LTC6946_15 datasheet(12/32 Pages) LINER

12 / 32 page

LTC6946

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pin FuncTions

GND (23): Negative Power Supply (Ground). This pin is

attached directly to the die attach paddle (DAP) and should

be tied directly to the ground plane.

VCP+(Pin24):4.0Vto5.25VPositiveSupplyPinforCharge

Pump Circuitry. This pin should be bypassed directly to

the ground plane using a 0.1µF ceramic capacitor as close

to the pin as possible.

CP (Pin 25): Charge Pump Output. This bi-directional cur-

rentoutputisnormallyconnectedtotheexternalloopfilter.

See the Applications Information section for more details.

VREF+ (Pin 26): 3.15V to 3.45V Positive Supply Pin for

Reference Input Circuitry. This pin should be bypassed

directly to the ground plane using a 0.1µF ceramic capaci-

tor as close to the pin as possible.

REF+, REF– (Pins 27, 28): Reference Input Signals. This

differential input is buffered with a low noise amplifier,

which feeds the reference divider and reference buffer.

They are self-biased and must be AC-coupled with 1µF

capacitors. If used single ended, bypass REF– to GND

with a 1µF capacitor. If the single-ended signal is greater

than 2.7VP-P, bypass REF– to GND with a 47pF capacitor.

GND (Exposed Pad Pin 29): Negative Power Supply

(Ground). The package exposed pad must be soldered

directly to the PCB land. The PCB land pattern should

have multiple thermal vias to the ground plane for both

low ground inductance and also low thermal resistance.

LTC6946 Datasheet(PDF) 12 Page - Linear Technology