®
RT9078
2μA I
Q
, 300mA Low-Dropout Linear Regulator
μ
General Description
The RT9078 is a low-dropout (LDO) voltage regulator with
enable function that operates from a 1.2V to 5.5V supply.
It provides up to 300mA of output current in miniaturized
packaging.
The feature of 2μA low quiescent current and 0.5μA
shutdown current are ideal for the battery application with
long service life. The other features include current limit
function, over temperature protection and output discharge
function.
Features
Input Voltage Range : 1.2V to 5.5V
2μA Ground Current (I
Q
) at no Load
μ
PSRR = 75dB at 1kHz
Adjustable Output Voltage Range :
½
0.8V to 5V (TSOT-23-5 Package with SNS Pin Only)
±
2% Output Accuracy
Low (0.1μA) Shutdown Current
μ
Dropout Voltage : 0.15V at 300mA when V
OUT
≥
3V
Support Fixed Output Voltage 0.8V, 1.0V, 1.05V, 1.1V,
1.2V, 1.25V, 1.3V, 1.5V, 1.8V, 1.85V, 2V, 2.5V, 2.8V,
2.85V, 3V, 3.1V, 3.3V, 3.45V
Current Limit Protection
Over Temperature Protection
Output Active Discharge Function
TSOT-23-5 and ZQFN-4L 1x1 (ZDFN-4L 1x1) Packages
Available
Pin Configuration
(TOP VIEW)
VOUT
5
2
SNS/NC
4
3
VIN GND EN
Applications
TSOT-23-5
VOUT
1
4
VIN
Portable, Battery Powered Equipment
Ultra Low Power Microcontrollers
Notebook Computers
SGND
GND
2
5
3
EN
ZQFN-4L 1x1 (ZDFN-4L 1x1)
Copyright
©
2019 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS9078-16
June 2019
www.richtek.com
1
RT9078
Ordering Information
RT9078/N-
Pin 1 Orientation
***
(2) : Quadrant 2, Follow EIA-481-D
Package Type
J5 : TSOT-23-5
QZ : ZQFN-4L 1x1 (Z-Type)
(ZDFN-4L 1x1)
Lead Plating System
G : Green (Halogen Free and Pb Free)
Output Voltage
08 : 0.8V
:
20 : 2.0V
:
33 : 3.3V
1B : 1.25V
1H : 1.85V
2H : 2.85V
1K : 1.05V
3D : 3.45V (ZQFN-4L 1x1 only)
Special Request : Any voltage between
0.8V and 3.3V under specific business
agreement
Pin Function
RT9078 : Without SNS Pin
RT9078N : With SNS Pin**
Marking Information
For marking information, contact our sales representative
directly or through a Richtek distributor located in your
area.
Note :
***Empty means Pin1 orientation is Quadrant 1
**Available for output target adjustment (Ex : RT9078N-08GJ5
with 0.8V reference level for output target adjustment)
Richtek products are :
½
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
Copyright
©
2019 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
2
DS9078-16
June 2019
RT9078
Functional Pin Description
Pin No.
TSOT-23-5 ZQFN-4L 1x1 (ZDFN-4L 1x1)
1
2
3
4
5
--
4
2
3
--
1
5 (Exposed Pad)
Pin Name
VIN
GND
EN
SNS
NC
VOUT
SGND
Pin Function
Regulator input pin. Input capacitor should be placed
directly at this pin.
Ground.
Chip enable pin. Pulling this pin below 0.4V turns the
regulator off, reducing the quiescent current to a fraction
of its operating value.
Output voltage sense. (RT9078N only)
No internal connection.
Regulator output pin. Output capacitor should be placed
directly at this pin.
Substrate of chip. Tie to GND plane for maximum
thermal dissipation.
Copyright
©
2019 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS9078-16
June 2019
www.richtek.com
3
RT9078
Functional Block Diagram
VIN
GND
Current/Thermal
Sense
(without sense
function)
VOUT
SNS
(with sense
function)
R1
EN
R2
+
-
EN
Bandgap
Reference
Operation
Basic Operation
The RT9078 is a low quiescent current linear regulator
designed especially for low external components system.
The input voltage range is from 1.2V to 5.5V.
The minimum required output capacitance for stable
operation is 1μF capacitance after consideration of the
temperature and voltage coefficient of the capacitor.
Pass Transistor
The RT9078 builds in a P-MOSFET pass transistor which
provides a low switch-on resistance for low dropout voltage
applications.
Error Amplifier
The Error Amplifier compares the internal reference voltage
with the output feedback voltage from the internal divider,
and controls the gate voltage of P-MOSFET.
Chip Enable and Shutdown
The RT9078 provides an EN pin, as an external chip enable
control, to enable or disable the device. The V
EN
below
0.4V turns the regulator off and enters the shutdown mode,
while V
EN
above 0.9V turns the regulator on. When the
regulator is shutdown, the ground current is reduced to a
maximum of 0.5μA.
Over-Temperature Protection
The over-temperature protection function will turn off the
P-MOSFET when the junction temperature exceeds 150°C
(typ.), and the output current exceeds 80mA. Once the
junction temperature cools down by approximately 20°C,
the regulator will automatically resume operation.
Output Active Discharge
When the RT9078 is operating at shutdown mode, the
device has an internal active pull down circuit that connects
the output to GND through a resistor for output discharging
purpose.
Current-Limit Protection
The RT9078 contains an independent current limiter, which
monitors and controls the pass transistor's gate voltage,
limiting the output current to 0.6A (typ.). The current
limiting level is reduced to around 0.3A named fold-back
current limit when the output voltage is further decreased.
The output can be shorted to ground indefinitely without
damaging the part.
Copyright
©
2019 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
4
DS9078-16
June 2019
RT9078
Absolute Maximum Ratings
(Note 1)
−0.3V
to 6.5V
−6.5V
to 0.3V
0.43W
0.44W
230.6°C/W
VIN, VOUT, SNS, EN to GND -------------------------------------------------------------------------------------------
VOUT to VIN ----------------------------------------------------------------------------------------------------------------
Power Dissipation, P
D
@ T
A
= 25°C
TSOT-23-5 -------------------------------------------------------------------------------------------------------------------
ZQFN-4L 1x1 (ZDFN-4L 1x1) --------------------------------------------------------------------------------------------
Package Thermal Resistance (Note 2)
TSOT-23-5,
θ
JA
-------------------------------------------------------------------------------------------------------------
TSOT-23-5,
θ
JC
------------------------------------------------------------------------------------------------------------- 21.8°C/W
ZQFN-4L 1x1 (ZDFN-4L 1x1),
θ
JA
-------------------------------------------------------------------------------------- 226°C/W
ZQFN-4L 1x1 (ZDFN-4L 1x1),
θ
JC
------------------------------------------------------------------------------------- 43°C/W
Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------------------- 260°C
Junction Temperature ----------------------------------------------------------------------------------------------------- 150°C
Storage Temperature Range --------------------------------------------------------------------------------------------
−65°C
to 150°C
ESD Susceptibility (Note 3)
HBM (Human Body Model) ---------------------------------------------------------------------------------------------- 2kV
(Note 4)
Recommended Operating Conditions
Input Voltage, VIN --------------------------------------------------------------------------------------------------------- 1.2V to 5.5V
Junction Temperature Range --------------------------------------------------------------------------------------------
−40°C
to 125°C
Electrical Characteristics
(V
OUT
+ 1 < V
IN
< 5.5V, T
A
= 25°C, unless otherwise specified)
Parameter
Fixed Output Voltage Range
DC Output Accuracy
SNS Reference Voltage (for
RT9078N-08GJ5 only)
Symbol
V
OUT
Test Conditions
I
LOAD
= 1mA
Min
0.8
2
0.784
--
--
--
--
--
--
--
--
--
--
--
Typ
--
--
0.8
0.7
0.5
0.4
0.3
0.24
0.21
0.18
0.16
0.15
0.16
2
Max
3.45
2
0.816
0.97
0.92
0.57
0.47
0.33
0.3
0.25
0.23
0.2
0.2
4
Unit
V
%
V
V
REF
I
LOAD
= 1mA
0.8V
V
OUT
1.05V
1.05V
V
OUT
1.2V
1.2V
V
OUT
1.5V
1.5V
V
OUT
1.8V
Dropout Voltage
(I
LOAD
= 300mA)
(Note 5)
V
DROP
1.8V
V
OUT
2.1V
2.1V
V
OUT
2.5V
2.5V
V
OUT
2.8V
2.8V
V
OUT
3V
3V
V
OUT
V
Dropout Voltage
(I
LOAD
= 200mA)
(Note 6)
V
DROP
I
Q
1.8V
V
OUT
2.1V
I
LOAD
= 0mA, V
OUT
5.5V
V
IN
V
OUT
+ V
DROP
V
A
V
CC
Consumption Current
Copyright
©
2019 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS9078-16
June 2019
www.richtek.com
5
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