RT9246A Datasheet, PDF (1/16 Pages) Richtek Technology Corporation – Multi-Phase PWM Controller for CPU Core Power Supply

RT9246A
Multi-Phase PWM Controller for CPU Core Power Supply
General Description
The RT9246A is a multi-phase buck DC/DC controller
integrated with all control functions for GHz CPU VRM.
The RT9246A 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.
RT9246A controls both voltage and current loops to achieve
good regulation, response & power stage thermal balance.
Precise current loop using Inductor DCR 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 RT9246A supports K8 CPU by 5-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
RT9246A
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.
DS9246A-04 March 2007
Features
z Multi-Phase Power Conversion with Automatic
Phase Selection
z K8 DAC Output with Active Droop Compensation
for Fast Load Transient
z Smooth V_CORE Transition at VID Jump
z Power Stage Thermal Balance by Inductor DCR
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 AMD^® Athlon^TM 64 and Opteron^TM Processors Voltage
Regulator
z Low Output Voltage, High Current DC-DC Converters
z Voltage Regulator Modules
Pin Configurations
(TOP VIEW)
VID4
VID3
VID2
VID1
VID0
NC
FBRTN
FB
COMP
PGOOD
DVD
SS
RT
VOSS
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
NC
GND
ADJ
IOUT
ICOMMON
IMAX
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