LT1714IGN datasheet(16/16 Pages) LINER

16 / 16 page

LT1713/LT1714

©LINEAR TECHNOLOGY CORPORATION 2000

171314f LT/TP 0501 4K • PRINTED IN USA

Linear Technology Corporation

1630 McCarthy Blvd., Milpitas, CA 95035-7417

(408)432-1900 q FAX:(408)434-0507 q www.linear-tech.com

RELATED PARTS

PART NUMBER

DESCRIPTION

COMMENTS

LT1016

UltraFast Precision Comparator

Industry Standard 10ns Comparator

LT1116

12ns Single Supply Ground Sensing Comparator

Single Supply Version of the LT1016

LT1394

7ns, UltraFast Single Supply Comparator

6mA Single Supply Comparator

LT1671

60ns, Low Power, Single Supply Comparator

450

µA Single Supply Comparator

LT1711/LT1712

Single/Dual, 4.5ns, 3V/5V/

±5V Rail-to-Rail Comparators Faster Versions of LT1713/LT1714

LT1719

4.5ns, Single Supply 3V/5V Comparator

4mA Comparator with Rail-to-Rail Outputs

LT1720/LT1721

Dual/Quad, 4.5ns, Single Supply Comparator

Dual/Quad Version of the LT1719

forte of this particular implementation is that it is rail-to-

rail allowing a full-scale analog input. Once the triangle

wave is achieved, the remainder of the pulse width modu-

lator is easy, and is constituted by doing a simple compari-

son using the second half of the LT1714. The triangle wave

and the relatively slow moving analog signal (the one to be

modulated or to do the modulation, depending on how you

look at it) are fed into the inputs of comparator B, whose

output is then the PWM representation of the analog input

voltage. The higher the analog input voltage, the wider the

output pulse. The time averaged output level is thus

proportional to the analog input voltage. This binary

output can then be fed into power transistors with direct

control over motor or speaker winding current, for

TYPICAL APPLICATIO

–

1/2 LT1714

–

V+

0.01

µF

V+ = 2.7V TO 7V

1MHz

TRIANGLE

WAVE

V+

26.1

Ω

499

Ω

10k

500pF

–

1/2 LT1714

171314 F09

V+

100pF

LT1809

0.001

µF

0.01

µF

0.001

µF

ANALOG

INPUT

ANTIALIASING

FILTER

16kHz ANALOG FILTER

FOR LINEARITY MEASUREMENT

COMPLEMENTARY

1MHz PWM

OUTPUTS

Figure 9. Rail-to-Rail 1MHz Pulse Width Modulator

example, with their inherent lowpass characteristic. Care

must be taken to avoid cross conduction in the output

power transistors.

The linearity of the pulse width modulated signal can easily

be ascertained by putting a simple 2-pole RC filter at the

output (as shown in Figure 9). This demodulates the signal

which can then be viewed and compared with the original

input signal on an oscilloscope. Using a spectrum analyzer

and a 1kHz reference signal, this circuit’s distortion prod-

ucts were measured as better than – 50dBc (0.3%) to

about 3.5VP-P, degrading to – 30dBc (3%) as the circuit

clips at 5VP-P on a single 5V supply.

LT1714IGN Scheda tecnica(PDF) 16 Page - Linear Technology

LT1714IGN Scheda tecnica(HTML) 16 Page - Linear Technology

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

Scheda tecnica Scarica

Link URL