RT9403 [RICHTEK]
暂无描述;
| 型号： | RT9403 |
| 厂家： | 
RICHTEK TECHNOLOGY CORPORATION |
| 描述： | 暂无描述 |
| 文件： | 总17页 (文件大小：196K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
RT9403
I2C Programmable High Precision Reference Voltage
Generator
General Description
Features
z 5V Supply Voltage
The RT9403 is a high precision reference voltage generating
console consisting of three I2C programmableDACs. Each
DAC output voltage is controlled by 7 digital bits that are
programmed by the I2C interface. The RT9403 features
adjustable output slew rate, low switching glitch and
adequate driving capability. The RT9403 is available in
SOT-23-8 package.
z Provide 3 Precise Voltage DACs
z I2C Programmable 128-Steps Output Voltage
z Output Range and Resolution
` DAC1 & DAC2 : 0.6V to 2.1875V, 12.5mV/Step
` DAC3 : 1.2V to 3.375V, 12.5mV (or 25mV)/Step for
Different Segments
z High Output Accuracy Up to 1% (VOUT 1V)
≥
z Low External Component Count
z Small Footprint SOT-23-8 Package
z RoHS Compliant and Halogen Free
Ordering Information
RT9403
Package Type
V8 : SOT-23-8
Applications
z Power SupplyAdjustment for Motherboard andGraphic
Lead Plating System
G : Green (Halogen Free and Pb Free)
Note :
Card
Richtek products are :
z Low Voltage, High Accuracy Reference Voltage Circuit
` RoHS compliant and compatible with the current require-
ments of IPC/JEDEC J-STD-020.
Pin Configurations
` Suitable for use in SnPb or Pb-free soldering processes.
(TOP VIEW)
Marking Information
For marking information, contact our sales representative
directly or through a Richtek distributor located in your
area.
8
7
2
6
3
5
4
SOT-23-8
Typical Application Circuit
V
IN1
REFIN
REFIN
REFIN
DC/DC
Converter
V1
V2
V3
3.3V/5V
5V
C
OUT1
C
OUT2
C
OUT3
RT9403
V
IN2
1
VDD
5
VOUT1
C
IN
DC/DC
Converter
6
7
2
VOUT2
VOUT3
GND
4
3
Data Bus Line
Clock Bus Line
SDA
SCL
V
IN3
8
S3/EN
S3/EN
DC/DC
Converter
DS9403-01 April 2011
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1
RT9403
Functional Pin Description
Pin No.
Pin Name
Pin Function
Power Supply Input. Default connected to 5V.
Ground.
1
2
3
4
5
6
7
VDD
GND
2
SCL
Serial Clock Input. This pin receives I C serial bus clock signal.
2
SDA
Serial Data Input. This pin is input or output of I C serial bus data signal.
2
VOUT1
VOUT2
VOUT3
I C Programmed VTT Output Voltage. Default = 1.1V
2
I C Programmed PCH_CORE Output Voltage. Default = 1.05V
2
I C Programmed DDR Output Voltage. Default = 1.5V
ACPI S3 State/Enable. Active low for entering ACPI S3 State(suspend to RAM),
VOUT1/VOUT2 are internally pulled down to zero, only VOUT3 is active.
8
S3/EN
Function Block Diagram
VDD
POR
DAC1
7 bit
VOUT1
S3/EN
SCL
2
DAC2
7 bit
Control and
Monitoring Unit
I C
VOUT2
VOUT3
Interface
SDA
DAC3
7 bit
GND
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DS9403-01 April 2011
RT9403
Table 1. DAC1/DAC2 Serial Code Table
SVID6
0
SVID5
0
SVID4
0
SVID3
0
SVID2
0
SVID1
0
SVID0
0
Output Voltage ( V )
2.1875
2.1750
2.1625
2.1500
2.1375
2.1250
2.1125
2.1000
2.0875
2.0750
2.0625
2.0500
2.0375
2.0250
2.0125
2.0000
1.9875
1.9750
1.9625
1.9500
1.9375
1.9250
1.9125
1.9000
1.8875
1.8750
1.8625
1.8500
1.8375
1.8250
1.8125
1.8000
1.7875
1.7750
1.7625
1.7500
1.7375
1.7250
1.7125
1.7000
0
0
0
0
0
0
1
0
0
0
0
0
1
0
0
0
0
0
0
1
1
0
0
0
0
1
0
0
0
0
0
0
1
0
1
0
0
0
0
1
1
0
0
0
0
0
1
1
1
0
0
0
1
0
0
0
0
0
0
1
0
0
1
0
0
0
1
0
1
0
0
0
0
1
0
1
1
0
0
0
1
1
0
0
0
0
0
1
1
0
1
0
0
0
1
1
1
0
0
0
0
1
1
1
1
0
0
1
0
0
0
0
0
0
1
0
0
0
1
0
0
1
0
0
1
0
0
0
1
0
0
1
1
0
0
1
0
1
0
0
0
0
1
0
1
0
1
0
0
1
0
1
1
0
0
0
1
0
1
1
1
0
0
1
1
0
0
0
0
0
1
1
0
0
1
0
0
1
1
0
1
0
0
0
1
1
0
1
1
0
0
1
1
1
0
0
0
0
1
1
1
0
1
0
0
1
1
1
1
0
0
0
1
1
1
1
1
0
1
0
0
0
0
0
0
1
0
0
0
0
1
0
1
0
0
0
1
0
0
1
0
0
0
1
1
0
1
0
0
1
0
0
0
1
0
0
1
0
1
0
1
0
0
1
1
0
0
1
0
0
1
1
1
To be continued
DS9403-01 April 2011
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3
RT9403
Table 1. DAC1/DAC2 Serial Code Table
SVID6
0
SVID5
SVID4
0
SVID3
1
SVID2
0
SVID1
0
SVID0
0
Output Voltage ( V )
1.6875
1.6750
1.6625
1.6500
1.6375
1.6250
1.6125
1.6000
1.5875
1.5750
1.5625
1.5500
1.5375
1.5250
1.5125
1.5000
1.4875
1.4750
1.4625
1.4500
1.4375
1.4250
1.4125
1.4000
1.3875
1.3750
1.3625
1.3500
1.3375
1.3250
1.3125
1.3000
1.2875
1.2750
1.2625
1.2500
1.2375
1.2250
1.2125
1.2000
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
1
0
0
1
0
1
0
0
0
1
0
1
1
0
0
1
1
0
0
0
0
1
1
0
1
0
0
1
1
1
0
0
0
1
1
1
1
0
1
0
0
0
0
0
1
0
0
0
1
0
1
0
0
1
0
0
1
0
0
1
1
0
1
0
1
0
0
0
1
0
1
0
1
0
1
0
1
1
0
0
1
0
1
1
1
0
1
1
0
0
0
0
1
1
0
0
1
0
1
1
0
1
0
0
1
1
0
1
1
0
1
1
1
0
0
0
1
1
1
0
1
0
1
1
1
1
0
0
1
1
1
1
1
1
0
0
0
0
0
1
0
0
0
0
1
1
0
0
0
1
0
1
0
0
0
1
1
1
0
0
1
0
0
1
0
0
1
0
1
1
0
0
1
1
0
1
0
0
1
1
1
1
0
1
0
0
0
1
0
1
0
0
1
1
0
1
0
1
0
1
0
1
0
1
1
1
0
1
1
0
0
1
0
1
1
0
1
1
0
1
1
1
0
1
0
1
1
1
1
To be continued
www.richtek.com
4
DS9403-01 April 2011
RT9403
Table 1. DAC1/DAC2 Serial Code Table
SVID6
1
SVID5
0
SVID4
1
SVID3
0
SVID2
0
SVID1
0
SVID0
0
Output Voltage ( V )
1.1875
1.1750
1.1625
1.1500
1.1375
1.1250
1.1125
1.1000
1.0875
1.0750
1.0625
1.0500
1.0375
1.0250
1.0125
1.0000
0.9875
0.9750
0.9625
0.9500
0.9375
0.9250
0.9125
0.9000
0.8875
0.8750
0.8625
0.8500
0.8375
0.8250
0.8125
0.8000
0.7875
0.7750
0.7625
0.7500
0.7375
0.7250
0.7125
0.7000
1
0
1
0
0
0
1
1
0
1
0
0
1
0
1
0
1
0
0
1
1
1
0
1
0
1
0
0
1
0
1
0
1
0
1
1
0
1
0
1
1
0
1
0
1
0
1
1
1
1
0
1
1
0
0
0
1
0
1
1
0
0
1
1
0
1
1
0
1
0
1
0
1
1
0
1
1
1
0
1
1
1
0
0
1
0
1
1
1
0
1
1
0
1
1
1
1
0
1
0
1
1
1
1
1
1
1
0
0
0
0
0
1
1
0
0
0
0
1
1
1
0
0
0
1
0
1
1
0
0
0
1
1
1
1
0
0
1
0
0
1
1
0
0
1
0
1
1
1
0
0
1
1
0
1
1
0
0
1
1
1
1
1
0
1
0
0
0
1
1
0
1
0
0
1
1
1
0
1
0
1
0
1
1
0
1
0
1
1
1
1
0
1
1
0
0
1
1
0
1
1
0
1
1
1
0
1
1
1
0
1
1
0
1
1
1
1
1
1
1
0
0
0
0
1
1
1
0
0
0
1
1
1
1
0
0
1
0
1
1
1
0
0
1
1
1
1
1
0
1
0
0
1
1
1
0
1
0
1
1
1
1
0
1
1
0
1
1
1
0
1
1
1
To be continued
DS9403-01 April 2011
www.richtek.com
5
RT9403
Table 1. DAC1/DAC2 Serial Code Table
SVID6
SVID5
SVID4
SVID3
SVID2
SVID1
SVID0
Output Voltage ( V )
0.6875
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0.6750
0.6625
0.6500
0.6375
0.6250
0.6125
0.6000
Note: (1) 0 : Pull Low to GND
(2) 1 : Open
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6
DS9403-01 April 2011
RT9403
Table 2. DAC3 Serial Code Table
SVID6
0
SVID5
0
SVID4
0
SVID3
0
SVID2
0
SVID1
0
SVID0
0
Output Voltage ( V )
3.3750
3.3500
3.3250
3.3000
3.2750
3.2500
3.2250
3.2000
3.1750
3.1500
3.1250
3.1000
3.0750
3.0500
3.0250
3.0000
2.9750
2.9500
2.9250
2.9000
2.8750
2.8500
2.8250
2.8000
2.7750
2.7500
2.7250
2.7000
2.6750
2.6500
2.6250
2.6000
2.5750
2.5500
2.5250
2.5000
2.4750
2.4500
2.4250
2.4000
0
0
0
0
0
0
1
0
0
0
0
0
1
0
0
0
0
0
0
1
1
0
0
0
0
1
0
0
0
0
0
0
1
0
1
0
0
0
0
1
1
0
0
0
0
0
1
1
1
0
0
0
1
0
0
0
0
0
0
1
0
0
1
0
0
0
1
0
1
0
0
0
0
1
0
1
1
0
0
0
1
1
0
0
0
0
0
1
1
0
1
0
0
0
1
1
1
0
0
0
0
1
1
1
1
0
0
1
0
0
0
0
0
0
1
0
0
0
1
0
0
1
0
0
1
0
0
0
1
0
0
1
1
0
0
1
0
1
0
0
0
0
1
0
1
0
1
0
0
1
0
1
1
0
0
0
1
0
1
1
1
0
0
1
1
0
0
0
0
0
1
1
0
0
1
0
0
1
1
0
1
0
0
0
1
1
0
1
1
0
0
1
1
1
0
0
0
0
1
1
1
0
1
0
0
1
1
1
1
0
0
0
1
1
1
1
1
0
1
0
0
0
0
0
0
1
0
0
0
0
1
0
1
0
0
0
1
0
0
1
0
0
0
1
1
0
1
0
0
1
0
0
0
1
0
0
1
0
1
0
1
0
0
1
1
0
0
1
0
0
1
1
1
To be continued
DS9403-01 April 2011
www.richtek.com
7
RT9403
Table 2. DAC3 Serial Code Table
SVID6
0
SVID5
SVID4
0
SVID3
1
SVID2
0
SVID1
0
SVID0
0
Output Voltage ( V )
2.3750
2.3625
2.3500
2.3375
2.3250
2.3125
2.3000
2.2875
2.2750
2.2625
2.2500
2.2375
2.2250
2.2125
2.2000
2.1875
2.1750
2.1625
2.1500
2.1375
2.1250
2.1125
2.1000
2.0875
2.0750
2.0625
2.0500
2.0375
2.0250
2.0125
2.0000
1.9875
1.9750
1.9625
1.9500
1.9375
1.9250
1.9125
1.9000
1.8875
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
1
0
0
1
0
1
0
0
0
1
0
1
1
0
0
1
1
0
0
0
0
1
1
0
1
0
0
1
1
1
0
0
0
1
1
1
1
0
1
0
0
0
0
0
1
0
0
0
1
0
1
0
0
1
0
0
1
0
0
1
1
0
1
0
1
0
0
0
1
0
1
0
1
0
1
0
1
1
0
0
1
0
1
1
1
0
1
1
0
0
0
0
1
1
0
0
1
0
1
1
0
1
0
0
1
1
0
1
1
0
1
1
1
0
0
0
1
1
1
0
1
0
1
1
1
1
0
0
1
1
1
1
1
1
0
0
0
0
0
1
0
0
0
0
1
1
0
0
0
1
0
1
0
0
0
1
1
1
0
0
1
0
0
1
0
0
1
0
1
1
0
0
1
1
0
1
0
0
1
1
1
1
0
1
0
0
0
1
0
1
0
0
1
1
0
1
0
1
0
1
0
1
0
1
1
1
0
1
1
0
0
1
0
1
1
0
1
1
0
1
1
1
0
1
0
1
1
1
1
To be continued
www.richtek.com
8
DS9403-01 April 2011
RT9403
Table 2. DAC3 Serial Code Table
SVID6
1
SVID5
0
SVID4
1
SVID3
0
SVID2
0
SVID1
0
SVID0
0
Output Voltage ( V )
1.8750
1.8625
1.8500
1.8375
1.8250
1.8125
1.8000
1.7875
1.7750
1.7625
1.7500
1.7375
1.7250
1.7125
1.7000
1.6875
1.6750
1.6625
1.6500
1.6375
1.6250
1.6125
1.6000
1.5875
1.5750
1.5625
1.5500
1.5375
1.5250
1.5125
1.5000
1.4875
1.4750
1.4625
1.4500
1.4375
1.4250
1.4125
1.4000
1.3875
1
0
1
0
0
0
1
1
0
1
0
0
1
0
1
0
1
0
0
1
1
1
0
1
0
1
0
0
1
0
1
0
1
0
1
1
0
1
0
1
1
0
1
0
1
0
1
1
1
1
0
1
1
0
0
0
1
0
1
1
0
0
1
1
0
1
1
0
1
0
1
0
1
1
0
1
1
1
0
1
1
1
0
0
1
0
1
1
1
0
1
1
0
1
1
1
1
0
1
0
1
1
1
1
1
1
1
0
0
0
0
0
1
1
0
0
0
0
1
1
1
0
0
0
1
0
1
1
0
0
0
1
1
1
1
0
0
1
0
0
1
1
0
0
1
0
1
1
1
0
0
1
1
0
1
1
0
0
1
1
1
1
1
0
1
0
0
0
1
1
0
1
0
0
1
1
1
0
1
0
1
0
1
1
0
1
0
1
1
1
1
0
1
1
0
0
1
1
0
1
1
0
1
1
1
0
1
1
1
0
1
1
0
1
1
1
1
1
1
1
0
0
0
0
1
1
1
0
0
0
1
1
1
1
0
0
1
0
1
1
1
0
0
1
1
1
1
1
0
1
0
0
1
1
1
0
1
0
1
1
1
1
0
1
1
0
1
1
1
0
1
1
1
To be continued
DS9403-01 April 2011
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9
RT9403
Table 2. DAC3 Serial Code Table
SVID6
SVID5
SVID4
SVID3
SVID2
SVID1
SVID0
Output Voltage ( V )
1.3750
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
1.3500
1.3250
1.3000
1.2750
1.2500
1.2250
1.2000
Note :
(1) VOUT = 1.2V to 1.375V and VOUT = 2.375V to 3.375V, Step = 25mV.
(2) VOUT = 1.375V to 2.375V, Step = 12.5mV.
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DS9403-01 April 2011
RT9403
Absolute Maximum Ratings (Note 1)
z Supply Voltage, VDD ------------------------------------------------------------------------------------------------------ 6.5V
z Input Voltage, SCL, SDA, S3/EN-------------------------------------------------------------------------------------- 6.5V
z Output Voltage, VOUT1, VOUT2, VOUT3 --------------------------------------------------------------------------------------------------------------------- 4V
z Power Dissipation, PD @ TA = 25°C
SOT-23-8 -------------------------------------------------------------------------------------------------------------------- 0.4W
z Package Thermal Resistance (Note 2)
SOT-23-8, θJA --------------------------------------------------------------------------------------------------------------- 250°C/W
z Junction Temperature ----------------------------------------------------------------------------------------------------- 150°C
z Lead Temperature (Soldering, 10 sec.)------------------------------------------------------------------------------- 260°C
z Storage Temperature Range -------------------------------------------------------------------------------------------- −65°C to 150°C
z ESD Susceptibility (Note 3)
HBM (Human Body Mode) ---------------------------------------------------------------------------------------------- 2kV
MM (Machine Mode) ------------------------------------------------------------------------------------------------------ 200V
Recommended Operating Conditions (Note 4)
z Supply Voltage, VDD ------------------------------------------------------------------------------------------------------ 5V 5%
z Junction Temperature Range-------------------------------------------------------------------------------------------- −40°C to 125°C
z Ambient Temperature Range-------------------------------------------------------------------------------------------- −40°C to 85°C
Electrical Characteristics
(VDD = 5V, TA = 25°C, unless otherwise specification)
Parameter
Symbol
VDD
Test Conditions
Min
Typ
Max
Unit
Supply Input Voltage
4.75
5
5.25
V
POR Threshold
VPOR_TH
VPOR_HYS
IVDD
4
--
--
4.25
250
4.4
--
V
POR Hysteresis
Supply Input Current
VREF & DAC
mV
mA
0.65
--
DAC Output Accuracy
Under−Voltage Lockout
Hysteresis
VOUT ≥ 1V, IOUT = 0A
−1
--
--
+1
%
VOUT < 1V, IOUT = 0A
−10
+10
mV
Output Buffer
DC Gain
Capacitive Load Only
CL = 1nF
--
70
1.64
11
--
--
--
--
--
dB
MHz
mV/μs
Ω
Bandwidth
GBW
SR
--
Slew Rate
CL = 0.1μF
--
Impedance
ROUT
IOUT
--
--
90
Output Driving Capability
Loading Effect Regulation
I2C Signal
1.1
--
mA
−0.002
0.002 %/μA
Input High Threshold
Input Low Threshold
SCL Clock Speed
EN High Threshold
EN Low Threshold
VIH
VIL
2.4
--
--
--
--
--
--
0.8
400
--
V
V
--
--
VDD − 0.3
--
k/bit/s
V
VEN_H
VEN_L
0.3
V
DS9403-01 April 2011
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11
RT9403
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. θJA is measured in the natural convection at TA = 25°C on a low effective single layer thermal conductivity test board of
JEDEC 51-3 thermal measurement standard.
Note 3. Devices are ESD sensitive. Handling precaution is recommended.
Note 4. The device is not guaranteed to function outside its operating conditions.
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DS9403-01 April 2011
RT9403
Typical Operating Characteristics
VOUT1 vs. Temperature
VOUT2 vs. Temperature
1.112
1.062
1.060
1.058
1.056
1.054
1.052
1.050
1.048
1.046
1.044
1.042
1.040
1.110
1.108
1.106
1.104
1.102
1.100
1.098
1.096
1.094
1.092
VDD = 5V, S3/EN = H, SDA = SCL = H
VDD = 5V. S3/EN = H, SDA = SCL = H
1.090
-50
-25
0
25
50
75
100
125
-50
-25
0
25
50
75
100
125
(°C)
Temperature
Temperature
(°C)
VOUT3 vs. Temperature
Star Up from VDD
1.514
1.512
1.510
1.508
1.506
1.504
1.502
1.500
1.498
1.496
1.494
1.492
VDD
(5V/Div)
VOUT1
(1V/Div)
VOUT2
(1V/Div)
VOUT3
(1V/Div)
COUT = 0.1μF
VDD = 5V, S3/EN = H, SDA = SCL = H
0 25 50 75 100 125
-50
-25
Time (40μs/Div)
Temperature (°C)
S3 State
Power Off from VDD
VDD
S3/EN
(5V/Div)
(5V/Div)
VOUT1
(1V/Div)
VOUT1
(1V/Div)
VOUT2
(1V/Div)
VOUT2
(1V/Div)
VOUT3
(1V/Div)
VOUT3
(1V/Div)
COUT = 0.1μF
COUT = 0.1μF, S3/EN = H to L
Time (4μs/Div)
Time (4μs/Div)
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13
RT9403
VOUT1 Ramp-Up by VID
VOUT1 Ramp-Down by VID
VOUT1
(1V/Div)
VOUT1
(1V/Div)
VOUT1 = 1 to 1.325V, COUT = 0.1μF
Time (10μs/Div)
VOUT1 = 1.325 to 1V, COUT = 0.1μF
Time (10μs/Div)
VOUT2 Ramp-Up by VID
VOUT2 Ramp-Down by VID
VOUT2
VOUT2
(1V/Div)
(1V/Div)
VOUT2 = 0.925 to 1.25V, COUT = 0.1μF
Time (10μs/Div)
VOUT2 = 1.25 to 0.925V, COUT = 0.1μF
Time (10μs/Div)
VOUT3 Ramp-Down by VID
VOUT3 Ramp-Up by VID
VOUT3
(1V/Div)
VOUT3
(1V/Div)
VOUT3 = 1.825 to 1.5V, COUT = 0.1μF
Time (10μs/Div)
VOUT3 = 1.5 to 1.825V, COUT = 0.1μF
Time (10μs/Div)
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DS9403-01 April 2011
RT9403
Applications Information
Output Capacitor
S3/EN Function
The output capacitance value determines the slew rate of
output voltage during voltage transition. For example, if
COUT = 0.1μF and the voltage step is 1.1V, the rising slew
rate can be calculated as the following.
The RT9403 can be enabled or set to S3 state by the
voltage of S3/ENpin. If the applied voltage of S3/ENpin is
greater than enable threshold, the RT9403 will be enabled
and all outputs ramp up to its own default preset voltage
(VOUT1 = 1.1V, VOUT2 = 1.05V, VOUT3 = 1.5V). Then the
RT9403 is available to decode the SCL and SDAinputs to
determine the programmed voltage for each output. Pulling
down this pin below the enable threshold will set the
RT9403 in S3 state. In the S3 state, both VOUT1 and VOUT2
will be turned off, only VOUT3 is active. If S3/ENgoes high
again, VOUT1 and VOUT2 will return to its previous active
level. Table 3 shows the S3/EN state and output status.
1.1×10−3
0.1×10−6
I
OUT
Slew Rate =
=
= 11mV/μs
C
OUT
For stability consideration, the recommended minimum
output capacitance is 10nF. This capacitor should be
located as close to the output pin as possible to minimize
the PCB trace parasitic inductance and resistance.
I2C Interface
The RT9403 receives and decodes the SCLand SDAinputs
from the master using the standard I2C 2-wire interface
to program each output voltage. SCL and SDA must be
pulled-up to typically 3.3V or 5V by external pull-up
resistors with value is between 10kΩ and 20kΩ. Figure 1
shows the data format of the RT9403. After the START
bit, the I2C master sends an address byte. This address
byte includes a 7-bits long address code followed by an
eighth bit which is a data direction bit (R/W).The RT9403's
address is 01100xx and is a write-only (slave) device.After
the address byte, the following 1st Data byte determines
which DAC's output voltage will be programmed. Then,
the 2ndData byte is written to set the target output voltage
of that selected DAC according to the VID table1 and
table2. After the STOP bit, the output voltage of the
selected DAC ramps up/down to the programmed target
level.
Table 3. S3/EN State and Output Status
S3/EN
VOUT1
VOUT2
VOUT3
H (Enable)
Active
Active
Active
L (S3 State)
OFF
OFF
Active
The 1st Data Byte
Address Byte
The 2nd Data Byte
E03
Stop
0
1
1
0
0
X
X
0
AC
K
0
0
0
X
X
X
G1 G0
ACK
X
E06E05 E04
E02 E01 E00
ACK
START
Fixed for Write
G1
G0
Rail to be Programmed
Note :
1. X = Don't Care
2. E [6:0] : Follow Serial Code Table
0
0
1
1
0
1
0
1
VOUT1
VOUT2
VOUT3
None
Figure 1. RT9403Data Transfer Format
DS9403-01 April 2011
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15
RT9403
Layout Considerations
Thermal Considerations
For best performance of the RT9403, the following layout
guideline should be strictly followed
For continuous operation, do not exceed absolute
maximum operation junction temperature. The maximum
power dissipation depends on the thermal resistance of
IC package, PCB layout, the rate of surroundings airflow
and temperature difference between junction to ambient.
The maximum power dissipation can be calculated by
following formula :
` The input capacitor should be placed as close to VDD
pin as possible.
` The output capacitor should be placed as close to VOUT
pin as possible.
Place the input and output capacitors
as close to the IC possible
PD(MAX) = (TJ(MAX) − TA ) / θJA
Where TJ(MAX) is the maximum operation junction
temperature, TA is the ambient temperature and the θJA
is the junction to ambient thermal resistance. For
recommended operating conditions specification of
RT9403, the maximum junction temperature is 125°C
and TA is the maximum ambient temperature. The junction
to ambient thermal resistance θJA is layout dependent.
For SOT-23-8 package, the thermal resistance θJA is
250°C/W on the standard JEDEC 51-3 single layer thermal
test board. The maximum power dissipation at TA = 25°C
can be calculated by following formula:
5V
GND
C
OUT3
1
2
3
4
8
7
S3/EN
VDD
GND
SCL
SDA
C
IN
VOUT3
VOUT2
VOUT1
C
OUT2
6
5
C
OUT1
3.3V5V
GND
Figure 3. PCB Layout Guide
PD(MAX) = (125°C − 25°C ) / (250°C/W) = 0.4W for
SOT-23-8 package
The maximum power dissipation depends on operating
ambient temperature for fixed TJ(MAX) and thermal resistance
θJA. For RT9403 package, the Figure 2 of derating curve
allows the designer to see the effect of rising ambient
temperature on the maximum power dissipation allowed.
0.50
Single Layer PCB
0.45
0.40
0.35
SOT-23-8
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
25
50
75
100
125
Ambient Temperature (°C)
Figure 2.Derating Curve for RT9403 Package
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16
DS9403-01 April 2011
RT9403
Outline Dimension
H
D
L
C
A
B
b
A1
e
Dimensions In Millimeters
Dimensions In Inches
Symbol
Min
Max
Min
Max
A
A1
B
1.000
0.000
1.500
0.220
2.600
2.800
0.585
0.100
0.300
1.450
0.150
1.700
0.500
3.000
3.000
0.715
0.220
0.600
0.039
0.000
0.059
0.009
0.102
0.110
0.023
0.004
0.012
0.057
0.006
0.067
0.020
0.118
0.118
0.028
0.009
0.024
b
C
D
e
H
L
SOT-23-8 Surface Mount Package
Richtek Technology Corporation
Headquarter
Richtek Technology Corporation
Taipei Office (Marketing)
5F, No. 20, Taiyuen Street, Chupei City
Hsinchu, Taiwan, R.O.C.
5F, No. 95, Minchiuan Road, Hsintien City
Taipei County, Taiwan, R.O.C.
Tel: (8863)5526789 Fax: (8863)5526611
Tel: (8862)86672399 Fax: (8862)86672377
Email: marketing@richtek.com
Information that is provided by Richtek Technology Corporation is believed to be accurate and reliable. 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.
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