IR3621 Datasheet, PDF (1/29 Pages) International Rectifier – 2-PHASE / DUAL SYNCHRONOUS PWM CONTROLLER WITH OSCILLATOR SYNCHRONIZATION AND PRE-BIAS STARTUP

Data Sheet No.PD60231 revA
IR3621 & (PbF)
2-PHASE / DUAL SYNCHRONOUS PWM CONTROLLER WITH
OSCILLATOR SYNCHRONIZATION AND PRE-BIAS STARTUP
FEATURES
Dual Synchronous Controller with 180!
Out of Phase Operation
Configurable to 2-Independent Outputs or
Current Share Single Output
Voltage Mode Control
Current Sharing Using Inductor's DCR
Selectable Hiccup or Latched Current
Limit using MOSFET's R_DS(on) sensing
Latched Over-Voltage Protection
Pre-Bias Start Up
Programmable Switching Frequency up to 500KHz
Two Independent Soft-Starts/Shutdowns
Precision Reference Voltage 0.8V
Power Good Output
External Frequency Synchronization
Thermal Protection
APPLICATIONS
Embedded Networking & Telecom Systems
Distributed Point-of-Load Power Architectures
2-Phase Power Supply
Graphics Card
DDR Memory Applications
DESCRIPTION
The IR3621 IC combines a dual synchronous buck control-
ler and drivers, providing a cost-effective, high performance
and flexible solution. The IR3621 operates in 2-Phase mode
to produce either 2-independent output voltages or current
share single output for high current application. The 180!
out-of-phase operation allows the reduction of input and
output capacitance.
Other key features include two independently programmable
soft-start functions to allow system level sequencing of out-
put voltages in various configurations. The pre-bias protec-
tion feature prevents the discharge of the output voltage and
possible damage to the load during start-up when a pre-
existing voltage is present at the output. Programmable
switching frequency up to 500KHz per phase allows flexibil-
ity to tune the operation of the IC to meet system level re-
quirements, and synchronization allows the simplification
of system level filter design. Protection features such as
selectable hiccup or latched current limit, and under voltage
lock-out are provided to give required system level security
in the event of a fault condition.
Vin
Vin
Rt
Comp1
HDrv1
OCSet1
LDrv1
PGnd1
Comp2 ^IR3621
Vin
SS1 / SD
SS2 / SD
Gnd
HDrv2
OCSet2
LDrv2
PGnd2
Rt
Comp1
HDrv1
OCSet1
LDrv1
PGnd1
Vout
Comp2 ^IR3621
Vin
SS1 / SD
SS2 / SD
Gnd
HDrv2
OCSet2
LDrv2
PGnd2
Vout1
Vout2
Current share, single output configuration
2-independent output voltage configuration
Figure 1 - Typical application of IR3621 in current share single output and 2-independent output voltage configuration
PKG
DESIG
M
M
F
F
ORDERING INFORMATION
PART
NUMBER
IR3621M
IR3621MTR
IR3621F
IR3621FTR
LEADFREE
PART NUMBER
IR3621MPbF
IR3621MTRPbF
N/A
N/A
PIN
COUNT
32
32
28
28
PARTS
PER TUBE
73
------
50
------
PARTS
PER REEL
------
6000
------
2500
T&R
Orientation
Fig A
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