RT9245B Datasheet, PDF (1/23 Pages) Richtek Technology Corporation – Multi-Phase PWM Controller for K8 CPU Core Power Supply

RT9245B
Multi-Phase PWM Controller for K8 CPU Core Power Supply
General Description
RT9245B is a multi-phase buck DC/DC controller
integrated with all control functions for AMD K8 CPU. The
RT9245B could be operated with 2, 3 or 4 buck switching
stages operating in interleaved phase set automatically.
The multiphase architecture provides high output current
while maintaining low power dissipation on power devices
and low stress on input and output capacitors. The high
equivalent operating frequency also reduces the
component dimension and the output voltage ripple in load
transient.
RT9245B implements both voltage and current loops to
achieve good regulation, response and power stage
thermal balance.
RT9245B applies the DCR sensing technology newly. The
RT9245B extracts the ESR of output inductor as sense
component to deliver a precise load line regulation and
good thermal balance for next generation processor
application.
Current sense setting, droop tuning, V_CORE initial offset
and ov er current protection are independent on
compensation circuit of voltage loop. The feature greatly
facilitates the flexibility of CPU power supply design and
tuning. The DAC output of RT9245B supports AMD K8
6-bit VID, precise offset value & smooth V_CORE transient
at V_ID jump. The IC monitors the V_CORE voltage for PGOOD
and over-voltage protection. Soft-start, over-current
protection and programmable under-voltage lockout are
also provided to assure the safety of microprocessor and
power system. The RT9245B comes to a small footprint
package TSSOP-28.
Ordering Information
RT9245B
Package Type
C : TSSOP-28
Operating Temperature Range
P : Pb Free with Commercial Standard
G : Green (Halogen Free with Commer-
cial Standard)
Features
l Multi-Phase Power Conversion with Automatic
Phase Selection
l 6-bit AMD K8 M2 DAC Output with Active Droop
Compensation for Fast Load Transient
l Smooth V_CORE Transition at VID Jump
l Power Stage Thermal Balance by DCR Current
Sense
l Hiccup Mode Over-Current Protection
l Programmable Switching Frequency (50kHz to
400kHz per Phase), Under-Voltage Lockout and Soft-
Start
l High Ripple Frequency Times Channel Number
l 28-TSSOP Package
l RoHS Compliant and 100% Lead (Pb)-Free
Applications
l AMD K8 Processors Voltage Regulator
l Low Output Voltage, High Current DC-DC Converters
l Voltage Regulator Modules
Pin Configurations
(TOP VIEW)
VID4
VID3
2
VID2
3
VID1
4
VID0
5
VID5
6
SGND
7
FB
8
COMP
9
PGOOD
10
DVD
11
SS
12
RT
13
VOSS
14
28
VCC
27
PWM1
26
PWM2
25
PWM3
24
PWM4
23
CSP4
22
CSP2
21
CSP3
20
CSP1
19
GND
18
ADJ
17
IOUT
16
CSN
15
IMAX
TSSOP-28
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.
DS9245B-02 March 2007
www.richtek.com
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