CYStech Electronics Corp.
Three Terminal Adjustable Output
Positive Voltage Regulators
Spec. No. : C513F3
Issued Date : 2003.05.24
Revised Date :
. .
Page No. : 1/9
PL317F3
The PL317F3 is an adjustable 3–terminal positive voltage regulator capable
of supplying in excess of 1.5 A over an output voltage range of 1.2 V to 37 V.
This voltage regulator is exceptionally easy to use and requires only two ex-
ternal resistors to set the output voltage. Further, it employs internal current
limiting, thermal shutdown and safe area compensation, making it essentially
blow–out proof.
The PL317F3 serves a wide variety of applications including local, on-card
regulation. This device can also be used to make a programmable output regu-
lator, or by connecting a fixed resistor between the adjustment and output, the
PL317F3 can be used as a precision current regulator.
●
Output Current in Excess of 1.5 A
●
Output Adjustable between 1.2 V and 37 V
●
Internal Thermal Overload Protection
●
Internal Short Circuit Current Limiting Constant with Temperature
●
Output Transistor Safe–Area Compensation
●
Floating Operation for High Voltage Applications
●
Eliminates Stocking many Fixed Voltages
TO-263
Standard Application
Vin
PL317
+
Vout
R1
+
＊Cin
is required if regulator is located an appreciate
distance from power supply filter.
＊＊Cout
is not needed for stability, however, it does
improve transient response.
I
Adj
R2
Cin
Cout
0.1µF
1.0µF
V
out=
1.25(
1+
R
2/
R
1
)+I
Adj
R
2
Since
I
Adj
is controlled to less than 100 µA, the
error associated with this term is negligible in
most applications.
Maximum Ratings
Rating
Input-Output Voltage Differential
Power Dissipation
T
A
=25℃
Thermal Resistance, Junction-to-Ambient
Thermal Resistance, Junction-to-Case
Operating Junction Temperature Range
Storage Temperature Range
PL317F3
Symbol
V
I
-V
O
P
D
θ
JA
θ
JC
T
J
Tstg
Value
40
Internally Limited
60
3.0
-40 to +125
-65 to +150
Unit
V
W
℃/W
℃/W
℃
℃
CYStek Product Specification
CYStech Electronics Corp.
Spec. No. : C513F3
Issued Date : 2003.05.24
Revised Date :
. .
Page No. : 2/9
Electrical Characteristics
(V
I
-V
O
=5V,I
O
=0.5A,T
J
=0 to 125℃, unless otherwise noted
)
Characteristics
Line Regulation(
Note 1
)
Load Regulation(
Note 1
)
Symbol Conditions
Reg
line
T
A
=25℃,3.0V≤V
I
-V
O
≤40V
Reg
load
T
A
=25℃,10mA≤I
O
≤1.5A
V
O
≤5.0V
V
O
≥5.0V
Thermal Regulation(
Note 4
) Reg
therm
T
A
=25℃, 20ms pulse
Adjust Pin Current
I
Adj
2.5V≤V
I
-V
O
≤40V,10mA≤I
L
≤1.5A
Adjust Pin Current Change
∆I
Adj
P
D
≤20W
3.0V≤V
I
-V
O
≤40V,10mA≤I
O
≤1.5A
Reference Voltage
Vref
P
D
≤20W
Temperature Stability
Ts
0
≤T
J
≤125℃
Minimum Load Current to I
Lmin
V
I
-V
O
=40V
maintain Regulation
Maximum Output Current Imax
V
I
-V
O
≤15V,P
D
≤20W
V
I
-V
O
≤40V,P
D
≤20W,T
A
=25℃
% of V
O
,T
A
=25℃,10Hz≤f≤10kHz
RMS Noise
N
Ripple Rejection(
Note 2
)
RR
V
O
=10V,f=120Hz
Without C
Adj
C
Adj
=10µF
Long-Term Stability(
Note 3)
S
T
J
=125℃,T
A
=25℃ for endpoint
measurements
Min
-
-
-
-
-
-
1.2
-
-
1. 5
0.15
-
-
66
-
Typ
0.01
5.0
0.1
0.03
50
0.2
1.25
0.7
3.5
2.2
0.4
0.003
65
80
0.3
Max
0.04
25
0.5
0.07
100
5.0
1.3
-
10
-
-
-
-
-
1.0
Unit
%/V
mV
%V
O
%V
O
/W
µA
µA
V
%V
O
mA
A
%V
O
dB
%/1.0k
Hrs
Notes:
1.Load and line regulation are specified at constant junction temperature. Changes in V
O
due to heating effects must be
taken into account separately. Pulse testing with low duty cycle is used.
2.C
Adj
, when used, is connected between the adjustment pin and ground.
3.Since long-term stability cannot be measured on each device before shipment, this specification is an engineering
estimate of average stability from lot to lot.
4.Power dissipation within an IC voltage regulator produces a temperature gradient on the die, affecting individual IC
components on the die. These effects can be minimized by proper integrated circuit design and layout techniques.
Thermal regulation is the effect of these temperature gradients on the output voltage and is expressed in percentage
of output change per watt of power change in a specified time.
PL317F3
CYStek Product Specification
CYStech Electronics Corp.
Representative Schematic Diagram
Spec. No. : C513F3
Issued Date : 2003.05.24
Revised Date :
. .
Page No. : 3/9
Vin
Vout
Adjust
∣V
OH
-V
OL
∣
Line Regulation(%/V)=
Vcc
VIH
VIL
Vin
PL317
Vout
×100
∣V
OL
∣
VOH
VOL
Pulse testing required
1% Duty Cycle is
suggested
Cin
0.1
μ
F
Adjust
IAdj
R1
1%
Co
+
1
μ
F
RL
R2
1%
Fig 1. Line Regulation and
∆I
Adj
/Line test circuit
PL317F3
CYStek Product Specification
CYStech Electronics Corp.
Vin
VI
PL317
Adjust
IAdj
Cin
0.1
μ
F
R2
1%
R1
1%
Co
+
Spec. No. : C513F3
Issued Date : 2003.05.24
Revised Date :
. .
Page No. : 4/9
Vout
IL
*
1
μ
F
RL
(max load)
Vo(min load)
Vo(max load)
RL
(min load)
*Pulse testing required.
1% Duty Cycle is suggest
Vo(min load)-Vo(max load)
Load Regulation(mV)=Vo(min load)-Vo(max load)
Load Regulation(%Vo)=
Vo(min load)
×100
Fig 2. Load Regulation and
∆I
Adj
/Load test circuit
Vin
PL317
Adjust
IAdj
Cin
VI
ISET
0.1
μ
F
Vout
IL
R1
1%
Vref
+
1
μ
F
Co
RL
Vo
R2
1%
＊
Pulse testing required.
1% Duty Cycle is suggested.
To calculate R2: Vout=I
SET
R2+1.250V
Assume I
SET
=5.25mA
Fig 3. Standard Test Circuit
PL317F3
CYStek Product Specification
CYStech Electronics Corp.
24V
14V
f=120Hz
Vin
PL317
Adjust
R1
1%
D1 *
1N4002
+
Spec. No. : C513F3
Issued Date : 2003.05.24
Revised Date :
. .
Page No. : 5/9
Vout
Cin
0.1
μ
F
1
μ
F
Co
RL
Vout=10V
Vo
R2
1%
CAdj
+
10
μ
F
* D1 Discharges CAdj if output is shorted to ground
Fig 4. Ripple Rejection Test Circuit
Application Information
Basic Circuit Operation
The PL317 is a 3-terminal floating regulator. In operation, the PL317 develops and maintains a nominal
1.25V reference (Vref) between its output and adjustment terminals. This reference voltage is converted
to a programming current (Iprog) by R1(see Fig 5), and this constant current flows through R2 to ground.
The regulated output voltage is given by:
Vout=Vref
(
1+R2/R1)+I
Adj
R2
Since the current from the adjustment terminal (I
Adj
) represents an error term in the equation, the PL317
was designed to control I
Adj
to less than 100 µA and keep it constant. To do this, all quiescent operating
current is returned to the output terminal. This imposes the requirement for a minimum load current. If
the load current is less than this minimum, the output voltage will rise.
Since the PL317 is a floating regulator, it is only the voltage differential across the circuit which is
important to performance, and operation at high voltages with respect to ground is possible.
Vin
PL317
Adjust
Vref
R1
Iprog
Vout
Vout
IAdj
R2
Vref=1.25V typical
Fig 5. Basic Circuit Configuration
PL317F3
CYStek Product Specification
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