SP207H View Datasheet(PDF) - Signal Processing Technologies
Part Name
Description
Manufacturer
SP207H Datasheet PDF : 14 Pages
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VCC = +5V
+
C1 –
+10V
+
C2 –
C4
+ – VDD Storage Capacitor
– + VSS Storage Capacitor
C3
Figure 5. Charge Pump — Phase 4
SHUTDOWN MODE
The SP207HB, SP211H and SP211HB all fea-
ture a control input which will disable the device
and reduce the power supply current to less than
10µA, making the parts ideal for battery–pow-
ered systems. In the “shutdown” mode the re-
ceivers and transmitters will both be tri–stated.
The V+ output of the charge pump will discharge
to V , and the V– output will discharge to
CC
ground.
For complete shutdown to occur and the 10µA
power drain to be realized, the following condi-
tions must be met:
• +5V must be applied to the SD pin
• ENABLE must be either 0V, +5.0V or not
connected
• the transmitter inputs must be either +5.0V
or not connected
• V must be +5V
CC
• Receiver inputs must be >0V and <+5V
ENABLE
The SP207HB, SP211H and SP211HB feature
an enable input pin, which allows the receiver
Power Receiver
SD EN Up/Down Outputs
0
0
Up
Enable
0
1
Up
Tri–state
1
0
Down Tri-state
1
1
Down Tri–state
Table 2. Truth Table for SP2xxH
outputs to be either tri–stated or enabled. This
can be especially useful when the receiver is tied
directly to a microprocessor data bus. The en-
able is active low; that is, 0V applied to the
ENABLE pin will enable the receiver outputs.
WAKEUP FUNCTION
The SP207HB and SP211HB have a wake–up
feature that keeps all the receivers in an enabled
state when the device is in the shutdown mode.
With only the receivers active during shutdown,
the devices draw 5–10µA of supply current. A
typical application of this function would be
where a modem is interfaced to a computer in a
power–down mode. The ring indicator signal
from the modem could be passed through an
active receiver that is in the shutdown mode.
The ring indicator signal would propagate
through the receiver to the power management
circuitry of the computer to power up the micro-
processor and the SP207HB/SP211HB drivers.
After the supply voltage to the transceivers
reaches +5.0V, the SHUTDOWN pin can be
disabled. All receivers that are active during
shutdown maintain 500mV (typ.) of hysteresis.
Power Receiver
SD EN Up/Down Outputs
0
0
Up
Enable
0
1
Up
Tri–state
1
0
Down
Enable
1
1
Down Tri–state
Table 3. Wake–Up Truth Table for SP2xxHB
TGoddard/SP207H/9614R0
SP207H/SP211H High–Speed Transceivers
7
© Copyright 2000 Sipex Corporation
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