LT1330
5V RS232 Transceiver with
3V Logic Interface and One
Receiver Active in Shutdown
FEATURES
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DESCRIPTIO
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3V Logic Interface
ESD Protection over
±10kV
Uses Small Capacitors: 0.1µF, 0.2µF, 1.0µF
One Low Power Receiver Remains Active While in
Shutdown
Pin Compatible with LT1137A and LT1237
120kBaud Operation for R
L
= 3k, C
L
= 2500pF
250kBaud Operation for R
L
= 3k, C
L
= 1000pF
CMOS Comparable Low Power: 30mW
Easy PC Layout—Flowthrough Architecture
Rugged Bipolar Design
Outputs Assume a High Impedance State When Off
or Powered Down
Absolutely No Latchup
60µA Supply Current in Shutdown
Available in SO and SSOP Packages
The LT
®
1330 is a three driver, five receiver RS232 trans-
ceiver with low supply current. Designed to interface with
new 3V logic, the LT1330 operates with both a 5V power
supply and a 3V logic power supply. The chip may be shut
down to micropower operation with one receiver remain-
ing active to monitor RS232 inputs such as ring detect
from a modem.
The LT1330 is fully compliant with all EIA RS232 specifi-
cations. Additionally, the RS232 line input and output pins
are resilient to multiple
±10kV
ESD strikes. This eliminates
the need for costly TransZorbs
®
on line pins for the RS232
part.
The LT1330 operates to 120kbaud even driving high
capacitive loads. During shutdown, driver and receiver
outputs are at a high impedance state allowing devices to
be paralleled.
, LTC and LT are registered trademarks of Linear Technology Corporation.
TransZorb is a registered trademark of General Instruments, GSI
APPLICATI
s
s
S
Notebook Computers
Palmtop Computers
TYPICAL APPLICATI
V
+
1.0µF
2
×
0.1µF
DRIVER 1 OUT
RX1 IN
DRIVER 2 OUT
TO
LINE
RX2 IN
RX3 IN
RX4 IN
DRIVER 3 OUT
RX5 IN (LOW-Q)
ON/OFF
3V V
L
5V V
CC
1
2
3
4
5
6
7
8
9
10
11
12
13
14
LT1330
28
27
26
25
24
23
22
21
20
19
18
17
16
15
V
–
2
×
0.1µF
DRIVER 1 IN
RX1 OUT
DRIVER 2 IN
RX2 OUT
RX3 OUT
RX4 OUT
DRIVER 3 IN
RX5 OUT (LOW-Q)
GND
DRIVER
DISABLE
INPUT
RING DETECT IN
µCONTROLLER
OR
µPROCESSOR
SHUTDOWN
CONTROL OUT
1330 TA01
1330 TA02
0.1µF
RECEIVER
OUTPUT
V
L
= 3V
C
L
= 50pF
DRIVER
OUTPUT
R
L
= 3k
C
L
= 2500pF
R
TO LOGIC
U
Output Waveforms
UO
UO
1
LT1330
ABSOLUTE
(Note 1)
AXI U
RATI GS
PACKAGE/ORDER I FOR ATIO
TOP VIEW
V
+
1
5V V
CC
2
C1
+
3
C1
–
4
DR1 OUT 5
RX1 IN 6
DR2 OUT 7
RX2 IN 8
RX3 IN 9
RX4 IN 10
DR3 OUT 11
RX5 IN 12
(LOW-Q)
ON/OFF 13
3V V
L
14
G PACKAGE
28-LEAD PLASTIC SSOP
NW PACKAGE
28-LEAD (WIDE) PDIP
28 V
–
27 C2
–
26 C2
+
25 DR1 IN
24 RX1 OUT
23 DR2 IN
22 RX2 OUT
21 RX3 OUT
20 RX4 OUT
19 DR3 IN
RX5 OUT
18 (LOW-Q)
17 GND
16 DRIVER
DISABLE
15 NC
JW PACKAGE
28-LEAD (WIDE) CERDIP
SW PACKAGE
28-LEAD (WIDE) PLASTIC SO
Supply Voltage (V
CC
) ................................................ 6V
Supply Voltage (V
L
) .................................................. 6V
V
+
........................................................................ 13.2V
V
–
...................................................................... –13.2V
Input Voltage
Driver ........................................................... V
–
to V
+
Receiver ................................................ – 30V to 30V
Output Voltage
Driver .................................................... – 30V to 30V
Receiver ...................................... – 0.3V to V
L
+ 0.3V
Short-Circuit Duration
V
+
................................................................... 30 sec
V
–
................................................................... 30 sec
Driver Output .............................................. Indefinite
Receiver Output .......................................... Indefinite
Operating Temperature Range
LT1330I ............................................. – 40°C to 85°C
LT1330C ................................................. 0°C to 70°C
Storage Temperature Range ................ – 65°C to 150°C
Lead Temperature (Soldering, 10 sec)................. 300°C
ORDER PART
NUMBER
LT1330CG
LT1330CJW
LT1330CNW
LT1330CSW
LT1330IJW
T
JMAX
= 150°C,
θ
JA
= 96°C/ W (G)
T
JMAX
= 150°C,
θ
JA
= 62°C/ W (JW)
T
JMAX
= 150°C,
θ
JA
= 56°C/ W (NW)
T
JMAX
= 150°C,
θ
JA
= 85°C/ W (SW)
Consult factory for Military grade parts.
ELECTRICAL CHARACTERISTICS
PARAMETER
Power Supply Generator
V
+
Output
V
–
Output
Supply Current (V
CC
)
Supply Current (V
L
)
Supply Current When OFF (V
CC
)
Supply Rise Time
Shutdown to Turn-On
ON/OFF Pin Thresholds
ON/OFF Pin Current
DRIVER DISABLE Pin Thresholds
DRIVER DISABLE Pin Current
Oscillator Frequency
CONDITIONS
(Note 2)
MIN
TYP
7.9
–7
6
6
0.1
0.06
3.00
0.2
0.8
–15
0.8
–10
130
1.4
1.4
1.4
1.4
MAX
UNITS
V
V
mA
mA
mA
mA
mA
ms
V
V
µA
V
V
µA
kHz
T
A
= 25°C (Note 3)
q
(Note 4)
Shutdown (Note 5)
Driver Disable
C1 = C2 = 0.2µF,
C
+
= 1.0µF, C
–
= 0.1µF
Input Low Level (Device Shutdown)
Input High Level (Device Enabled)
0V
≤
V
ON/OFF
≤
5V
Input Low Level (Drivers Enabled)
Input High Level (Drivers Disabled)
0V
≤
V
DRIVER DISABLE
≤
5V
Driver Outputs Loaded R
L
= 3k
q
12
14
1
0.15
q
q
q
q
q
q
2.4
80
2.4
500
2
U
W
U
U
W W
W
LT1330
ELECTRICAL CHARACTERISTICS
PARAMETER
Any Driver
Output Voltage Swing
Logic Input Voltage Level
Logic Input Current
Output Short-Circuit Current
Output Leakage Current
Data Rate (Note 8)
Slew Rate
Propagation Delay
Any Receiver
Input Voltage Thresholds
Hysteresis
Input Resistance
Output Leakage Current
Receivers 1, 2, 3, 4
Output Voltage
Output Short-Circuit Current
Propagation Delay
Receiver 5 (LOW Q-Current RX)
Output Voltage
Output Short-Circuit Current
Propagation Delay
CONDITIONS
Load = 3k to GND
(Note 2)
MIN
Positive
Negative
q
q
q
q
q
TYP
7.5
– 6.3
1.4
1.4
5
17
10
MAX
UNITS
V
V
V
V
µA
mA
µA
kBaud
kBaud
V/µs
V/µs
µs
µs
V
V
V
kΩ
µA
V
V
mA
mA
ns
ns
V
V
mA
mA
µs
µs
5.0
Input Low Level (V
OUT
= High)
Input High Level (V
OUT
= Low)
0.8V
≤
V
IN
≤
2V
V
OUT
= 0V
Shutdown V
OUT
=
±30V
(Note 5)
R
L
= 3k, C
L
= 2500pF
R
L
= 3k, C
L
= 1000pF
R
L
= 3k, C
L
= 51pF
R
L
= 3k, C
L
= 2500pF
Output Transition t
HL
High to Low (Note 6)
Output Transition t
LH
Low to High
Input Low Threshold (V
OUT
= High)
Input High Threshold (V
OUT
= Low)
– 5.0
0.8
20
100
2.0
±9
q
120
250
4
15
15
0.6
0.5
1.3
1.7
0.4
5
1
0.2
2.9
– 20
20
250
350
0.2
2.9
–4
4
1
1
30
1.3
1.3
0.8
q
V
IN
=
±10V
Shutdown (Note 5) 0
≤
V
OUT
≤
V
CC
Output Low, I
OUT
= – 1.6mA
Output High, I
OUT
= 160µA (V
L
= 3V)
Sinking Current, V
OUT
= V
CC
Sourcing Current, V
OUT
= 0V
Output Transition t
HL
High to Low (Note 7)
Output Transition t
LH
Low to High
Output Low, I
OUT
= – 500µA
Output High, I
OUT
= 160µA (V
L
= 3V)
Sinking Current, V
OUT
= V
CC
Sourcing Current, V
OUT
= 0V
Output Transition t
HL
High to Low (Note 7)
Output Transition t
LH
Low to High
0.1
3
q
q
q
2.4
1.0
7
10
0.4
2.7
– 10
10
600
600
0.4
q
q
2.7
–2
2
3
3
The
q
denotes specifications which apply over the operating temperature
range (0°C
≤
T
A
≤
70°C for commercial grade, and – 40°C
≤
T
A
≤
85°C for
industrial grade).
Note 1:
Absolute Maximum Ratings are those values beyond which the life
of the device may be impaired.
Note 2:
Testing done at V
CC
= 5V and V
ON/OFF
= 3V.
Note 3:
Supply current is measured as the average over several charge
pump burst cycles. C
+
= 1.0µF, C
–
= 0.1µF, C1 = C2 = 0.2µF. All outputs
are open, with all driver inputs tied high.
Note 4:
V
L
supply current is measured with all receiver outputs low.
Note 5:
Measurements in shutdown are performed with V
ON/OFF
≤
0.1V.
Supply current measurements using driver disable are performed with
V
DRIVER DISABLE
≥
3V.
Note 6:
For driver delay measurements, R
L
= 3k and C
L
= 51pF. Trigger
points are set between the driver’s input logic threshold and the output
transition to the zero crossing (t
HL
= 1.4V to 0V and t
LH
= 1.4V to 0V).
Note 7:
For receiver delay measurements, C
L
= 51pF. Trigger points are
set between the receiver’s input logic threshold and the output transition
to standard TTL/CMOS logic threshold (t
HL
= 1.3V to 2.4V and t
LH
= 1.7V
to 0.8V).
Note 8:
Data rate operation guaranteed by slew rate, short-circuit current
and propagation delay tests.
3
LT1330
TYPICAL PERFOR A CE CHARACTERISTICS
Driver Output Voltage
10
8
R
L
= 3k
OUTPUT HIGH
V
CC
= 5V
3.00
2.75
DRIVER OUTPUT VOLTAGE (V)
THRESHOLD VOLTAGE (V)
6
4
2
0
–2
–4
–6
–8
–10
–55 –25
OUTPUT LOW
V
CC
= 4.5V
2.25
2.00
1.75
1.50
1.25
1.00
0.75
INPUT LOW
INPUT HIGH
SUPPLY CURRENT (mA)
V
CC
= 4.5V
V
CC
= 5V
50
25
0
75
TEMPERATURE (°C)
V
CC
Supply Current in Shutdown
150
125
100
75
50
25
0
–55 –25
SUPPLY CURRENT (mA)
THRESHOLD VOLTAGE (V)
SUPPLY CURRENT (µA)
50
25
75
0
TEMPERATURE (°C)
ON/OFF Thresholds
3.0
2.5
THRESHOLD VOLTAGE (V)
40
35
SUPPLY CURRENT (mA)
30
25
20
15
10
5
LEAKAGE CURRENT (
µA)
2.0
ON THRESHOLD
1.5
1.0
OFF THRESHOLD
0.5
0
–55 –25
50
25
75
0
TEMPERATURE (°C)
4
U W
100
1330 G01
Receiver Input Thresholds
80
70
60
50
40
30
20
10
50
25
0
75
TEMPERATURE (°C)
100
125
Supply Current vs Data Rate
3DRIVERS ACTIVE
R
L
= 3k
C
L
= 2500pF
2.50
125
0.50
–55 –25
0
0
25
75
50
100
DATA RATE (kBAUD)
125
150
1330 G02
1330 G03
V
CC
Supply Current in
Driver Disable
5
3.0
2.5
2.0
1.5
1.0
0.5
DRIVER DISABLE Threshold
4
3
2
1
100
125
0
–55 –25
50
25
75
0
TEMPERATURE (°C)
100
125
0
–55 –25
50
25
75
0
TEMPERATURE (°C)
100
125
1330 G04
1330 G05
1330 G06
V
CC
Supply Current
100
3DRIVERS LOADED
R
L
= 3k
Driver Leakage in Shutdown
10
1DRIVER LOADED
R
L
= 3k
1
V
OUT
= 30V
V
OUT
= –30V
NO LOAD
100
125
0
–55 –25
50
25
0
75
TEMPERATURE (°C)
100
125
0.1
–55 –25
50
25
0
75
TEMPERATURE (°C)
100
125
1330 G07
1330 G08
1330 G09
LT1330
TYPICAL PERFOR A CE CHARACTERISTICS
Driver Short-Circuit Current
30
SHORT-CIRCUIT CURRENT (mA)
SHORT-CIRCUIT CURRENT (mA)
40
35
30
25
20
15
10
5
0
–55 –25
RX5 I
SC –
RX5 I
SC +
RX1 TO RX4
I
SC –
RX1 TO RX4
I
SC +
25
20
15
10
5
0
–55 –25
50
25
75
0
TEMPERATURE (°C)
Receiver Output Waveforms
RX5 OUTPUT
C
L
= 50pF
DRIVER OUTPUT
R
L
= 3k
C
L
= 2500pF
RX1 TO RX4
OUTPUT
C
L
= 50pF
INPUT
V
L
= 3V
PI FU CTIO S
V
CC
:
5V Input Supply Pin. This pin should be decoupled
with a 0.1µF ceramic capacitor close to the package pin.
Insufficient supply bypassing can result in low output
drive levels and erratic charge pump operation.
V
L
:
3V Logic Supply Pin for all RS232 Receivers. Like V
CC
,
the V
L
input should be decoupled with a 0.1µF ceramic
capacitor. This pin may also be connected to 5V.
GND:
Ground Pin.
ON/OFF:
TTL/CMOS Compatible Operating Mode Control.
A logic low puts the device in the low power shutdown
mode. All three drivers and four receivers (RX1, RX2, RX3,
and RX4) assume a high impedance output state in shut-
down. Only receiver RX5 remains active while the trans-
ceiver is in shutdown. The transceiver consumes only
60µA of supply current while in shutdown. A logic high
fully enables the transceiver.
DRIVER DISABLE:
This pin provides an alternate control
for the charge pump and RS232 drivers. A logic high on
this pin shuts down the charge pump and places all driver
outputs in a high impedance state. All five receivers remain
active under these conditions. Floating the driver disable
pin or driving it to a logic low level fully enables the
transceiver. A logic low on the ON/OFF pin supersedes the
state of the DRIVER DISABLE pin. Supply current drops to
3mA when in driver disable mode.
V
+
:
Positive Supply Output. V
+
≈
2V
CC
– 1.5V. This pin
requires an external charge storage capacitor, C
≥
1.0µF,
tied to ground or 5V. Larger value capacitors may be used
U W
Receiver Short-Circuit Current
I
SC+
I
SC–
100
125
50
0
75
25
TEMPERATURE (°C)
100
125
1330 G10
1330 G11
Driver Output Waveforms
DRIVER OUTPUT
R
L
= 3k
INPUT
1330 G12
1330 G13
U
U
U
5
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