Datasheet

ManualsBrandsLINEAR TECHNOLOGY ManualsData collecting ICsData acquisition IC - DA converter (DAC) MSOP 8

LTC1658

14-Bit Rail-to-Rail

Micropower DAC in MSOP

FEATURES

■

14-Bit Resolution

■

8-Lead MSOP Package

■

Buffered True Rail-to-Rail Voltage Output

■

3V or 5V Single Supply Operation

■

Very Low Power: I

CC(TYP)

= 270µA

■

Power-On Reset

■

3-Wire Cascadable Serial Interface is Compatible

with SPI and MICROWIRE

■

Maximum DNL Error: 1LSB

■

Low Cost

The LTC

1658 is a single supply, rail-to-rail voltage out-

put, 14-bit digital-to-analog converter (DAC) in an 8-lead

MSOP package. It includes an output buffer amplifier and

an easy-to-use 3-wire cascadable serial interface.

The LTC1658 output swings from 0V to V

REF

. The REF pin

can be tied to V

for rail-to-rail output swing. The LTC1658

operates from a single 2.7V to 5.5V supply. The typical

power supply current is 270µA.

The low power supply current makes the LTC1658 ideal

for battery-powered applications. The space saving MSOP

provides the smallest 14-bit DAC system available.

DESCRIPTION

Functional Block Diagram: 14-Bit Rail-to-Rail DAC

■

Digital Calibration

■

Industrial Process Control

■

Automatic Test Equipment

■

Cellular Telephones

APPLICATIONS

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

TYPICAL APPLICATION

–

14-BIT

DAC

2.7V TO 5.5V

GND

POWER-ON

RESET

TO

OTHER

DACS

16-BIT

SHIFT

REG

AND

DAC

LATCH

µP

REF

OUT

1658 TA01

CLK1

CS/LD3

RAIL-TO-RAIL

VOLTAGE

OUTPUT

OUT



MICROWIRE is a trademark of National Semiconductor Corporation.

CODE

–1.0

–0.2

–0.4

–0.6

–0.8

0.2

0.4

0.6

0.8

1.0

DNL ERROR (LSB)

4096 8192

1658 TA02

12288

16383

Differential Nonlinearity

vs Input Code

Summary of content (12 pages)

PAGE 1
LTC1658 14-Bit Rail-to-Rail Micropower DAC in MSOP U DESCRIPTION FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ 14-Bit Resolution 8-Lead MSOP Package Buffered True Rail-to-Rail Voltage Output 3V or 5V Single Supply Operation Very Low Power: ICC(TYP) = 270µA Power-On Reset 3-Wire Cascadable Serial Interface is Compatible with SPI and MICROWIRETM Maximum DNL Error: 1LSB Low Cost U APPLICATIONS ■ ■ ■ ■ The LTC®1658 is a single supply, rail-to-rail voltage output, 14-bit digital-to-analog converter (DAC) in an 8-lead MSOP p
PAGE 2
LTC1658 W W U W ABSOLUTE MAXIMUM RATINGS (Note 1) VCC to GND .............................................. – 0.5V to 7.5V TTL Input Voltage .................................... – 0.5V to 7.5V VREF ..........................................................– 0.5V to 7.5V VOUT ........................................... – 0.5V to (VCC + 0.5V) Junction Temperature .......................... – 65°C to 125°C Operating Temperature Range Commercial ............................................
PAGE 3
LTC1658 ELECTRICAL CHARACTERISTICS VCC = 2.7V to 5.5V, VOUT unloaded, REF ≤ VCC, TA = TMIN to TMAX, unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN Output Impedance to GND Input Code = 0 ● Output Line Regulation Input Code = 16383, VCC = 2.7V to 5.5V, REF = 2.5V ● TYP MAX UNITS 70 200 Ω 1.5 mV/V AC Performance Voltage Output Slew Rate Voltage Output Settling Time ● 0.35 (Note 3) to ±0.5LSB Digital Feedthrough 1.0 V/µs 12 µs 0.
PAGE 4
LTC1658 ELECTRICAL CHARACTERISTICS The ● denotes specifications which apply over the full operating temperature range. Note 1: Absolute Maximum Ratings are those values beyond which the life a device may be impaired. Note 2: Nonlinearity is defined from code 50 to code 16383 (full scale). See Applications Information. Note 3: DAC switched between code 16383 and code 50. Note 4: Digital inputs at 0V or VCC. Note 5: VOUT can only swing from (GND + VOS) to (VCC – VOS) when output is unloaded.
PAGE 5
LTC1658 U W TYPICAL PERFOR A CE CHARACTERISTICS Gain Error vs Temperature Broadband Noise 5 4 3 GAIN ERROR (LSB) 2 1LSB/DIV 1 0 –1 –2 –3 BW = 1Hz TO 100kHz –4 –5 –55 –25 5 35 65 TEMPERATURE (°C) 95 200µs/DIV 1658 G08 125 1658 G06 U U U PIN FUNCTIONS CLK (Pin 1): The TTL Level Input for the Serial Interface Clock. DOUT (Pin 4): Output of the Shift Register Which Becomes Valid on the Rising Edge of the Serial Clock. DIN (Pin 2): The TTL Level Input for the Serial Interface Data.
PAGE 6
LTC1658 WU W TI I G DIAGRA t1 t2 t4 t3 t6 t7 CLK t9 B13 MSB DIN B12 CS/LD DOUT B11 B0 LSB BX DUMMY BX DUMMY t8 B13 PREVIOUS WORD B12 t5 B11 BX BX B13 CURRENT WORD 1658 TD U U DEFI ITIO S Differential Nonlinearity (DNL): The difference between the measured change and the ideal 1LSB change for any two adjacent codes. The DNL error between any two codes is calculated as follows: DNL = (∆VOUT – LSB)/LSB Where ∆VOUT is the measured voltage difference between two adjacent codes.
PAGE 7
LTC1658 U OPERATIO Serial Interface The data on the DIN input is loaded into the shift register on the rising edge of the clock. The MSB is loaded first. The DAC register loads the data from the shift register when CS/LD is pulled high. The clock is disabled internally when CS/LD is high. Note: CLK must be low before CS/LD is pulled low to avoid an extra internal clock pulse. The input word must be 16 bits wide. The last two bits are don’t cares.
PAGE 8
LTC1658 U W U U APPLICATIONS INFORMATION Rail-to-Rail Output Considerations In any rail-to-rail DAC, the output swing is limited to voltages within the supply range. If the DAC offset is negative, the output for the lowest codes limits at 0V as shown in Figure 1b. (FSE) is positive, the output for the highest codes limits at VCC as shown in Figure 1c. No full-scale limiting can occur if VREF is less than VCC – FSE.
PAGE 9
LTC1658 U TYPICAL APPLICATIO S An Optoisolated 4mA to 20mA Process Controller VLOOP 3.8V TO 30V LT®1121-3.3 IN OUT 237k 1% 20k 60.4k 1% 5k + 1µF FROM OPTOISOLATED INPUTS CLK REF VCC DIN LTC1658 VOUT + 3.01k 1% CS/LD 1k LT1077 Q1 2N3440 – RS 10Ω IOUT 3.3V 1658 TA04 OPTOISOLATORS CLK DIN CS/LD 500Ω 3.6k 4N28 CLK DIN CS/LD This circuit shows how to use an LTC1658 to make an optoisolated digitally controlled 4mA to 20mA process controller.
PAGE 10
LTC1658 U TYPICAL APPLICATIO S A 14-Bit Analog Input/Output Channel for a PC 5V D1 510Ω DIFFERENTIAL INPUT D2 510Ω 1 510Ω D3 U1 LTC1417 510Ω 2 3 D4 1µF 4 10µF 5 6 7 8 U2 LTC1658 1 2 3 4 CLK VCC DIN VOUT CS/LD DOUT REF GND 1µF AIN + VCC AIN – VSS VREF BUSY VREFCOMP 15 14 13 CONVST 12 RD AGND EXTCLKIN SHDN SCLK DGND CLKOUT 16 11 10 9 DOUT U3 1/2 74HC74 1µF 8 2 7 4 6 3 D 6 Q PR CLR CK Q 5 1 6 U4 LT1021-5 C5 47µF 5V 2 C4 150µF 4 5 D6 ANALOG OUTPUT U3 1
PAGE 11
LTC1658 U PACKAGE DESCRIPTION Dimensions in inches (millimeters) unless otherwise noted. MS8 Package 8-Lead Plastic MSOP (LTC DWG # 05-08-1660) 0.118 ± 0.004* (3.00 ± 0.102) 0.040 ± 0.006 (1.02 ± 0.15) 0.007 (0.18) 0.034 ± 0.004 (0.86 ± 0.102) 8 7 6 5 0° – 6° TYP SEATING PLANE 0.012 (0.30) 0.0256 REF (0.65) TYP 0.021 ± 0.006 (0.53 ± 0.015) 0.006 ± 0.004 (0.15 ± 0.102) 0.118 ± 0.004** (3.00 ± 0.102) 0.192 ± 0.004 (4.88 ± 0.
PAGE 12
LTC1658 U TYPICAL APPLICATION 14-Bit, 3V to 5V Single Supply, Voltage Output DAC 2.7V TO 5.5V 0.1µF REF DIN VCC µP CLK LTC1658 VOUT CS/LD DOUT OUTPUT 0V TO REF GND TO NEXT DAC FOR DAISY-CHAINING 1658 TA03 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LTC1257 Single 12-Bit VOUT DAC, Full Scale: 2.048V, VCC: 4.75V to 15.75V, Reference Can Be Overdriven Up to 12V, i.e.