RT9247 Datasheet, PDF (1/15 Pages) Richtek Technology Corporation – Multi-Phase PWM Controller for CPU Core Power Supply

Preliminary
RT9247
Multi-Phase PWM Controller for CPU Core Power Supply
General Description
The RT9247 is a multi-phase buck DC/DC controller
integrated with all control functions for GHz CPU VRM.
The RT9247 controls 2 or 3 buck switching stages operating
in interleaved phase set automatically. The multi-phase
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.
RT9247 controls both voltage and current loops to achieve
good regulation, response & power stage thermal balance.
Precise current loop using R_DS(ON) as sense component
builds precise load line for strict VRM DC & transient
specification and also ensures thermal balance of different
power stages. The settings of current sense, droop tuning,
V_CORE initial offset and over current protection are
independent to compensation circuit of voltage loop. The
feature greatly facilitates the flexibility of CPU power supply
design and tuning.
The DAC output of RT9247 supports VRD10 by 6-bit VID
input, precise initial value & smooth V_CORE transient at
VID 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.
Ordering Information
RT9247
Package Type
C : TSSOP-28
Operating Temperature Range
P : Pb Free with Commercial Standard
G : Green (Halogen Free with Commer-
cial Standard)
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.
DS9247-05 March 2007
Features
z Multi-Phase Power Conversion with Automatic
Phase Selection
z VRD10 DAC Output with Active Droop Compensation
for Fast Load Transient
z Smooth V_CORE Transition at VID Jump
z Power Stage Thermal Balance by R_DS(ON) Current
Sense
z Hiccup Mode Over-Current Protection
z Programmable Switching Frequency (50kHz to
400kHz per Phase), Under-Voltage Lockout and
Soft-Start
z High Ripple Frequency Times Channel Number
z RoHS Compliant and 100% Lead (Pb)-Free
Applications
z Intel^® Processors Voltage Regulator: VRD10
z Low Output Voltage, High Current DC-DC Converters
z Voltage Regulator Modules
Pin Configurations
VID4
VID3
VID2
VID1
VID0
VID125
SGND
FB
COMP
PGOOD
DVD
SS
RT
VOSS
(TOP VIEW)
28
2
27
3
26
4
25
5
24
6
23
7
22
8
21
9
20
10
19
11
18
12
17
13
16
14
15
TSSOP-28
VCC
PWM1
PWM2
PWM3
ISN1
ISP1
ISP2
ISP3
ISN23
GND
ADJ
VDIF
VSEN
IMAX
www.richtek.com
1