®
RT2519
1A, Low Noise, Ultra High PSRR, Low-Dropout Linear Regulator
General Description
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, the 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.
Features
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 4.7μF Output Ceramic Capacitor
μ
Accurate Output Voltage 3% Over Load, Line,
Process, and Temperature Variations
Enable Control
Over-Current Protection
Over-Temperature Protection
Ordering Information
RT2519
Pin 1 Orientation
***
(2) : Quadrant 2, Follow EIA-481-D
Package Type
QV : VDFN-8AL 3x3 (V-Type)
Lead Plating System
G : Green (Halogen Free and Pb Free)
Note :
***Empty means Pin1 orientation is Quadrant 1
Richtek products are :
½
Applications
Telecom/Networking Cards
Motherboards/Peripheral Cards
Industrial Applications
Wireless Infrastructures
Set-Top Boxes
Medical Equipments
Notebook Computers
Battery Powered Systems
RoHS compliant and compatible with the current require-
ments of IPC/JEDEC J-STD-020.
Suitable for use in SnPb or Pb-free soldering processes.
½
Simplified Application Circuit
RT2519
V
IN
C
IN
Enable
C
NR
EN
NR
GND
FB
R2
VIN
VOUT
R1
C
OUT
V
OUT
Copyright
©
2018 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS2519-04 January 2018
www.richtek.com
1
RT2519
Pin Configuration
(TOP VIEW)
VOUT
VOUT
FB
GND
1
2
3
4
8
7
Marking Information
KN= : Product Code
VIN
VIN
NR
EN
KN=YM
DNN
YMDNN : Date Code
GND
9
6
5
VDFN-8AL 3x3
Functional Pin Description
Pin No.
1, 2
3
Pin Name
VOUT
FB
Pin Function
Output of the regulator. Decouple this pin to GND with at least 4.7F for stability.
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.
System ground. The exposed pad must be soldered to a large PCB and
connected to GND for maximum power dissipation.
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.)
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.
Supply input. A minimum of 1F ceramic capacitor should be placed as close as
possible to this pin for better noise rejection.
4, 9 (Exposed Pad) GND
5
EN
6
7, 8
NR
VIN
Functional Block Diagram
VIN
UVLO
Thermal
Protection
Current
Limit
VOUT
-
Quick Start-Up
Bandgap
+
EN
Control Logic
FB
NR
GND
Copyright
©
2018 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
2
DS2519-04 January 2018
RT2519
Operation
The RT2519 is a low noise, high PSRR LDO which
supports very low dropout operation. The operating input
range from 2.2V to 6V and the output voltage is
programmable as low to 0.8V 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.
Start-Up
The RT2519 has a quick-start circuit to charge the noise
reduction capacitor (C
NR
). 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 C
NR
and the resistance which is
connected with bandgap, as Functional Block Diagrams
present.
At the start-up, the quick-start switch is closed, with only
35kΩ resistance between bandgap and NR pin. The quick-
start switch opens approximate 2ms after the device is
enabled, the resistance between NR and bandgap is about
224kΩ to form a very good low pass filter and with great
noise reduction performance.
The 35kΩ resistance is used to slow down the reference
voltage ramp to avoid inrush current at chip start-up, and
the start-up time can be calculated as :
t
SS
(sec) = 160000 x C
NR
(F)
(1)
opens the quick-start switch, the C
NR
will be charged
through higher resistance 224kΩ and takes much longer
time to finish the start up process.
Enable and Shutdown 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 bandgap are all turned off, reducing the
supply current to only 2μA (max.). If the shutdown mode
is not required, the EN pin can be directly tied to VIN pin
to keep the LDO on.
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.
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 under voltage 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.
It is recommend the C
NR
value larger than 0.01μF to reduce
noise, and low leakage ceramic capacitors are suitable.
However, with too large C
NR
will extend the start-up time
very long if the C
NR
is not fully charged during 2ms and
Copyright
©
2018 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS2519-04 January 2018
www.richtek.com
3
RT2519
Absolute Maximum Ratings
(Note 1)
−0.3V
to 7V
3.31W
30.2°C/W
5.5°C/W
260°C
All Pins ----------------------------------------------------------------------------------------------------------------------
Power Dissipation, P
D
@ T
A
= 25°C
VDFN-8AL 3x3 -------------------------------------------------------------------------------------------------------------
Package Thermal Resistance (Note 2)
VDFN-8AL 3x3,
θ
JA
--------------------------------------------------------------------------------------------------------
VDFN-8AL 3x3,
θ
JC
-------------------------------------------------------------------------------------------------------
Lead Temperature (Soldering, 10 sec.) -------------------------------------------------------------------------------
Junction Temperature ----------------------------------------------------------------------------------------------------- 150°C
Storage Temperature Range --------------------------------------------------------------------------------------------
−65°C
to 150°C
ESD Susceptibility (Note 3)
HBM (Human Body Model) ---------------------------------------------------------------------------------------------- 2kV
CDM (Charged Device Model) ------------------------------------------------------------------------------------------ 1kV
Recommended Operating Conditions
(Note 4)
Supply Voltage, VIN ------------------------------------------------------------------------------------------------------ 2.2V to 6V
Junction Temperature Range --------------------------------------------------------------------------------------------
−40°C
to 125°C
Electrical Characteristics
(V
IN
= V
OUT
+ 0.5V or 2.2V, V
OUT
= 0.8V and 5.5V, I
OUT
= 1mA, V
EN
= 2.2V, C
NR
= 10nF, C
OUT
= 4.7μF, T
J
=
−40°C
to 125°C, unless
otherwise specified)
Parameter
Supply Voltage
Symbol
Test Conditions
Min
2.2
Typ
--
2
200
0.2
190
--
--
±0.3
0.2
0.3
Max
6
2.1
--
2
350
5.5
+2
Unit
Input Operating Voltage V
IN
Under-Voltage Lockout
Threshold
Under-Voltage Lockout
Threshold Hysteresis
Shutdown Current
Quiescent Current
Output Voltage
Output Supply Voltage
V
OUT
V
OUT
+ 0.5V
V
IN
6V, V
IN
2.5V,
100mA
I
OUT
500mA,
0°C
T
J
85°C
V
OUT
+ 0.5V
V
IN
6V, V
IN
2.2V,
100mA
I
OUT
1A
V
OUT
/V
IN
V
OUT
+ 0.5V
V
IN
6V, V
IN
2.2V,
I
OUT
= 100mA
V
UVLO
V
UVLO
I
SHDN
I
Q
R
OUT
= 1k
R
OUT
= 1k
V
EN
0.4V, V
IN
2.2V, R
OUT
= 1k,
0°C
T
J
85°C
1.86
--
--
--
0.8
2
3
--
--
V
mV
A
A
V
Output Supply Voltage
Accuracy
(Note 5)
%
+3
--
--
%
%
Line Regulation
Load Regulation
V
OUT
/I
OUT
100mA
I
OUT
1A
Copyright
©
2018 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
4
DS2519-04 January 2018
RT2519
Parameter
Enable Voltage
Enable Threshold Voltage
Enable Input Current
Feedback Input Current
Current Limit
Output Current Limit
Power-Up Time
Power-Up Time
Dropout Voltage
V
IN
2.2V,
I
OUT
= 500mA
Dropout Voltage
V
DROP
V
OUT
+ 0.5V
V
IN
6V, V
IN
2.5V,
V
FB
= 0V
I
OUT
= 750mA
V
IN
2.5V,
I
OUT
= 1A
Power Supply Ripple Rejection and Noise
f = 100Hz
Power Supply Ripple
Rejection
PSRR
V
IN
= 4.3V, V
OUT
= 3.3V, f = 1kHz
I
OUT
= 750mA
f = 10kHz
f = 1MHz
C
NR
= 1nF
Output Noise Voltage
BW = 100Hz to 100kHz,
V
IN
= 4.3V, V
OUT
= 3.3V, C
NR
= 10nF
I
OUT
= 100mA
C
NR
= 0.1F
Over-Temperature Protection
Thermal Shutdown
Thermal Shutdown
Recovery
T
SD
--
--
160
140
--
--
°C
--
--
--
--
--
--
--
48
63
63
38
15.6 x
V
OUT
15.6 x
V
OUT
15.1 x
V
OUT
--
--
--
--
--
--
--
V
RMS
dB
--
--
--
--
--
--
160
210
370
mV
V
OUT
= 3.3V,
R
OUT
= 3.3k,
C
OUT
= 4.7F
C
NR
= 1nF
C
NR
= 10nF
--
--
0.16
1.6
--
--
ms
I
LIM
V
IN
=
3.3V, V
OUT
= 0.85 x V
OUT
1.1
1.4
2
A
V
IH
V
IL
I
IH
I
FB
V
EN
rising
2.2V
V
IN
6V,
R
OUT
= 1k
1.2
--
--
--
--
--
0.02
0.02
--
0.4
1
1
A
A
V
Symbol
Test Conditions
Min
Typ
Max
Unit
V
EN
falling, R
OUT
= 1k
V
IN
= 6V, V
EN
= 6V
V
IN
= 5.5V, V
FB
= 0.8V
Copyright
©
2018 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS2519-04 January 2018
www.richtek.com
5
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