MAX3225EETP-T Maxim Integrated, MAX3225EETP-T Datasheet - Page 11

• Manufacturer Part Number: MAX3225EETP-T
• Description: RS-232 Interface IC
• Manufacturer: Maxim Integrated
• Series: MAX3224E, MAX3225E, MAX3226E, MAX3227E, MAX3244E, MAX3245Er

Specifications of MAX3225EETP-T

• Data Rate: 1 Mbps
• Operating Supply Voltage: 3 V to 5.5 V
• Supply Current: 1 mA
• Operating Temperature Range: 0 C to + 70 C
• Mounting Style: SMD/SMT
• Function: Transceiver
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Number Of Drivers: 2
• Number Of I/os: 8
• Number Of Receivers: 2
• Propagation Delay Time Ns: 0.15 us
• Shutdown: Yes

Maxim Integrated
peripheral transmitters are turned off, and the UART dri-
ving the transmitter inputs is inactive. The system turns
on again when a valid transition is applied to any
RS-232 receiver or transmitter input. As a result, the sys-
tem saves power without changes to the existing BIOS
or operating system.
Figures 3a and 3b depict valid and invalid RS-232
receiver voltage levels. INVALID indicates the receiver
input’s condition, and is independent of FORCEON and
FORCEOFF states. Figure 3 and Tables 1 and 2 sum-
marize the operating modes of the MAX3224E–
MAX3227E/MAX3244E/MAX3245E. FORCEON and
FORCEOFF override AutoShutdown Plus circuitry.
When neither control is asserted, the IC selects
between these states automatically based on the last
receiver or transmitter input edge received.
Figure 3a. INVALID Functional Diagram, INVALID Low
Figure 3b. INVALID Functional Diagram, INVALID High
Table 2. INVALID Truth Table
±15kV ESD-Protected, 1µA, 1Mbps 3.0V to 5.5V,
+2.7V
-2.7V
R_IN
INVALID DEASSERTED IF ANY RECEIVER INPUT HAS BEEN BETWEEN +2.7V AND -2.7V
FOR LESS THAN 30μs.
+0.3V
-0.3V
R_IN
MAX3226E/MAX3227E/MAX3244E/MAX3245E
INVALID ASSERTED IF ALL RECEIVER INPUTS ARE BETWEEN +0.3V AND -0.3V FOR
AT LEAST 30μs.
RS-232 Transceivers with AutoShutdown Plus
PRESENT AT ANY
RECEIVER INPUT
RS-232 SIGNAL
Yes
No
INVALID OUTPUT
TIMER
30μs
TIMER
30μs
R
R
High
Low
INVALID
INVALID
When shut down, the device’s charge pumps turn off,
V+ is pulled to V
ter outputs are high impedance, and READY
(MAX3224E–MAX3227E) is driven low. The time
required to exit shutdown is typically 100µs (Figure 8).
By connecting FORCEON to INVALID, the MAX3224E–
MAX3227E/MAX3244E/MAX3245E shut down when no
valid receiver level and no receiver or transmitter edge is
detected for 30s, and wake up when a valid receiver
level or receiver or transmitter edge is detected.
Figure 3c. AutoShutdown Plus Logic
Figure 3d. Power-Down Logic
Figure 4a. Receiver Positive/Negative Thresholds for INVALID
* POWERDOWN IS ONLY AN INTERNAL SIGNAL.
THE TRANSMITTERS AND THE POWER SUPPLIES.
R_IN
IT CONTROLS THE OPERATIONAL STATUS OF
T_IN
AUTOSHDN
FORCEOFF
FORCEON
+2.7V
+0.3V
-0.3V
-2.7V
DETECT
DETECT
EDGE
EDGE
0
CC
FORCEON
, V- is pulled to ground, the transmit-
INDETERMINATE
INDETERMINATE
INVALID HIGH
INVALID HIGH
INVALID LOW
FORCEOFF
TIMER
30s
S
R
POWERDOWN*
AUTOSHDN
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