Preliminary
RT9184
500mA Dual LDO Regulator
General Description
The RT9184 is a dual-channel, low noise, and low
dropout regulator supplying up to 500mA current at
each channel. The output voltage ranges from 1.5V
to 3.3V in 100mV increment and 2% accuracy by
operating from a +2.7V to +6.5V input.
The RT9184 uses two internal PMOS as the pass
device, which consumes 185µA supply current (both
LDOs on) independent of load current and dropout
conditions. Other features include a current limiting
and over temperature protection.
Features
Up to 500mA Output Current (Each LDO)
Current Limiting and Thermal Protection
Short Circuit Protection
650mV Dropout at 500mA Load
Two LDOs in Power SOP-8 Package
Pin Configurations
Part Number
RT9184 CH
(Plastic PSOP-8)
Pin Configurations
TOP VIEW
GND
1
GND
2
GND
3
VOUT2
4
8
VIN
7
VIN
6
VOUT1
5
NC
Applications
Desktop Computers
CD-RW
LCD Monitor
Information Appliance
Typical Application Circuit
V
OUT2
VOUT2 VOUT1
10
µ
F
V
OUT1
Ordering Information
RT9184
Package type
H : PSOP-8
Operating temperature range
C : Commercial standard
Output voltage
A : 3.3V (Output1), 1.8V (Output2)
B : 3.3V (Output1), 2.5V (Output2)
Other voltage versions please
contact RichTek for detail.
RT9184
GND
VIN
10
µ
F 10
µ
F
DS9184-00 March 2002
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1
RT9184
Pin Description
Pin Name
VIN
GND
VOUT1
VOUT2
NC
Ground
Output1 Voltage
Output2 Voltage
No Connected
Pin Function
Power Input
Preliminary
Function Block Diagram
VIN
Current Limit
Thermal Protection
Current Limit
+
VOUT1
Bias
www.richtek-ic.com.tw
2
_
_
Vref
+
VOUT2
GND
DS9184-00 March 2002
Preliminary
Absolute Maximum Ratings
Input Voltage
Package Thermal Resistance
PSOP-8,
θ
JC
Junction Temperature Range
Storage Temperature Range
Operating Temperature Range
Lead Temperature (Soldering, 10 sec.)
RT9184
7V
28°C/W
-40°C ~ 125°C
-65°C ~ 150°C
-40°C ~ 85°C
260°C
Electrical Characteristics
(V
IN
= 5V, C
IN
= C
OUT
= 10µF, typical values at T
A
= 25°C, for each LDO unless otherwise specified.)
Parameter
Input Voltage Range
Output Voltage Accuracy
Maximum Output Current
Current Limit
GND Pin Current (Whole Chip)
Dropout Voltage
Line Regulation
Load Regulation
Thermal Shutdown Temperature
Thermal Shutdown Hysteresis
Output Voltage AC PSRR
T
SD
100Hz, C
OUT
= 10µF
I
LOAD
= 100mA
Note
Symbol
V
IN
∆V
OUT
I
MAX
I
LIMIT
I
G
V
DROP
∆V
LINE
Test Conditions
Min
2.7
Typ
--
--
--
--
185
650
--
-20
180
20
62
Max
6.5
+2
--
1000
260
--
+0.2
+5
--
--
--
Units
V
%
mA
mA
µA
mV
%/V
mV
°C
°C
dB
I
OUT
= 1mA
Continuous
R
LOAD
= 1Ω
No Load
I
OUT
= 500mA
V
IN
= (V
OUT
+0.4V or 2.7V) to 6.5V
I
OUT
= 1mA
-2
500
510
--
--
-0.2
-35
125
--
--
∆V
LOAD
I
OUT
= 1mA to 500mA
Note : Dropout voltage definition: V
IN
– V
OUT
when V
OUT
is 50mV below the value of V
OUT
(normal)
DS9184-00 March 2002
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3
RT9184
Preliminary
Typical Operating Characteristics
I
LOAD
= 100mA, V
IN
= 5V, C
OUT
= 10µF, and C
IN
= 10µF, unless otherwise noted.
Quiescent Current vs. Temp.
200
1.0
0.8
Output Voltage Accuracy vs. Temp.
Quiescent Current (
µ
A)
180
0.6
Output Voltage (%)
-40
-15
35
Temperature (
°
C)
10
60
85
0.4
0.2
0.0
-0.2
-0.4
-0.6
-0.8
160
140
120
100
-1.0
-40
-15
10
35
60
85
Temperature (
°
C)
120
100
Channel-to-Channel Isolation
vs. Frequency
70
60
50
PSRR vs. Frequency
I
LOAD
= 1mA
Channel Isolation (dB)
PSRR (dB)
R
LOAD
= 100Ω
100
1K
80
60
40
20
0
40
30
20
10
0
Frequency (Hz)
10K
100K
1M
10
100
1K
10K
100K
1M
Frequency (Hz)
Output Voltage Deviation
(AC-Coupled)
Line Transient Response
T
Load Transient Response
(I
LOAD
= 10 to 500mA)
V
OUT
3>
20mV/Div
1>
T
T
Input Voltage (V)
≈
4.5
3.5
2↓
≈
T
T
I
LOAD
50µS/Div
Time
T
T
1>
1) Ch 1: 1 Volt 250 us
500mA
3) Ref B: 50 mVolt 250 us
C
OUT
= 100µF
Time
DS9184-00 March 2002
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4
Preliminary
Functional Description
The RT9184 integrate two low noise, low dropout,
and low quiescent current linear regulators. Output
voltages are optional ranging from 1.5V to 3.3V, and
each channel can supply current up to 500mA.
Internal P-Channel Pass Transistor
The RT9184 features double typical 1.3Ω P-channel
MOSFET
pass
transistors. It
provides
several
advantages over similar designs using PNP pass
transistors. The P-channel MOSFET requires no
base
drive,
which
reduces
quiescent
current
significantly than PNP-based regulator, which wastes
considerable current in dropout when the pass
transistor saturates. They also use high base-drive
currents under large loads. The RT9184 does not
suffer from these problems and consume only 185µA
of quiescent current whether in dropout, light-load, or
heavy-load applications.
Current Limit and Thermal Protection
The RT9184 includes two independent current limit
structure which monitor and control each pass
transistor’s gate voltage limiting the guaranteed
maximum output current to 510mA minimum.
Thermal-overload
protection
limits
total
power
dissipation in the RT9184. When the junction
temperature exceeds T
J
= +180°C, the thermal
sensor signals the shutdown logic turning off the pass
transistor and allowing the IC to cool down. The
thermal sensor will turn the pass transistor on again
after the IC’s junction temperature cools by 20°C,
resulting in a pulsed output during continuous
thermal-overload
conditions.
Thermal-overloaded
protection is designed to protect the RT9184 in the
event of fault conditions. Do not exceed the absolute
maximum junction-temperature rating of T
J
= +125°C
for continuous operation. The output can be shorted
to ground for an indefinite amount of time without
damaging the part by cooperation of current limit and
thermal protection.
RT9184
DS9184-00 March 2002
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5
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