RT9187
1A, Ultra-Low Dropout, Ultra-Fast CMOS LDO Regulator
General Description
The RT9187 is a high-performance, 1A LDO regulator,
offering extremely high PSRR and ultra-low dropout. Ideal
for portable RF and wireless applications with demanding
performance and space requirements.
A noise reduction pin is also available for further reduction
of output noise. Regulator ground current increases only
slightly in dropout, further prolonging the battery life. The
RT9187 also works with low-ESR ceramic capacitors,
reducing the amount of board space necessary for power
applications, critical in hand-held wireless devices.
The RT9187 consumes less than 0.1uA in shutdown mode
and has fast turn-on time less than 40μs. The other features
include ultra-low dropout voltage, high output accuracy,
current limiting protection, and high ripple rejection ratio.
Available in the VDFN-8L 3x3 and SOP-8 (Exposed Pad)
package.
Features
Ultra-Low-Noise for RF Application
Ultra-Fast Response in Line/Load Transient
Quick Start-Up
(Typically 40μs)
μ
< 0.1uA Standby Current When Shutdown
Low Dropout : 240mV
at 1A
Wide Operating Voltage Ranges : 2.5V to 5.5V
TTL-Logic-Controlled Shutdown Input
Current Limiting Protection
Thermal Shutdown Protection
Only 2.2uF Output Capacitor Required for Stability
High Power Supply Rejection Ratio
RoHS Compliant and 100% Lead (Pb)-Free
Applications
CDMA/GSM Cellular Handsets
Battery-Powered Equipment
Laptop, Palmtops, Notebook Computers
Hand-Held Instruments
Mini PCI & PCI-Express Cards
PCMCIA & New Cards
Portable Information Appliances
Ordering Information
RT9187(
-
)
Package Type
QV : VDFN-8L 3x3 (V-Type)
SP : SOP-8 (Exposed Pad-Option 1)
Operating Temperature Range
P : Pb Free with Commercial Standard
For marking information, contact our sales representative
G : Green (Halogen Free with Commer-
directly or through a RichTek distributor located in your
cial Standard)
area, otherwise visit our website for detail.
None : Adjustable Output
Fixed Output Voltage Code
Pin Configurations
10 : 1.0V
(TOP VIEW)
11 : 1.1V
:
8
EN
VIN
1
32 : 3.2V
7
NC
VIN
2
33 : 3.3V
6
GND
VOUT
3
9
5
BP/ADJ
VOUT
4
1L : 1.34V
Note :
Richtek Pb-free and Green products are :
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.
100% matte tin (Sn) plating.
VIN
VIN
VOUT
VOUT
2
8
7
GND
3
6
9
4
5
EN
NC
GND
BP/ADJ
Marking Information
VDFN-8L 3x3
SOP-8 (Exposed Pad)
DS9187-09 April 2008
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1
RT9187
Typical Application Circuit
V
IN
C
IN
2.2uF
VIN
VOUT
C
OUT
2.2uF
RT9187
BP
V
OUT
V
IN
VIN
C
IN
2.2uF
VOUT
R1
ADJ
RT9187
C
BP
10nF
Chip Enable
EN
GND
C
OUT
2.2uF
V
OUT
Chip Enable
EN
GND
R2
Figure 1. Fixed Operation
Figure 2. Adjustable Operation
V
OUT
= 0.8 x (
1+
R
1
) Volts
R
2
Note: The value of R2 should be less than 80k to
maintain regulation.
Function Pin Description
Pin No.
Fixed Output
Voltage
1
2
3
4
5
Adjustable
Output Voltage
1
2
3
4
--
VIN
VIN
VOUT
VOUT
BP
Supply Input.
Supply Input.
Regulator Output.
Regulator Output.
Noise Reduction. Connecting a 10nF capacitor to GND to reduce
output noise.
If external feedback resistors are applied, the output voltage will be:
--
6
7
8
5
6
7
8
ADJ
GND
NC
EN
NC
V
OUT
= 0.8
×
(1+
Ground
No Internal Connection.
Enable Input Logic, Active High. W hen the EN goes to a logic low, the
device is in shutdown mode.
No Internal Connection. The exposed pad must be soldered to a
large PCB and connected to GND for maximum power dissipation.
R
1
) Volts
R
2
Pin
Name
Pin Function
Exposed Pad (9)
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2
DS9187-09 April 2008
RT9187
Function Block Diagram
VIN
EN
EN
OTP
POR
BIAS
-
V
REF
+
Current Limit
Quick start
VOUT
ADJ
Adjustable
GND
VIN
EN
EN
OTP
POR
BIAS
-
V
REF
+
VOUT
Current Limit
BP
Quick start
Fixed
GND
DS9187-09 April 2008
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3
RT9187
Absolute Maximum Ratings
(Note 1)
Supply Input Voltage -------------------------------------------------------------------------------------------------- 6V
EN Input Voltage ------------------------------------------------------------------------------------------------------- 6V
Power Dissipation, P
D
@ T
A
= 25°C
VDFN-8L 3x3 ----------------------------------------------------------------------------------------------------------- 0.923W
SOP-8 (Exposed Pad) ----------------------------------------------------------------------------------------------- 1.33W
Package Thermal Resistance (Note 9)
VDFN-8L 3x3,
θ
JC
----------------------------------------------------------------------------------------------------- 8.2°C/W
VDFN-8L 3x3,
θ
JA
------------------------------------------------------------------------------------------------------ 108°C/W
SOP-8 (Exposed Pad),
θ
JC
----------------------------------------------------------------------------------------- 15°C/W
SOP-8 (Exposed Pad)-8,
θ
JA
--------------------------------------------------------------------------------------- 75°C/W
Lead Temperature (Soldering, 10 sec.) --------------------------------------------------------------------------- 260°C
Junction Temperature ------------------------------------------------------------------------------------------------- 150°C
Storage Temperature Range ----------------------------------------------------------------------------------------
−
65°C to 150°C
ESD Susceptibility (Note 2)
HBM ---------------------------------------------------------------------------------------------------------------------- 2kV
MM ------------------------------------------------------------------------------------------------------------------------ 200V
Recommended Operating Conditions
(Note 3)
Supply Input Voltage -------------------------------------------------------------------------------------------------- 2.5V to 5.5V
EN Input Voltage ------------------------------------------------------------------------------------------------------- 0V to 5.5V
Junction Temperature Range ----------------------------------------------------------------------------------------
−
40°C to 125°C
Ambient Temperature Range ----------------------------------------------------------------------------------------
−
40°C to 85°C
Electrical Characteristics
(V
IN
= V
OUT
+ 1V, V
EN
= V
IN
, C
IN
= C
OUT
= 2.2μF (Ceramic) & C
BP
= 10nF,
T
A
= 25°C unless otherwise specified)
Parameter
Output Voltage Accuracy
(Fixed Output Voltage)
Output Voltage Range (Adjustable)
Quiescent Current (Note 6)
Standby Current (Note 7)
Current Limit
Dropout Voltage (Note 4)
Symbol
ΔV
OUT
V
OUT_Adj
I
Q
I
S TBY
I
LIM
V
DROP
Test Conditions
I
O UT
= 10mA
Min
−2
0.8
Typ
0
--
380
0.1
2.8
60
120
240
0.4
--
--
0.1
Max
+2
4.5
500
1
3
100
180
360
--
0.6
--
1
Units
%
V
μA
μA
A
mV
V
EN
≥
V
IH
, I
OUT
= 0mA
V
EN
≤
V
IL
,V
IN
= 3.3V
R
LO AD
= 0.5Ω, V
IN
= 3.3V
I
OUT
= 0.25A (Note 8)
I
O UT
= 0.5A
I
O UT
= 1.0A
V
IN
= (V
OUT
+ 0.5V)
10mA < I
OUT
< 1.0A
V
IN
= 3.3V
V
IN
= 3.3V
V
IN
= 3.3V, Enable
--
--
2
--
--
--
--
--
1.8
--
Load Regulation (Note 5)
(Fixed Output Voltage)
EN Threshold
Logic-Low Voltage
Logic-High Voltage
ΔV
LOAD
V
IL
V
IH
I
E N
%/A
V
μA
Enable Pin Current
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4
To be continued
DS9187-09 April 2008
RT9187
Parameter
Power Supply
Rejection Rate
Line Regulation
Start-Up Time
Thermal Shutdown Temperature
Thermal Shutdown Hysteresis
ADJ
Reference Voltage Tolerance
ADJ Pin Current
V
REF
I
A DJ
V
ADJ
0.784
0.8
10
0.816
100
V
nA
f = 100Hz
f = 10kHz
Symbol
PSRR
ΔV
LINE
T
Start_Up
T
SD
ΔT
SD
Test Conditions
I
OUT
= 300mA
V
IN
= (V
OUT
+0.5) to 5.5V,
I
OUT
= 1mA
R
LO AD
= 3Ω, 1nF
≤
C
BP
≤
0.1μF
Min
--
--
--
--
--
--
Typ
−60
−50
--
40
170
30
Max
--
--
0.3
--
--
--
Units
dB
%
μs
°C
=
V
REF
--
Note 1.
Stresses listed as the above
“Absolute
Maximum Ratings” may cause permanent damage to the device. These are for
stress ratings. 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 for extended periods may
remain possibility to affect device reliability.
Note 2.
Devices are ESD sensitive. Handling precaution is recommended.
Note 3.
The device is not guaranteed to function outside its operating conditions.
Note 4.
The dropout voltage is defined as V
IN
-V
OUT
, which is measured when V
OUT
is V
OUT(NORMAL)
- 100mV.
Note 5.
Regulation is measured at constant junction temperature by using a 2ms current pulse. Devices are tested for load
regulation in the load range from 10mA to 1.0A.
Note 6.
Quiescent, or ground current, is the difference between input and output currents. It is defined by I
Q
= I
IN
- I
OUT
under no
load condition (I
OUT
= 0mA). The total current drawn from the supply is the sum of the load current plus the ground pin
current.
Note 7.
Standby current is the input current drawn by a regulator when the output voltage is disabled by a shutdown signal (V
EN
>1.8V ).
Note 8.
Performance at -5°C
≤
T
A
≤
85°C is assured by design.
Note 9.
θ
JA
is measured in the natural convection at T
A
= 25°C on a low effective thermal conductivity test board of
JEDEC 51-3 thermal measurement standard.
DS9187-09 April 2008
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5
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