°C
VIN – VOUT = 9.0 V
7.1
–
8.5
1.0
–
–
A
A
Minimum Load Current
VIN – VOUT = 7.0 V
–
1.2
6.0
mA
–
–
50
100
µA
Adjust Pin Current Change
1.6 V ≤ VIN – VOUT ≤ 4.0 V; 10 mA ≤ IOUT ≤ 7.0 A
–
0.2
5.0
µA
Thermal Regulation
30 ms Pulse, TA = 25°C
–
0.003
–
%W
Ripple Rejection
f = 120 Hz; CAdj = 25 µF; IOUT = 7.0 A
–
80
–
dB
–
0.5
–
%
–
0.003
–
%VOUT
Adjust Pin Current
Temperature Stability
RMS Output Noise
–
10 Hz ≤ f ≤ 10 kHz; TA = 25°C
Thermal Shutdown
–
150
180
–
°C
Thermal Shutdown Hysteresis
–
–
25
–
°C
2. Load regulation and output voltage are measured at a constant junction temperature by low duty cycle pulse testing. Changes in output
voltage due to thermal gradients or temperature changes must be taken into account seperately.
3. Specifications apply for an external Kelvin sense connection at a point on the output pin 1/4” from the bottom of the package.
4. Dropout voltage is a measurement of the minimum input/output differential at full load.
PACKAGE PIN DESCRIPTION
Package Pin Number
TO–220
Pin Symbol
1
Adj
2
VOUT
3
VIN
Function
Adjust pin (low side of the internal reference).
Regulated output voltage (case).
Input voltage.
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2
CS5207–1
0.10
1.55
1.50
1.45
1.40
1.35
1.30
1.25
1.20
1.15
1.10
1.05
1.00
0.95
0.90
0.85
0.80
0.75
0.70
0.08
Output Voltage Deviation (%)
Dropout Voltage (V)
TYPICAL PERFORMANCE CHARACTERISTICS
TCASE = 0°C
TCASE = 25°C
TCASE = 125°C
0.06
0.04
0.02
0.00
–0.02
–0.04
–0.06
–0.08
–0.10
–0.12
0
1
2
3
4
5
6
7
0
TJ (°C)
Figure 2. Dropout Voltage vs. Output
Current
Figure 3. Reference Voltage vs.
Temperature
0.200
0.175
Minimum Load Current (mA)
2.500
TCASE = 125°C
0.150
0.125
TCASE = 25°C
0.100
0.075
0.050
TCASE = 0°C
0.025
2.175
TCASE = 0°C
1.850
1.525
TCASE = 25°C
1.200
0.875
TCASE = 125°C
0.550
0.000
0
1
2
3
4
5
6
7
1
2
3
4
5
6
7
Output Current (A)
VIN – VOUT (V)
Figure 4. Load Regulation vs. Output
Current
Figure 5. Minimum Load Current
100
90
80
Ripple Rejection (dB)
Output Voltage Deviation (%)
10 20 30 40 50 60 70 80 90 100 110 120 130
Output Current (A)
70
60
50
40
30
20
10
0
101
TCASE = 25°C
IOUT = 7.0 A
(VIN – VOUT) = 3.0 V
VRIPPLE = 1.6 VPP
CAdj = 25 µF
102
103
104
Frequency (Hz)
Figure 6. Ripple Rejection vs. Frequency
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3
105
8
9
CS5207–1
APPLICATIONS INFORMATION
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
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 manufacturer’s data sheet
provides this information.
A 22 µF tantalum capacitor will work for most
applications, but with high current regulators such as the
CS5207–1 the transient response and stability improve with
higher values of capacitor. 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:
The CS5207–1 linear regulator provides adjustable
voltages at currents up to 7.0 A. The regulator is protected
against short circuit, and includes thermal shutdown and
safe area protection (SOA) circuitry. The SOA protection
circuitry decreases the maximum available output current as
the input–output differential voltage increases.
The CS5207–1 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.
Adjustable Operation
The adjustable regulator has an output voltage range of
1.25 V to 13 V. An external resistor divider sets the output
voltage as shown in Figure 7. 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 current
to flow to ground. This current creates a voltage across R2
that adds to the 1.25 V across R1 and sets the overall output
voltage. The adjust pin current (typically 50 µA) also flows
through R2 and adds a small error that should be taken into
account if precise adjustment of VOUT is necessary.
The output voltage is set according to the formula:
VOUT VREF 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
transient load conditions. The output capacitor network
should be as close to the load as possible for the best results.
R2
R1 R1
IAdj R2
Protection Diodes
The term IAdj × R2 represents the error added by the adjust
pin current.
R1 is chosen so that the minimum load current is at least
10 mA. R1 and R2 should be the same type, e.g. metal film
for best tracking over temperature. The adjust pin is
bypassed to improve the transient response and ripple
rejection of the regulator.
VIN
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
CS5207–1 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 8 is recommended.
VOUT
VOUT
VIN
CS5207–1
VREF
C1
Adj
C2
R1
IN4002 (Optional)
IAdj
CAdj
VIN
R2
VOUT
VIN
VOUT
CS5207–1
C1
C2
Adj
Figure 7. Resistor Divider Scheme
for the Adjustable Version
R1
CAdj
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.
R2
Figure 8. Protection Diode Scheme for Adjustable
Output Regulator
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4
CS5207–1
Output Voltage Sensing
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:
Since the CS5207–1 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.
Best load regulation occurs when R1 is connected directly
to the output pin of the regulator as shown in Figure 9. If R1
is connected to the load, RC is multiplied by the divider ratio
and the effective resistance between the regulator and the
load becomes.
RC R1 R2
R1
PD(max) {VIN(max) VOUT(min)}IOUT(max) VIN(max)IQ
(2)
where:
VIN(max) is the maximum input voltage,
VOUT(min) is the minimum output voltage,
IOUT(max) is the maximum output current, for the
application
IQ is the maximum quiescent current at IOUT(max).
where RC = conductor parasitic resistance.
VIN
VIN
RC
VOUT
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 RΘJA, the total thermal resistance between the
junction and the surrounding air.
1. Thermal Resistance of the junction to case, RΘJC
(°C/W)
2. Thermal Resistance of the case to Heat Sink, RΘCS
(°C/W)
3. Thermal Resistance of the Heat Sink to the ambient
air, RΘSA (°C/W)
These are connected by the equation:
Conductor Parasitic
Resistance
CS5207–1
R1
Adj
RLOAD
R2
Figure 9. Grounding Scheme for Adjustable Output
Regulator to Minimize Parasitic Resistance Effects
Calculating Power Dissipation and Heat Sink
Requirements
RJA RJC RCS RSA
The CS5207–1 linear regulator includes thermal
shutdown and safe operating area 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 VOUT on the CS5207–1,
electrical isolation may be required for some applications.
Thermal compound should always be used with high current
regulators such as these.
The thermal characteristics of an IC depend on the
following four factors:
1.
2.
3.
4.
The value for RΘJA is calculated using equation (3) and
the result can be substituted in equation (1).
The value for RΘJC is normally quoted as a single figure
for a given package type based on average die size. For a
high current regulator such as the CS5207–1 the majority of
the heat is generated in the power transistor section. The
value for RΘSA depends on the heat sink type, while RΘCS
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 RΘJA can be calculated and the proper heat sink selected.
For further discussion on heat sink selection, see application
note “Thermal Management for Linear Regulators,”
document number SR006AN/D, available through the
Literature Distribution Center or via our website at
http://onsemi.com.
Maximum Ambient Temperature TA (°C)
Power dissipation PD (Watts)
Maximum junction temperature TJ (°C)
Thermal resistance junction to ambient RΘJA (°C/W)
These four are related by the equation
TJ TA PD RJA
(3)
(1)
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5
CS5207–1
ADDITIONAL ORDERING INFORMATION
Orderable Part
Number
CS5207–1GT3
Type
Description
7.0 A, Adj. Output
TO–220 THREE LEAD, STRAIGHT
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6
CS5207–1
PACKAGE DIMENSIONS
TO–220
THREE LEAD
T SUFFIX
CASE 221A–09
ISSUE AA
B
NOTES:
1. DIMENSIONING AND TOLERANCING PER ANSI
Y14.5M, 1982.
2. CONTROLLING DIMENSION: INCH.
3. DIMENSION Z DEFINES A ZONE WHERE ALL
BODY AND LEAD IRREGULARITIES ARE
ALLOWED.
SEATING
PLANE
–T–
C
F
T
S
4
DIM
A
B
C
D
F
G
H
J
K
L
N
Q
R
S
T
U
V
Z
A
Q
1 2 3
U
H
K
Z
L
R
V
J
G
D
N
INCHES
MIN
MAX
0.570
0.620
0.380
0.405
0.160
0.190
0.025
0.035
0.142
0.147
0.095
0.105
0.110
0.155
0.018
0.025
0.500
0.562
0.045
0.060
0.190
0.210
0.100
0.120
0.080
0.110
0.045
0.055
0.235
0.255
0.000
0.050
0.045
----0.080
MILLIMETERS
MIN
MAX
14.48
15.75
9.66
10.28
4.07
4.82
0.64
0.88
3.61
3.73
2.42
2.66
2.80
3.93
0.46
0.64
12.70
14.27
1.15
1.52
4.83
5.33
2.54
3.04
2.04
2.79
1.15
1.39
5.97
6.47
0.00
1.27
1.15
----2.04
PACKAGE THERMAL DATA
Parameter
TO–220
THREE LEAD
Unit
RΘJC
Typical
1.6
°C/W
RΘJA
Typical
50
°C/W
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CS5207–1
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are trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC reserves the right to make changes without
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CS5207–1/D