LTC2803_15 Datasheet, PDF (8/18 Pages) Linear Technology – 1.8V to 5.5V RS-232 Single and Dual Transceivers

LTC2801/LTC2802/
LTC2803/LTC2804
Pin Functions
PIN NAME
V_CC
V_DD
V_EE
SW
GND
CAP
V_L
TIN (T1IN, T2IN)
TOUT (T1OUT, T2OUT)
RIN (R1IN, R2IN)
ROUT (R1OUT, R2OUT)
PS
MODE
ON/OFF
*Backside thermal pad
PIN NUMBER
2801 2803 2803-1
2802 2804 2804-1
3
5
5
4
6
6
13*
17*
9
5
7
7
6
8
8
7
9
10
10
12
12
11 14, 13 14, 13
2
3, 4
3, 4
1
1, 2
1, 2
12 16, 15 16, 15
8
10
—
9
11
—
—
—
11
COMMENTS
Input Supply (1.8V-5.5V). Bypass to GND with a 1µF capacitor.
Generated Positive Supply Voltage for RS-232 Driver (7V). Connect a 1µF capacitor between
V_DD and GND.
Generated Negative Supply Voltage for RS-232 Driver (–6.3V). Connect a 1µF capacitor
between V_EE and GND.
Switch Pin. Connect a 10µH inductor between SW and V_CC.
Ground.
Charge Pump Capacitor for Generated Negative Supply Voltage. Connect a 220nF capacitor
between CAP and SW.
Logic Supply (1.8V-5.5V) for the receiver outputs, driver inputs, and control inputs. This pin
should be bypassed to GND with a 220nF capacitor if it’s not tied to V_CC.
Driver Input(s), referenced to V_L.
RS-232 Driver Output(s).
RS-232 Receiver Input(s). Includes internal 5kΩ termination resistor(s).
Receiver Output(s), referenced to V_L. Output is short-circuit protected to GND/V_CC/V_L, and is
high impedance in Shutdown mode, allowing data line sharing.
Power Supply control pin, referenced to V_L. Enables the integrated DC-DC converter.
Mode control pin, referenced to V_L. See Table 1 for functionality.
Transceiver enable pin, referenced to V_L. A logic low puts the device in Shutdown mode and
places both driver and receiver outputs in a high impedance state.
Mode Control
Table 1. LTC2801, LTC2802, LTC2803, LTC2804
MODE NAME
PS
SHUTDOWN
L
RECEIVER(S) ACTIVE
L
DRIVER(S) DISABLED
H
MODE
L
H
L
NORMAL
H
H
RECEIVER
OUTPUT(S)
HI-Z
ON
ON
ON
DC-DC
OFF
OFF
ON
ON
Table 2. LTC2803-1, LTC2804-1
MODE NAME
SHUTDOWN
NORMAL
ON/OFF
L
H
RECEIVER
OUTPUTS
HI-Z
ON
DC-DC
OFF
ON
*Typical currents for static drivers. Normal mode currents are for unloaded outputs.
DRIVER
OUTPUT(S)
HI-Z
HI-Z
HI-Z
ON
DRIVER
OUTPUTS
HI-Z
ON
I_VCC*
1µA
1µA
2.1mA
2.3mA
I_VCC*
1µA
2.3mA
I_VL*
1µA
15µA
80µA OR
150µA
80µA OR
150µA
I_VL*
1µA
150µA

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