LTM4637 datasheet(7/32 Pages) LINER

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LTM4633

4633f

For more information www.linear.com/LTM4633

pin FuncTions

GND (A4, A8-A9, D1- D12, E1-E12, F4, F8, F12, G3-G4,

G7-G8, G11-G12, H3-H4, H7-H8, H11-H12, J1-J5, J7,

J9-J12, K1-K3, K8-K10, K12,L1-L2,L12, M1, M6-M8,

M12): Ground Pins for Both Input and Output Returns.

All ground pins need to connect with large copper areas

underneath the unit.

VOUT1, VOUT2, VOUT3 (A10-A12, B9-B12, and C10-C12);

(A5-A7, B5-B8, C6-C8); (A1-A3, B1-B4, C1-C4): Power

Output Pins. Apply output load between these pins and

the GND pins. Recommend placing output decoupling

capacitance directly between these pins and the GND

pins. See Table 5.

TEMP1 AND TEMP2 (C9, C5): Two Onboard Temperature

Diodes for Monitoring the VBE Junction Voltage Change

with Temperature. Each of these two temperature diode

connected PNP transistors is placed in the middle of

channel 1 and channel 2, and in the middle of channel 2

and channel 3. See the Applications Information section

and an example in Figure 19.

VIN1,VIN2,VIN3 (F9-F10,G9-G10,H9-H10);(F5-F6,G5-

G6,H5-H6);(F1-F2,G1-G2,H1-H2): Power Input Pins.

Apply input voltage between these pins and the GND pins.

Recommendplacinginputdecouplingcapacitancedirectly

between the VIN pins and the GND pins. The VIN paths

can be all combined from one power source, or powered

from independent power sources. The VIN paths can

operate down to 2.375V when the CNTL_PWR is biased

separately from a supply in the range of 4.7V to 16V. See

the Applications Information section.

SW1 (F11), SW2 (F7), SW3 (F3): The internal switch

node for each of the regulator channels for monitoring

the switching waveform. An R-C snubber circuit can be

placed on these pins to ground to eliminate switch node

ringing noise.

CNTL_PWR (J6): Input Supply to an Internal Bias LDO to

Power the Internal Controller and MOSFET Drivers. This

pin is connected to an input supply voltage range of 4.7V

to 16V. If the voltage at CNTL_PWR is ≤5.5V, the INTVCC

pin should be tied to CNTL_PWR for optimum efficiency.

If the voltage at CNTL_PWR is >5.5V, leave INTVCC floating

with the recommended decoupling capacitor. When using

multiple input supplies, choose the lowest input supply

between 4.7V to 16V to supply the CNTL_PWR pin. This

will lower the internal power loss and improve efficiency.

INTVCC (J8): Output of the Internal Bias LDO for Powering

InternalControlCircuitry.Connecta4.7µFceramiccapaci-

tor to ground for decoupling. If the voltage at CNTL_PWR

is ≤5.5V, tie the INTVCC pin to CNTL_PWR for optimum

efficiency. If the voltage at CNTL_PWR is >5.5V, leave

INTVCC floating. See the Applications Information section.

SGND (K6-K7, L6-L7): Signal Ground Connections. The

signal ground connection in the module is separated from

normal power ground (GND) by an internal 2.2Ω resistor.

This allows the designer to connect the signal ground pin

close to GND near the external output capacitors on the

regulatorchannel’soutputs.Theentireinternalsmall-signal

feedback circuitry is referenced to SGND, thus allowing

for better output regulation. See the recommended layout

in the Applications Information section.

EXTVCC (L3): External Bias Power Input. The internal bias

LDO is bypassed whenever the voltage at EXTVCC is above

4.7V. Never exceed 6V at this pin and ensure CNTL_PWR >

EXTVCC at all times to avoid reverse polarity on the internal

bias LDO. Connect a 1µF capacitor to ground when used

otherwise leave floating. When generating a 5V output on

channel 3, connect the 5V output to this pin to improve

efficiency.

PACKAGE ROW AND COLUMN LABELING MAY VARY

AMONG µModule PRODUCTS. REVIEW EACH PACKAGE

LAYOUT CAREFULLY.

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