Datasheet

ADM2485
Rev. A | Page 3 of 20
SPECIFICATIONS
2.7 V ≤ V
DD1
≤ 5.5 V, 4.75 V ≤ V
DD2
≤ 5.25 V, T
A
= T
MIN
to T
MAX
, unless otherwise noted.
Table 1.
Parameter Min Typ Max Unit Test Conditions/Comments
DRIVER
Differential Outputs
Differential Output Voltage, V
OD
5 V R = ∞, see Figure 21
2.1 5 V R = 50 Ω (RS-422), see Figure 21
2.1 5 V R = 27 Ω (RS-485), see Figure 21
2.1 5 V V
TST
= –7 V to +12 V, V
DD1
≥ 4.75 V, see Figure 22
Δ|V
OD
| for Complementary Output States 0.2 V R = 27 Ω or 50 Ω, see Figure 21
Common-Mode Output Voltage, V
OC
3 V R = 27 Ω or 50 Ω, see Figure 21
Δ|V
OC
| for Complementary Output States 0.2 V R = 27 Ω or 50 Ω, see Figure 21
Output Short-Circuit Current, V
OUT
= High 60 200 mA −7 V ≤ V
OUT
≤ +12 V
Output Short-Circuit Current, V
OUT
= Low 60 200 mA −7 V ≤ V
OUT
≤ +12 V
Bus Enable Output
Output High Voltage V
DD2
− 0.1 V I
ODE
= 20 μA
V
DD2
− 0.3 V
DD2
− 0.1 V I
ODE
= 1.6 mA
V
DD2
− 0.4 V
DD2
− 0.2 V I
ODE
= 4 mA
Output Low Voltage 0.1 V I
ODE
= −20 μA
0.1 0.3 V I
ODE
= −1.6 mA
0.2 0.4 V I
ODE
= −4 mA
Logic Inputs
Input High Voltage 0.7 V
DD1
V
TxD, RTS,
RE
Input Low Voltage 0.25 V
DD1
V
TxD, RTS,
RE
CMOS Logic Input Current (TxD, RTS, RE)
−10 +0.01 +10 μA
TxD, RTS, RE = V
DD1
or 0 V
RECEIVER
Differential Inputs
Differential Input Threshold Voltage, V
TH
−200 +200 mV −7 V ≤ V
CM
≤ +12V
Input Hysteresis 70 mV −7 V ≤ V
CM
≤ +12V
Input Resistance (A, B) 20 30 kΩ −7 V ≤ V
CM
≤ +12V
Input Current (A, B) 0.6 mA V
IN
= +12 V
−0.35 mA V
IN
= −7 V
RxD Logic Output
Output High Voltage V
DD1
− 0.1 V I
OUT
= +20 μA, V
A
− V
B
= +0.2 V
V
DD1
− 0.4 V
DD1
− 0.2 V I
OUT
= +1.5 mA, V
A
− V
B
= +0.2 V
Output Low Voltage 0.1 V I
OUT
= −20 μA, V
A
− V
B
= −0.2 V
0.2 0.4 V I
OUT
= −4 mA, V
A
− V
B
= −0.2 V
Output Short-Circuit Current 7 85 mA V
OUT
= GND or V
CC
Tristate Output Leakage Current ±1 μA 0.4 V ≤ V
OUT
≤ 2.4 V
TRANSFORMER DRIVER
Oscillator Frequency 400 500 600 kHz V
DD1
= 5.5 V
230 330 430 kHz V
DD1
= 3.3 V
Switch-On Resistance 0.5 1.5 Ω
Start-Up Voltage 2.2 2.5 V