IR3523MTRPBF International Rectifier, IR3523MTRPBF Datasheet - Page 16

• Manufacturer Part Number: IR3523MTRPBF
• Description: IC XPHASE3 CTLR VR11.1 40-MLPQ
• Manufacturer: International Rectifier
• Series: XPhase3™r

Specifications of IR3523MTRPBF

• Applications: Processor
• Current - Supply: 10mA
• Voltage - Supply: 4.75 V ~ 7.5 V
• Operating Temperature: 0°C ~ 100°C
• Mounting Type: Surface Mount
• Package / Case: 40-MLPQ
• Ic Function: Dual Output Control IC
• Supply Voltage Range: 4.75V To 7.5V
• Operating Temperature Range: 0°C To +150°C
• Digital Ic Case Style: MLPQ
• No. Of Pins: 40
• Controller Type: XPhase
• Rohs Compliant: Yes
• Package: 40-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

Output 1 (Vtt) Adaptive Voltage Positioning
Adaptive Voltage Positioning is needed to reduce the output voltage deviations during load transients and the power
dissipation of the load at heavy load. IR3523 only provides AVP on output1. The circuitry related to the voltage
positioning is shown in Figure 9. Resistor R
and the remote sense differential amplifier output. An internal current source whose value is programmed by the
same external resistor that programs the oscillator frequency sinks current from the FB1 pin. The error amplifier
forces the converter’s output voltage higher to maintain a balance at its inputs. R
desired amount of fixed offset voltage above the DAC voltage.
The VDRP1 pin voltage is a buffered reproduction of the IIN1 pin which is connected to the current share bus
ISHARE. The voltage on ISHARE represents the system average inductor current information. At each phase IC, an
RC network across the inductor provides current information which is gained up 32.5X and then added to the
VDAC
The VDRP1 pin is connected to the FB1 pin through the resistor R
to maintain FB1 to be equal to the VDAC1 reference voltage, an additional current will flow into the FB1 pin equal to
(VDRP1-VDAC1) / R
More current flows through the feedback resistor R
current. The positioning voltage can be programmed by the resistor R
the desired converter output impedance. The offset and slope of the converter output impedance are referenced to
VDAC1 and therefore independent of the VDAC1 voltage.
X
voltage. This phase current information is provided on the ISHARE bus via a 3K resistor in the phase ICs.
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Remote
Sense
Amplifier
IFB
Control IC
DRP1
VDAC1
. When the load current increases, the adaptive positioning voltage increases accordingly.
VDRP
Amplifier
Error
Amplifier
+
-
-
+
+
-
VDAC1
EAOUT1
VDRP1
IIN1
VOUT1
VOSEN1+
VOSEN1-
FB1
Figure 9 - Adaptive voltage positioning
FB1
RDRP1
RFB1
is connected between the error amplifier’s inverting input pin FB1
FB1
, and makes the output voltage lower proportional to the load
ISHARE
ISHARE
VDAC
VDAC
DRP1
Phase IC
Phase IC
3k
3k
DRP1
. Since the error amplifier will force the loop
so that the droop impedance produces
Current Sense
Amplifier
Current Sense
Amplifier
FB1
+
-
+
-
is selected to program the
June 20, 2008
CSIN+
CSIN-
CSIN+
CSIN-
IR3523