ONSEMI LM350BT#

Order this document by LM350/D
The LM350 is an adjustable three–terminal positive voltage regulator
capable of supplying in excess of 3.0 A over an output voltage range of 1.2 V
to 33 V. This voltage regulator is exceptionally easy to use and requires only
two external 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 LM350 serves a wide variety of applications including local, on card
regulation. This device also makes an especially simple adjustable switching
regulator, a programmable output regulator, or by connecting a fixed resistor
between the adjustment and output, the LM350 can be used as a precision
current regulator.
• Guaranteed 3.0 A Output Current
•
•
•
•
•
•
•
•
•
THREE–TERMINAL
ADJUSTABLE POSITIVE
VOLTAGE REGULATOR
SEMICONDUCTOR
TECHNICAL DATA
T SUFFIX
PLASTIC PACKAGE
CASE 221A
Output Adjustable between 1.2 V and 33 V
Pin 1. Adjust
2. Vout
3. Vin
Load Regulation Typically 0.1%
Line Regulation Typically 0.005%/V
Internal Thermal Overload Protection
1
2
Internal Short Circuit Current Limiting Constant with Temperature
3
Output Transistor Safe Area Compensation
Heatsink surface is connected to Pin 2.
Floating Operation for High Voltage Applications
Standard 3–lead Transistor Package
Eliminates Stocking Many Fixed Voltages
Simplified Application
Vin
LM350
vout
R1
240
IAdj
Adjust
Cin*
0.1µF
+ C **
O
1µF
R2
ORDERING INFORMATION
Device
* = Cin is required if regulator is located an appreciable distance from power supply filter.
** = CO is not needed for stability, however, it does improve transient response.
Vout
ǒ Ǔ
+ 1.25 V 1 ) RR21 ) IAdj R2
Since IAdj is controlled to less than 100 µA, the error associated with
this term is negligible in most applications.
LM350T
LM350BT#
Operating
Temperature Range
TJ = 0° to +125°C
Plastic Power
TJ = –40° to +125°C
Plastic Power
# Automotive temperature range selections are
available with special test conditions and additional
tests. Contact your local Motorola sales office for
information.
 Motorola, Inc. 1996
MOTOROLA ANALOG IC DEVICE DATA
Package
Rev 0
1
LM350
MAXIMUM RATINGS
Rating
Symbol
Value
Unit
VI–VO
35
Vdc
Power Dissipation
PD
Internally Limited
W
Operating Junction Temperature Range
TJ
– 40 to +125
°C
Tstg
– 65 to +150
°C
Tsolder
300
°C
Input–Output Voltage Differential
Storage Temperature Range
Soldering Lead Temperature (10 seconds)
ELECTRICAL CHARACTERISTICS (VI–VO = 5.0 V; IL = 1.5 A; TJ = Tlow to Thigh; Pmax [Note 1], unless otherwise noted.)
Figure
Symbol
Min
Typ
Max
Unit
Line Regulation (Note 2)
TA = 25°C, 3.0 V ≤ VI–VO ≤ 35 V
1
Regline
–
0.0005
0.03
%/V
Load Regulation (Note 2)
TA = 25°C, 10 mA ≤ Il ≤ 3.0 A
VO ≤ 5.0 V
VO ≥ 5.0 V
2
Regload
–
–
5.0
0.1
25
0.5
mV
% VO
Regtherm
–
0.002
–
% VO/W
3
IAdj
–
50
100
µA
Adjustment Pin Current Change
3.0 V ≤ VI–VO ≤ 35 V
10 mA ≤ IL ≤ 3.0 A, PD ≤ Pmax
1,2
∆IAdj
–
0.2
5.0
µA
Reference Voltage
3.0 V ≤ VI–VO ≤ 35 V
10 mA ≤ IO ≤ 3.0 A, PD ≤ Pmax
3
Vref
1.20
1.25
1.30
V
Line Regulation (Note 2)
3.0 V ≤ VI–VO ≤ 35 V
1
Regline
–
0.02
0.07
%/V
Load Regulation (Note 2)
10 mA ≤ IL ≤ 3.0 A
VO ≤ 5.0 V
VO ≥ 5.0 V
2
Regload
–
–
20
0.3
70
1.5
mV
% VO
Temperature Stability (Tlow ≤ TJ ≤ Thigh)
3
TS
–
1.0
–
% VO
Minimum Load Current to
Maintain Regulation (VI–VO = 35 V)
3
ILmin
–
3.5
10
mA
Maximum Output Current
VI–VO ≤ 10 V, PD ≤ Pmax
VI–VO = 30 V, PD ≤ Pmax, TA = 25°C
3
Imax
3.0
0.25
4.5
1.0
–
–
–
0.003
–
–
66
65
80
–
–
–
0.3
1.0
–
–
2.3
–
–
1.5
Characteristics
Thermal Regulation, Pulse = 20 ms,
(TA = +25°C)
Adjustment Pin Current
RMS Noise, % of VO
TA= 25°C, 10 Hz ≤ f ≤ 10 kHz
N
Ripple Rejection, VO = 10 V, f = 120 Hz (Note 3)
Without CAdj
CAdj = 10 µF
4
Long Term Stability, TJ = Thigh (Note 4)
TA= 25°C for Endpoint Measurements
3
Thermal Resistance, Junction–to–Case
Peak (Note 5)
Average (Note 6)
A
RR
S
RθJC
% VO
dB
%/1.0 k
Hrs.
°C/W
NOTES: 1. Tlow to Thigh = 0° to +125°C; Pmax = 25 W for LM350T; Tlow to Thigh = – 40° to +125°C; Pmax = 25 W for LM350BT
2. Load and line regulation are specified at constant junction temperature. Changes in VO due to heating effects must be taken into account separately.
Pulse testing with low duty cycle is used.
3. CAdj, when used, is connected between the adjustment pin and ground.
4. 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.
5. Thermal Resistance evaluated measuring the hottest temperature on the die using an infrared scanner. This method of evaluation yields very
accurate thermal resistance values which are conservative when compared to the other measurement techniques.
6. The average die temperature is used to derive the value of thermal resistance junction to case (average).
2
MOTOROLA ANALOG IC DEVICE DATA
LM350
Representative Schematic Diagram
Vin
310
310
230
5.6K
120
6.3V
160
6.8K
510
12K
5.0pF
12.4K
135
125K
6.7K
170
13K
200
6.3V
6.3V
30
pF
5.1K
110
190
5.8K
3.6K
30
pF
2.4K
105
12.5K
4
0.45
Vout
Adjust
Figure 1. Line Regulation and ∆IAdj/Line Test Circuit
VCC
Line Regulation (%/V) =
*
VOH – VOL
x 100
VOL
VIH
VIL
Vin
LM350
Adjust
Cin
0.1µF
* Pulse Testing Required:
1% Duty Cycle is suggested.
MOTOROLA ANALOG IC DEVICE DATA
IAdj
Vout
VOH
VOL
IL
R1
240
1%
RL
+
CO
1µF
R2
1%
3
LM350
Figure 2. Load Regulation and ∆IAdj/Load Test Circuit
VO (min Load) – VO (max Load)
X 100
VO (min Load)
Load Regulation (mV) = VO (min Load) –VO (max Load)
Load Regulation (% VO) =
Vin
Vin
Vout
LM350
Adjust
VO (min Load)
VO (max Load)
IL
R1
RL
(max Load)
240
1%
RL
(min Load)
*
+
Cin
0.1µF
CO
IAdj
1.0µF
R2
1%
* Pulse Testing Required:
1% Duty Cycle is suggested.
Figure 3. Standard Test Circuit
Vout
Vin
IL
LM350
Adjust
240
1%
R1
VI
IAdj
Vref
RL
+
0.1µF
Cin
1.0µF
CO
VO
ISET
R2
1%
To Calculate R2:
Vout = ISET R2 + 1.250 V
Assume ISET = 5.25 mA
Pulse Testing Required:
1% Duty Cycle is suggested.
Figure 4. Ripple Rejection Test Circuit
24V
Vout
Vin
14V
LM350
f = 120 Hz
Adjust
Cin
Vout = 10 V
IL
R1
240
1%
0.1µF
D1 *
1N4002
CO
R2
1.65K
1%
**
CAdj
RL
+
1.0µF
VO
+
10µF
* D1 Discharges CAdj if Output is Shorted to Ground.
**CAdj provides an AC ground to the adjust pin.
4
MOTOROLA ANALOG IC DEVICE DATA
LM350
Figure 6. Current Limit
7
0.4
I out , OUTPUT CURRENT (A)
∆ Vout , OUTPUT VOLTAGE CHANGE (%)
Figure 5. Load Regulation
0.2
0
IL = 0.5 A
–0.2
IL = 1.5 A
–0.4
–0.6
Vin = 15 V
Vout = 10 V
–0.8
TJ = 55°C
5
TJ = 25°C
3
TJ = 150°C
1
–1.0
–75 –50
–25
0
25
50
75
100
125
0
150
0
10
TJ, JUNCTION TEMPERATURE (°C)
20
Figure 7. Adjustment Pin Current
V in –Vout , INPUT–OUTPUT VOLTAGE
DIFFERENTIAL (Vdc)
IAdj, ADJUSTMENT PIN CURRENT ( µA)
70
65
60
55
50
45
40
–50
–25
0
25
50
75
100
125
∆V0 = 100 mV
IL = 3.0 A
2.5
IL = 2.0 A
2.0
IL = 500 mA
1.5
1.0
–75
150
IL = 20 mA
–50
–25
TJ, JUNCTION TEMPERATURE (°C)
0
25
50
75
100
IL = 200 mA
125
150
TJ, JUNCTION TEMPERATURE (°C)
Figure 9. Temperature Stability
Figure 10. Minimum Operating Current
1.260
5.0
IB , QUIESCENT CURRENT (mA)
Vref, REFERENCE VOLTAGE (V)
40
Figure 8. Dropout Voltage
3.0
35
–75
30
Vin–Vout, INPUT VOLTAGE DIFFERENTIAL (Vdc)
1.250
1.240
1.230
4.5
TJ = –55°C
4.0
TJ = 25°C
3.5
3.0
TJ = 150°C
2.5
2.0
1.5
1.0
0.5
1.220
–75 –50
–25
0
25
50
75
100
TJ, JUNCTION TEMPERATURE (°C)
MOTOROLA ANALOG IC DEVICE DATA
125
150
0
0
10
20
30
40
Vin–Vout, INPUT–OUTPUT VOLTAGE DIFFERENTIAL (Vdc)
5
LM350
Figure 11. Ripple Rejection versus Output Voltage
Figure 12. Ripple Rejection versus Output Current
100
140
RR, RIPPLE REJECTION (dB)
RR, RIPPLE REJECTION (dB)
CAdj = 10 µF
80
Without CAdj
60
40
Vin – Vout = 5 V
IL = 500 mA
f = 120 Hz
TJ = 25°C
20
0
0
5
10
120
100
60
40
20
15
20
25
30
Vout, OUTPUT VOLTAGE (V)
CAdj = 10 µF
80
Without CAdj
Vin – Vout = 5 V
IL = 500 mA
f = 120 Hz
TJ = 25°C
0
0.01
35
0.1
1
Iout, OUTPUT CURRENT (A)
Figure 13. Ripple Rejection versus Frequency
Figure 14. Output Impedance
101
Z O , OUTPUT IMPEDANCE ( Ω )
60
40
CAdj = 10 µF
Without CAdj
20
100
1.0 k
10 k
100 k 1.0 M
f, FREQUENCY (Hz)
Vin = 15 V
Vout = 10 V
IL = 500 mA
TJ = 25°C
100
10–1
Without CAdj
10–2
CAdj = 10 µF
10–3
10
10 M
100
Figure 15. Line Transient Response
1.5
1.0
CL = 1.0 µF; CAdj = 10 µF
0.5
0
–0.5
Vout = 10 V
IL = 50 mA
TJ = 25°C
–1.0
–1.5
CL = 0; Without CAdj
1.0
0
10
20
t, TIME (µs)
30
100 k
1.0 M
3
2
1
CL = 1.0 µF; CAdj = 10 µF
0
–2
CL = 0; Without CAdj
–3
1.5
IL
0.5
40
Vin = 15 V
Vout = 10 V
INL = 50 mA
TJ = 25°C
–1
1.0
Vin
0.5
0
1.0 k
10 k
f, FREQUENCY (Hz)
Figure 16. Load Transient Response
∆ Vout , OUTPUT VOLTAGE
DEVIATION (V)
∆ Vout , OUTPUT VOLTAGE
DEVIATION (V)
∆ Vin , INPUT VOLTAGE
CHANGE (V)
6
IL = 500 mA
Vin = 15 V
Vout = 10 V
TJ = 25°C
80
I L , LOAD
CURRENT (A)
RR, RIPPLE REJECTION (dB)
100
0
10
10
0
0
10
20
t, TIME (µs)
30
40
MOTOROLA ANALOG IC DEVICE DATA
LM350
APPLICATIONS INFORMATION
Basic Circuit Operation
The LM350 is a three–terminal floating regulator. In
operation, the LM350 develops and maintains a nominal
1.25 V reference (Vref) between its output and adjustment
terminals. This reference voltage is converted to a
programming current (IPROG) by R1 (see Figure 17), and this
constant current flows through R2 to ground. The regulated
output voltage is given by:
R2
Vout = Vref (1 +
) + IAdj R2
R1
Since the current from the terminal (IAdj) represents an
error term in the equation, the LM350 was designed to control
IAdj 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 LM350 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.
Figure 17. Basic Circuit Configuration
Vin
LM350
Vout
External Capacitors
A 0.1 µF disc or 1 µF tantalum input bypass capacitor (Cin)
is recommended to reduce the sensitivity to input line
impedance.
The adjustment terminal may be bypassed to ground to
improve ripple rejection. This capacitor (CAdj) prevents ripple
from being amplified as the output voltage is increased. A
10 µF capacitor should improve ripple rejection about 15 dB
at 120 Hz in a 10 V application.
Although the LM350 is stable with no output capacitance,
like any feedback circuit, certain values of external
capacitance can cause excessive ringing. An output
capacitance (CO) in the form of a 1 µF tantalum or 25 µF
aluminum electrolytic capacitor on the output swamps this
effect and insures stability.
Protection Diodes
When external capacitors are used with any IC regulator, it
is sometimes necessary to add protection diodes to prevent
the capacitors from discharging through low current points
into the regulator.
Figure 18 shows the LM350 with the recommended
protection diodes for output voltages in excess of 25 V or high
capacitance values (CO > 25 µF, CAdj > 10 µF). Diode D1
prevents CO from discharging thru the IC during an input
short circuit. Diode D2 protects against capacitor CAdj
discharging through the IC during an output short circuit. The
combination of diodes D1 and D2 prevents CAdj from
discharging through the IC during an input short circuit.
+
R1
Vref
Adjust
Figure 18. Voltage Regulator with
Protection Diodes
IPROG
Vout
IAdj
D1
R2
1N4002
Vref = 1.25 V Typical
Vin
Vout
LM350
+
Load Regulation
The LM350 is capable of providing extremely good load
regulation, but a few precautions are needed to obtain
maximum performance. For best performance, the
programming resistor (R1) should be connected as close to
the regulator as possible to minimize line drops which
effectively appear in series with the reference, thereby
degrading regulation. The ground end of R2 can be returned
near the load ground to provide remote ground sensing and
improve load regulation.
MOTOROLA ANALOG IC DEVICE DATA
Cin
R1
Adjust
D2
CO
1N4002
R2
CAdj
7
LM350
Figure 19. “Laboratory” Power Supply with Adjustable Current Limit and Output Voltage
D6
1N4002
Vin
32V
Vout1 RSC
LM350
(1)
Vin1
Vin2
IO
Vout 2
LM350
(2)
VO
240
0.1µF
D1
1N4001
Adjust 1
1K
Current
Limit
Adjust
1N4001
D2
Adjust 2
5.0K
10µF
1N4001
D3
D4
–10V
Diodes D1 and D2 and transistor Q2 are added to allow adjustment
of output voltage to 0 V.
Figure 20. Adjustable Current Limiter
Vout
1N4001
Q2
2N5640
Figure 21. 5.0 V Electronic Shutdown Regulator
D1
Iout
620
Vin
1N4002
Vin
Adjust
100
Vout
LM350
D1
1N4001
R2
* To provide current limiting of IO
to the system ground, the source of
the FET must be tied to a negative
voltage below –1.25 V.
R2 ≤
Vout
R1
Output Range:
0 ≤ VO ≤ 25 V
0 ≤ IO ≤ 1.5 A
–10V
D6 protects both LM350’s during an input short circuit.
LM350
+
1.0µF
120
D2
1N4001
Adjust
MPS2222
720
1.0k
2N5640
Vref
IDSS
Vref
R1 =
IOmax + IDSS
VO < V(BR)DSS + 1.25 V + VSS
ILmin – IDSS < IO < 3.0 A
As shown O < IO < 1.0 A
D1 protects the device during an input short circuit.
Figure 23. Current Regulator
Vin
Vout
LM350
Vout
Iout
R1
LM350
240
Adjust
R2
TTL
Control
Minimum Vout = 1.25 V
VSS*
Figure 22. Slow Turn–On Regulator
Vin
1.0µF
Tantalum
+
Voltage
Adjust
Q1
2N3822
+25V
+
D5
IN4001
1N4001
MPS2907
IAdj
Adjust
50k
+
10µF
Iout
+
^
ǒ Ǔ)
Vref
R1
IAdj
1.25 V
R1
10 mA ≤ Iout ≤ 3.0 A
8
MOTOROLA ANALOG IC DEVICE DATA
LM350
OUTLINE DIMENSIONS
T SUFFIX
PLASTIC PACKAGE
CASE 221A–06
ISSUE Y
–T–
B
C
F
T
S
SEATING
PLANE
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.
4
A
Q
1 2 3
U
H
K
Z
L
R
V
J
G
D
N
MOTOROLA ANALOG IC DEVICE DATA
DIM
A
B
C
D
F
G
H
J
K
L
N
Q
R
S
T
U
V
Z
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
9
LM350
NOTES
10
MOTOROLA ANALOG IC DEVICE DATA
LM350
NOTES
MOTOROLA ANALOG IC DEVICE DATA
11
LM350
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the suitability of its products for any particular purpose, nor does Motorola assume any liability arising out of the application or use of any product or circuit, and
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12
◊
*LM350/D*
MOTOROLA ANALOG IC DEVICE
DATA
LM350/D