5A Low-Voltage Low-Dropout Regulator
LM39500/39501/39502
TO263-3L / TO220-3L
(39500-x.x Fixed only)
FEATURES
•5.0A minimum guaranteed output current
•400mV typical dropout voltage
Ideal for 3.0V to 2.5V conversion
Ideal for 2.5V to 1.8V or 1.5V conversion
•1% initial accuracy
1. In
2. Gnd
3. Out
•Low ground current
•Current limiting and thermal shutdown
TO263-5L / TL220-5L
(39501-x.x & 39502 only)
•Reversed-battery protection
•Reversed-leakage protection
•Fast transient response
•TTL/CMOS compatible enable pin-LM39501 only
•Error flag output - LM39501 only
•Ceramic capacitor stable(See application information)
•Adjustable version - LM39502 only
1.
2.
3.
4.
5.
En
In
Gnd
Out
Flg or Adj
APPLICATIONS
•Low-voltage Digatal Ics
•LDO linear regulator for PC add-in cards
•High-efficiency linear power supplies
•Multimedia and PC processor supplies
•SMPS post regulator
•Low-voltage microcontrollers
•Strong ARM™ processor supply
PIN DESCRIPTION
CMOS-compatible control input.
Enable
(Input)
IN
GND
OUT
FLG
ADJ
Logic high = enable, logic
Logic low or open = Shutdown
Supply (Input): +16V maximum supply
Ground pin and TAB are internally connected.
Regulator Output
Flag (Output): Open-collector error flag output.
Adjustment Input: Feedback input.
ORDERING INFORMATION
Device
LM39500R- X.X
LM39500T-X.X
LM39501R-X.X
LM39501T-X.X
LM39502R-Adj
LM39502T-Adj
Marking
LM39500-X.X
LM39500-X.X
LM39501-X.X
LM39501-X.X
LM39502-Adj
LM39502-Adj
Package
TO-263
TO-220
TO-263
TO-220
TO-263
TO-220
DESCRIPTION
The LM39500, LM39501 and LM39502 is a 5A
low-dropout linear voltage regulator that provides
a low-voltage, high-current output with a
minimum of external components. Utilizing Super
* X.X = Fixed Vout = 1.5V, 1.8V, 2.5V, 3.3V, 5.0V
beta PNP pass element, The LM39500 offers
extremely low dropout (typically 400mV at 5A)
and low ground current (typically 70mA at 5A).
The LM39500/1/2 is ideal for PC Add-In cards that need to convert from standard 5V or 3.3V, down to
new, lower core voltages. A guaranteed maximum dropout voltage of 500mV over all operating conditions
allows the LM39500/1/2 to provide 2.5V from a supply as low as 3V. The LM39500 also has fast transient
response, for heavy switching applications. The device requires only 47F of output capacitance to maintain
stability and achieve fast transient responseThe LM39500/1/2 is fully protected with overcurrent
limiting,thermal shutdown, reversed-battery and reversed-lead in-sertion protection. The LM39501 offers a
TTL-logic-compat-ible enable pin and an error flag that indicates undervoltage and overcurrent
conditions. The LM39500/1/2 comes in the TO-220 and TO-263 packages and is an ideal upgrade to
older,NPN-based linear voltage regulators.
The LM39502 is adjustable version.
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5A Low-Voltage Low-Dropout Regulator
LM39500/39501/39502
Typical Application Circuit
LM39500
LM39501
LM39502
Absolute Maximum Ratings (Note 1)
Supply Voltage (VIN) : –20V to +20V
Enable Voltage (VEN) : +20V
Storage Temperature (TS) : –65°C to +150°C
Lead Temperature (soldering, 5 sec) : 260°C
ESD,
Note 3
Operating Ratings (Note 2)
Supply Voltage (VIN) : +2.25V to +16V
Enable Voltage (VEN) : +16V
Maximum Power Dissipation (PD(max))
Note 4
Junction Temperature (TJ) : –40°C to +125°C
Package Thermal Resistance
TO-263(θ
JC
) : 2°C/W
TO-220(θ
JC
) : 2°C/W
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5A Low-Voltage Low-Dropout Regulator
Block Diagram
LM39500/39501/39502
LM39500 Fixed (1.5V,1.8V,2.5V,3.3V,5.0V)
LM39501 Fixed with Flag and Enable
LM39502 Adjustable
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5A Low-Voltage Low-Dropout Regulator
LM39500/39501/39502
Note
Note
Note
Note
Note
Note
Note
Note
Note
1. Exceeding the absolute maximum ratings may damage the device.
2. The device is not guaranteed to function outside its operating rating.
3. Devices are ESD sensitive. Handling precautions recommended.
4. P
D(max)
= (T
J(max)
– T
A
)
θ
JA
, where
θ
JA
depends upon the printed circuit layout. See “Applications Information.”
5.Vout temperature coefficient is ∆V
OUT(worst case)
(T
J(max)
– T
J(min)
) where T
J(max)
is +125℃ and T
J(min)
is 0℃
6. V
DO
= V
IN
– V
OUT
when V
OUT
decreases to 98% of its nominal output voltage with V
IN
= V
OUT
+ 1V.
7. I
GND
is the quiescent current. IIN = I
GND
+ I
OUT
.
8. V
EN
0.8V, V
IN
8V, and V
OUT
= 0V
9. For a 2.5V device, V
IN
= 2.250V (device is in dropout).
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5A Low-Voltage Low-Dropout Regulator
Application Information
LM39500/39501/39502
The LM39500/1 is a high-performance low-dropout voltage regulator suitable for moderate to high-current voltage
regu-lator applications. Its 400mV dropout voltage at full load makes it especially valuable in battery-powered
systems and as a high-efficiency noise filter in post-regulator applications. Unlike older NPN-pass transistor
designs, where the mini-mum dropout voltage is limited by the base-to-emitter voltage drop and collector-to-
emitter saturation voltage, dropout per-formance of the PNP output of these devices is limited only by the low V
CE
saturation voltage.A trade-off for the low dropout voltage is a varying base drive requirement.
The LM39500/1/2 regulator is fully protected from damage due to fault conditions. Current limiting is provided. This
limiting is linear output current during overload conditions is constant. Thermal shutdown disables the device when
the die temperature exceeds the maximum safe operating tem-perature. Transient protection allows device (and
load) sur-vival even when the input voltage spikes above and below nominal. The output structure of these regulators
allows voltages in excess of the desired output voltage to be applied without reverse current flow.
Thermal Design
Linear regulators are simple to use. The most complicated design parameters to consider are thermal
characteristics.Thermal design requires four application-specific param-eters:
•Maximum ambient temperature (T
A
)
•Output Current (I
OUT
)
•Output Voltage (V
OUT
)
•Input Voltage (V
IN
)
•Ground Current (I
GND
)
Calculate the power dissipation of the regulator from these numbers and the device parameters from this
datasheet,where the ground current is taken from the data sheet.
PD = (V
IN
– V
OUT
) I
OUT
+ V
IN
·I
GND
The heat sink thermal resistance is determined by:
θ
SA=
(T
JMAX
-T
A
)/P
D
-(θ
JC
+θ
CS
)
where TJ (max) 125 ℃ and
θ
CS
is between 0℃ and 2℃/W.
The heat sink may be significantly reduced in applications where the minimum input voltage is known and is large
compared with the dropout voltage. Use a series input resistor to drop excessive voltage and distribute the heat
between this resistor and the regulator. The low dropout properties of Taejin regulators allow signifi-cant reductions
in regulator power dissipation and the asso-ciated heat sink without compromising performance. When this
technique is employed, a capacitor of at least 1.0F is needed directly between the input and regulator ground.Refer
to Application Note 9 for further details and examples on thermal design and heat sink specification.
Output Capacitor
The LM39500/1/2 requires an output capacitor to maintain stability and improve transient response. Proper capacitor
selection is important to ensure proper operation. The LM39500/1/2 output capacitor selection is dependent upon
the ESR (equivalent series resistance) of the output capacitor to maintain stability. When the output capacitor is 47F
or greater, the output capacitor should have less than 1 of ESR. This will improve transient response as well as
promote stability. Ultralow ESR capacitors, such as ceramic chip capacitors may promote instability. These very low
ESR levels may cause an oscillation and/or underdamped tran-sient response. A low-ESR solid tantalum capacitor
works extremely well and provides good transient response and stability over temperature. Aluminum electrolytics can
also be used, as long as the ESR of the capacitor is < 1.The value of the output capacitor can be increased without
limit. Higher capacitance values help to improve transient response and ripple rejection and reduce output noise.
Input Capacitor
An input capacitor of 1uF or greater is recommended when the device is more than 4 inches away from the bulk ac
supply capacitance, or when the supply is a battery. Small, surface-mount, ceramic chip capacitors can be used for
the bypass-ing. Larger values will help to improve ripple rejection by bypassing the input to the regulator, further
improving the integrity of the output voltage.Transient Response and 3.3V.
Fig 1. Capacitor Requirements
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