NAVIOR-24S
™
CHAPTER II
Hardware Integration
36
NAVIOR-24S ™
Revision
V1.00 20.05.2008
Battery Back-up
The NAVIOR-24S GPS/GLONASS receiver provides an input for battery back-up (BBU) power to
keep the module's RAM memory alive and to power the real-time clock when the receiver's prime
power is turned off. RAM memory is used to store the GPS/GLONASS almanac, ephemeris, and
last position. By using battery back-up, time to first fix in a warm start is reduced to 30 seconds
(typical). Though not required, providing BBU power can reduce time to first fix. A 3.0 volt lithium
battery used for back-up power can last up for three years.
Pin 19 is recommended to connect to GND, if it’s not in use.
Warning – If battery power is not present, the receiver’s power can be turned off and then
back on to force a system reset and a cold start.
Note
– 2.0 V is the minimum allowable battery back-up voltage. When the battery back-up power
output drops below 2.0 V, the real-time clock may not operate over the specified temperature range.
This can also significantly extend the time to first fix. NAVIS does not recommend the use of Super
Caps as battery back-up.
Table II-3 - Power Requirements
Signal
Voltage
Current
X501 Pin#
VCC
+3.20 VDC to +3.45 VDC
max 500 mA
1
VCC
+3.20 VDC to +3.45 VDC
max 500 mA
3
BBP
+2.0 VDC to +3.0 VDC,
max 20 µA
19
VANT
+3.0 VDC to +5.0 VDC
max 60 mA
20
GND
0 V
-
2
GND
0 V
-
4