RT9174
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DS9174-08 April 2011 www.richtek.com
Features
zz
zz
zIntegrated Three Linear Controllers in a SOP-8
Package
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zz
zDriving NPN or NMOSFET
zz
zz
zSourcing ( > 100mA) and Sinking ( > 5mA) Driver
zz
zz
zT ri-State Output Driver
zz
zz
zLow Internal 0.8V Reference
zz
zz
zAdjustable Output Voltage Setting
zz
zz
zHigh Output Stability
zz
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zVDDQ 1.5/3.3V Automatic Changing for AGP
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zz
zWide 3V to 8V Input Voltage Range
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zz
zCurrent Limiting and Thermal Protection
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zz
zRoHS Compliant and 100% Lead (Pb)-Free
Pin Configurations
Applications
zMother Boards Power Supply
zGra phic Cards
Triple Linear Regulator Controllers
Ordering Information
General Description
The RT9174 is a triple linear regulator controller designed
for motherboard a pplication.
The regulators are intended to regulate the computer
system AGP (2X/4X) power , the 2.5V clock power, and the
1.8V power for North/South Bridge core voltage and/or cache
memory circuits. All controllers can drive NPN or
NMOSFET pass tran sistor. A speci al sche me employing
driver voltage could be higher than VDD when driving
NMOSFET through the 12V power .
The RT9174 future a small SOP-8 package for saving board
area. It also builds in current limiting and thermal shutdown
protection function.
VDD
DRI 1
FB1
GND FB2
DRI 2
FB3
DRI 3
2
3
45
6
7
8
(TOP VIEW)
SOP-8
Note :
Richtek 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.
Function Block Diagram
+
-
+
-
OC
+
-
+
-
OC
DRI2
FB2
DRI3
FB3
+
-
+
-
OC
0.8V 1.3V
Reference
Thermal
Limit
DRI1
FB1
GND
VDD
RT9174
Package Type
S : SOP-8
Lead Plating System
P : Pb Free
G : Green (Halogen Free and Pb Free)
RT9174
2DS9174-08 April 2011www.richtek.com
Figure 2. Dual LDOs with VTTPG for V RM 8.5 Application
VDD
DRI1
FB1
GND
DRI3
FB3
DRI2
FB2
RT9174
18
7
6
5
4
3
2
C1
1uF
5V
R8
1K
#TYPEDET
D1
3.3V 1N4148
C6
10nF
R2
4.3K
R3
4.99K
+
VDDQ
1.5 / 3.3V
C2
1000uF
Q1
3.3V
PHD45N03LT
C1
1uF
12V
R1
5K
R4
250
R5
200
+
C3
470uF
R9
1K
Q3
Q2
2SD1802
MMBT3904
VTTPG
3.3V
R11
374
VTTESL
R6
3K
VTT
C7
1uF R12
8.2K
R10
1K C8
0.01uF
Typical Application Circuit
Figure 1. T riple LDOs with V DDQ for M/B Application
V DDQ = 3.3V if FB1>1.3V
#TYPEDET = 0V to V DDQ = 1.5V
#TYPEDET = Open to V DDQ = 3.3V
VDD
DRI1
FB1
GND
DRI3
FB3
DRI2
FB2
RT9174
18
7
6
5
4
3
2
C1
1uF
5V
R8
1K
#TYPEDET
D1
3.3V 1N4148
C6
10nF
R1
1K
R1
1K
+
VDDQ
1.5 / 3.3V
C2
1000uF
Q1
3.3V
PHD45N03LT
C1
1uF
12V
R1
5K
R4
250
R5
200
+
C3
470uF
Q2
2SD1802 VO2
1.8V
R6
424
R7
200
+
C3
470uF
Q3
2SD1802 VO3
2.5V
3.3V
RT9174
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DS9174-08 April 2011 www.richtek.com
Functional Pin Description
Pin Name Pin Function
VDD Power Supply Input
DRI1 Regulator 1 Driver Output
FB1 Regulator 1 Feedback Non-inverting Input
GND Power Ground
DRI2 Regulator 2 Driver Output
FB2 Regulator 2 Feedback Non-inverting Input
DRI3 Regulator 3 Driver Output
FB3 Regulator 3 Feedback Non-inverting Input
Figure 3. Triple LDOs Driving MOS Application
VDD
DRI1
FB1
GND
DRI3
FB3
DRI2
FB2
RT9174
18
7
6
5
4
3
2
C1
1uF
7.5V
R2
624
R3
200
+
VO1
3.3V
C2
1000uF
Q1
5V
PHD45N03LT
C5
0.1uF
12V
R1
5K
R4
250
R5
200
+
C3
470uF
Q2
VO2
R9
1.2K
R8
3K
PHD4503LT
1.8V
R6
424
R7
200
+
C4
470uF
Q3
VO3
PHD4503LT
2.5V
3.3V
RT9174
4DS9174-08 April 2011www.richtek.com
Absolute Maximum Ratings
Electrical Characteristics
zInput V oltage VDD ---------------------------------------------------------------------------------------------------- 8V
zFeedback FB1/FB2/FB3 ------------------------------------------------------------------------------------------- −0.3 to 8V
zDriver DRI1/DRI2/DRI3 ---------------------------------------------------------------------------------------------- −0.3 to 12V
zPower Dissipation, PD @ TA = 25°C
SOP-8 ------------------------------------------------------------------------------------------------------------------ 0.625W
zPackage Thermal Resistance
SOP-8, θJA ------------------------------------------------------------------------------------------------------------ 160°C/W
zOperating Junction Temperature Range ------------------------------------------------------------------------- −40°C to 125°C
zStorage T emperature Range --------------------------------------------------------------------------------------- −65°C to 150°C
(VDD = 5V, CIN = 1F, TA = 25°C, unless otherwise specified)
Parameter Symbol Test Conditions Min Typ Max Unit
Supply Current IDD No Load -- 0.8 2 mA
F eedback Reference Voltage VREF No Load 0.78 0.8 0.82 V
Line Regul ati on VLINE VDD = 4 to 7V -- 2 10 mV
S our ce 100m A, DRI1/DRI2/DRI3 = 2.5V -- 5 10
Load Regulation VLOAD Sink 5mA, DRI1/DRI2/DRI3 = 2.5V -- 10 15 mV
S our cing, DRI1/DRI2/DRI3 = 2.5V 100 -- --
Driving Capability IO Sink DRI1/DRI2/DRI3 = 2.5V 5 - --
mA
S our cing, DRI1/DRI2/DRI3 = 2.5V -- 300 700
Driver Current Limiting ICL Sink DRI1/DRI2/DRI3 = 2.5V -- 40 150
mA
Driver Tri-State Threshold VTS Sweep FB1/FB2/FB3 to Driver Outpu t Off 1.0 1.35 2.0 V
Thermal Limit -- 150 -- °C
Power On Reset Voltage POR -- 2.4 -- V
RT9174
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DS9174-08 April 2011 www.richtek.com
Typical Operating Characteristics
Driv er Sourc ing vs Drop Out
0
50
100
150
200
250
300
012345
VDD - VDRI1,2,3 (V)
Sourcing(mA)
VDD = 5V
-20°C
25°C
85°C
Supply Current vs Temperature
0.4
0.6
0.8
1
1.2
1.4
345678
VDD (V)
IQ(mA)
-20°C
25°C
85°C
Driver Sink ing vs VOUT
10
20
30
40
50
012345
VOUT (V)
Sinking (mA)
VDD = 5V
-20°C
25°C
85°C
Tri-Sate Vth vs Temperature
0.8
1.0
1.2
1.4
1.6
-50 -10 30 70 110 150
Temperature
Vth(V)
VDD = 5V
(°C)
Short Current vs Temperature
100
150
200
250
300
350
400
-50 -20 10 40 70 100 130
Temperature
Short Current (mA)
(°C)
VDD = 5V
Reference vs Temperature
0.78
0.79
0.80
0.81
0.82
-50 -10 30 70 110 150
Temperature
Reference (V)
VDD = 5V
(°C)
RT9174
6DS9174-08 April 2011www.richtek.com
Application Information
Ca pa citors Sele ction
A 0.1μF minimum capacitor is recommended between VDD
and ground to increa se stability . The linear controllers use
dominant pole compensation integrated into the error
amplifier and are sensitive to output capacitor selection.
When driving external pa ss transistor, normally a minimum
470μF ca pacitor must be pla ced at output for stability and
good transient response. When using internal pass
tran sistor, just need 10μF capa citor f or sta ble.
Pa ss Transistor Selection
The RT9174 are designed specifically to driver external
NPN or NMOSFET pass transistor for up to 5A output
current. The driver could deliver more 100mA when driving
NPN transistor and sinking for a pull up resistor load when
driving a NMOSFET.
Typically pass transistor with NPN hfe > 50 at Imax or
NMOSFET Rds-on 100mΩ are suitable in most
application.
Output Voltage Setting
The RT9174 develop a 0.8V reference voltage, especially
suit for low voltage a pplication. As shown in Figure 4, the
output voltage could be easy set by R1 & R2 resistor.
The divided resistor must keep below 1kΩ for quick
response a nd stability.
T ri-state Operation
A special Tri-state design is empolyed in the RT9174 for
AGP 2X/4X power supply. T ypical application shown the
detail circuit. In AGP 2X SELECT = open, FB1 will be
pulled up over 1.3V through R8 to trip the Tri-state
threshold. R8 has to meet the following relation shi p:
R8 < 0.75 (V 33 - 1.3) x R2,
if 1.50.8
RRR 323 =×
+.
When in AGP 4X SELECT = GND, VDDQ will work in
normal 1.5V setting.
Layout Considerations
There are two critical layout considerations. One is the
divider resistors should be located to RT9174 as possible
to avoid inducing any noise. The second is COUT should
be put at near the pass tran sistor to avoid oscillation.
Figure 4
RT9174VDD DR11
DR12
DR13
FB1
FB2
FB3
+
COUT
R1
R2
VOUT
VIN
VDD
1uF
As close as to RT9174
RT9174
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DS9174-08 April 2011 www.richtek.com
Information that is provided by Richtek Technology Corporation is believed to be accurate and reli able. Richtek reserves the right to make any change in circuit design,
specification or other related things if necessary without notice at any time. No third party intellectual property infringement of the applications should be guaranteed
by users when integrating Richtek products into any application. No legal responsibility for any said applications is assumed by Richtek.
Richtek Technology Corporation
Headquarter
5F, No. 20, Taiyuen Street, Chupei City
Hsinchu, Taiwan, R.O.C.
Tel: (8863)5526789 Fax: (8863)5526611
Richtek Technology Corporation
Taipei Office (Marketing)
5F, No. 95, Minchiuan Road, Hsintien City
Taipei County, Taiwan, R.O.C.
Tel: (8862)86672399 Fax: (8862)86672377
Email: marketing@richtek.com
Outline Dimension
A
B
J
F
H
M
C
D
I
8-Lead SOP Plastic Package
Dim e nsion s In Mill imet e rs Dimensions In I nches
Symbol Min Max Min Max
A 4.801 5.004 0.189 0.197
B 3.810 3.988 0.150 0.157
C 1.346 1.753 0.053 0.069
D 0.330 0.508 0.013 0.020
F 1.194 1.346 0.047 0.053
H 0.170 0.254 0.007 0.010
I 0.050 0.254 0.002 0.010
J 5.791 6.200 0.228 0.244
M 0.400 1.270 0.016 0.050
