LT1330 LINER [Linear Technology], LT1330 Datasheet - Page 7

• Manufacturer Part Number: LT1330
• Description: 5V RS232 Transceiver with 3V Logic Interface and One Receiver Active in Shutdown
• Manufacturer: LINER [Linear Technology]

PACKAGE DESCRIPTIO
Storage Capacitor Selection
The V
fully to insure low ripple and stable operation. The LT1330
charge pump operates in a power efficient Burst Mode
operation. When storage capacitor voltage drops below a
preset threshold, the oscillator is gated on until V
are boosted up to levels exceeding a second threshold.
The oscillator then turns off, and current is supplied from
the V
The V
operation. It is therefore important to insure lower V
ripple than V
pump will result. Proper operation is insured in most
applications by choosing the V
least 5 times the V
heavily loaded than V
The V
ripple when the drivers are loaded, forcing the charge
pump into continuous mode. A minimum value 0.1 F is
suggested.
A
PPLICATI
NOTE: LEAD DIMENSIONS APPLY TO SOLDER DIP
+
+
–
OR TIN PLATE LEADS
–
and V
(0.203 – 0.457)
and V
filter capacitor should be selected to obtain low
0.008 – 0.018
potential is monitored to control charge pump
(15.240 TYP)
0.685
17.40
0.600 TYP
–
+0.635
–1.524
–
+0.025
–0.060
–
storage capacitors.
**
ripple, or erratic operation of the charge
0.005 – 0.009
storage capacitors must be chosen care-
(0.13 – 0.22)
*
DIMENSIONS DO NOT INCLUDE MOLD FLASH. MOLD FLASH
SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
DIMENSIONS DO NOT INCLUDE INTERLEAD FLASH. INTERLEAD
FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE
O
–
U
filter capacitor value. If V
–
0 – 15
0.205 – 0.212**
S
(5.20 – 5.38)
0.022 – 0.037
(0.55 – 0.95)
, a larger ratio may be needed.
(0.381 – 1.904)
0.015 – 0.075
I FOR ATIO
U
(3.175)
0.125
MIN
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.
+
filter capacitor to be at
0 – 8
(0.127)
0.005
MIN
W
U
0.0256
(0.65)
BSC
28-Lead CERDIP (Wide 0.600, Hermetic)
Dimensions in inches (millimeters) unless otherwise noted.
0.010 – 0.015
(0.25 – 0.38)
28-Lead Plastic SSOP (0.209)
+
(0.360 – 0.660)
U
+
0.014 – 0.026
(1.143 – 1.727)
is more
(LTC DWG # 05-08-1120)
0.045 – 0.068
(LTC DWG # 05-08-1640)
and V
JW Package
G Package
TM
–
+
0.002 – 0.008
(0.05 – 0.21)
(2.540 0.254)
Do not attempt to reduce V
is in discontinuous Burst Mode operation. The ripple in
this mode is determined by internal comparator thresh-
olds. Larger storage capacitor values increase the burst
period, and do not reduce ripple amplitude.
Power Saving Operational Modes
The LT1330 has both shutdown and driver disable operat-
ing modes. These operating modes can optimize power
consumption based upon applications needs.
The On/Off shutdown control turns off all circuitry except
for Low-Q RX5. When RX5 detects a signal, this informa-
tion can be used to wake up the system for full operation.
If more than one line must be monitored, the driver disable
mode provides a power efficient operating option. The
driver disable mode turns off the charge pump and RS232
drivers, but keeps all five receivers active. Power con-
sumption in driver disable mode is 3mA from V
Burst Mode is a trademark of Linear Technology Corporation
0.100 0.010
0.068 – 0.078
(1.73 – 1.99)
(5.715)
0.225
MAX
(12.95 – 15.75)
0.510 – 0.620
MAX
28
RAD TYP
1 2 3 4 5 6 7 8 9 10 11 12
(0.635)
0.025
27
26
25
24
0.397 – 0.407*
(10.07 – 10.33)
23
22 21 20 19 18 17 16 15
28
1
27
2
26
3
25
–
4
13
ripple when the charge pump
14
24
5
0.301 – 0.311
(7.65 – 7.90)
G28 SSOP 0694
23
6
(37.85)
1.490
MAX
22
7
21
8
20
9
19
10
18
11
LT1330
17
12
16
13
CC
J28 1197
.
15
14
7