L6756D STMicroelectronics, L6756D Datasheet - Page 29

• Manufacturer Part Number: L6756D
• Description: IC CTLR 2/3/4PH BUCK 40-VFQFPN
• Manufacturer: STMicroelectronics

Specifications of L6756D

• Applications: Controller, Intel VR10, VR11, VR11.1
• Voltage - Input: 12V
• Number Of Outputs: 4
• Voltage - Output: 0.3 ~ 1.6 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 40-VFQFN, 40-VFQFPN
• Output Voltage: 3 V
• Input Voltage: - 0.3 V to + 15 V
• Switching Frequency: 185 KHz to 215 KHz
• Operating Temperature Range: - 40 C to + 150 C
• Mounting Style: SMD/SMT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

L6756D
8
Main oscillator
The internal oscillator generates the triangular waveform for the PWM charging and
discharging with a constant current an internal capacitor. The switching frequency for each
channel, F
side results in being multiplied by N (number of configured phases).
The current delivered to the oscillator may be varied using an external resistor (R
typically connected between the OSC pin and SGND. Since the OSC pin is fixed at 1.24 V,
the frequency is varied proportionally to the current sunk from the pin considering the
internal gain of 10 kHz/μA (See
Connecting R
according to the following relationships:
Figure 13. R
F
SW
=
200kHz
SW
, is internally fixed at 200 kHz: the resulting switching frequency at the load
OSC
OSC
+
--------------------------- - 10
R
to SGND the frequency is increased (current is sunk from the pin),
1.240V
OSC
vs. switching frequency per phase
(
kΩ
)
⋅
kHz
---------- -
μA
Figure
13).
Main oscillator
OSC
)
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