Datasheet LTM4657 (Analog Devices) - 6

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PIN FUNCTIONS PACKAGE ROW AND COLUMN LABELING MAY VARY PHMODE (G5):
Control Input to the Phase Selector of the
AMONG µModule PRODUCTS. REVIEW EACH PACKAGE
Switching Mode Regulator. Determines the phase rela-
LAYOUT CAREFULLY.
tionship between internal oscillator and CLKOUT. Tie it to
VOUT (A1-A5, F3, G1-G3):
Power Output Pins of the INTV Switching Mode Regulator. Apply output load between CC for 2-phase operation, tie it to GND for 3-phase operation, and tie it to INTV these pins and GND pins. Recommend placing output CC/2 for 4-phase operation. See Application Information section for details. decoupling capacitance directly between these pins and GND pins. See the Applications Information section for
TRACK/SS (E2):
Output Tracking and Soft-Start Pin of the paralleling outputs. Switching Mode Regulator. Allows the user to control the rise time of the output voltage. Putting a voltage below
COMPb (F1):
Internal Loop Compensation Network. 0.5V on this pin bypasses the internal reference input Connect to COMPa to use the internal compensation in to the error amplifier, instead it servos the FB pin to the majority of applications. TRACK voltage. Above 0.5V, the tracking function stops
FREQ (E1):
Switching Frequency Program Pin. Frequency and the internal reference resumes control of the error is set internally to 500kHz. An external resistor can be amplifier. There’s an internal 6µA pull-up current from placed from this pin to GND to increase frequency, or from INTVCC on this pin, so putting a capacitor here provides this pin to INTVCC to reduce frequency. See the Applications soft-start function. See the Applications Information sec- Information section for frequency adjustment. tion for details.
COMPa (D1):
Current control threshold and error ampli-
MODE/CLKIN (D2):
Discontinuous Mode Select Pin and fier compensation point of the switching mode regulator External Synchronization Input to Phase Detector. Tie channel. The internal current comparator threshold is MODE/CLKIN to GND for discontinuous mode of opera- linearly proportional to this voltage. Tie the COMPa pins tion. Floating MODE/CLKIN or tying it to a voltage above from different channels together for parallel operation. 1V will select forced continuous mode. Furthermore, con- The device is internal compensated. Connect to COMPb necting MODE/CLKIN to an external clock will synchronize to use the internal compensation. Or connect to a Type-II the system clock to the external clock and puts the part C-R-C network to use customized compensation. in forced continuous mode. See Applications Information
FB (C1):
The Negative Input of the Error Amplifier for section for details. the switching mode regulator. This pin is internally con-
V – OSNS (C2):
Negative Input to the Differential Remote nected to V + OSNS with a 60.4kΩ precision resistor. Output Sense Amplifier. Connect an external resistor between FB voltages can be programmed with an additional resistor and V – OSNS pin to set the output voltage of the specific between FB and V – OSNS pins. In PolyPhase® operation, channel. See the Applications Information section for tying the FB pins together allows for parallel operation. details. See the Applications Information section for details.
CLKOUT (F2):
Output Clock Signal for PolyPhase
V + OSNS (B1):
Positive Input to the Differential Remote Operation. The phase of CLKOUT with respect to CLKIN Sense Amplifier. Internally, this pin is connected to FB is determined by the state of the respective PHMODE pin. with a 60.4k 0.5% precision resistor. See the Applications CLKOUT’s peak-to-peak amplitude is INTVCC to GND. See Information section for details. Application Information section for details. Rev 0 6 For more information www.analog.com Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Order Information Electrical Characteristics Pin Configuration Typical Performance Characteristics Pin Functions Block Diagram Decoupling Requirements Operation Applications Information Package Description Package Photo Design Resources Related Parts