LINER LT1237 5v rs232 transceiver with advanced power management and one receiver active in shutdown Datasheet

LT1237
5V RS232 Transceiver with
Advanced Power Management and
One Receiver Active in Shutdown
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FEATURES
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DESCRIPTIO
One Receiver Remains Active While in Shutdown
ESD Protection over ±15kV
Uses Small Capacitors: 0.1µF, 0.2µF, 1.0µF
60µA Supply Current in Shutdown
Pin Compatible with LT1137A
120kBaud Operation for RL = 3k, CL = 2500pF
250kBaud Operation for RL = 3k, CL = 1000pF
Operates to 120kBaud
CMOS Comparable Low Power 30mW
Operates from a Single 5V Supply
Easy PC Layout—Flowthrough Architecture
Rugged Bipolar Design
Outputs Assume a High Impedance State When Off
or Powered Down
Absolutely No Latchup
Available in SO and SSOP Packages
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APPLICATIO S
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The LT®1237 is an advanced low power three driver, five
receiver RS232 transceiver. Included on the chip is a
shutdown pin for reducing supply current near zero.
During shutdown one receiver remains active to detect
incoming RS232 signals, for example, to wake up a
system.
The LT1237 is fully compliant with all EIA RS232 specifications. New ESD structures on the chip allow the LT1237
to survive multiple ±15kV strikes, eliminating the need for
costly TransZorbs® on the RS232 line pins.
The LT1237 operates in excess of 120kbaud even driving
heavy capacitive loads. Two shutdown modes allow the
driver outputs to be shut down separately from the receivers for more versatile control of the RS232 interface.
During shutdown, drivers and receivers assume a high
impedance state.
, LTC and LT are registered trademarks of Linear Technology Corporation.
TransZorb is a registered trademark of General Instruments, GSI
Notebook Computers
Palmtop Computers
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TYPICAL APPLICATIO
Output Waveforms
V+
1.0µF
5V VCC
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
1
2
28
LT1237
V–
27
3
26
4
25
5
24
6
23
7
22
8
21
9
20
10
19
11
18
12
17
13
16
14
15
0.1µF
RECEIVER
OUTPUT
CL = 50pF
2 × 0.1µF
DRIVER 1 IN
RX1 OUT
DRIVER 2 IN
RX2 OUT
TO LOGIC
R
DRIVER
OUTPUT
RL = 3k
CL = 2500pF
RX3 OUT
RX4 OUT
DRIVER 3 IN
RX5 OUT (LOW-Q)
GND
DRIVER
DISABLE
INPUT
RING DETECT IN
µCONTROLLER OR
µPROCESSOR
1237 TA02
SHUTDOWN
CONTROL OUT
LT1237 TA01
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LT1237
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ABSOLUTE
PACKAGE/ORDER I FOR ATIO
(Note 1)
Supply Voltage (VCC) ................................................ 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 VCC + 0.3V
Short Circuit Duration
V + ................................................................... 30 sec
V – ................................................................... 30 sec
Driver Output .............................................. Indefinite
Receiver Output .......................................... Indefinite
Operating Temperature Range
LT1237C ................................................. 0°C to 70°C
Storage Temperature Range ................ – 65°C to 150°C
Lead Temperature (Soldering, 10 sec)................. 300°C
ORDER PART
NUMBER
TOP VIEW
V+ 1
28 V –
27 C2 –
5V VCC 2
C1
+
3
26 C2+
C1
–
4
25 DR1 IN
DR1 OUT 5
24 RX1 OUT
RX1 IN 6
LT1237CG
LT1237CNW
LT1237CSW
23 DR2 IN
DR2 OUT 7
22 RX2 OUT
RX2 IN 8
21 RX3 OUT
RX3 IN 9
20 RX4 OUT
RX4 IN 10
19 DR3 IN
RX5 OUT
18 (LOW-Q)
17 GND
16 DRIVER
DISABLE
15 NC
DR3 OUT 11
RX5 IN 12
(LOW-Q)
ON/OFF 13
NC 14
G PACKAGE
NW PACKAGE
28-LEAD PLASTIC SSOP 28-LEAD (WIDE) PDIP
SW PACKAGE
28-LEAD (WIDE) PLASTIC SO
TJMAX = 150°C, θJA = 96°C/ W (G)
TJMAX = 150°C, θJA = 56°C/ W (NW)
TJMAX = 150°C, θJA = 85°C/ W (SW)
Consult factory for Industrial and Military grade parts.
ELECTRICAL CHARACTERISTICS
The ● denotes specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. (Note 2)
PARAMETER
Power Supply Generator
V + Output
V – Output
Supply Current (VCC)
CONDITIONS
MIN
7.9
–7
6
6
0.06
3.00
2
TA = 25°C (Note 3)
●
Supply Current when OFF (VCC)
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
2
Shutdown (Note 4)
Driver Disable
C1 = C2 = 0.2µF,
C + = 1.0µF, C – = 0.1µF
Input Low Level (Drivers Enabled)
Input High Level (Drivers Disabled)
0V ≤ VON/OFF ≤ 5V
Input Low Level (Drivers Enabled)
Input High Level (Drivers Disabled)
0V ≤ VDRIVER DISABLE ≤ 5V
Driver Outputs Loaded RL = 3k
●
0.8
●
●
●
●
TYP
–15
0.8
1.2
1.6
1.4
1.4
–10
130
MAX
UNITS
12
14
0.15
V
V
mA
mA
mA
mA
ms
2.4
80
2.4
500
V
V
µA
V
V
µA
kHz
LT1237
ELECTRICAL CHARACTERISTICS
The ● denotes specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. (Note 2)
PARAMETER
CONDITIONS
Any Driver
Output Voltage Swing
Load = 3k to GND
Logic Input Voltage Level
Logic Input Current
Output Short-Circuit Current
Output Leakage Current
Data Rate (Note 7)
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 ISUPPLY RX)
Output Voltage
Output Short-Circuit Current
Propagation Delay
Positive
Negative
Input Low Level (VOUT = High)
Input High Level (VOUT = Low)
0.8V ≤ VIN ≤ 2V
VOUT = 0V
Shutdown VOUT = ±30V (Note 4)
RL = 3k, CL = 2500pF
RL = 3k, CL = 1000pF
RL = 3k, CL = 51pF
RL = 3k, CL = 2500pF
Output Transition tHL High to Low (Note 5)
Output Transition tLH Low to High
●
●
●
●
TYP
5.0
7.5
– 6.3
1.4
1.4
5
17
10
2.0
●
±9
●
4
0.8
●
VIN = ±10V
Shutdown (Note 4) 0 ≤ VOUT ≤ VCC
MAX
0.1
3
●
Output Low, IOUT = – 1.6mA
Output High, IOUT = 160µA (VCC = 5V)
Sinking Current, VOUT = VCC
Sourcing Current, VOUT = 0V
Output Transition tHL High to Low (Note 6)
Output Transition tLH Low to High
●
●
Output Low, IOUT = – 500µA
Output High, IOUT = 160µA (VCC = 5V)
Sinking Current, VOUT = VCC
Sourcing Current, VOUT = 0V
Output Transition tHL High to Low (Note 6)
Output Transition tLH Low to High
●
●
3.5
– 10
10
3.5
–2
2
UNITS
15
7
0.6
0.5
1.3
1.3
V
V
V
V
µA
mA
µA
kBaud
kBaud
V/µs
V/µs
µs
µs
1.3
1.7
0.4
5
1
2.4
1.0
7
10
V
V
V
kΩ
µA
– 5.0
0.8
20
100
120
250
Input Low Threshold (VOUT = High)
Input High Threshold (VOUT = Low)
Note 1: Absolute Maximum Ratings are those values beyond which the life
of the device may be impaired.
Note 2: Testing done at VCC = 5V and VON/OFF = 3V, unless otherwise
specified.
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: Measurements in shutdown are performed with VON/OFF ≤ 0.1V.
Supply current measurements using driver disable are performed with
VDRIVER DISABLE ≥ 3V.
MIN
0.2
4.2
– 20
20
250
350
0.2
4.2
–4
4
1.0
0.6
30
0.4
600
600
0.4
3
3
V
V
mA
mA
ns
ns
V
V
mA
mA
µs
µs
Note 5: For driver delay measurements, RL = 3k and CL = 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 tLH = 1.4V to 0V).
Note 6: For receiver delay measurements, CL = 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 tLH = 1.7V
to 0.8V).
Note 7: Data rate operation guaranteed by slew rate, short-circuit current
and propagation delay tests.
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LT1237
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TYPICAL PERFOR A CE CHARACTERISTICS
Receiver Input Thresholds
Driver Output Voltage
VCC = 5V
OUTPUT HIGH
2.75
VCC = 4.5V
6
4
2
0
–2
–4
OUTPUT LOW
VCC = 4.5V
–6
VCC = 5V
–8
–10
–55 –25
50
25
0
75
TEMPERATURE (°C)
100
80
2.50
2.25
2.00
INPUT HIGH
1.75
1.50
INPUT LOW
1.25
1.00
50
25
0
75
TEMPERATURE (°C)
Supply Current in Shutdown
40
30
20
100
0
125
0
125
4
2.5
50
THRESHOLD VOLTAGE (V)
150
3.0
75
3
2
1
25
50
25
75
0
TEMPERATURE (°C)
100
0
–55 –25
125
50
25
0
75
TEMPERATURE (°C)
35
SUPPLY CURRENT (mA)
ON THRESHOLD
1.5
1.0
OFF THRESHOLD
0.5
1.0
0
–55 –25
125
50
25
75
0
TEMPERATURE (°C)
100
30
1237 G06
Driver Leakage in Shutdown
100
3 DRIVERS LOADED
RL = 3k
25
20
1 DRIVER LOADED
RL = 3k
15
10
125
NO LOAD
10
1
VOUT = 30V
VOUT = –30V
5
50
25
75
0
TEMPERATURE (°C)
100
125
1237 G07
4
100
40
2.5
0
–55 –25
1.5
Supply Current
ON/OFF Thresholds
3.0
150
2.0
1237 G05
1237 G04
2.0
125
0.5
LEAKAGE CURRENT (µA)
0
–55 –25
75
50
100
DATA RATE (kBAUD)
DRIVER DISABLE Threshold
Supply Current in Driver Disable
100
25
1237 G03
5
SUPPLY CURRENT (mA)
SUPPLY CURRENT (µA)
50
1237 G02
1237 G01
THRESHOLD VOLTAGE (V)
60
10
0.75
0.50
–55 –25
125
3 DRIVERS ACTIVE
RL = 3k
CL = 2500pF
70
SUPPLY CURRENT (mA)
RL = 3k
THRESHOLD VOLTAGE (V)
DRIVER OUTPUT VOLTAGE (V)
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Supply Current vs Data Rate
3.00
10
0
–55 –25
50
25
0
75
TEMPERATURE (°C)
100
125
1237 G08
0.1
–55 –25
50
25
0
75
TEMPERATURE (°C)
100
125
1237 G09
LT1237
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TYPICAL PERFOR A CE CHARACTERISTICS
Driver Short-Circuit Current
Receiver Short-Circuit Current
50
25
SHORT-CIRCUIT CURRENT (mA)
SHORT-CIRCUIT CURRENT (mA)
30
ISC+
20
15
ISC–
10
5
0
–55 –25
50
25
75
0
TEMPERATURE (°C)
100
125
40
RX1 TO RX4
ISC–
30
RX1 TO RX4
ISC+
20
RX5 ISC –
10
RX5 ISC+
0
–55 –25
50
25
0
75
TEMPERATURE (°C)
100
125
1237 G11
1237 G10
Driver Output Waveforms
Receiver Output Waveforms
RX5 OUTPUT
CL = 50pF
DRIVER OUTPUT
RL = 3k
CL = 2500pF
RX1 TO RX4
OUTPUT
CL = 50pF
DRIVER OUTPUT
RL = 3k
INPUT
INPUT
1237 G12
1237 G13
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PI FU CTIO S
VCC: 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.
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 shutdown. Only receiver RX5 remains active while the transceiver 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 (RS232 Drivers). V + ≈ 2VCC –
1.5V. This pin requires an external charge storage capacitor C ≥ 1.0µF, tied to ground or VCC. Larger value capacitors may be used to reduce supply ripple. The ratio of the
capacitors on V + and V – should be greater than 5 to 1.
V –: Negative Supply Output (RS232 Drivers). V – ≈
–(2VCC – 2.5V). This pin requires an external charge
storage capacitor C ≥ 0.1µF. See the Applications Information section for guidance in choosing filter capacitors
for V + and V –.
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LT1237
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PI FU CTIO S
C1+, C1–, C2+, C2 –: Commutating Capacitor Inputs, require two external capacitors C ≥ 0.2µF: one from C1+ to
C1–, and another from C2 + to C2 –. The capacitor’s effective series resistance should be less than 2Ω. For C ≥ 1µF,
low ESR tantalum capacitors work well in this application,
although small value ceramic capacitors may be used with
a minimal reduction in charge pump compliance.
DRIVER IN: RS232 Driver Input Pins. These inputs are
TTL/CMOS compatible. Inputs should not be allowed to
float. Tie unused inputs to VCC.
DRIVER OUT: Driver Outputs at RS232 Voltage Levels.
Driver output swing meets RS232 levels for loads up to 3k.
Slew rates are controlled for lightly loaded lines. Output
current capability is sufficient for load conditions up to
2500pF. Outputs are in a high impedance state when in
shutdown mode, VCC = 0V, or when the DRIVER DISABLE
pin is active. Outputs are fully short-circuit protected from
V – + 30V to V + – 30V. Applying higher voltages will not
damage the device if the overdrive is moderately current
limited. Short circuits on one output can load the power
supply generator and may disrupt the signal levels of the
other outputs. The driver outputs are protected against
ESD to ±15kV for human body model discharges, ±8kV
for IEC 1000-4-2 contact mode discharges and ±15kV for
IEC 1000-4-2 air gap discharges.
RX IN: Receiver Inputs. These pins accept RS232 level
signals (±30V) into a protected 5k terminating resistor.
The receiver inputs are protected against ESD to ±15kV for
human body model discharges, ±8kV for IEC 1000-4-2
contact mode discharges and ±15kV for IEC 1000-4-2 air
gap discharges. Each receiver provides 0.4V of hysteresis
for noise immunity. Open receiver inputs assume a logic
low state.
RX OUT: Receiver Outputs with TTL/CMOS Voltage Levels. Outputs RX1, RX2, RX3, and RX4 are in a high
impedance state when in shutdown mode to allow data
line sharing. Outputs, including LOW-Q RX OUT, are fully
short-circuit protected to ground or VCC with the power
on, off, or in shutdown mode.
LOW Q-CURRENT RX IN: Low Power Receiver Input. This
special receiver remains active when the part is in shutdown mode, consuming typically 60µA. This receiver has
the same 5k input impedance and ±10kV ESD protection
characteristics as the other receivers.
LOW Q-CURRENT RX OUT: Low Power Receiver Output.
This pin produces the same TTL/CMOS output voltage
levels as receivers RX1, RX2, RX3, and RX4 with slightly
decreased speed and short-circuit current. Data rates to
120kbaud are supported by this receiver.
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ESD PROTECTIO
The RS232 line inputs of the LT1237 have on-chip protection from ESD transients up to ±15kV for human body
discharges, ±8kV for IEC 1000-4-2 contact mode discharges and ±15V for IEC 1000-4-2 air gap discharges.
The protection structures act to divert the static discharge
safely to system ground. In order for the ESD protection to
function effectively, the power supply and ground pins of
the LT1237 must be connected to ground through low
impedances. The power supply decoupling capacitors and
charge pump storage capacitors provide this low impedance in normal application of the circuit. The only constraint is that low ESR capacitors must be used for
bypassing and charge storage. ESD testing must be done
with pins VCC, VL, V +, V – and GND shorted to ground or
connected with low ESR capacitors.
6
ESD Test Circuit
1
V+
5V VCC 2
1µF
3
26
0.2µF
4
25
5
24
6
23
7
22
8
21
9
20
10
19
11
18
12
17
13
16
14
15
RX1 IN
DRIVER 2 OUT
RX2 IN
RX3 IN
RX4 IN
DRIVER 3 OUT
RX5 IN (LOW-Q)
ON/OFF
V–
27
0.1µF
DRIVER 1 OUT
RS232
LINE PINS
PROTECTED
TO ±10kV
28
LT1237
0.1µF
0.2µF
DRIVER 1 IN
RX1 OUT
DRIVER 2 IN
RX2 OUT
RX3 OUT
RX4 OUT
DRIVER 3 IN
RX5 OUT (LOW-Q)
GND
DRIVER DISABLE
1237 TC01
LT1237
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APPLICATI
S I FOR ATIO
Storage Capacitor Selection
The V + and V – storage capacitors must be chosen carefully to insure low ripple and stable operation. The LT1237
charge pump operates in a power efficient Burst ModeTM
operation. When storage capacitor voltage drops below a
preset threshold, the oscillator is gated on until V+ and V –
are boosted up to levels exceeding a second threshold.
The oscillator then turns off, and current is supplied from
the V+ and V – storage capacitors.
The V – potential is monitored to control charge pump
operation. It is therefore important to insure lower V +
ripple than V – ripple, or erratic operation of the charge
pump will result. Proper operation is insured in most
applications by choosing the V+ filter capacitor to be at
least 5 times the V – filter capacitor value. If V + is more
heavily loaded than V –, a larger ratio may be needed.
The V – filter capacitor should be selected to obtain low
ripple when the drivers are loaded, forcing the charge
pump into continuous mode. A minimum value 0.1µF is
suggested.
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PACKAGE DESCRIPTIO
Do not attempt to reduce V – ripple when the charge pump
is in discontinuous Burst Mode operation. The ripple in
this mode is determined by internal comparator thresholds. Larger storage capacitor values increase the burst
period, and do not reduce ripple amplitude.
Power Saving Operational Modes
The LT1237 has both shutdown and driver disable operating 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 information 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 consumption in driver disable mode is 3mA from VCC.
Burst Mode is a trademark of Linear Technology Corporation
Dimensions in inches (millimeters) unless otherwise noted.
G Package
28-Lead Plastic SSOP (0.209)
(LTC DWG # 05-08-1640)
0.205 – 0.212**
(5.20 – 5.38)
0.397 – 0.407*
(10.07 – 10.33)
0.068 – 0.078
(1.73 – 1.99)
28 27 26 25 24 23 22 21 20 19 18 17 16 15
0° – 8°
0.0256
(0.65)
BSC 0.010 – 0.015
(0.25 – 0.38)
0.005 – 0.009 0.022 – 0.037
(0.13 – 0.22) (0.55 – 0.95)
0.301 – 0.311
(7.65 – 7.90)
0.002 – 0.008
(0.05 – 0.21)
*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
1 2 3 4 5 6 7 8 9 10 11 12 13 14
G28 SSOP 0694
NW Package
28-Lead PDIP (Wide 0.600)
(LTC DWG # 05-08-1520)
0.600 – 0.625
(15.240 – 15.875)
0.150 ± 0.005
(3.810 ± 0.127)
0.070
(1.778)
TYP
0.045 – 0.065
(1.143 – 1.651)
1.455*
(36.957)
MAX
28
27
26
25
24
23
22
21
20
19
18
17
16
1
2
3
4
5
6
7
8
9
10
11
12
13
0.015
(0.381)
MIN
0.009 – 0.015
(0.229 – 0.381)
(
+0.035
0.625 –0.015
15.87
+0.889
–0.381
)
15
0.505 – 0.560*
(12.827 – 14.224)
0.125
(3.175)
MIN
0.035 – 0.080
(0.889 – 2.032)
0.100 ± 0.010
(2.540 ± 0.254)
0.018 ± 0.003
(0.457 ± 0.076)
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N28 1197
*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.010 INCH (0.254mm)
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 representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
7
LT1237
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PACKAGE DESCRIPTIO
Dimensions in inches (millimeters) unless otherwise noted.
SW Package
28-Lead Plastic Small Outline (Wide 0.300)
(LTC DWG # 05-08-1620)
0.291 – 0.299**
(7.391 – 7.595)
0.037 – 0.045
(0.940 – 1.143)
0.010 – 0.029 × 45° 0.093 – 0.104
(2.362 – 2.642)
(0.254 – 0.737)
0.697 – 0.712*
(17.70 – 18.08)
28 27 26 25 24 23 22 21 20 19 18 17 16 15
0° – 8° TYP
0.009 – 0.013
(0.229 – 0.330)
0.050
(1.270)
TYP 0.014 – 0.019
(0.356 – 0.482)
TYP
NOTE 1
0.394 – 0.419
(10.007 – 10.643)
NOTE 1
0.004 – 0.012
(0.102 – 0.305)
0.016 – 0.050
(0.406 – 1.270)
NOTE:
1. PIN 1 IDENT, NOTCH ON TOP AND CAVITIES ON THE BOTTOM OF PACKAGES ARE THE MANUFACTURING OPTIONS.
THE PART MAY BE SUPPLIED WITH OR WITHOUT ANY OF THE OPTIONS
1
2
3
4
5
6
7
8
9 10 11 12 13 14
S28 (WIDE) 0996
*DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
**DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE
UO
TYPICAL APPLICATI
Typical Mouse Driving Application
V+
1.0µF
5V VCC
MOUSE
2 × 0.1µF
(1)
OPTICS
(5)
(9)
V–
27
3
26
4
25 DRIVER 1 IN
5
24 RX1 OUT
DCD
RX1 IN
6
23 DRIVER 2 IN
DSR
DRIVER 2 OUT
7
22 RX2 OUT
RX
RX2 IN
8
21 RX3 OUT
RTS
RX3 IN
9
20 RX4 OUT
TX
V–
2
28
LT1237
DRIVER 1 OUT
V+
LOGIC
1
RX4 IN 10
CTS
DRIVER 3 OUT 11
DTR
RX5 IN (LOW-Q) 12
RI
ON/OFF 13
14
DB9
0.1µF
2 × 0.1µF
19 DRIVER 3 IN
LOGIC “0”
LOGIC “0”
MOUSE DATA
LOGIC “1”
18 RX5 OUT (LOW-Q)
17 GND
16 DRIVER DISABLE
15
1237 TA03
RELATED PARTS
PART NUMBER
LTC®485
LT1137A
LTC1387
LT1780/LT1781
LT1785/LT1791
8
DESCRIPTION
Low Power RS485 Transceiver
3Dx/5Rx RS232 Transceiver
RS232/RS485 Multiprotocol Transceiver
2Dx/2Rx RS232 Transceiver
60V Fault Tolerant RS485 Transceiver
Linear Technology Corporation
COMMENTS
15kV ESD
15kV ESD
15kV ESD
1237fa LT/TP 0799 2K REV A • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408)432-1900 ● FAX: (408) 434-0507 ● www.linear-tech.com
 LINEAR TECHNOLOGY CORPORATION 1992
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