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參數(shù)資料
| 型號： | MAX1490B |
| 廠商： | Maxim Integrated Products, Inc. |
| 英文描述： | Complete, Isolated RS-485/RS-422 Data Interface(2.5Mbps，全雙工，完全隔離的RS-485/422收發(fā)器) |
| 中文描述： | 完備的隔離型、RS-485/RS-422數(shù)據(jù)接口 |
| 文件頁數(shù)： | 10/20頁 |
| 文件大?。?/td> | 315K |
| 代理商： | MAX1490B |
M
Complete, Isolated,
RS -485/RS -422 Data Interfac e
10
______________________________________________________________________________________
_______________Detailed Desc ription
The MAX1480A/MAX1480B/MAX1490A/MAX1490B are
complete, electrically isolated, RS-485/RS-422 data-
communications interface solutions. Transceivers, opto-
couplers, a power driver, and a transformer in one
standard 28-pin DIP package (24-pin for the
MAX1490A/B) provide a complete interface. Signals
and power are internally transported across the isola-
tion barrier (Figures 1, 2). Power is transferred from the
logic side (non-isolated side) to the isolated side of the
barrier through a center-tapped transformer. Signals
cross the barrier through high-speed optocouplers. A
single +5V supply on the logic side powers both sides
of the interface. The MAX1480A/B offer half-duplex
communications while the MAX1490A/B feature full-
duplex communication. The functional input/output rela-
tionships are shown in Tables 3–6.
The MAX1480B/MAX1490B feature reduced-slew-rate
drivers that minimize EMI and reduce reflections
caused by improperly terminated cables, allowing
error-free transmission at data rates up to 250kbps. The
MAX1480A/MAX1490A driver slew rate is not limited,
allowing transmission rates up to 2.5Mbps.
The MAX1480B/MAX1490B shutdown feature reduces
supply current to as low as 0.2μA by using the SD pin (see
Low-Power Shutdown Mode section).
Use the FS pin to select between high and low switching
frequencies for the isolated power driver. The driver
switches at the lower frequency (200kHz for the
MAX1480A/B, 535kHz for the MAX1490A/B) when FS is
low, and at the higher frequency (350kHz for the
MAX1480A/B, 725kHz for the MAX1490A/B) when FS is
high. At the lower switching frequency, the devices’ oper-
ating voltage ranges increase from 5V ±5% to 5V ±10%.
The FS pin has a weak internal pull-up that switches the
device to the high-frequency mode when FS is left
unconnected. With FS high or open, no-load supply
current is reduced by approximately 4mA, and by up to
8mA when fully loaded.
Drivers are short-circuit current limited and are protect-
ed against excessive power dissipation by thermal
shutdown circuitry that puts the driver outputs into a
high-impedance state. The receiver input has a fail-safe
feature that guarantees a logic-high RO (logic-low RO)
output if the input is open circuit.
On the MAX1480A/B, the driver outputs are enabled by
bringing DE
′
high. Driver-enable times are typically 0.5μs
for the MAX1480A and 35μs for the MAX1480B. Allow
time for the devices to be enabled before sending data
(see the Driver Enable Time vs. Temperature graph in
the Typical Operating Characteristics). When enabled,
driver outputs function as line drivers. Driver outputs are
high impedance when DE
′
is low. While outputs are high
impedance, they function as line receivers.
________________________________________________Pin Desc riptions (c ontinued)
FUNCTION
NAME
Isolated Driver-Enable Input. Connect to ISO DI DRV for normal operation.
Isolated Driver Input. Connect to ISO DI DRV for normal operation.
Noninverting Driver Output and Noninverting Receiver Input
—
—
—
21
22
23
Noninverting Receiver Input
20
—
Inverting Receiver Input
19
—
ISO DE IN
ISO DI IN
A
A
B
Inverting Driver Output
18
—
Noninverting Driver Output
17
—
Z
Y
Internal Connections. Leave these pins unconnected.
23, 24
27, 28
Isolated Supply Voltage Source
22
26
AC2, AC1
ISO V
CC1
Inverting Driver Output and Inverting Receiver Input
—
25
Isolated Receiver-Output Drive. Connect to ISO RO LED through a resistor
(Table 1 of Figure 1 for MAX1480, Table 2 of Figure 2 for MAX1490).
21
24
B
ISO RO DRV
MAX1480A/B
MAX1490A/B
PIN
PINS ON THE ISOLATED RS-485/RS-422 SIDE (continued)
Note:
For DE
′
and DI
′
pin descriptions, see Detailed Block Diagram and Typical Application Circuit(Figure 1 for MAX1480A/B,
Figure 2 for MAX1490A/B).
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| MAX1490BCPG | 功能描述:RS-422/RS-485 接口 IC RoHS:否 制造商:Maxim Integrated 數(shù)據(jù)速率:1136 Kbps 工作電源電壓:3 V to 5.5 V 電源電流:5.9 mA 工作溫度范圍:- 40 C to + 85 C 安裝風格:SMD/SMT 封裝 / 箱體:SOIC-28 封裝:Tube |
| MAX1490BCPG+ | 功能描述:RS-422/RS-485 接口 IC Isolated RS-485/422 Data Interface RoHS:否 制造商:Maxim Integrated 數(shù)據(jù)速率:1136 Kbps 工作電源電壓:3 V to 5.5 V 電源電流:5.9 mA 工作溫度范圍:- 40 C to + 85 C 安裝風格:SMD/SMT 封裝 / 箱體:SOIC-28 封裝:Tube |
| MAX1490BEPG | 功能描述:RS-422/RS-485 接口 IC RoHS:否 制造商:Maxim Integrated 數(shù)據(jù)速率:1136 Kbps 工作電源電壓:3 V to 5.5 V 電源電流:5.9 mA 工作溫度范圍:- 40 C to + 85 C 安裝風格:SMD/SMT 封裝 / 箱體:SOIC-28 封裝:Tube |
| MAX1490BEPG+ | 功能描述:RS-422/RS-485 接口 IC Isolated RS-485/422 Data Interface RoHS:否 制造商:Maxim Integrated 數(shù)據(jù)速率:1136 Kbps 工作電源電壓:3 V to 5.5 V 電源電流:5.9 mA 工作溫度范圍:- 40 C to + 85 C 安裝風格:SMD/SMT 封裝 / 箱體:SOIC-28 封裝:Tube |
| MAX1490EACPCS | 制造商:Maxim Integrated Products 功能描述: |
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