®
RT9081A
500mA, 5.5V, Ultra Low Dropout Linear Regulator
General Description
The
RT9081A is a high performance positive voltage
regulator with separated bias voltage (V
BIAS
), designed
for applications requiring low input voltage and ultra low
dropout voltage, output current up to 500mA. The feature
of ultra low dropout voltage is ideal for applications where
output voltage is very close to input voltage. The input
voltage can be as low as 0.8V and the output voltage is
adjustable by an external resistive divider. The RT9081A
features very low quiescent current consumption for
portable applications. The device is available in the ZADFN-
6L 1.2x1.2 package.
Features
Input Voltage Range : 0.8V to 5.5V
Bias Voltage Range : 2.4 V to 5.5 V
Output Voltage Fixed and Adjustable Versions
0.9V to 1.8V (Fixed)
½
0.8V to 3.6V (Adjustable)
°
1.5% Output Voltage Accuracy @ 25°C
½
Ultra Low Dropout Voltage : 140mV at 500mA
Low Bias Input Current
80μA in Operating Mode
μ
0.5μA in Disable Mode
μ
Enable Control
Output Active Discharge Function (Optional)
Stable with a 1μF Output Ceramic Capacitor
μ
RoHS Compliant and Halogen Free
Pin Configuration
(TOP VIEW)
VOUT
ADJ/NC
EN
1
GND
2
3
7
6
5
4
VIN
GND
BIAS
Applications
ZADFN-6L 1.2x1.2
Battery Powered Systems
Portable Electronic Device
Digital Set Top Boxes
Ordering Information
Product No.
RT9081A-09GQZA(2)
RT9081A-10GQZA
RT9081A-1KGQZA
RT9081A-11GQZA
RT9081A-1AGQZA(2)
RT9081A-12GQZA
RT9081A-1BGQZA(2)
RT9081A-13GQZA(2)
RT9081A-15GQZA(2)
RT9081A-18GQZA(2)
RT9081AGQZA(2)
Nominal Output
Voltage
0.90V
1.00V
1.05V
1.10V
1.15V
1.20V
1.25V
1.30V
1.50V
1.80V
Adjustable
Output Active
Discharge
ZADFN-6L
1.2x1.2 (Z-Type)
G : Green
(Halogen Free
and Pb Free)
(2): Quadrant
2
Follow EIA-
481-D
***Empty
means Pin1
orientation is
Quadrant 1
Option
Package
Lead Plating
System
Pin 1
Orientation
Copyright
©
2016 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS9081A-00 November 2016
www.richtek.com
1
RT9081A
Marking Information
For marking information, contact our sales representative
directly or through a Richtek distributor located in your
area.
Typical Application Circuit
V
IN
2.5V
6
C
IN
1µF
3
4
C
BIAS
100nF
RT9081A
VIN
VOUT
1
C
OUT
1µF (Effective value)
EN
BIAS
GND
5, 7 (Exposed Pad)
V
OUT
1.2V/500mA
Enable
V
BIAS
3.3V
Figure 1. Fixed Voltage Regulator
RT9081A
VIN
VOUT
1
R1
33.2k
3
4
C
BIAS
100nF
EN
BIAS
ADJ
2
R2
66.5k
GND
5, 7 (Exposed Pad)
V
OUT
1.2V/500mA
C
OUT
1µF (Effective value)
V
IN
2.5V
6
C
IN
1µF
Enable
V
BIAS
3.3V
Figure 2. Adjustable Voltage Regulator
Functional Pin Description
Pin No.
1
2 (Fixed)
2 (Adj)
3
4
Pin Name
VOUT
NC
ADJ
EN
BIAS
Power output for the LDO.
Test pin. Internal pull down by 2A. This pin should be floating or connected to
ground.
Power output for the LDO.
LDO enable.
Supply voltage for the LDO control circuit. Mandatory to power up V
BIAS
before
EN and VIN, this will ensure RT9081A performance follows datasheet spec. For
more information please see Chip Enable Operation section.
Ground. The exposed pad must be soldered to a large PCB and connected to
GND for maximum power dissipation.
Power input for the LDO.
is a registered trademark of Richtek Technology Corporation.
Pin Function
5, 7 (Expose pad) GND
6
VIN
Copyright
©
2016 Richtek Technology Corporation. All rights reserved.
www.richtek.com
2
DS9081A-00 November 2016
RT9081A
Functional Block Diagram
V
OUT
Fixed Version
VIN
Enable
Logic
UVLO
VOUT
EN
VREF
+
-
Driver
Current
Limit
BIAS
Thermal
Shutdown
150
GND
V
OUT
Adjustable Version
VIN
Enable
Logic
UVLO
VOUT
EN
VREF
+
-
Driver
Current
Limit
BIAS
Thermal
Shutdown
150
GND
ADJ
Operation
The
RT9081A is using N-MOSFET pass transistor for
output voltage regulation from VIN voltage. The separated
bias voltage (V
BIAS
) power the low current internal control
circuit for applications requiring low input voltage and ultra
low dropout voltage.
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 RT9081A has an over-temperature protection. When
the device triggers the OTP, the device shuts down until
the temperature
back to normal state.
Copyright
©
2016 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS9081A-00 November 2016
www.richtek.com
3
RT9081A
Absolute Maximum Ratings
(Note 1)
−0.3V
to 6V
−0.3V
to 6V
0.73W
136.5°C/W
0.98°C/W
Supply Input Voltage, VIN -----------------------------------------------------------------------------------------------
All Other Pins --------------------------------------------------------------------------------------------------------------
Power Dissipation, P
D
@ T
A
= 25°C
ZADFN-6L 1.2x1.2 ---------------------------------------------------------------------------------------------------------
Package Thermal Resistance (Note 2)
ZADFN-6L 1.2x1.2,
θ
JA
---------------------------------------------------------------------------------------------------
ZADFN-6L 1.2x1.2,
θ
JC
---------------------------------------------------------------------------------------------------
Junction Temperature ----------------------------------------------------------------------------------------------------- 150°C
Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------------------- 260°C
Storage Temperature Range --------------------------------------------------------------------------------------------
−65°C
to 150°C
ESD Susceptibility (Note 3)
HBM (Human Body Model) ------------------------------------------------------------------------------------------------ 2kV
CDM (Charged Device Model) -------------------------------------------------------------------------------------------- 1kV
(Note 4)
Recommended Operating Conditions
Supply Input Voltage, VIN ----------------------------------------------------------------------------------------------- 0.8V to 5.5V
Supply Input Voltage, V
BIAS --------------------------------------------------------------------------------------------------------------------------------------
2.4V to 5.5V
Junction Temperature Range --------------------------------------------------------------------------------------------
−40°C
to 125°C
Ambient Temperature Range --------------------------------------------------------------------------------------------
−40°C
to 85°C
Electrical Characteristics
(V
BIAS
= 2.7V, or (V
OUT
+ 1.6V), whichever is greater, V
IN
= V
OUT(Normal)
+ 0.3V, I
OUT
= 1mA, V
EN
= 1V, C
IN
= 1μF,
C
OUT
= 1μF (Effective value), T
A
= 25°C, unless otherwise specified).
(Note 6)
Parameter
Operating Input Voltage
Range
Operating Bias Voltage
Range
Under Voltage Lock-Out
Reference Voltage (Adj
devices only)
Symbol
V
IN
V
BIAS
V
UVLO
V
REF
(Note 5)
Test Conditions
Min
V
OUT
+
V
DROP
(V
OUT
+1.4)
2.4
Typ
--
--
1.6
0.2
0.8
--
Max
5.5
5.5
--
--
--
0.5
Unit
V
V
V
V
V
%
V
BIAS
rising
Hysteresis
--
--
--
0.5
Output Voltage Accuracy V
OUT
Output Voltage Accuracy
V
OUT
(Note 5)
V
IN
Line Regulation
V
BIAS
Line Regulation
V
LINE_VIN
V
LINE_BIAS
V
OUT(Normal)
+ 0.3V
V
IN
V
OUT(Normal)
+ 1V, 2.7V or
(V
OUT(Normal)
+ 1.6V), whichever is
greater
V
BIAS
5.5V, 1mA
I
OUT
< 500mA
V
OUT(NOM)
+ 0.3V
V
IN
5V
2.7V or (V
OUT(Normal)
+ 1.6V),
whichever is greater
V
BIAS
5.5V
1.5
--
1.5
%
--
--
0.01
0.01
--
--
%/V
%/V
Copyright
©
2016 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
4
DS9081A-00 November 2016
RT9081A
Parameter
Load Regulation
V
IN
Dropout Voltage
V
BIAS
Dropout Voltage
Output Current Limit
Symbol
V
LOAD
V
DROP_VIN
V
DROP_BIAS
I
LIM
Test Conditions
I
OUT
= 1mA to 500mA
I
OUT
= 150mA
I
OUT
= 500mA
(Note 7)
(Note 7)
Min
--
--
--
--
550
--
V
BIAS
= 2.7V
V
EN
0.4 V
V
EN
0.4 V
--
--
--
0.9
--
V
EN
= 5.5V, V
BIAS
= 5.5V
From assertion of V
EN
to V
OUT
=
98% V
OUT(NOM)
. V
OUT(NOM)
= 1V
V
IN
to V
OUT
, f = 1kHz,
I
OUT
= 150mA, V
IN
V
OUT
+ 0.5V
V
BIAS
to V
OUT
, f = 1kHz,
I
OUT
= 150mA, V
IN
V
OUT
+ 0.5V
V
IN
= V
OUT
+ 0.5 V, V
OUT(NOM)
= 1V,
f = 10Hz to 100kHz
V
IN
= V
OUT
+ 0.5V, f = 10Hz to
100kHz
Temperature increasing
Temperature decreasing
R
DISCHG
V
EN
0.4V, V
OUT
= 0.5V
--
--
--
--
--
--
--
--
--
Typ
1.5
37
140
1.1
800
0.1
80
0.5
0.5
--
--
1
150
70
80
40
50 x
V
OUT
160
140
150
Max
--
75
250
1.5
1000
0.5
110
1
1
--
0.4
--
--
--
--
--
--
--
--
--
Unit
mV
mV
mV
V
mA
A
A
A
A
V
A
s
dB
dB
V
RMS
V
RMS
C
C
I
OUT
= 500mA, V
IN
= V
BIAS
(Note 7, Note 8)
V
OUT
= 90% V
OUT(Normal)
ADJ Pin Operating Current
I
ADJ
(ADJ devices only)
Bias Pin Operating Current I
BIAS
Bias Pin Disable Current
VIN Pin Disable Current
EN Input
Voltage
Logic_High
Logic_Low
I
BIAS(DIS)
I
VIN(DIS)
V
IH
V
IL
I
EN
t
ON
PSRR_V
IN
PSRR_V
BIAS
e
NO_FIXED
e
NO_ADJ
EN Pull Down Current
Turn-On Time
Power Supply Rejection
Ratio
Output Noise Voltage
(Fixed Volt.)
Output Noise Voltage (Adj
devices)
Thermal Shutdown
Threshold
Output Discharge
Pull-Down
Copyright
©
2016 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS9081A-00 November 2016
www.richtek.com
5
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