LTC2872
3
2872f
elecTrical characTerisTics
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
CC
= V
L
= 3.3V, TE485_1 = TE485_2 = 0V, LB = 0V unless otherwise noted.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Power Supply
V
CC
Supply Voltage Operating Range
l
3 5.5 V
V
L
Logic Supply Voltage Operating Range V
L
≤ V
CC
l
1.7 V
CC
V
V
CC
Supply Current in Shutdown Mode RXEN1 = RXEN2 = V
L
,
DXEN1 = DXEN2 = FEN = H/F = 0V
l
8 60 µA
V
CC
Supply Current in RS485 Transceiver Mode
(Outputs Unloaded) (Note 3)
485/232_1 = 485/232_2 = DXEN1 =
DXEN2 = V
L
, RXEN1 = RXEN2 = 0V
l
4.5 7 mA
V
CC
Supply Current in RS232 Transceiver Mode
(Outputs Unloaded) (Note 3)
DXEN1 = DXEN2 = V
L
; 485/232_1 =
485/232_2 = RXEN1 = RXEN2 = 0V
l
5.5 8 mA
V
L
Supply Current in RS485 or RS232 Transceive
Mode (Outputs Unloaded)
DXEN1 = DXEN2 = V
L
, RXEN1 = RXEN2 = 0V
l
0 5 µA
RS485 Drivers
|V
OD
| Differential Output Voltage R
L
= ∞, V
CC
= 3V (Figure 1)
R
L
= 27Ω, V
CC
= 4.5V (Figure 1)
R
L
= 27Ω, V
CC
= 3V (Figure 1)
R
L
= 50Ω, V
CC
= 3.13V (Figure 1)
l
l
l
l
2.1
1.5
2
6
V
CC
V
CC
V
CC
V
V
V
V
∆|V
OD
| Difference in Magnitude of Differential Output
Voltage for Complementary Output States
R
L
= 27Ω, V
CC
= 3V (Figure 1)
R
L
= 50Ω, V
CC
= 3.13V (Figure 1)
l
l
0.2
0.2
V
V
V
OC
Common Mode Output Voltage R
L
= 27Ω or 50Ω (Figure 1)
l
3 V
∆|V
OC
| Difference in Magnitude of Common Mode
Output Voltage for Complementary Output States
R
L
= 27Ω or 50Ω (Figure 1)
l
0.2 V
I
OZD485
Three-State (High Impedance) Output Current V
OUT
= 12V or –7V,
V
CC
= 0V or 3.3V (Figure 2)
l
–100 125 µA
I
OSD485
Maximum Short-Circuit Current –7V ≤ V
OUT
≤ 12V (Figure 2)
l
–250 250 mA
RS485 Receiver
I
IN485
Input Current V
IN
= 12V or –7V, V
CC
= 0V or 3.3V
(Figure 3) (Note 5)
l
–100 125 µA
R
IN485
Input Resistance V
IN
= 12V or –7V, V
CC
= 0V or 3.3V
(Figure 3) (Note 5)
125 kΩ
Differential Input Signal Threshold Voltage (A–B) –7V ≤ (A or B) ≤ 12 (Note 5)
l
±200 mV
Differential Input Signal Hysteresis B = 0V (Notes 3, 5) 190 mV
Differential Input DC Failsafe Threshold Voltage
(A–B)
–7V ≤ (A or B) ≤ 12 (Note 5)
l
–200 –65 0 mV
Differential Input DC Failsafe Hysteresis B = 0V (Note 5) 30 mV
V
OL
Output Low Voltage Output Low, I(RA) = 3mA (Sinking),
3V ≤ V
L
≤ 5.5V
l
0.4 V
Output Low, I(RA) = 1mA (Sinking),
1.7V ≤ V
L
< 3V
l
0.4 V
V
OH
Output High Voltage Output High, I(RA) = –3mA (Sourcing),
3V ≤ V
L
≤ 5.5V
l
V
L
– 0.4 V
Output High, I(RA) = –1mA (Sourcing),
1.7V ≤ V
L
< 3V
l
V
L
– 0.4 V
Three-State (High Impedance) Output Current 0V ≤ RA ≤ V
L
, V
L
= 5.5V
l
0 ±5 μA
Short-Circuit Output Current 0V ≤ RA ≤ V
L
, V
L
= 5.5V
l
±135 mA
R
TERM
Terminating Resistor TE485 = V
L
, A–B = 2V, B = –7V, 0V, 10V
(Figure 8) (Note 5)
l
108 120 156 Ω
