IR3503MTRPBF International Rectifier, IR3503MTRPBF Datasheet - Page 23

• Manufacturer Part Number: IR3503MTRPBF
• Description: IC CTRL XPHASE VR11.0/1 32-MLPQ
• Manufacturer: International Rectifier
• Series: XPhase3™r

Specifications of IR3503MTRPBF

• Applications: Processor
• Current - Supply: 8mA
• Voltage - Supply: 4.75 V ~ 7.5 V
• Operating Temperature: 0°C ~ 100°C
• Mounting Type: Surface Mount
• Package / Case: *
• Package: 32-Lead MLPQ
• Circuit: X-Phase Control IC
• Switch Freq (khz): 250kHz to 1.5MHz
• Pbf: PbF Option Available
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: IR3503MTRPBFTR

output low and inhibiting switching in the phase ICs and de-asserting the VRRDY signal. The output current is not
controlled during the delay time. The SS/DEL capacitor will discharge until it reaches 200 mV and the fault latch is
reset allowing a normal soft.
VCCL Under Voltage Lockout (UVLO)
The IR3503 has no under voltage lockout for converter input voltage (VCC), but monitors the VCCL voltage instead,
which is used for the gate drivers of phase ICs and circuits in control IC and phase ICs. During power up, the fault
latch will be reset if VCCL is above 4.2 V. If VCCL voltage drops below 3.8 V, the fault latch will be set.
Over Voltage Protection (OVP)
Output over-voltage happens during normal operation if a high side MOSFET short occurs or if output voltage is out of
regulation. The over-voltage protection comparator monitors VO pin voltage. If VO pin voltage exceeds VDAC by
130mV after SS, as shown in Figure 15, IR3503 raises ROSC/OVP pin voltage above to V (VCCL) - 1V, which sends
over voltage signal to system. The ROSC/OVP pin can also be connected to a thyristor in a crowbar circuit, which
pulls the converter input low in over voltage conditions. The over voltage condition also sets the over voltage fault
latch, which pulls error amplifier output low to turn off the converter output. At the same time IIN pin (IIN of phase ICs)
is pulled up to VCCL to communicate the over voltage condition to phase ICs, as shown in Figure 15. In each phase
IC, the OVP circuit overrides the normal PWM operation and will fully turn-on the low side MOSFET within
approximately 150ns. The low side MOSFET will remain on until IIN pin voltage drops below V(VCCL) - 800mV, which
signals the end of over voltage condition. An over voltage fault condition is latched in the IR3503 and can only be
cleared by recycling VCCL or ENABLE.
OCP THRESHOLD
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INTERNAL
OC DELAY
ENABLE
SS/DEL
VRRDY
IOUT
EA
VOUT
3.92V
3.88V
4.0V
1.1V
Figure 14: Constant over-current protection during and after soft-start
START-UP WITH
OUTPUT SHORTED
HICCUP OVER-CURRENT
PROTECTION (OUTPUT
SHORTED)
NORMAL
START-UP
NORMAL
OPERATION
(OUTPUT
SHORTED)
OCP
DELAY
OVER-CURRENT
PROTECTION
(OUTPUT SHORTED)
NORMAL
START-UP
February 12, 2010
NORMAL
OPERATION
IR3503
POWER-DOWN