LTC2247 View Datasheet(PDF) - Linear Technology

Part Name

Description

Manufacturer

LTC2247

Dual 14-Bit, 80Msps Low Power 3V ADC

Linear Technology 

LTC2299

PI FU CTIO S

AINA+ (Pin 1): Channel A Positive Differential Analog

Input.

AINA– (Pin 2): Channel A Negative Differential Analog

Input.

REFHA (Pins 3, 4): Channel A High Reference. Short

together and bypass to Pins 5, 6 with a 0.1µF ceramic chip

capacitor as close to the pin as possible. Also bypass to

Pins 5, 6 with an additional 2.2µF ceramic chip capacitor

and to ground with a 1µF ceramic chip capacitor.

REFLA (Pins 5, 6): Channel A Low Reference. Short

together and bypass to Pins 3, 4 with a 0.1µF ceramic chip

capacitor as close to the pin as possible. Also bypass to

Pins 3, 4 with an additional 2.2µF ceramic chip capacitor

and to ground with a 1µF ceramic chip capacitor.

VDD (Pins 7, 10, 18, 63): Analog 3V Supply. Bypass to

GND with 0.1µF ceramic chip capacitors.

CLKA (Pin 8): Channel A Clock Input. The input sample

starts on the positive edge.

CLKB (Pin 9): Channel B Clock Input. The input sample

starts on the positive edge.

REFLB (Pins 11, 12): Channel B Low Reference. Short

together and bypass to Pins 13, 14 with a 0.1µF ceramic

chip capacitor as close to the pin as possible. Also bypass

to Pins 13, 14 with an additional 2.2µF ceramic chip ca-

pacitor and to ground with a 1µF ceramic chip capacitor.

REFHB (Pins 13, 14): Channel B High Reference. Short

together and bypass to Pins 11, 12 with a 0.1µF ceramic

chip capacitor as close to the pin as possible. Also bypass

to Pins 11, 12 with an additional 2.2µF ceramic chip ca-

pacitor and to ground with a 1µF ceramic chip capacitor.

AINB– (Pin 15): Channel B Negative Differential Analog

Input.

AINB+ (Pin 16): Channel B Positive Differential Analog

Input.

GND (Pins 17, 64): ADC Power Ground.

SENSEB (Pin 19): Channel B Reference Programming Pin.

Connecting SENSEB to VCMB selects the internal reference

and a ±0.5V input range. VDD selects the internal reference

and a ±1V input range. An external reference greater than

0.5V and less than 1V applied to SENSEB selects an input

range of ±VSENSEB. ±1V is the largest valid input range.

VCMB (Pin 20): Channel B 1.5V Output and Input Common

Mode Bias. Bypass to ground with 2.2µF ceramic chip

capacitor. Do not connect to VCMA.

MUX (Pin 21): Digital Output Multiplexer Control. If MUX

isHigh,ChannelAcomesoutonDA0-DA13,OFA;Channel B

comes out on DB0-DB13, OFB. If MUX is Low, the output

busses are swapped and Channel A comes out on DB0-

DB13, OFB; Channel B comes out on DA0-DA13, OFA. To

multiplex both channels onto a single output bus, connect

MUX, CLKA and CLKB together.

SHDNB (Pin 22): Channel B Shutdown Mode Selection

Pin. Connecting SHDNB to GND and OEB to GND results

in normal operation with the outputs enabled. Connecting

SHDNB to GND and OEB to VDD results in normal opera-

tion with the outputs at high impedance. Connecting

SHDNB to VDD and OEB to GND results in nap mode with

the outputs at high impedance. Connecting SHDNB to VDD

and OEB to VDD results in sleep mode with the outputs at

high impedance.

OEB (Pin 23): Channel B Output Enable Pin. Refer to

SHDNB pin function.

DB0 – DB13 (Pins 24 to 30, 33 to 39): Channel B Digital

Outputs. DB13 is the MSB.

OGND (Pins 31, 50): Output Driver Ground.

OVDD (Pins 32, 49): Positive Supply for the Output Driv-

ers. Bypass to ground with 0.1µF ceramic chip capacitor.

OFB (Pin 40): Channel B Overflow/Underflow Output.

High when an overflow or underflow has occurred.

DA0 – DA13 (Pins 41 to 48, 51 to 56): Channel A Digital

Outputs. DA13 is the MSB.

OFA (Pin 57): Channel A Overflow/Underflow Output.

High when an overflow or underflow has occurred.

OEA (Pin 58): Channel A Output Enable Pin. Refer to

SHDNA pin function.

2299fa

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