LT1130A Datasheet, PDF (7/12 Pages) Linear Technology – Advanced Low Power 5V RS232 Drivers/Receivers with Small Capacitors

LT1130A/LT1140A Series
TYPICAL PERFOR A CE CHARACTERISTICS
Driver Short-Circuit Current
30
25
ISC⁺
20
15
ISC ^–
10
5
0
–55 –25
0 25 50 75 100 125
TEMPERATURE (°C)
LT1137A • TPC10
Shutdown to Driver Output
DRIVER ₁₀
OUTPUT HIGH
R_L = 3k ⁵
0
DRIVER _{– 5}
OUTPUT LOW
R_L = 3k – 10
ON/OFF PIN
LT1137A • TPC12
Receiver Short-Circuit Current
50
40
ISC^–
30
ISC⁺
20
10
0
–55 –25
0 25 50 75 100 125
TEMPERATURE (°C)
LT1137A • TPC11
Driver Output Waveforms
DRIVER OUTPUT
R_L = 3k
DRIVER OUTPUT
R_L = 3k
C_L = 2500pF
INPUT
LT1137A • TPC13
PI FU CTIO S
V_CC: 5V Input Supply Pin. Supply current drops to zero in
the shutdown mode. This pin should be decoupled with a
0.1µF ceramic capacitor close to the package pin. Insuffi-
cient supply bypassing can result in low output drive levels
and erratic charge pump operation.
GND: Ground Pin.
ON/OFF: Control the operation mode of the device and is
TTL/CMOS compatible. A logic low puts the device in the
shutdown mode which reduces input supply curent to zero
and places all of the drivers and receivers in high imped-
ance state. 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 drivers
in a high impedance state. 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 4mA when
in driver disable mode.
V⁺: Positive Supply Output (RS232 Drivers). V⁺ ≈ 2V_CC –
1.5V. This pin requires an external charge storage capaci-
tor C ≥ 1.0µF, tied to ground or V_CC. Larger value capaci-
tors may be used to reduce supply ripple. With multiple
transceivers, the V ⁺ and V ^– pins may be paralleled into
common capacitors. For large numbers of transceivers,
increasing the size of the shared common storage capaci-
tors is recommended to reduce ripple.
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