Home > Integrated Circuits ICs > Analog Linear ICs > BAP1321-02

BAP1321-02

Varactor Tuning Diode, 95pF@1V, C-ratio 5.5, SOD-323

6789

Effective Inventory

Go to Inquiry

Image for reference only

Manufacturer Part：

BAP1321-02

Package：

SOD-323 (1.7 x 1.25 x 0.85 mm)

Description

Product Overview

The BAP1321-02 from Nexperia is a silicon planar varactor (tuning) diode with a capacitance ratio of 5.5 and high Q factor, suitable for RF tuning and VCO applications in an SOD-323 package.

Key Specifications

Type	Silicon Planar Varactor Diode (Tuning Diode)
Reverse Voltage (max)	20 V
Forward Current (max)	20 mA
Capacitance @ VR=1V	95 pF (typical)
Capacitance @ VR=28V	17 pF (typical)
Capacitance Ratio (C1/C28)	5.5 (typical)
Q Factor	>100 @ VR=3V, f=50 MHz
Total Power Dissipation	250 mW
Package	SOD-323
Operating Temperature	-55C to +150C

Features

Variable capacitance with reverse voltage
Capacitance ratio of 5.5:1 (1V to 28V)
95 pF capacitance at 1V
High Q factor >100 at 50 MHz
SOD-323 surface mount package

Applications

Voltage-controlled oscillators (VCO)
RF tuning circuits
Frequency modulators
Automatic frequency control (AFC)

Product Introduction:BAP1321-02 Product Introduction

The BAP1321-02 from Nexperia is a silicon planar varactor diode (also known as a tuning diode or varicap) in an SOD-323 surface mount package. The device exploits the voltage-dependent capacitance of a reverse-biased P-N junction, where the depletion width increases with reverse voltage, reducing the junction capacitance from 95 pF at 1V to 17 pF at 28V, yielding a capacitance ratio of 5.5. This variable capacitance is the fundamental building block for voltage-controlled oscillators, frequency tuners, and automatic frequency control circuits. The high Q factor (>100 at 50 MHz) ensures low signal loss in RF resonant circuits. The SOD-323 package provides a compact footprint with low parasitic inductance for RF applications.

Working Principle:BAP1321-02 Working Principle

The BAP1321-02 operates as a voltage-variable capacitor by exploiting the depletion region of a reverse-biased P-N junction. When a reverse voltage (VR) is applied, the depletion region widens, effectively increasing the dielectric thickness of the capacitor formed by the P and N regions. The junction capacitance follows the relationship: C = C0 / (1 + VR/Vbi)^n, where C0 is the zero-bias capacitance, Vbi is the built-in potential (~0.7V for silicon), and n is the grading coefficient (typically 0.5 for abrupt junctions). The 5.5:1 capacitance ratio from 1V to 28V makes this device suitable for wide-range VCO tuning. The Q factor of >100 at 50 MHz is determined by the ratio of the junction capacitance to the series resistance (including bulk semiconductor resistance and contact resistance). High Q is critical for VCO phase noise performance. The varactor must always be operated in reverse bias to avoid forward conduction, which would short-circuit the RF signal.

Pin Description:BAP1321-02 Pin Definition and Functions

Pin	Name	Type	Function
1	Anode	Terminal	P-side (ground in typical circuit)
2	Cathode	Terminal	N-side (reverse bias / tuning voltage)

Application Scenarios:In which products and applications isBAP1321-02 used

VCO in 100-500 MHz PLL with 5.5:1 tuning range for FM radio
LC tank tuning circuit for automatic frequency control in TV tuners
Frequency modulator with linearity compensation using anti-series varactor pair
RF filter center frequency adjustment with DC tuning voltage

Alternative Models:What chips are recommended as replacements for BAP1321-02

Manufacturer	Part Number	Package	Notes
Nexperia	BAP1321-02,235	SOD-323	Same device, different packing
NXP	BBY58-02V	SOD-323	Varactor, similar class
Infineon	BBY58-02V	SOD-323	Varactor, similar class
Nexperia	BAP64-02	SOD-323	Pin diode, different function
Skyworks	SMV1231-079LF	SOD-323	Hyperabrupt varactor, wider ratio