LTC2854_15 Datasheet, PDF (4/16 Pages) Linear Technology – 3.3V 20Mbps RS485/RS422 Transceivers with Integrated Switchable Termination

LTC2854/LTC2855
ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T_A = 25°C, V_CC = 3.3V, T_E = 0V unless otherwise noted (Note 2).
SYMBOL
I_CCT
I_CCTR
I_CCTERM
I_CCTERMR
I_CCTERMT
PARAMETER
Supply Current in Transmit Mode
Supply Current with Both Driver and
Receiver Enabled
Supply Current in Termination Mode
Supply Current in Receive and
Termination Mode
Supply Current in Transmit and
Termination Mode
CONDITIONS
No Load, DE = V_CC, RE = V_CC, TE = 0V
No Load, DE = V_CC, RE = 0V, TE = 0V
DE = 0V, RE = V_CC, TE = V_CC
DE = 0V, RE = 0V, TE = V_CC
DE = V_CC, RE = V_CC, TE = V_CC
MIN TYP MAX
●
450 1000
●
450 1000
●
110
180
●
450
950
●
470 1000
I_CCTERMTR
Supply Current with Driver, Receiver
and Termination Enabled
DE = V_CC, RE = 0V, TE = V_CC
●
470 1000
ESD Protection
ESD Protection for RS485/RS422 Pins A, B on LTC2854, Human Body Model
±25
Y, Z, A, B on LTC2855, Human Body Model
±15
UNITS
μA
μA
μA
μA
μA
μA
kV
kV
SWITCHING CHARACTERISTICS The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T_A = 25°C, V_CC = 3.3V, T_E = 0V unless otherwise noted (Note 2).
SYMBOL
PARAMETER
CONDITIONS
MIN TYP MAX UNITS
Driver
f_MAX
t_PLHD, t_PHLD
Δt_PD
t_SKEWD
t_RD, t_FD
t_ZLD, t_ZHD, t_LZD, t_HZD
t_ZHSD, t_ZLSD
t_SHDN
Maximum Data Rate
Driver Input to Output
Driver Input to Output Difference
|t_PLHD-t_PHLD|
Driver Output Y to Output Z
Driver Rise or Fall Time
Driver Enable or Disable Time
Driver Enable from Shutdown
Time to Shutdown
Note 3
R_DIFF = 54Ω, C_L = 100pF (Figure 4)
R_DIFF = 54Ω, C_L = 100pF (Figure 4)
● 20
●
●
R_DIFF = 54Ω, C_L = 100pF (Figure 4)
●
R_DIFF = 54Ω, C_L = 100pF (Figure 4)
●
R_L = 500Ω, C_L = 50pF, RE = 0 (Figure 5)
●
R_L = 500Ω, C_L = 50pF, RE = V_CC (Figure 5) ●
(RD^LE==5↓^{00, Ω}RE^,
C_L = 50pF
= V_CC) or
(DE
=
0,
RE
↑)
●
(Figure 5)
Mbps
10
50
ns
1
6
ns
1
±6
ns
4
12.5
ns
70
ns
8
μs
100
ns
Receiver
t_PLHR, t_PHLR
Receiver Input to Output
t_SKEWR
t_RR, t_FR
t_ZLR, t_ZHR, t_LZR, t_HZR
t_ZHSR, t_ZLSR
t_RTEN, t_RTZ
Differential Receiver Skew
|t_PLHR-t_PHLR|
Receiver Output Rise or Fall Time
Receiver Enable/Disable
Receiver Enable from Shutdown
Termination Enable or Disable Time
C_L = 15pF, V_CM = 1.5V, |V_AB| = 1.5V, t_R and t_F ●
< 4ns (Figure 6)
C_L = 15pF (Figure 6)
●
C_L = 15pF (Figure 6)
●
R_L = 1k, C_L =15pF, DE = V_CC (Figure 7)
●
R_L = 1k, C_L = 15pF, DE = 0V (Figure 7)
●
V_B = 0V, V_AB = 2V, RE = V_CC, DE = 0V
●
(Figure 8)
50
70
ns
1
6
ns
3
12.5
ns
50
ns
8
μs
100
μs
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime. High temperatures degrade operating lifetimes.
Operating lifetime is derated at temperatures greater than 105°C
Note 2: All currents into device pins are positive; all currents out of device
pins are negative. All voltages are referenced to device ground unless
otherwise specified.
Note 3: Maximum data rate is guaranteed by other measured parameters
and is not tested directly.
Note 4: This IC includes overtemperature protection that is intended
to protect the device during momentary overload conditions.
Overtemperature protection activates at a junction temperature exceeding
150°C. Continuous operation above the specified maximum operating
junction temperature may result in device degradation or failure.
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