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Chapter 3 New for OEM7 – Hardware
OEM6
In Rush Current (Typ-
Receiver
OEM617
6.0 A for less than 60 µs
OEM617D
6.0 A for less than 60 µs
OEM628
6.6 A for less than 60 µs
OEM638
12.0 A for less than 60 µs
USB Interfaces
The layout guidelines are identical to those provided for OEM6, but the recommended common-mode
choke value has changed. See USB Interface on page 168.
The OEM719 and OEM729 USB interfaces default to 12 Mb/s ("Full-Speed") operation for back-
wards-compatibility reasons. The OEM729 may be changed to 480 Mb/s ("Hi-Speed") operation
through the use of a software command. Due to the multiplexing of COM3 with the USB interface
on the OEM719 design, the OEM719 does not support operation at 480 Mb/s.
3.2.3 Input and Output lines
The voltage limits and drive currents on the input and output lines of the OEM7 receivers are dif-
ferent than the levels on the OEM6 receivers. See Table 83: OEM719 Strobe Electrical Spe-
cification on page 189 and Table 92: OEM729 Strobe Electrical Specifications on page 205 for
details.
3.2.4 LNA Power
If a short circuit or other problem causes an overload of the current supplied to the
antenna, the receiver hardware shuts down the power supplied to the antenna. To
restore power, power cycle the receiver. The Receiver Status word, available in the
RXSTATUS log (see page 134), provides more information about the cause of the prob-
lem.
OEM719
On OEM615 receivers, LNA power is provided by an external power supply connected to pin 1 of
the main connector.
On OEM719 receivers, LNA power is generated on the receiver and pin 1 of the main connector
has no electrical connection on the board. The OEM719 provides up to 200 mA of current at
+5 VDC. The LNA is generated from the 3.3 V supply; therefore the OEM719 will draw more
power on the 3.3 V rail than a similarly configured OEM615.
The typical current draw for a NovAtel active antenna is <40 mA. For a typical antenna, this may
increase the power drawn from the 3.3 V supply by as much as 70 mA (as the LNA supply is
approximately 85-90% efficient).
OEM6 to OEM7 Integration Guide v1
ical)
OEM7
In Rush Current (Typ-
Receiver
OEM729
2.0 A for less than 1.8 ms
OEM7700
ical)
2.0 A for less than
1.8 ms
159
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