Precision RF Ceramic Capacitor for Motorola Radio Circuits
The Motorola 2111078B29 is a precision RF ceramic chip capacitor specifically designed for use in Motorola two-way radio frequency circuits. This component features 33 picofarad capacitance with NPO (also designated C0G) temperature-compensating dielectric, providing exceptional stability across the operating temperature range. The 100V voltage rating ensures reliable performance in RF amplifier, oscillator, and filter applications where voltage transients may occur. NPO dielectric capacitors are the preferred choice for frequency-determining circuits due to their near-zero temperature coefficient and minimal capacitance drift over time.
Key Features
- Genuine Motorola component ensures exact specifications matching original radio design requirements
- NPO/C0G dielectric provides ultra-stable capacitance with near-zero temperature coefficient (0 ±30 ppm/°C)
- 33 picofarad capacitance ideal for RF tuning, coupling, and bypass applications
- 100V working voltage rating accommodates voltage spikes in RF power amplifier circuits
- Low dissipation factor ensures minimal signal loss in high-frequency applications
- Surface mount chip design enables compact PCB layouts and reliable automated assembly
- High Q factor provides excellent performance in resonant and filter circuits
Technical Specifications
- Motorola Part Number: 2111078B29
- Component Type: Multilayer Ceramic Chip Capacitor (MLCC)
- Capacitance: 33 pF (picofarads)
- Tolerance: Typically ±5% (J tolerance) for NPO types
- Rated Voltage: 100V DC
- Dielectric Type: NPO (C0G) - Class I temperature-compensating ceramic
- Temperature Coefficient: 0 ±30 ppm/°C (exceptionally stable)
- Operating Temperature Range: -55°C to +125°C
- Dissipation Factor: Typically <0.1% at 1 MHz
- Insulation Resistance: >10,000 MΩ or 100 GΩ-μF (whichever is less)
- Mounting Style: Surface mount chip capacitor
Compatible Radio Models
This component is used in various Motorola portable and mobile two-way radio models, particularly in RF sections including transmitter power amplifiers, receiver front-ends, oscillator circuits, and frequency synthesis modules. Consult your radio's service manual or contact a Motorola authorized service center for specific compatibility information and circuit location details.
What's Included
- One (1) Motorola 2111078B29 RF Ceramic Chip Capacitor
Applications
- RF oscillator frequency-determining circuits requiring temperature stability
- Transmitter power amplifier coupling and bypass applications
- Receiver front-end tuning and filtering circuits
- Frequency synthesizer phase-locked loop (PLL) filtering
- RF impedance matching networks
- High-frequency signal coupling between circuit stages
Installation and Service Notes
Professional installation by qualified radio technicians with surface mount soldering experience is required. This precision RF capacitor requires a temperature-controlled soldering station with fine tip (350°C maximum temperature), precision tweezers or vacuum pickup tool, fine-diameter solder wire (0.5mm or smaller) or solder paste, no-clean flux, and magnification (10x minimum recommended). The work area must be ESD-safe with proper grounding, as RF capacitors can be damaged by electrostatic discharge.
Surface mount installation begins with thorough PCB pad cleaning using isopropyl alcohol to remove oxidation and contaminants. Apply a small amount of no-clean flux to both pads. Orient the capacitor correctly (non-polarized component, either orientation acceptable) and place it precisely on the pads using tweezers or vacuum pickup. Heat one pad with the soldering iron tip while feeding a minimal amount of solder to create the first connection, then repeat on the second pad. The entire soldering process should take no more than 2-3 seconds per pad to prevent thermal damage. After cooling, inspect both solder joints under magnification for proper fillet formation, checking for cold solder joints, insufficient solder, or solder bridges.
This capacitor is typically replaced during troubleshooting of RF performance issues including transmitter power reduction, frequency drift, spurious emissions, receiver desensitization, or intermittent operation. In frequency-determining circuits such as oscillators and synthesizers, even small changes in capacitance can cause the radio to operate outside its assigned frequency allocation. Always use the exact specified Motorola part number as a replacement - substituting with generic capacitors of similar ratings may result in out-of-specification RF performance due to differences in parasitic inductance, Q factor, or temperature stability.
After installation, the affected circuit should be tested and aligned according to the radio's service manual procedures. For transmitter circuits, verify output power, frequency accuracy, modulation characteristics, and spurious emission levels using appropriate test equipment (RF power meter, frequency counter, spectrum analyzer, modulation meter). For receiver circuits, verify sensitivity, selectivity, and frequency accuracy. Never substitute this component with non-NPO dielectric types (X7R, Y5V, etc.) as they lack the temperature stability required for RF applications and will cause frequency drift and performance degradation.
This component is intended for service by Motorola authorized service centers, professional radio technicians, and experienced electronics repair specialists with RF circuit expertise. Due to the precision nature of RF circuit alignment and the specialized test equipment required, end-user installation is not recommended.
Manufacturer Part Number: 2111078B29
Description: RF Ceramic Chip Capacitor, 33pF, NPO/C0G, 100V
Dielectric Type: NPO (C0G) Temperature-Compensating
Application: RF Circuits, Frequency-Determining Networks
