RT9248A Datasheet, PDF (1/14 Pages) Richtek Technology Corporation – Multi-Phase PWM Controller for CPU Core Power Supply

Preliminary
RT9248A
Multi-Phase PWM Controller for CPU Core Power Supply
General Description
The RT9248A is a cost-effective multi-phase buck DC/DC
controller integrated with all control functions for GHz CPU
VRM. The RT9248A 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.
RT9248A 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 RT9248A supports VRM9 & VRD10 by
VID125 multi-level input, precise initial 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 micro-
processor and power system.
Ordering Information
RT9248A
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.
DS9248A-06 March 2006
Features
z Multi-Phase Power Conversion with Automatic
Phase Selection
z VRM9 & VRD10 DAC Output with Active Droop
Compensation for Fast Load Transient
z Smooth V_CORE Transition at VID Jump
z Multi-Level VID125 Input for VRM9 & VRD10
Selection
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: VRM9 and 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
NC
ISP1
ISP2
ISP3
ISN
GND
ADJ
VDIF
VSEN
IMAX
www.richtek.com
1