LTC1277ISW#TRPBF Datasheet LTC1274ISW#PBF, LTC1274CSW#PBF, LTC1274CSW#TRPBF | P1-P3

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LTC1274/LTC1277

12-Bit, 10mW, 100ksps

ADCs with 1µA Shutdown

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ESCRIPTIO

The LTC

®

1274/LTC1277 are 8µs sampling 12-bit A/D

converters which draw only 2mA (typ) from single 5V or

±5V supplies. These easy-to-use devices come complete

with a 2µs sample-and-hold, a precision reference and an

internally trimmed clock. Unipolar and bipolar conversion

modes add to the flexibility of the ADCs.

Two power-down modes are available in the LTC1277. In

Nap mode, the LTC1277 draws only 180µA and the instant

wake-up from Nap mode allows the LTC1277 to be pow-

ered down even during brief inactive periods. In Sleep

mode only 1µA will be drawn. A REFRDY signal is used to

show the ADC is ready to sample after waking up from

Sleep mode. The LTC1274 also provides the Sleep mode

and REFRDY signal.

The A/D converters convert 0V to 4.096V unipolar inputs

from a single 5V supply or ±2.048V bipolar inputs from

±5V supplies.

The LTC1274 has a single-ended input and a 12-bit

parallel data format. The LTC1277 offers a differential

input and a 2-byte read format. The bipolar mode is

formatted as 2’s complement for the LTC1274 and offset

binary for the LTC1277.

■

Low Power Dissipation: 10mW

■

Sample Rate: 100ksps

■

Samples Inputs Beyond Nyquist, 72dB S/(N + D)

and 82dB THD at f

IN

= 100kHz

■

Single Supply 5V or ±5V Operation

■

Power Shutdown to 1µA in Sleep Mode

■

180µA Nap Mode (LTC1277) with Instant Wake-Up

■

Internal Reference Can Be Overdriven

■

Internal Synchronized Clock

■

0V to 4.096V or ±2.048V Input Ranges (1mV/LSB)

■

24-Lead SO Package

, LTC and LT are registered trademarks of Linear Technology Corporation.

Supply Current vs Sample Rate with

Sleep and Nap Modes

SAMPLE RATE (Hz)

SUPPLY CURRENT (µA)

10000

1000

100

10

1

0.1 1k 100k

LTC1274/77 • TA02

101 10k100

WITHOUT SLEEP OR NAP

NAP = 5V

(SLEEP MODE)

NAP = REFRDY

(SLEEP MODE)

NAP MODE

C

REF

= 4.7µF

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Battery-Powered Portable Systems

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High Speed Data Acquisition for PCs

■

Digital Signal Processing

■

Multiplexed Data Acquisition Systems

■

Audio and Telecom Processing

■

Spectrum Analysis

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A

IN

+

A

IN

–

V

REF

AGND

REFRDY

SLEEP

NAP

D7

D6

D5

D4

DGND

V

DD

V

SS

BUSY

CS

RD

CONVST

HBEN

V

LOGIC

D0/8

D1/9

D2/10

D3/11

LTC1277

0.1µF

+

10µF

ANALOG

DIFFERENTIAL INPUTS

(0V TO 4.096V)

2.42V

V

REF

OUTPUT

10µF

0.1µF

5V

8-BIT

PARALLEL

BUS

µP

CONTROL

LINES

OPTIONAL 3V SUPPLY

TO INTERFACE WITH 3V

PROCESSOR

LTC1274/77 • TA01

+

Single 5V Supply, 10mW, 100kHz, 12-Bit ADC

2

LTC1274/LTC1277

(Notes 1, 2)

Supply Voltage (V

DD

) ................................................ 7V

Negative Supply Voltage (V

SS

)

Bipolar Operation Only .......................... – 6V to GND

Total Supply Voltage (V

DD

to V

SS

)

Bipolar Operation Only ....................................... 12V

Analog Input Voltage (Note 3)

Unipolar Operation ................... – 0.3V to V

DD

+ 0.3V

Bipolar Operation............... V

SS

– 0.3V to V

DD

+ 0.3V

Digital Input Voltage (Note 4)

Unipolar Operation .............................. – 0.3V to 12V

Bipolar Operation.......................... V

SS

– 0.3V to 12V

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PACKAGE

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RDER I FOR ATIO

ORDER

PART NUMBER

LTC1274CSW

LTC1274ISW

ORDER

PART NUMBER

LTC1277CSW

LTC1277ISW

Digital Output Voltage

Unipolar Operation ................... – 0.3V to V

DD

+ 0.3V

Bipolar Operation...................... – 0.3V to V

DD

+ 0.3V

Power Dissipation............................................. 500mW

Operating Temperature Range

Commercial ............................................ 0°C to 70°C

Industrial ........................................... –40°C to 85°C

Storage Temperature Range ................ –65°C to 150°C

Lead Temperature (Soldering, 10 sec)................. 300°C

T

JMAX

= 110°C, θ

JA

= 130°C/W

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TOP VIEW

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A

IN

V

REF

AGND

D11 (MSB)

D10

D9

D8

D7

D6

D5

D4

DGND

V

DD

V

SS

BUSY

CS

RD

CONVST

SLEEP

REFRDY

D0

D1

D2

D3

SW PACKAGE

24-LEAD PLASTIC SO WIDE

T

JMAX

= 110°C, θ

JA

= 130°C/W

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TOP VIEW

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13

A

IN

+

A

IN

–

V

REF

AGND

REFRDY

SLEEP

NAP

D7

D6

D5

D4

DGND

V

DD

V

SS

BUSY

CS

RD

CONVST

HBEN

V

LOGIC

D0/8

D1/9

D2/10

D3/11

(D11 = MSB)

SW PACKAGE

24-LEAD PLASTIC SO WIDE

Consult factory for Military grade parts.

PARAMETER CONDITIONS MIN TYP MAX UNITS

Resolution (No Missing Codes) ● 12 Bits

Integral Linearity Error (Note 7) ● ±1 LSB

Differential Linearity Error ● ±1 LSB

Unipolar Offset Error ±6 LSB

● ±8 LSB

Bipolar Offset Error (Note 8) ±8 LSB

● ±10 LSB

Gain Error ±20 LSB

Gain Error Tempco I

OUT(REF)

= 0 ● ±10 ±45 ppm/°C

CCHARA TERIST

ICS

CO

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VERTER

With Internal Reference (Notes 5, 6)

3

LTC1274/LTC1277

(Note 5)

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

V

IN

Analog Input Range (Note 10) 4.75V ≤ V

DD

≤ 5.25V (Unipolar) ● 0 to 4.096 V

4.75V ≤ V

DD

≤ 5.25V, – 5.25V ≤ V

SS

≤ –2.45V (Bipolar) ● ±2.048 V

I

IN

Analog Input Leakage Current CS = High ● ±1 µA

C

IN

Analog Input Capacitance Between Conversions (Sample Mode) 45 pF

During Conversions (Hold Mode) 5 pF

PUT

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ACCURACY

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DY

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(Notes 5, 9)

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

S/(N + D) Signal-to-Noise 50kHz Input Signal 73 dB

Plus Distortion Ratio 100kHz Input Signal

● 70 72.5 dB

THD Total Harmonic Distortion 50kHz Input Signal – 84 dB

Up to 5th Harmonic 100kHz Input Signal

● –82 –76 dB

Peak Harmonic or 50kHz Input Signal – 84 dB

Spurious Noise 100kHz Input Signal

● –82 –76 dB

IMD Intermodulation Distortion fa = 96.95kHz, fb = 97.68kHz 2nd Order Terms – 78 dB

3rd Order Terms – 81 dB

Full Power Bandwidth 2 MHz

Full Linear Bandwidth 350 kHz

[S/(N + D) ≥ 68dB]

I TER AL REFERE CE CHARACTERISTICS

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(Note 5)

PARAMETER CONDITIONS MIN TYP MAX UNITS

V

REF

Output Voltage I

OUT

= 0 2.400 2.420 2.440 V

V

REF

Output Tempco I

OUT

= 0 ● ±10 ±45 ppm/°C

V

REF

Line Regulation 4.75V ≤ V

DD

≤ 5.25V 0.01 LSB/V

–5.25V ≤ V

SS

≤ –4.75V 0.01 LSB/V

V

REF

Load Regulation –5mA ≤ I

OUT

≤ 70µA 2 LSB/mA

(Note 5)

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

V

IH

High Level Input Voltage V

DD

= 5.25V ● 2.4 V

V

IL

Low Level Input Voltage V

DD

= 4.75V ● 0.8 V

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Digital Input Current V

IN

= 0V to V

DD

● ±10 µA

C

IN

Digital Input Capacitance 5pF

V

OH

High Level Output Voltage, All Logic Outputs V

DD

= 4.75V

I

O

= – 10µA 4.70 V

I

O

= –200µA ● 4.0 V

V

LOGIC

= 2.7V (LTC1277)

I

O

= – 10µA 2.65 V

I

O

= –200µA 2.60 V

V

OL

Low Level Output Voltage, V

DD

= 4.75V

All Logic Outputs I

O

= 160µA 0.05 V

I

O

= 1.6mA ● 0.10 0.4 V

V

LOGIC

=2.7V (LTC1277)

I

O

= 160µA 0.05 V

I

O

= 1.6mA 0.10 V

DIGITAL I PUTS A D DIGITAL OUTPUTS

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LTC1277ISW#TRPBF

LTC1277ISW#TRPBF

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