Garmin GPS 35 LP Technical Specification

Also see for GPS 35 LP: Declaration of conformity Quick start guide Technical specification

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Garmin GPS 35 LP Technical Specification Manual pdf 17 page image

133.3 CONNECTION WIRING DESCRIPTIONThe GPS 35LP features a stripped and pre-tinned cable assembly for connection flexibility. The followingis a functional description of each wire in the cable assembly.Red: Vin - Regulated +3.6V to +6V, 150 mA (maximum) in the -LVx versions. Typical operatingcurrent is 120 mA. Transients and overvoltages are protected by an internal 6.8V transientzener diode and a positive temperature coefficient thermistor. With voltages greater than6.8Vdc the zener will draw several amps of current through the thermistor, causing it to heatrapidly and eventually power the unit off, unless an external fuse blows first. When propersupply voltages are returned, the thermistor will cool and allow the GPS 35-LVx to operate.The CMOS/TTL output buffers are powered by Vin, therefore a 3.6Vdc supply will create3.6V logic output levels.In the -HVx versions, Vin can be an unregulated 6.0Vdc to 40Vdc, optimized for 12Vdc.Typical operating power is 800mW This voltage drives a switching regulator with a nominal4.4Vdc output, which powers the internal linear regulators, and the CMOS output buffers.Black: GND - Power and Signal GroundWhite: TXD1 - First Serial Asynchronous Output. CMOS/TTL output levels vary between 0V andVin in the -LVC version. In the -LVS and -HVS versions a RS-232 compatible output driveris available. This output normally provides serial data which is formatted per “NMEA 0183,Version 2.0”. Switchable to 300, 600, 1200, 2400, 4800, 9600 or 19200 BAUD. The defaultBAUD is 4800.Blue: RXD1 - First Serial Asynchronous Input. RS-232 compatible with maximum input voltagerange -25 < V < 25. This input may also be directly connected to standard 3 to 5VdcCMOS logic. The minimum low signal voltage requirement is 0.8V, and the maximum highsignal voltage requirement is 2.4V. Maximum load impedance is 4.7K ohms. This inputmay be used to receive serial initialization / configuration data, as specified in Section 4.1.Purple: TXD2 - Second Serial Asynchronous Output. Electrically identical to TXD1. This outputprovides phase data information for software version 2.03 or above. See Appendix C fordetails.Green: RXD2 - Second Serial Asynchronous Input. Electrically identical to RXD1. This input maybe used to receive serial differential GPS data formatted per “RTCM RecommendedStandards For Differential Navstar GPS Service, Version 2.1” (see Section 4 for moredetails).Gray: PPS - One-Pulse-Per-Second Output. Typical voltage rise and fall times are 300 nSec.Impedance is 250 ohms. Open circuit output voltage is 0V and Vin in the -LVx versions,and 0V and 4.4V in the -HVx. The default format is a 100 millisecond high pulse at a 1Hzrate, the pulse width is programmable from a configuration command in 20msecincrements. Rising edge is synchronized to the start of each GPS second. This output willprovide a nominal 700 mVp-p signal into a 50 Ohm load. The pulse time measured at the50% voltage point will be about 50 nSec earlier with a 50 Ohm load than with no load.Yellow: POWER DOWN - External Power Down Input. Inactive if not connected or less than 0.5V.Active if greater than 2.7V. Typical switch point is 2.0V @ 0.34 mA. Input impedance is15K Ohms. Activation of this input powers the internal regulators off and drops thesupply current below 20mA in the -LVx versions, and below 1mA in the -HVx. Thecomputer will be reset when power is restored.Section 4