®
RT2519
1A, Low Noise, Ultra High PSRR, Low-Dropout Linear Regulator
General Description
Features
The RT2519 is a high performance positive low dropout
(LDO) regulator designed for applications requiring very
low dropout voltage and ultra high Power Supply Ripple
Rejection (PSRR) at up to 1A. The input voltage range is
from 2.2V to 6V and the output voltage is programmable
as low as 0.8V. A P-MOSFET switch provides excellent
transient response with just a 4.7μF ceramic output
capacitor. The external enable control effectively reduces
power dissipation while shutdown and further output noise
immunity is achieved through bypass capacitor on NR pin.
Additionally, RT2519 features a precise 3% output
regulation over line, load, and temperature variations. The
device is available in the VDFN-8AL 3x3 package and is
specified from −40°C to 125°C.
Very Low Dropout : 170mV Typical at 1A
Ultra High PSRR : 63dB @ 1kHz, 38dB @ 1MHz
Input Voltage Range : 2.2V to 6V
Adjustable Output Voltage : 0.8V to 5.5V
−40°°C to 125°°C Operating Junction Temperature
Range
Excellent Noise Immunity
Fast Response Over Load and Line Transient
Stable with a 4.7μ
μF Output Ceramic Capacitor
Accurate Output Voltage 3% Over Load, Line,
Process, and Temperature Variations
Enable Control
Over-Current Protection
Over-Temperature Protection
Ordering Information
Applications
RT2519
Pin 1 Orientation***
(2) : Quadrant 2, Follow EIA-481-D
Package Type
QV : VDFN-8AL 3x3 (W-Type)
Lead Plating System
G : Green (Halogen Free and Pb Free)
Note :
Telecom/Networking Cards
Motherboards/Peripheral Cards
Industrial Applications
Wireless Infrastructures
Set-Top Boxes
Medical Equipments
Notebook Computers
Battery Powered Systems
***Empty means Pin1 orientation is Quadrant 1
Richtek products are :
RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020.
Suitable for use in SnPb or Pb-free soldering processes.
Simplified Application Circuit
RT2519
VIN
VIN
VOUT
EN
FB
CIN
Enable
R1
CNR
Copyright © 2016 Richtek Technology Corporation. All rights reserved.
COUT
R2
NR
DS2519-00 July 2016
VOUT
GND
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RT2519
Pin Configuration
Marking Information
KN= : Product Code
(TOP VIEW)
VOUT
1
8
VIN
VOUT
2
7
VIN
FB
3
6
NR
4
5
EN
GND
KN=YM
DNN
YMDNN : Date Code
VDFN-8AL 3x3
Functional Pin Description
Pin No.
1, 2
Pin Name
Pin Function
VOUT
Output of the regulator. Decouple this pin to GND with at least 4.7F for stability.
3
FB
Feedback voltage input. This pin is used to set the desired output voltage via an
external resistive divider. The feedback reference voltage is 0.8V typically.
4
GND
System ground.
5
EN
Enable control input. Connecting this pin to logic high enables the regulator or
driving this pin low puts it into shutdown mode. EN can be connected to IN if not
used. (EN pin is not allowed to be left floating.)
6
NR
Noise reduction input. Decouple this pin to GND with an external capacitor can not
only reduce output noise to very low levels but also slow down the VOUT rise like a
soft-start behavior.
7, 8
VIN
Supply input. A minimum of 1F ceramic capacitor should be placed as close as
possible to this pin for better noise rejection.
Functional Block Diagram
VOUT
VIN
UVLO
Control Logic
Quick Start-Up
Bandgap
+
EN
Thermal
Protection
Current
Limit
FB
NR
GND
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DS2519-00 July 2016
RT2519
Operation
The RT2519 is a low input voltage LDO. It is designed for
input range from 2.2V to 6V and the output current can be
up to 1A. The internal compensation network is well
designed to achieve fast transient response with good
stability.
In steady-state operation, the feedback voltage is
regulated to the reference voltage by the internal regulator.
When the feedback voltage signal is less than the
reference, the output current passes through the power
MOSFET will be increased. The extra amount of the
current is sent to the output until the voltage level of FB
pin returns to the reference.
On the other hand, if the feedback voltage is higher than
the reference, the power MOSFET current is decreased.
The excess charge at the output can be released by the
loading current.
Over-Temperature Protection (OTP)
The RT2519 has an over-temperature protection. When
the device triggers the OTP, the device shuts down until
the temperature back to normal state.
Under Voltage Lock-Out (UVLO)
The RT2519 utilizes an undervoltage lock-out circuit to
keep the output shut off until the internal circuitry is
operating properly. The UVLO circuit has a de-glitch feature
so that it typically ignores undershoot transients on the
input if they are less than 30μs duration.
Start-Up
RT2519 has a quick-start circuit to charge the noise
reduction capacitor (CNR). The switch of the quick-start
circuit is closed at start up.
To reduce the noise from bandgap, there is a low-pass
(RC) filter consist of the CNR and the resistance which is
connected with bandgap, as Functional Block Diagrams
present.
A resistance is used to slow down the reference voltage
ramp to avoid inrush current at chip start-up, and the
Startup time can be calculated as :
It is recommend the CNR value larger than 0.01μF to reduce
noise, and low leakage ceramic capacitors are suitable.
Copyright © 2016 Richtek Technology Corporation. All rights reserved.
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RT2519
Absolute Maximum Ratings
(Note 1)
Supply Voltage, VIN -----------------------------------------------------------------------------------------------------Other Pins ------------------------------------------------------------------------------------------------------------------Power Dissipation, PD @ TA = 25°C
VDFN-8AL 3x3 ------------------------------------------------------------------------------------------------------------Package Thermal Resistance (Note 2)
VDFN-8AL 3x3, θJA -------------------------------------------------------------------------------------------------------VDFN-8AL 3x3, 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
3.31W
30.2°C/W
5.5°C/W
260°C
150°C
−65°C to 150°C
2kV
1kV
(Note 4)
Supply Voltage, VIN ------------------------------------------------------------------------------------------------------ 2.2V to 6V
Junction Temperature Range -------------------------------------------------------------------------------------------- −40°C to 125°C
Electrical Characteristics
(VIN = VOUT + 0.5V or 2.2V, VOUT = 0.8V and 5.5V, IOUT = 1mA, VEN = 2.2V, CNR = 10nF, COUT = 4.7μF, TJ = −40°C to 125°C,
unless otherwise specified)
Parameter
Symbol
Test Conditions
Min
Typ
Max
2.2
--
6
Unit
Supply Voltage
Input Operating Voltage VIN
V
Under-Voltage Lockout
Threshold
VUVLO
ROUT = 1k
1.86
2
2.1
Under-Voltage Lockout
Threshold Hysteresis
VUVLO
ROUT = 1k
--
200
--
mV
Shutdown Current
ISHDN
VEN 0.4V, VIN 2.2V, ROUT = 1k,
0°C TJ 85°C
--
0.2
2
A
Quiescent Current
IQ
--
190
--
A
0.8
--
5.5
V
VOUT + 0.5V VIN 6V, VIN 2.5V,
100mA IOUT 500mA,
0°C TJ 85°C
2
--
+2
VOUT + 0.5V VIN 6V, VIN 2.2V,
100mA IOUT 1A
3
±0.3
+3
VOUT + 0.5V VIN 6V, VIN 2.2V,
IOUT = 100mA
--
0.2
--
%
--
0.3
--
%
Output Voltage
Output Supply Voltage
Output Supply Voltage
Accuracy
(Note 5)
VOUT
Line Regulation
VOUT/VIN
Load Regulation
VOUT/IOUT 100mA IOUT 1A
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%
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RT2519
Parameter
Symbol
Test Conditions
Min
Typ
Max
1.2
--
--
Unit
Enable Voltage
2.2V VIN 3.6V,
ROUT = 1k
Enable Threshold
Voltage
VIH
VEN Rising
VIL
VEN Falling, ROUT = 1k
--
--
0.4
Enable Input Current
IIH
VIN = 6V, VEN = 6V
--
0.02
1
A
VIN = 5.5V, VFB = 0.8V
--
0.02
1
A
1.1
1.4
2
A
CNR = 1nF
--
0.16
--
CNR = 10nF
--
1.6
--
VIN 2.2V,
IOUT = 500mA
--
--
250
VIN 2.5V,
IOUT = 750mA
--
--
350
VIN 2.5V,
IOUT = 1A
--
--
500
f = 100Hz
--
48
--
VIN = 4.3V, VOUT = 3.3V, f = 1kHz
IOUT = 750mA
f = 10kHz
--
63
--
--
63
--
f = 1MHz
--
38
--
CNR = 1nF
--
--
BW = 100Hz to 100kHz,
VIN = 4.3V, VOUT = 3.3V, CNR = 10nF
IOUT = 100mA
15.6 x
VOUT
--
15.6 x
VOUT
--
CNR = 0.1F
--
15.1 x
VOUT
--
--
160
--
--
140
--
Feedback Input Current IFB
V
Current Limit
Output Current Limit
ILIM
VIN = 3.3V, VOUT = 0.85 x VOUT
Power-Up Time
VOUT = 3.3V,
ROUT = 3.3k,
COUT = 4.7F
Power-Up Time
ms
Dropout Voltage
Dropout Voltage
VDROP
VOUT + 0.5V VIN 6V,
VFB = 0V
mV
Power Supply Ripple Rejection and Noise
Power Supply Ripple
Rejection
PSRR
Output Noise Voltage
dB
VRMS
Over-Temperature Protection
Thermal Shutdown
TSD
Thermal Shutdown
Recovery
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°C
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RT2519
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 under natural convection (still air) at TA = 25°C with the component mounted on a high effectivethermal-conductivity four-layer test board on a JEDEC 51-7 thermal measurement standard. θJC is measured at the
exposed pad of the package.
Note 3. Devices are ESD sensitive. Handling precaution is recommended.
Note 4. The device is not guaranteed to function outside its operating conditions.
Note 5. The spec. doesn't cover the tolerances from external resistors, and which is not tested at condition of VOUT = 0.8V, 4.5V
≤ VIN ≤ 6V, and 750mA ≤ IOUT ≤ 1A since the power dissipation of the device is totally higher than the maximum rating
of the package to lead a thermal shutdown issue.
Typical Application Circuit
VIN
2.2V to 6V
Enable
7, 8
RT2519
VIN
1, 2
VOUT
R1
5
6
CNR
10nF
FB
EN
3
COUT
4.7µF
R2
NR
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VOUT
CIN
1µF
GND
4
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RT2519
Typical Operating Characteristics
UVLO vs. Temperature
Reference Voltage vs. Temperature
2.2
0.810
Logic-High
0.805
2.0
UVLO (V)
Reference Voltage (V)
2.1
VIN = 2.2V
VIN = 3.3V
VIN = 4.3V
VIN = 5.5V
VIN = 6V
0.800
0.795
1.9
Logic-Low
1.8
1.7
1.6
VOUT = 0.8V, VEN = 2.2V
IOUT = 1mA
1.5
0.790
-50
-25
0
25
50
75
100
-50
125
-25
0
Temperature (°C)
Shutdown Current vs. Temperature
50
75
100
125
Dropout Voltage vs. Input Voltage
200
VEN = 0.4V
2.0
Dropout Voltage (mV)
Shutdown Current (μA)1
2.5
25
Temperature (°C)
VIN = 2.2V
VIN = 3.3V
VIN = 4.3V
VIN = 5V
VIN = 5.5V
VIN = 6V
1.5
1.0
0.5
125°C
85°C
25°C
0°C
−40°C
150
100
50
IOUT = 1000mA
0.0
0
-50
-25
0
25
50
75
100
125
2
3
Temperature (°C)
Dropout Voltage vs. Output Current
5
6
PSRR vs. Frequency
90
200
125°C
85°C
25°C
0°C
−40°C
150
80
70
PSRR (dB)
Dropout Voltage (mV)
4
Input Voltage (V)
100
50
60
IOUT = 10mA
IOUT = 100mA
IOUT = 750mA
IOUT = 1000mA
50
40
30
20
VIN = 2.5V
0
No CIN, VIN = 4.3V,
COUT = 4.7μF, VOUT = 3.3V
10
0
0
200
400
600
800
Output Current (mA)
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1000
10
100
1k
10k
100k
1M
10M
Frequency (Hz)
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Output Spectral Noise Density (μV/√ Hz)
RT2519
Output Spectral Noise Density
100.00
Load Transient Response
RMS Noise (100Hz to 100kHz)
69.72μVRMS (IOUT = 10mA),
59.01μVRMS (IOUT = 100mA),
56.11μVRMS (IOUT = 750mA)
VOUT = 3.3V, VIN = 3.8V,
COUT = 4.7μF, CNR = 0.01μF
10.00
VIN = 4.3V, VOUT = 3.3V,
IOUT = 0.1A to 1A (1A/μs, only shows the
transient component)
VOUT
(50mV/Div)
1.00
IOUT = 10mA
IOUT = 100mA
IOUT = 750mA
0.10
IOUT
(500mA/Div)
0.01
10
100
1000
10000
100000
Time (50μs/Div)
Frequency (Hz)
Line Transient Response
Power On from EN
VEN
(2V/Div)
VOUT
(5mV/Div)
VIN
(1V/Div)
VIN = 3.8V to 4.8V, VOUT = 3.3V,
IOUT = 0.1A
Time (50μs/Div)
VOUT
(1V/Div)
IOUT
(500mA/Div)
VIN = 4.3V, VOUT = 3.3V
Time (500μs/Div)
Power Off from EN
VEN
(2V/Div)
VOUT
(1V/Div)
IOUT
(500mA/Div)
VIN = 4.3V, VOUT = 3.3V
Time (50μs/Div)
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RT2519
Application Information
The RT2519 is a low voltage, low dropout linear regulator
with input voltage from 2.2V to 6V and a fixed output voltage
from 0.8V to 5.5V.
Output Voltage Setting
For RT2519, the voltage on the FB pin sets the output
voltage and is determined by the values of R1 and R2.
The values of R1 and R2 can be calculated for any voltage
using the formula given in Equation :
VOUT =
R1 + R2
R2
0.8
Using lower values for R1 and R2 is recommended to
reduces the noise injected from the FB pin. Note that R1
is connected from VOUT pin to FB pin, and R2 is
connected from FB to GND.
Chip Enable Operation
The RT2519 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 2μA (max.). The EN pin can be
directly tied to VIN to keep the part on.
a capacitor with larger value and lower ESR (Equivalent
Series Resistance) is recommended since it will provide
better PSRR and line transient response.
The RT2519 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 4.7μF on the RT2519 output ensures stability.
Thermal Considerations
Thermal protection limits power dissipation in the RT2519.
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 down by 20°C.
The RT2519 output voltage will be closed to zero when
output short circuit occurs as shown in Figure 1. It can
reduce the chip temperature and provides maximum safety
to end users when output short circuit occurs.
VOUT Short to GND
Current Limit
The RT2519 continuously monitors the output current to
protect the pass transistor against abnormal operations.
When an overload or short circuit is encountered, the
current limit circuitry controls the pass transistor's gate
voltage to limit the output within the predefined range. By
reason of the build-in body diode, the pass transistor
conducts current when the output voltage exceeds input
voltage. Since the current is not limited, external current
protection should be added if device may work at reverse
voltage state.
VOUT
ILIM’
IOUT
IC Temperature
Figure 1. Short-Circuit Protection when Output ShortCircuit Occurs
CIN and COUT Selection
Like any low dropout regulator, the external capacitors of
the RT2519 must be carefully selected for regulator stability
and performance. Using a capacitor of at least 4.7μF is
suitable. The input capacitor must be located at a distance
of no more than 0.5 inch from the input pin of the chip.
Any good quality ceramic capacitor can be used. However,
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RT2519
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 continuous operation, the maximum operating junction
temperature indicated under Recommended Operating
Conditions is 125°C. The junction-to-ambient thermal
resistance, θJA, is highly package dependent. For a
VDFN-8AL 3x3 package, the thermal resistance, θJA, is
30.2°C/W on a standard JEDEC 51-7 high effective-thermalconductivity four-layer test board. The maximum power
dissipation at TA = 25°C can be calculated as below :
4.0
Maximum Power Dissipation (W)1
The junction temperature should never exceed the
absolute maximum junction temperature TJ(MAX), listed
under Absolute Maximum Ratings, to avoid permanent
damage to the device. The maximum allowable power
dissipation depends on the thermal resistance of the IC
package, the PCB layout, the rate of surrounding airflow,
and the difference between the junction and ambient
temperatures. The maximum power dissipation can be
calculated using the following formula :
Four-Layer PCB
3.2
2.4
1.6
0.8
0.0
0
25
50
75
100
125
Ambient Temperature (°C)
Figure 2. Derating Curve of Maximum Power Dissipation
PD(MAX) = (125°C − 25°C) / (30.2°C/W) = 3.31W for a
VDFN-8AL 3x3 package.
The maximum power dissipation depends on the operating
ambient temperature for the fixed TJ(MAX) and the thermal
resistance, θJA. The derating curves in Figure 2 allows
the designer to see the effect of rising ambient temperature
on the maximum power dissipation.
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RT2519
Outline Dimension
2
1
2
1
DETAIL A
Pin #1 ID and Tie Bar Mark Options
Note : The configuration of the Pin #1 identifier is optional,
but must be located within the zone indicated.
Symbol
Dimensions In Millimeters
Dimensions In Inches
Min.
Max.
Min.
Max.
A
0.800
1.000
0.031
0.039
A1
0.000
0.050
0.000
0.002
A3
0.175
0.250
0.007
0.010
b
0.250
0.370
0.010
0.015
b1
0.230
0.009
D
2.900
3.100
0.114
0.122
D2
1.700
1.800
0.067
0.071
E
2.900
3.100
0.114
0.122
E2
1.450
1.550
0.057
0.061
e
0.650
0.026
e1
0.650
0.026
L
0.350
0.450
0.014
0.018
V-Type 8AL DFN 3x3 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.
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