Document
RT8869A
Advanced 2/1-Phase PWM Controller for CPU Core Power
General Description
The RT8869A is an advanced 2/1-phase synchronous buck controller with 2 integrated MOSFET drivers. It integrates an 8-bit DAC that supports Intel VR11.x CPUs power application.
The IC adopts state-of-the-art dynamic phase control capability by PS1 pin and achieves high efficiency over a wide load range. It uses lossless RDS(ON) current sensing to achieve phase current balance. Other features include adjustable operating frequency, adjustable soft-start, short circuit protection, adjustable over current protection, over voltage protection, under voltage protection, power good indication, VR_HOT indication and VR_SHDN indication.
The RT8869A is available in a small footprint with WQFN40L 5x5 package.
Ordering Information
RT8869A
Package Type QW : WQFN-40L 5x5 (W-Type)
Lead Plating System Z : ECO (Ecological Element with
Halogen Free and Pb free))
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.
Marking Information
RT8869A ZQW YMDNN
RT8869AZQW : Product Number YMDNN : Date Code
Features
z 12V Power Supply Voltage z 2/1-Phase Power Conversion z Integrated 2 MOSFET Drivers with Internal
Bootstrap Diode z Dynamic Phase Control Capability z 8-bit DAC Supports Intel VR11.x CPUs z Lossless RDS(ON) Current Sensing for Current Balance z Adjustable Frequency : 50kHz to 1MHz z Adjustable Over Current Protection z Adjustable Soft-Start z VR_RDY, VR_HOT and VR_SHDN Indications z Small 40-Lead WQFN Package z RoHS Compliant and Halogen Free
Applications
z Desktop CPU Core Power z Middle/High End Graphic Cards z Low Voltage, High Current DC/ DC Converters
Pin Configurations
(TOP VIEW)
FBRTN VID0 VID1 VID2 VID3 VID4 VID5 VID6 VID7 BOOT1
40 39 38 37 36 35 34 33 32 31
VRSEL 1
30
VR_RDY 2
29
SS 3
28
EN 4
27
DAC 5 EAP 6
GND
26 25
FB 7
24
COMP 8
CSP 9 CSN 10
41 23 22 21
11 12 13 14 15 16 17 18 19 20
UGATE1 PHASE1
LGATE1
VCC12A VCC12B LGATE2
PHASE2 UGATE2 BOOT2 VR_HOT
IMAX VR_SHDN
PS1 ISEN2 ISEN1
RT VCC5
TB VOUT
TM
WQFN-40L 5x5
DS8869A-00 May 2011
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DS8869A-00 May 2011
VSHDN
VVR_SHDN
PH1 PH2
VCC5 R18 R19
C1
C23
RT8869A
17 VCC5
IMAX 11
R2
VIN 4.5V to 13.2V
Q9
NTC2 R1
R20 R21
20 TM
CSN+ NTC1
RPS1
12 VR_SHDN 13 PS1
C17 R23 R30
R31
C5 R24
10 CSN
9 CSP
Chip Enable
VTT VVR_HOT
R17
4 EN 21 VR_HOT RRT 16 RT
VCC_SNS
R29
18 TB C26
R15 12V
27 VCC12A
C15
R16 26 VCC12B C16
41 (Exposed Pad) GND
BOOT1 31 UGATE1 30
PHASE1 29
R3 C2 R4
C3 Q1 L1
LGATE1 28 ISEN1 15 DAC 5
EAP 6
R5 R6
Q2 R38
R40
C7 CSN+
VID[7:0] 32 to 39
C4
VRSEL 1 VR_RDY 2
VVR_RDY
VIN 4.5V to 13.2V
VTT R35
BOOT2 22
R7 C5
C6
C29
UGATE2 23 PHASE2 24
R8
Q3 L2
LGATE2 25 ISEN2 14 VOUT 19 FB 7 COMP 8
FBRTN 40 SS 3
R9
Q4
R37
R41 C30
C8 CSN+
C9 R10 C10
R11 C11 R12
C33
C12
C13
C14
VCORE C34 LOAD
R13 R14
VCC_SNS VSS_SNS
RT8869A
Typical Application Circuit
RT8869A
Table 1. VR11.1 VID Code Table
VID7 VID6 VID5 VID4 VID3 VID2 VID1 VID0 Voltage
VID7 VID6 VID5 VID4 VID3 VID2 VID1 VID0 Voltage
0 0 0 0 0 0 0 0 OFF
0 0 1 0 0 0 1 1 1.39375
0 0 0 0 0 0 0 1 OFF
0 0 1 0 0 1 0 0 1.38750
0 0 0 0 0 0 1 0 1.60000
0 0 1 0 0 1 0 1 1.38125
0 0 0 0 0 0 1 1 1.59375
0 0 1 0 0 1 1 0 1.37500
0 0 0 0 0 1 0 0 1.58750
0 0 1 0 0 1 1 1 1.36875
0 0 0 0 0 1 0 1 1.58125
0 0 1 0 1 0 0 0 1.36250
0 0 0 0 0 1 1 0 1.57500
0 0 1 0 1 0 0 1 1.35625
0 0 0 0 0 1 1 1 1.56875
0 0 1 0 1 0 1 0 1.35000
0 0 0 0 1 0 0 0 1.56250
0 0 1 0 1 0 1 1 1.34375
0 0 0 0 1 0 0 1 1.55625
0 0 1 0 1 1 0 0 1.33750
0 0 0 0 1 0 1 0 1.55000
0 0 1 0 1 1 0 1 1.33125
0 0 0 0 1 0 1 1 1.54375
0 0 1 0 1 1 1 0 1.32500
0 0 0 0 1 1 0 0 1.53750
0 0 1 0 1 1 1 1 1.31875
0 0 0 0 1 1 0 1 1.53125
0 0 1 1 0 0 0 0 1.31250
0 0 0 0 1 1 1 0 1.52500
0 0 1 1 0 0 0 1 1.30625
0 0 0 0 1 1 1 1 1.51875
0 0 1 1 0 0 1 0 1.30000
0 0 0 1 0 0 0 0 1.51250
0 0 1 1 0 0 1 1 1.29375
0 0 0 1 0 0 0 1 1.50625
0 0 1 1 0 1 0 0 1.28750
0 0 0 1 0 0 1 0 1.50000
0 0 1 1 0 1 0 1 1.28125
0 0 0 1 0 0 1 1 1.49375
0 0 1 1 0 1 1 0 1.27500
0 0 0 1 0 1 0 0 1.48750
0 0 1 1 0 1 1 1 1.26875
0 0 0 1 0 1 0 1 1.48125
0 0 1 1 1 0 0 0 1.26250
0 0 0 1 0 1 1 0 1.47500
0 0 1 1 1 0 0 1 1.25625
0 0 0 1 0 1 1 1 1.46875
0 0 1 1 1 0 1 0 1.25000
0 0 0 1 1 0 0 0 1.46250
0 0 1 1 1 0 1 1 1.24375
0 0 0 1 1 0 0 1 1.45625
0 0 1 1 1 1 0 0 1.23750
0 0 0 1 1 0 1 0 1.45000
0 0 1 1 1 1 0 1 1.23125
0 0 0 1 1 0 1 1 1.44375
0 0 1 1 1 1 1 0 1.22500
0 0 0 1 1 1 0 0 1.43750
0 0 1 1 1 1 1 1 1.21875
0 0 0 1 1 1 0 1 1.43125
0 1 0 0 0 0 0 0 1.21250
0 0 0 1 1 1 1 0 1.42500
0 1 0 0 0 0 0 1 1.20625
0 0 0 1 1 1 1 1 1.41875
0 1 0 0 0 0 1 0 1.20000
0 0 1 0 0 0 0 0 1.41250
0 1 0 0 0 0 1 1 1.19375
0 0 1 0 0 0 0 1 1.40625
0 1 0 0 0 1 0 0 1.18750
0 0 1 0 0 0 1 0 1.40000
0 1 0 0 0 1 0 1 1.18125
DS8869A-00 May 2011
To be continued
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