Datasheet LTM4647 (Analog Devices) - 7

LTM4647
PIN FUNCTIONS PACKAGE ROW AND COLUMN LABELING MAY VARY
external supply 4.5V or above through a 2.2Ω plus 1µF
AMONG µModule PRODUCTS. REVIEW EACH PACKAGE
R-C filter. See the Application Information section.
LAYOUT CAREFULLY. INTV V CC (C6):
Internal 5.5V LDO for driving the control
IN (A1-A3, B1-B2, C1-C2):
Power Input Pins. Apply input circuitry decouple with pin to GND with a minimum of voltage between these pins and GND pins. Recommend 2.2µF low ESR ceramic capacitor. The 5.5V LDO has a placing input decoupling capacitance directly between VIN 10mA current limit. pins and GND pins.
PHASMD (C7):
This pin determines the relative phases
GND (A4, A7, B3, C3, C4, D1-D4, E2-E4, F2, F4, F6, G1-
between the internal controllers and the phasing of the
G4, H1-H5, J5-J7, K5-K7):
Ground Pins for Both Input CLKOUT signal. See Table 2 in the Application Informa- and Output Returns. All ground pins need to connect with tion section. large copper areas underneath the unit.
FREQ (D7):
Frequency Set Pin. A 20µA current is sourced
RUN (A6):
Run Control Pin. A voltage above 1.35V will from this pin. A resistor from this pin to ground sets a turn on the module. This is a 1µA pull-up current on this voltage that in turn programs the operating frequency. pin. Once the RUN pin rises above the 1.35V threshold Alternatively, this pin can be driven with a DC voltage the pull-up current increases to 5µA. that can set the operating frequency. See the Applications
PWM (B4):
Control PWM Three-State Output Signal. For Information section. monitor and test purpose only. Do not drive this pin.
HIZB (E5):
Phase Shedding Input Pin. When this pin is low,
CLKOUT (B5):
Clock output with phase control using the TRACK/SS, COMP and PWM pin go to high impedance. PHASMD pin to enable multiphase operation between Tie to INTVCC or VIN to disable this function. devices. See the Applications Information section.
VFB (E6):
The Negative Input of the Error Amplifier. Inter-
TEST1, TEST2, TEST3 (B6, D5, F7):
These pins are for nally, this pin is connected to V + OSNS with a 60.4k 0.5% µModule initial test purposes. Please connect these pins precision resistor. Different output voltages can be pro- to GND with a large GND copper area. grammed with an additional resistor between VFB and V – pins. In PolyPhase® operation, tying the V
MODE/PLLIN (B7):
Mode Selection Pin and External SNS FB pins together allows for parallel operation. See the Applications Synchronization Pin. Connect this pin to SGND to force Information section for details. the module into force continuous current mode (CCM) of operation. Connect to INTVCC to enable pulse-skipping
SGND (E7):
Signal Ground Pin. Return ground path for all mode of operation. Leaving the pin floating will enable analog and low power circuitry. Tie a single connection Burst Mode operation. A clock on the pin will force the to the output capacitor GND in the application. See layout module into continuous current mode of operation and guidelines in Figure 22. synchronized to the external clock applied to this pin. See
SW (F3):
Switching node of the circuit is used for testing the Applications Information section. purposes. Also an R-C snubber network can be applied
SVIN (D6):
Signal VIN. Input voltage to the internal 5.5V to reduce or eliminate switch node ringing, or otherwise regulator for the control circuitry of the regulator. Tie this leave floating. See the Applications Information section. pin to VIN pin through a 2.2Ω plus 1µF R-C filter in most
TRACK/SS (F5):
Output Voltage Tracking Pin and Soft-Start application. See the Application Information section. Inputs. The pin has a 1.25µA pull-up current. A capacitor
DRVCC (C5):
Power Input Pin for the MOSFET driver cir- from this pin to ground will set a soft-start ramp rate. In cuitry. Connect to INTVCC output for the application with tracking, the regulator output can be tracked to a different the input voltage 6V and above or connect this pin to an voltage. The voltage ramp rate at his pin sets the voltage ramp rate of the output. See the Applications Information section. 4647fb For more information www.linear.com/LTM4647 7 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Decoupling Requirements Operation Applications Information Typical Applications