RT9245
Multi-Phase PWM Controller for CPU Core Power Supply
General Description
RT9245 is a multi-phase buck DC/DC controller integrated
with all control functions for Intel
®
GHz CPU which is
VRD10.X-compliant. The RT9245 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.
RT9245 implements both voltage and current loops to
achieve good regulation, response and power stage
thermal balance.
RT9245 applies the DCR sensing technology newly. The
RT9245 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 over 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 RT9245 supports VRD10.x with
6-bit V
ID
input, 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 RT9245 comes to a small footprint
package TSSOP-28.
Features
Multi-Phase Power Conversion with Automatic
Phase Selection
6-bits VRD10.x DAC Output with Active Droop
Compensation for Fast Load Transient
Smooth V
CORE
Transition at VID Jump
Power Stage Thermal Balance by DCR Current
Sense
Hiccup Mode Over-Current Protection
Programmable Switching Frequency (50kHz to
400kHz per Phase), Under-Voltage Lockout and Soft-
Start
High Ripple Frequency Times Channel Number
28-TSSOP Package
RoHS Compliant and 100% Lead (Pb)-Free
Applications
Intel
®
Processors Voltage Regulator : VRD10.x
Low Output Voltage, High Current DC-DC Converters
Voltage Regulator Modules
Pin Configurations
(TOP VIEW)
VID4
VID3
VID2
VID1
VID0
VID125
SGND
FB
COMP
PGOOD
DVD
SS
RT
VOSS
2
3
4
5
6
7
8
9
10
11
12
13
14
28
27
26
25
24
23
22
21
20
19
18
17
16
15
VCC
PWM1
PWM2
PWM3
PWM4
CSP4
CSP2
CSP3
CSP1
GND
ADJ
NC
CSN
IMAX
Ordering Information
RT9245
Package Type
C : TSSOP-28
Operating Temperature Range
P : Pb Free with Commercial Standard
G : Green (Halogen Free with Commer-
cial Standard)
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.
DS9245-06 March 2007
www.richtek.com
1
RICHTEK [ RICHTEK TECHNOLOGY CORPORATION ]
