®
RT2516
2A, Low Input Voltage, Ultra-Low Dropout LDO Regulator
with Enable
General Description
Features
The RT2516 is a high performance positive voltage regulator
designed for use in applications requiring ultra-low input
voltage and ultra-low dropout voltage at up to 2 amperes.
It operates with an input voltage as low as 1.4V, with output
voltage programmable as low as 0.5V. The RT2516
features ultra low dropout, ideal for applications where
output voltage is very close to input voltage. Additionally,
the RT2516 has an enable pin to further reduce power
dissipation while shutdown. The RT2516 provides
excellent regulation over variations in line, load and
temperature. The RT2516 is available in the SOP-8
(Exposed Pad) package. The output voltage can be set
by an external divider depending on how the FB pin is
configured.
Input Voltage as Low as 1.4V
Ultra-Low Dropout Voltage 400mV @ 2A
Over Current Protection
Over Temperature Protection
1μ
μA Input Current in Shutdown Mode
Enable Control
RoHS Compliant and Halogen Free
Applications
Ordering Information
RT2516
Package Type
SP : SOP-8 (Exposed Pad-Option 2)
Telecom/Networking Cards
Motherboards/Peripheral Cards
Industrial Applications
Wireless Infrastructure
Set Top Box
Medical Equipment
Notebook Computers
Battery Powered Systems
Pin Configurations
Lead Plating System
G : Green (Halogen Free and Pb Free)
(TOP VIEW)
NC
Note :
Richtek products are :
RoHS compliant and compatible with the current require-
8
EN
2
VIN
NC
3
GND
ADJ
6
VOUT
5
NC
9
4
GND
7
ments of IPC/JEDEC J-STD-020.
SOP-8 (Exposed Pad)
Suitable for use in SnPb or Pb-free soldering processes.
Simplified Application Circuit
RT2516
VIN
VIN
VOUT
C1
VOUT
R1
C2
ADJ
Chip Enable
R2
EN
GND
Copyright © 2013 Richtek Technology Corporation. All rights reserved.
DS2516-03
November 2013
is a registered trademark of Richtek Technology Corporation.
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RT2516
Marking Information
RT2516GSP : Product Number
RT2516
GSPYMDNN
YMDNN : Date Code
Functional Pin Description
Pin No.
Pin Name
1, 4, 5
NC
2
EN
3
VIN
6
VOUT
7
ADJ
Pin Function
No Internal Connection.
Chip Enable (Active-High). Pulling this pin below 0.4V to turn the regulator off. The
device will be enabled if this pin is left open. Connect to VIN for controlling by VIN.
Power Input. For regulation at full load, the input to this pin must be between
(VOUT + 0.5V) and 6V. Minimum input voltage is 1.4V. A large bulk capacitance
should be placed closely to this pin to ensure that the input supply does not sag
below 1.4V. A minimum of 10F ceramic capacitor should be placed directly at this
pin.
Output of the Regulator. A minimum of 10F capacitor should be placed directly at
this pin.
Feedback Voltage Input. If connected to the VOUT pin, the output voltage will be
set at 0.5V. If external feedback resistors are used, the output voltage will be
determined by the resistor ratio.
Ground. The exposed pad must be soldered to a large PCB and connected to GND
for maximum power dissipation.
8,
GND
9 (Exposed pad)
Function Block Diagram
RSENSE
VOUT
VIN
VPUMP
-
-
+
+
ADJ
VIN
0.5µA
0.5V
EN
VIN
Thermal
Shutdown
VOUT
+
VIN
-
GND
Reverse Voltage
Shutdown
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Reference
Generator
is a registered trademark of Richtek Technology Corporation.
DS2516-03
November 2013
RT2516
Absolute Maximum Ratings
(Note 1)
Supply Voltage, VIN -----------------------------------------------------------------------------------------------------Other Pins ------------------------------------------------------------------------------------------------------------------Power Dissipation, PD @ TA = 25°C
SOP-8 (Exposed Pad) --------------------------------------------------------------------------------------------------Package Thermal Resistance (Note 2)
SOP-8 (Exposed Pad), θJA ---------------------------------------------------------------------------------------------SOP-8 (Exposed Pad), θJC --------------------------------------------------------------------------------------------Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------------------Junction Temperature ----------------------------------------------------------------------------------------------------Storage Temperature Range -------------------------------------------------------------------------------------------ESD Susceptibility (Note 3)
HBM (Human Body Model) ---------------------------------------------------------------------------------------------CDM (Charged Device Model) ------------------------------------------------------------------------------------------
Recommended Operating Conditions
0.3V to 7V
0.3V to 7V
2.500W
40°C/W
8°C/W
260°C
150°C
−65°C to 150°C
2kV
1kV
(Note 4)
Supply Voltage, VIN ------------------------------------------------------------------------------------------------------ 1.4V to 6V
Junction Temperature Range -------------------------------------------------------------------------------------------- −40°C to 125°C
Ambient Temperature Range -------------------------------------------------------------------------------------------- −40°C to 105°C
Electrical Characteristics
(VIN = 1.4V to 6V, IOUT = 10μA to 2A, VADJ = VOUT, −40°C ≤ TA ≤ 105°C, unless otherwise specified)
Parameter
Symbol
Test Conditions
Min
Typ
Max
Unit
Quiescent Current
IQ
VIN = 3.3V, IOUT = 0A
--
0.7
1.5
mA
Shutdown Current
ISHDN
VIN = 6V, VEN = 0V
--
1.5
10
A
Line Regulation
VLINE
IOUT = 10mA
--
0.2
0.4
%/V
Load Regulation
VLOAD
IOUT = 10mA to 2A
--
0.5
1.5
%
IOUT = 1A, VIN 1.6V
--
120
200
IOUT = 1A, 1.4V < VIN < 1.6V
--
--
400
IOUT = 1.5A, VIN 1.6V
--
180
300
IOUT = 1.5A, 1.4V < VIN < 1.6V
--
--
500
IOUT = 2A, VIN 1.6V
--
240
400
IOUT = 2A, 1.4V < VIN < 1.6V
--
--
600
2.3
3
4.4
VIN = 3.3V, VADJ = VOUT,
IOUT = 10mA, TA = 25C
0.495
--
0.505
VIN = 3.3V, VADJ = VOUT,
IOUT = 10mA
0.4925
--
0.5075
--
20
200
Dropout Voltage
Current Limit
VDROP
ILIM
VIN = 3.3V
mV
A
Feedback
ADJ Reference Voltage
ADJ Pin Current
VREF
IADJ
VADJ = 0.5V
Copyright © 2013 Richtek Technology Corporation. All rights reserved.
DS2516-03
November 2013
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nA
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RT2516
Parameter
Symbol
Test Conditions
Min
Typ
Max
Unit
--
1
10
A
Enable
EN Pin Current
IEN
VEN = 0V, V IN = 6V
Logic-High
VIH
VIN = 3.3V
1.6
--
--
Logic-Low
VIL
VIN = 3.3V
--
--
0.4
OTP Trip Level
--
160
--
°C
Hysteresis
--
30
--
°C
EN Threshold
Voltage
V
Over Temperature Protection
Note 1. Stresses beyond those listed “Absolute Maximum Ratings” may cause permanent damage to the device. These are
stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in
the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions may
affect device reliability.
Note 2. θJA is measured in the natural convection (air flow = 0 ft/min) at TA = 25°C on a highly thermal conductive four-layer test
board of JEDEC 51-7 thermal measurement standard. The test board size is 75.6mm x 114.3mm (3"x4.5") with 1.6mm
thickness FR4 refer to JEDEC 51 standard. The test board exist four-layer copper, 2oz. (0.07mm) thickness. The case
point of θJC is on the expose pad for SOP-8 (Exposed Pad) package. The copper area of top copper plane is about
100mm 2 .
Note 3. Devices are ESD sensitive. Handling precaution is recommended.
Note 4. The device is not guaranteed to function outside its operating conditions.
Copyright © 2013 Richtek Technology Corporation. All rights reserved.
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is a registered trademark of Richtek Technology Corporation.
DS2516-03
November 2013
RT2516
Typical Application Circuit
RT2516
3
VIN
VIN
VOUT
6
C1
10µF
Chip Enable
VOUT =
0.5(R1+R2)
R2
2
November 2013
ADJ 7
EN
C2
10µF
R2
GND
8,
9 (Exposed Pad)
(V)
Copyright © 2013 Richtek Technology Corporation. All rights reserved.
DS2516-03
VOUT
R1
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RT2516
Typical Operating Characteristics
Quiescent Current vs. Temperature
Reference Voltage vs. Temperature
1.15
0.520
Quiescent Current (mA)
Reference Voltage (V)
0.515
0.510
0.505
VIN = 5V
0.500
VIN = 3.3V
0.495
0.490
0.95
VIN = 5V
0.75
VIN = 3.3V
0.55
0.485
VOUT = 2.52V
0.35
0.480
-50
-25
0
25
50
75
100
-50
125
-25
0
Shutdown Current vs. Temperature
75
100
125
UVLO vs. Temperature
1.20
1.50
1.05
1.40
Rising
1.30
VIN = 5V
UVLO (V)
Shutdown Current (µA)1
50
Temperature (°C)
Temperature (°C)
0.90
25
0.75
VIN = 3.3V
1.20
1.10
Falling
0.60
1.00
0.45
0.90
0.30
0.80
VEN = 5V
-50
-25
0
25
50
75
100
125
-50
-25
0
Temperature (°C)
Dropout Voltage vs. Load Current
50
75
100
125
EN Threshold Voltage vs. Temperature
1.3
350
EN Threshold Voltage (V)
300
Dropout Voltage (mV)
25
Temperature (°C)
125°C
250
25°C
200
150
−40°C
100
50
1.2
Rising
1.1
1.0
Falling
0.9
0.8
VOUT = 2.5V
VIN = 5V
0.7
0
0
0.5
1
1.5
Load Current (A)
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2
-50
-25
0
25
50
75
100
125
Temperature (°C)
is a registered trademark of Richtek Technology Corporation.
DS2516-03
November 2013
RT2516
Load Transient Response
Line Transient Response
VOUT
(20mV/Div)
VIN
(1V/Div)
VOUT
(10mV/Div)
IOUT
(1A/Div)
VIN = 3.3V, VOUT = 2.5V, IOUT = 1A to 2A
VIN = 3.3V to 4.3V, VOUT = 2.5V, IOUT = 2A
Time (50μs/Div)
Time (500μs/Div)
Power On from EN
Power Off from EN
VEN
(5V/Div)
VEN
(5V/Div)
VOUT
(2V/Div)
VOUT
(2V/Div)
I IN
(2A/Div)
I IN
(2A/Div)
VIN = 3.3V, VOUT = 2.5V, IOUT = 2A
VIN = 3.3V, VOUT = 2.5V, IOUT = 2A
Time (250μs/Div)
Time (250μs/Div)
PSRR
VEN Rising vs. Input Voltage
0
1.25
IOUT = 1mA
IOUT = 100mA
IOUT = 300mA
-10
VEN Rising (V)
PSRR (dB)
-20
−40°C
1.20
-30
-40
-50
25°C
1.15
125°C
1.10
-60
1.05
-70
VIN = 3.25V to 3.35V, VOUT = 2.5V
-80
1.00
100
1000
10000
100000
Frequency (Hz)
Copyright © 2013 Richtek Technology Corporation. All rights reserved.
DS2516-03
November 2013
1000000
1
2
3
4
5
6
Input Voltage (V)
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RT2516
Soft-Start Time vs. Temperature
320
Soft-Start Time (µs)
310
300
290
280
270
-50
-25
0
25
50
75
100
125
Temperature (°C)
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is a registered trademark of Richtek Technology Corporation.
DS2516-03
November 2013
RT2516
Application Information
The RT2516 is a low voltage, low dropout linear regulator
with an external bias supply input capable of supporting
an input voltage range from 1.4V to 6V with a fixed output
voltage from 1V to 2V in 0.1V increments.
Output Voltage Setting
The RT2516 output voltage is adjustable from 1.4V to 6V
via the external resistive voltage divider. The voltage divider
resistors can have values of up to 800kΩ because of the
very high impedance and low bias current of the sense
comparator. The output voltage is set according to the
following equation :
VOUT = VREF 1+ R1
R2
The RT2516 is designed specifically to work with low ESR
ceramic output capacitor for space saving and performance
consideration. Using a ceramic capacitor with capacitance
of at least 10μF and ESR larger than 1mΩ on the RT2516
output ensures stability. Nevertheless, the RT2516 can
still work well with other types of output capacitors due to
its wide range of stable ESR. Figure 1 shows the allowable
ESR range as a function of load current for various output
capacitance. Output capacitors with larger capacitance can
reduce noise and improve load transient response,
stability, and PSRR. The output capacitor should be located
at a distance of not more than 0.5 inch from the output pin
of the RT2516.
Region of Stable COUT ESR vs. Load Current
100
where VREF is the reference voltage with a typical value of
0.5V.
Unstable Range
The RT2516 goes into sleep mode when the EN pin is in
a logic low condition. In this condition, the pass transistor,
error amplifier, and band gap are all turned off, reducing
the supply current to only 10μA (max.). The EN pin can
be directly tied to VIN to keep the part on.
Current Limit
The RT2516contains an independent current limit circuitry,
which monitors and controls the pass transistor's gate
voltage, limiting the output current to 3A (typ.).
COUT ESR (Ω)
10
Chip Enable Operation
1
Stable Range
0.1
0.01
VIN = 3.3V, VOUT = 2.5V, COUT = 10μF / X7R
0.001
0.0
0.3
0.5
0.8
1.0
Load Current (A)
Figure 1
CIN and COUT Selection
Thermal Considerations
Like any low dropout regulator, the external capacitors of
the RT2516 must be carefully selected for regulator stability
and performance. Using a capacitor of at least 10μF is
suitable. The input capacitor must be located at a distance
of not more than 0.5 inch from the input pin of the IC. Any
good quality ceramic capacitor can be used. However, a
capacitor with larger value and lower ESR (Equivalent
Series Resistance) is recommended since it will provide
better PSRR and line transient response.
Thermal protection limits power dissipation in RT2516.
When the operation junction temperature exceeds 160°C,
the OTP circuit starts the thermal shutdown function and
turns the pass element off. The pass element turns on
again after the junction temperature cools by 30°C.
Copyright © 2013 Richtek Technology Corporation. All rights reserved.
DS2516-03
November 2013
RT2516 output voltage will be closed to zero when output
short circuit occurs as shown in Figure 2. It can reduce
the IC temperature and provides maximum safety to end
users when output short circuit occurs.
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RT2516
VOUT
ILIM
ILIM＇
IOUT
IC Temperature
2.8
Maximum Power Dissipation (W)1
VOUT Short to GND
Four-Layer PCB
2.4
2.0
1.6
1.2
0.8
0.4
0.0
Figure 2. Short Circuit Protection when Output Short
Circuit Occurs
0
25
50
75
100
125
Ambient Temperature (°C)
Figure 3. Derating Curve of Maximum Power Dissipation
For continuous operation, do not exceed absolute
maximum junction temperature. The maximum power
dissipation depends on the thermal resistance of the IC
package, PCB layout, rate of surrounding airflow, and
difference between junction and ambient temperature. The
maximum power dissipation can be calculated by the
following formula :
PD(MAX) = (TJ(MAX) − TA) / θJA
where TJ(MAX) is the maximum junction temperature, TA is
the ambient temperature, and θJA is the junction to ambient
thermal resistance.
For recommended operating condition specifications, the
maximum junction temperature is 125°C. The junction to
ambient thermal resistance, θJA, is layout dependent. For
SOP-8 (Exposed Pad) package, the thermal resistance,
θJA, is 40°C/W on a standard JEDEC 51-7 four-layer
thermal test board. The maximum power dissipation at TA
= 25°C can be calculated by the following formula :
PD(MAX) = (125°C − 25°C) / (40°C/W) = 2.500W for
SOT-8 (Exposed Pad) package
The maximum power dissipation depends on the operating
ambient temperature for fixed T J(MAX) and thermal
resistance, θJA. The derating curve in Figure 3 allows the
designer to see the effect of rising ambient temperature
on the maximum power dissipation.
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is a registered trademark of Richtek Technology Corporation.
DS2516-03
November 2013
RT2516
Outline Dimension
H
A
M
EXPOSED THERMAL PAD
(Bottom of Package)
Y
J
X
B
F
C
I
D
Dimensions In Millimeters
Dimensions In Inches
Symbol
Min
Max
Min
Max
A
4.801
5.004
0.189
0.197
B
3.810
4.000
0.150
0.157
C
1.346
1.753
0.053
0.069
D
0.330
0.510
0.013
0.020
F
1.194
1.346
0.047
0.053
H
0.170
0.254
0.007
0.010
I
0.000
0.152
0.000
0.006
J
5.791
6.200
0.228
0.244
M
0.406
1.270
0.016
0.050
X
2.100
2.500
0.083
0.098
Y
3.000
3.500
0.118
0.138
Option 2
8-Lead SOP (Exposed Pad) Plastic Package
Richtek Technology Corporation
14F, No. 8, Tai Yuen 1st Street, Chupei City
Hsinchu, Taiwan, R.O.C.
Tel: (8863)5526789
Richtek products are sold by description only. Richtek reserves the right to change the circuitry and/or specifications without notice at any time. Customers should
obtain the latest relevant information and data sheets before placing orders and should verify that such information is current and complete. Richtek cannot
assume responsibility for use of any circuitry other than circuitry entirely embodied in a Richtek product. Information furnished by Richtek is believed to be
accurate and reliable. However, no responsibility is assumed by Richtek or its subsidiaries for its use; nor for any infringements of patents or other rights of third
parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Richtek or its subsidiaries.
DS2516-03
November 2013
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