LT1713 LINER [Linear Technology], LT1713 Datasheet - Page 15

• Manufacturer Part Number: LT1713
• Manufacturer: LINER [Linear Technology]

PACKAGE DESCRIPTIO
Rail-to-Rail Pulse Width Modulator
Using the LT1714
Binary modulation schemes are used in order to improve
efficiency and reduce physical circuit size. They do this by
reducing the power dissipation in the output driver tran-
sistors. In a normal Class A or Class AB amplifier, voltage
drop and current flow exist simultaneously in the output
transistors and power losses proportional to V • I occur.
In a binary modulation scheme, the output transistors,
whether bipolar or FET, are switched hard-on and hard-off
so that voltage drops do not occur simultaneously with
TYPICAL APPLICATIO
** DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD
(0.178 – 0.249)
* DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH
0.007 – 0.0098
SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE
(0.406 – 1.270)
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
0.016 – 0.050
U
U
16-Lead Plastic SSOP (Narrow 0.150)
Dimensions in inches (millimeters) unless otherwise noted.
0 – 8 TYP
0.015 0.004
(0.38 0.10)
(LTC DWG # 05-08-1641)
GN Package
45
current flow. The circuit of Figure 9 shows an example of
a binary modulation scheme, in this case pulse width
modulation.
The LT1809 is configured as an integrator in order to
generate nice linear rail-to-rail voltage ramps. The polarity
of the ramp is determined by the output of the LT1714’s
comparator A into R4. The heavy hysteresis of R1 around
the LT1714’s comparator A combined with the feedback of
the LT1809 force the devices to perpetually reverse each
other, resulting in a 1MHz triangle wave. This constitutes
the usual first half of any pulse width modulator, but the
(5.817 – 6.198)
(0.203 – 0.305)
0.008 – 0.012
0.229 – 0.244
(1.351 – 1.727)
0.053 – 0.068
16 15 14 13
1
2 3
(4.801 – 4.978)
0.189 – 0.196*
4
12 11 10 9
5 6 7
(0.635)
0.0250
BSC
LT1713/LT1714
0.004 – 0.0098
(0.102 – 0.249)
8
GN16 (SSOP) 1098
(3.810 – 3.988)
0.150 – 0.157**
(0.229)
0.009
REF
15