Datasheet

LTC2870/LTC2871
4
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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 = 0V, LB = 0V unless otherwise noted.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Power Supply
V
CC
Supply Voltage Operating Range 3 5.5 V
V
L
Logic Supply Voltage Operating Range V
L
≤ V
CC
1.7 V
CC
V
V
CC
Supply Current in Shutdown Mode RXEN = V
L
, DXEN = TE485 = FEN = 0V,
(LTC2870)
DX485 = DX232 = TE485 = FEN = H/F = 0V,
RX485 = RX232 = V
L
(LTC2871)
l
8 60 µA
V
CC
Supply Current in Transceiver Mode
(Outputs Unloaded) (Note 3)
485/232 = DXEN = V
L
, RXEN = 0V,
DY/DZ = 0V or V
L
(LTC2870)
DX485 = DX232 = V
L
, RX485 = RX232 = 0V,
DI/DIN1/DIN2 = 0V or V
L
(LTC2871)
3.3 mA
V
L
Supply Current in Transceiver Mode
(Outputs Unloaded)
l
0 5 µA
RS485 Driver
|V
OD
| Differential Output Voltage R
L
= ∞, V
CC
= 3V (Figure 1)
R
L
= 27Ω, V
CC
= 3V (Figure 1)
R
L
= 50Ω, V
CC
= 3.13V (Figure 1)
l
l
l
1.5
1.5
2
6
V
CC
V
CC
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)
l
96 125 kΩ
Differential Input Signal Threshold Voltage
(A-B)
–7V ≤ (A or B) ≤ 12V (Note 5)
l
±200 mV
Input Hysteresis B = 0V (Notes 3, 5) 220 mV
Differential Input Failsafe Threshold Voltage –7V ≤ (A or B) ≤ 12V, (A-B) Rising (Note 5)
l
–200 –70 0 mV
Input DC Failsafe Hysteresis B = 0V (Note 5) 35 mV
V
OL
Output Low Voltage Output Low, I(RA, RO) = 3mA (Sinking),
3V ≤ V
L
≤ 5.5V
l
0.4 V
Output Low, I(RA, RO) = 1mA (Sinking),
1.7V ≤ V
L
< 3V
l
0.4 V
V
OH
Output High Voltage Output High, I(RA, RO) = –3mA (Sourcing),
3V ≤ V
L
≤ 5.5V
l
V
L
– 0.4 V
Output High, I(RA, RO) = –1mA (Sourcing),
1.7V ≤ V
L
< 3V
l
V
L
– 0.4 V
Three-State (High Impedance) Output Current 0V ≤ (RA, RO) ≤V
L
, V
L
= 5.5V
l
0 ±5 µA
Short-Circuit Output Current 0V ≤ (RA, RO) ≤V
L
, V
L
= 5.5V
l
±125 mA
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