Ultra-Stable Class 1 Ceramic Capacitor for Precision RF Circuits
The Motorola 2113740A28 is a precision Class 1 (NPO/C0G) ceramic chip capacitor designed for temperature-critical applications in Motorola two-way radio circuits. This component features 9.1 picofarad capacitance with an exceptional ±30 ppm/°C temperature coefficient, providing superior stability compared to standard NPO capacitors. Class 1 ceramic dielectrics are specifically engineered for frequency-determining circuits where capacitance drift would cause unacceptable performance degradation. This capacitor is sold as a convenient 5-pack, ideal for service centers maintaining multiple radios or technicians stocking commonly replaced components.
Key Features
- Genuine Motorola component ensures exact specifications for original equipment performance
- 9.1 picofarad capacitance provides precision tuning for RF oscillator and filter circuits
- Class 1 NPO/C0G dielectric offers exceptional temperature stability (±30 ppm/°C maximum)
- Ultra-low dissipation factor ensures minimal signal loss in high-frequency applications
- High Q factor maintains sharp resonance characteristics in tuned circuits
- Surface mount chip design enables compact radio layouts and automated assembly
- Sold in convenient 5-pack for service inventory and multiple repairs
Technical Specifications
- Motorola Part Number: 2113740A28
- Component Type: Multilayer Ceramic Chip Capacitor (MLCC)
- Capacitance: 9.1 pF (picofarads)
- Tolerance: Typically ±0.5 pF or ±5% (whichever is greater) for Class 1 types
- Dielectric Type: Class 1 NPO (C0G) - Temperature-Compensating Ceramic
- Temperature Coefficient: ±30 ppm/°C maximum
- Operating Temperature Range: -55°C to +125°C
- Rated Voltage: Typically 50V DC for this capacitance range
- Dissipation Factor: <0.1% at 1 MHz (exceptionally low loss)
- Insulation Resistance: >10,000 MΩ minimum
- Mounting Style: Surface mount chip capacitor
- Package Quantity: 5 capacitors per order
Compatible Radio Models
This component is used in various Motorola portable and mobile two-way radio models, particularly in precision RF circuits including voltage-controlled oscillators (VCOs), frequency synthesizers, crystal oscillator circuits, and RF filter networks. The tight temperature coefficient specification indicates this capacitor is selected for applications where frequency stability is critical. Consult your radio's service manual or contact a Motorola authorized service center for specific compatibility and circuit location information.
What's Included
- Five (5) Motorola 2113740A28 Class 1 Ceramic Chip Capacitors
Applications
- Voltage-controlled oscillator (VCO) frequency-determining circuits requiring tight temperature stability
- Crystal oscillator load capacitance for precise frequency generation
- Phase-locked loop (PLL) synthesizer loop filter circuits
- RF bandpass and notch filter temperature compensation
- Transmitter carrier frequency stabilization networks
- Receiver local oscillator tuning circuits
- Temperature-critical timing and reference circuits
Installation and Service Notes
Professional installation by qualified radio technicians with surface mount soldering experience and RF alignment capability is required. This precision capacitor requires a temperature-controlled soldering station with fine conical 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 specifically formulated for SMD work, and high-magnification inspection capability (stereo microscope 10-20x recommended). The work area must be ESD-protected with proper grounding and anti-static work surface, as even minor ESD events can degrade capacitor performance or cause latent failures.
Surface mount installation procedure: Clean PCB pads thoroughly with isopropyl alcohol (99% purity) and allow complete evaporation. Apply minimal no-clean flux to both pads - excess flux can alter high-frequency characteristics. Orient the capacitor (non-polarized, either direction acceptable) and position precisely using tweezers or vacuum pickup. Tack-solder one end by touching the iron tip to the pad while feeding minimal solder to form the joint, maintaining contact for no more than 2 seconds. Allow cooling for 5 seconds, then solder the opposite end. Inspect both joints under magnification for proper concave fillet formation, adequate wetting to both pad and component termination, and absence of solder bridges, cold joints, or flux residue that could introduce parasitic effects.
This capacitor is typically replaced during troubleshooting of frequency-related failures including transmitter frequency drift with temperature changes, receiver frequency instability, failure to maintain FCC frequency tolerance specifications, synthesizer unlock conditions, or intermittent frequency errors. In precision frequency-determining circuits, even sub-picofarad capacitance changes can cause the radio to drift outside its assigned frequency allocation, potentially causing interference with adjacent channels and FCC compliance violations. The ±30 ppm/°C specification is tighter than standard ±100 ppm NPO capacitors, indicating this component is reserved for the most critical frequency-stability applications.
After installation, comprehensive RF alignment and frequency verification are mandatory. Use a calibrated frequency counter or service monitor to verify transmit and receive frequencies at multiple temperatures (ideally -20°C, +25°C, and +60°C minimum) to confirm proper frequency stability across the operating range. For transmitter circuits, verify output power remains within specification, modulation characteristics are correct, and spurious emission levels comply with regulatory requirements. Document all measurements in the radio's service record. Never substitute this component with standard NPO capacitors having wider temperature coefficients, as frequency stability will be compromised and the radio may fail FCC type acceptance requirements.
The 5-pack configuration is designed for professional service centers and technicians who regularly service Motorola radios. Store unused capacitors in their original packaging or in anti-static tubes within a controlled environment (temperature 15-30°C, relative humidity 30-70%) away from direct sunlight and moisture. Capacitors should be used within 2 years of purchase for optimal solderability. If storage exceeds 2 years, pad oxidation may require gentle cleaning before installation.
This component is intended for service by Motorola authorized service centers, professional radio technicians with RF alignment equipment, and experienced electronics repair specialists. Due to the critical nature of frequency stability in two-way radio systems and the specialized test equipment required for proper alignment (frequency counter accurate to ±1 ppm minimum, RF power meter, modulation meter, spectrum analyzer for spurious emission verification), end-user installation is strongly discouraged.
Manufacturer Part Number: 2113740A28
Description: Class 1 Ceramic Chip Capacitor, 9.1pF, NPO/C0G, ±30ppm/°C
Dielectric Type: Class 1 NPO (C0G) Temperature-Compensating
Temperature Coefficient: ±30 ppm/°C (Tighter than standard ±100 ppm NPO)
Package Quantity: 5 Capacitors
Application: Precision RF Frequency-Determining Circuits
