RT9641B

Manufacturer Part NumberRT9641B
ManufacturerRichtek Technology Corporation
RT9641B datasheet
 
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General Description
The RT9641A/B, paired with either the RT9230 or RT9231
simplifies the implementation of ACPI-compliant designs
in microprocessor and computer applications. The IC
integrates two linear controllers and a low-current pass
transistor, as well as the monitoring and control functions
into a 16-pin SOIC package. One linear controller generates
the 3.3V
voltage plane from an ATX power supply's
DUAL
5VSB output during sleep states (S3,S4/S5), powering
the PCI slots through an external pass transistor, as
instructed by the status of the 3.3V
additional pass transistor is used to switch in the ATX
3.3V output for PCI operation during S0 and S1 (active)
operating states. The second linear controller supplies
the computer system's 2.5V/3.3V memory power through
an external pass transistor in active states. During S3
state, an integrated pass transistor supplies the 2.5V/
3.3V sleep-state power. A third controller powers up a
5V
plane by switching in the ATX 5V output in active
DUAL
states, or the ATX 5VSB in sleep states.
The RT9641A/B's operating mode (active-state outputs
or sleep-state outputs) is selectable through two control
pins: S3 and S5 Further control of the logic governing
activation of different power modes is offered through two
enabling pins: EN3VDL and EN5VDL. In active states, the
3.3V
linear regulator uses an external N-channel pass
DUAL
MOSFET to connect the output (V
3.3V input supplied by an ATX (or equivalent) power supply,
while incurring minimal losses. In sleep state, the 3.3V
output is supplied from the ATX 5VSB through a NPN
transistor, also external to the controller. Active state power
delivery for the 2.5V/3.3V or 2.6V/3.43V V
done through an external NPN or a NMOS transistor. In
sleep states, conduction on this output is transferred to
an internal pass transistor. The 5V
through two external MOS transistors. In sleep states, a
PMOS (or PNP) transistor conducts the current from the
ATX 5VSB output, while in active states, current flow is
transferred to a NMOS transistor connected to the ATX
5V output. Similar to the 3.3V
DUAL
of the 5V
output is dictated not only by the status of
DUAL
the S3 and S5 pins, but that of the EN5VDL pin as well.
DS9641A/B-03 August 2003
Triple Linear Regulator Controller Support
Features
Provides 3 ACPI-Controlled Voltages
Simple Control Design
Excellent Output Voltage Accuracy
enable pin. An
DUAL
Fixed Output Voltages Require No Precision
External Resistors
Small Size
Selectable 2.5V/3.3V (2.6/3.43) V
via FAULT/MSEL Pin
Under-voltage Monitoring of All Outputs with
Centralized FAULT Reporting
Adjustable Soft-start Function Eliminates
5VSBPerturbations
) directly to the
Ordering Information
OUT1
RT9641A/B
DUAL
output is
MEM
output is powered
DUAL
output, the operation
1
RT9641A/B
ACPI Control Interface
5V Active/Sleep(5V
)
DUAL
3.3V Active/Sleep(3.3V
)
DUAL
2.5V/3.3V Active/Sleep(V
) with RT9641A
MEM
2V/3.43V Active and 2.5V/3.3V Sleep(V
RT9641B
No Compensation Required
3.3V
Output : ±2.0% ; Sleep States Only
DUAL
2.5V/3.3V (2.6V/3.43V) Output :
Operational States
Small External Component Count
2.5V/2.6V for RDRAM Memory
3.3V/3.43V for SDRAM Memory
Package Type
S : SOP-16
Operating Temperature Range
C : Commercial Standard
V
Voltage
MEM
A : 2.5V/3.3V
B : 2.6V/3.43V
) with
MEM
2.0% ; Both
Output Voltage
MEM

RT9641B Summary of contents