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LTC1390

sn1390 1390fs

8-Channel

Analog Multiplexer

with Serial Interface

ESCRIPTIO

The LTC

1390 is a high performance CMOS 8-to-1 analog

multiplexer. It features a 3-wire digital interface with a

bidirectional data retransmission feature, allowing it to be

wired in series with a serial A/D converter while using only

one serial port. The interface also allows several LTC1390s

to be wired in series or parallel, increasing the number of

MUX channels available using only a single digital port. All

the above features are also valid when LTC1390 operates

as a demultiplexer such as with a D/A converter.

The LTC1390 features a typical R

of 45Ω, typical switch

leakage of 50pA, and guaranteed break-before-make op-

eration. Charge injection is ±10pC maximum. All digital

inputs are TTL and CMOS compatible when operated from

single or dual supplies. The inputs can withstand 100mA

fault currents.

The LTC1390 is available in 16-pin PDIP and narrow SO

packages.

■

3-Wire Serial Digital Interface

■

Data Retransmission Allows Series Connection

with Serial A/D Converters

■

Single 3V to ±5V Supply Operation

■

Analog Inputs May Extend to Supply Rails

■

Low Charge Injection

■

Low R

: 75Ω Max

■

Low Leakage: ±5nA Max

■

Guaranteed Break-Before-Make

■

TTL/CMOS Compatible for All Digital Inputs

■

Cascadable to Allow Additional Channels

■

Can Be Used as a Demultiplexer

■

Data Acquisition Systems

■

Communication Systems

■

Signal Multiplexing/Demultiplexing

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

ITY

ANALOG INPUT VOLTAGE, V

(V)

–5

ON-RESISTANCE (Ω)

150

200

250

LTC1390 • TA02

100

–3

–1

–4 4

–2

= 3V

–

= 0V

= 5V

–

= –5V

= 25°C

ON-Resistance vs

Analog Input Voltage

–

DATA 2

DATA 1

CLK

GND

ANALOG

INPUTS

3-WIRE

SERIAL

INTERFACE

TO MUX AND ADC

DATA

CLK

LTC1390

47k

+IN

–IN

GND

CLK

OUT

REF

LTC1096

LTC1390 • TA01

OPTIONAL A/D

INPUT FILTER

Summary of content (8 pages)

PAGE 1
LTC1390 8-Channel Analog Multiplexer with Serial Interface U DESCRIPTIO FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ The LTC®1390 is a high performance CMOS 8-to-1 analog multiplexer. It features a 3-wire digital interface with a bidirectional data retransmission feature, allowing it to be wired in series with a serial A/D converter while using only one serial port.
PAGE 2
LTC1390 U U RATI GS W W W W AXI U U ABSOLUTE PACKAGE/ORDER I FOR ATIO (Note 1) Total Supply Voltage (V + to V –) .............................. 15V Input Voltage Analog Inputs ........................ V – – 0.3V to V + + 0.3V Digital Inputs ........................................ – 0.3V to 15V Digital Outputs ........................... – 0.3V to V + + 0.3V Power Dissipation ............................................. 500mW Operating Temperature Range .....................
PAGE 3
LTC1390 ELECTRICAL CHARACTERISTICS V + = 5V, V – = – 5V, GND = 0V, TA = operating temperature unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Dynamic fCLK Clock Frequency 5 tON Enable Turn-On Time VS = 2.5V, RL = 1k, CL = 35pF 260 400 ns tOFF Enable Turn-Off Time VS = 2.
PAGE 4
LTC1390 ELECTRICAL CHARACTERISTICS V + = 3V, V – = GND = 0V, TA = operating temperature unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Dynamic fCLK Clock Frequency 5 tON Enable Turn-On Time VS = 1.5V, RL = 1k, CL = 35pF (Note 4) 490 700 ns tOFF Enable Turn-Off Time VS = 1.
PAGE 5
LTC1390 U U U PIN FUNCTIONS CS (Pin 11): Chip Select Input (TTL/CMOS Compatible). A logic high on this input enables LTC1390 to read in the channel selection bits and allow data transfer from Data 1 to Data 2. A logic low enables the desired channel for analog signal transmission and allows data transfer from Data 2 to Data 1. Data 1 (Pin 12): Bidirectional Digital Input/Output (TTL/ CMOS Compatible). Input for the channel selection bits.
PAGE 6
LTC1390 U U W U APPLICATIO S I FOR ATIO transmission. Table 1 shows the various bit combinations for channel selection. Table 1. Logic Table for Channel Selection CHANNEL STATUS All Off S0 S1 S2 S3 S4 S5 S6 S7 EN 0 1 1 1 1 1 1 1 1 B2 X 0 0 0 0 1 1 1 1 B1 X 0 0 1 1 0 0 1 1 B0 X 0 1 0 1 0 1 0 1 selection or to Data 2 via Buffer 1 for data transfer. Data appears at Data 2 after the fourth rising edge of the clock.
PAGE 7
LTC1390 U U W U APPLICATIO S I FOR ATIO CLK 1 2 3 4 5 6 7 8 CS DATA ENA A2 A1 A0 ENB B2 B1 NULL BIT D11 B0 D10 D9 D8 D7 tSMPL D6 D5 D4 D3 D2 D1 D0 tCONV DIGITAL INPUT FROM LTC1390 Hi-Z tDATA DIGITAL OUTPUT FROM LTC1286 LTC1390 • F06 Figure 6.
PAGE 8
LTC1390 U TYPICAL APPLICATIONS N Interfacing LTC1390 with LTC1257 for Demultiplex Operation VCC VEE 1 S1 3 4 ANALOG OUTPUTS V+ S0 2 5 6 7 8 LTC1390 D S2 V– S3 DATA 2 S4 DATA 1 S5 CS S6 CLK S7 GND OPTIONAL D/A OUTPUT FILTER 16 15 VCC VCC 14 13 1 8 VCC CLK LTC1257 7 DIN VOUT 3 6 LOAD VREF 4 5 DOUT GND 47k 2 12 11 10 9 DATA CLK CS LTC1390 • F03 U PACKAGE DESCRIPTION Dimensions in inches (millimeters) unless otherwise noted. N Package 16-Lead Plastic DIP 0.130 ± 0.005 (3.