LTC2870/LTC2871
4
28701f
ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VCC = VL = 3.3V, TE485 = 0V, LB = 0V unless otherwise noted.
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Power Supply
VCC
Supply Voltage Operating Range
3
5.5
V
VL
Logic Supply Voltage Operating Range
VL ≤ VCC
1.7
VCC
V
VCC Supply Current in Shutdown Mode
RXEN = VL, DXEN = TE485 = FEN = 0V, (LTC2870)
DX485 = DX232 = TE485 = FEN = H/F = 0V,
RX485 = RX232 = VL (LTC2871)
l
860
μA
VCC Supply Current in Transceiver Mode
(Outputs Unloaded) (Note 3)
485/232 = DXEN = VL, RXEN = 0V,
DY/DZ = 0V or VL (LTC2870)
DX485 = DX232 = VL, RX485 = RX232 = 0V,
DI/DIN1/DIN2 = 0V or VL (LTC2871)
3.3
mA
VL Supply Current in Transceiver Mode
(Outputs Unloaded)
l
05
μA
RS485 Driver
|VOD|
Differential Output Voltage
RL = ∞, VCC = 3V (Figure 1)
RL = 27Ω, VCC = 3V (Figure 1)
RL = 50Ω, VCC = 3.13V (Figure 1)
l
1.5
2
6
VCC
V
Δ|VOD|
Difference in Magnitude of Differential Output
Voltage for Complementary Output States
RL = 27Ω, VCC = 3V (Figure 1)
RL = 50Ω, VCC = 3.13V (Figure 1)
l
0.2
V
VOC
Common Mode Output Voltage
RL = 27Ω or 50Ω (Figure 1)
l
3V
Δ|VOC|
Difference in Magnitude of Common Mode
Output Voltage for Complementary Output
States
RL = 27Ω or 50Ω (Figure 1)
l
0.2
V
IOZD485
Three-State (High Impedance) Output Current
VOUT = 12V or –7V, VCC = 0V or 3.3V (Figure 2)
l
–100
125
μA
IOSD485
Maximum Short-Circuit Current
–7V ≤ VOUT ≤ 12V (Figure 2)
l
–250
250
mA
RS485 Receiver
IIN485
Input Current
VIN = 12V or –7V, VCC = 0V or 3.3V (Figure 3)
(Note 5)
l
–100
125
μA
RIN485
Input Resistance
VIN = 12V or –7V, VCC = 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)
130
mV
Differential Input Failsafe Threshold Voltage
–7V ≤ (A or B) ≤ 12V (Note 5)
l
–200
–50
0
mV
Input DC Failsafe Hysteresis
B = 0V (Note 5)
25
mV
VOL
Output Low Voltage
Output Low, I(RA, RO) = 3mA (Sinking),
3V ≤ VL ≤ 5.5V
l
0.4
V
Output Low, I(RA, RO) = 1mA (Sinking),
1.7V ≤ VL < 3V
l
0.4
V
VOH
Output High Voltage
Output High, I(RA, RO) = –3mA (Sourcing),
3V ≤ VL ≤ 5.5V
l VL – 0.4
V
Output High, I(RA, RO) = –1mA (Sourcing),
1.7V ≤ VL < 3V
l VL – 0.4
V
Three-State (High Impedance) Output Current
0V ≤ (RA, RO), ≤VL, VL = 5.5V
l
0±5
μA
Short-Circuit Output Current
0V ≤ (RA, RO), ≤VL, VL = 5.5V
l
±125
mA