UM9301 - 75V PIN Attenuator/Switch Diode | Microchip Technology
Référence : UM9301 ⚠ Dernier achat| Qté | Prix unitaire | Total |
|---|---|---|
| 1 | $2.45 | $2,45 |
| 10 | $2.18 | $21,80 |
| 100 | $1.92 | $192,00 |
| 500 | $1.71 | $855,00 |
| 1 000 | $1.52 | $1 520,00 |
UM9301 Présentation
A PIN diode is a semiconductor device with an intrinsic (undoped) high-resistivity "I" region sandwiched between P-type and N-type regions. Under forward bias, charge carriers flood the I region, lowering its RF resistance and allowing the diode to conduct RF energy. Under zero or reverse bias, the I region is depleted and the diode presents a high impedance. This variable-resistance behavior makes PIN diodes the workhorse component for RF switching, attenuation, AGC loops, and transmit/receive (T/R) switching in radar and communications systems.
The UM9301 uses special chip geometry with an extremely thick intrinsic I region. The thick I region delivers lower distortion at high RF power levels and lower series resistance per unit capacitance, supporting attenuator use. Key features include 75 V minimum reverse breakdown voltage, 1 W power dissipation at 25 C, low diode capacitance, and fast switching speed. The thick I region geometry optimizes the part for switch applications where little or no bias voltage is applied, while also providing low distortion in attenuator mode.
Typical applications include broadband RF switches, PIN-diode AGC attenuators, T/R switches in radar transceivers, antenna switching matrices, and RF power monitoring. The UM9301 is qualified for commercial and industrial environments and is RoHS-compliant.
When designing with the UM9301, observe maximum reverse voltage (75 V) and power dissipation (1 W) limits. For attenuator designs, bias the diode in the linear resistance region (typically 1-10 mA forward current) to avoid distortion; for switch designs, drive the diode hard on/off (10-50 mA forward, 0 V reverse). Use proper RF PCB layout techniques: short lead lengths, controlled-impedance traces, and via-fenced ground returns to preserve the part's high-frequency performance.
This page synthesizes distributor pricing, drop-in same-package alternatives, and practical RF design notes not found in the manufacturer datasheet.
Alternatives de remplacement direct pour UM9301 — même boîtier, compatible broche à broche. Les références à boîtier différent nécessitant une retouche du PCB sont exclues.
Variantes de cette série
Modèles de la même série directement compatibles avec UM9301 (même facteur de forme et même empreinte) — différant par RoHS Status.
Outil de comparaison rapide — sélectionnez des références alternatives pour une comparaison côte à côte :
UM9300
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
UM9401
✅ Remplacement direct ⚠️ Spécifications non vérifiées📋 Alternative de référence (hors catalogue)
UM9301 Valeurs maximales et caractéristiques électriques
| Diode Type | PIN Diode |
| Configuration | Single |
| Maximum Reverse Voltage (VR) | 75 V |
| Power Dissipation (PD) | 1 W |
| Package Type | Axial (glass-leaded, DO-35 style, see factory) |
| Type de montage | Through-Hole |
| Application | RF Switch / Attenuator |
| Intrinsic Region | Extremely thick "I" region (special chip geometry) |
| Use Mode 1 | RF Switch (low or zero bias) |
| Use Mode 2 | RF Attenuator (low distortion) |
| Statut RoHS | Compliant (per Microchip product page) |
Configuration des broches de UM9301
| Broche 1 | Anode — Axial PIN diode anode (banded end); forward-bias terminal for switch ON state |
| Broche 2 | Cathode — Axial PIN diode cathode (unbanded end); reverse-bias terminal for switch OFF state |
Applications typiques
UM9301 convient pour 6 applications: Broadband RF Switch (SPST/SPDT), PIN-Diode AGC Attenuator, Transmit/Receive (T/R) Switch, Antenna Switching Matrix, RF Power Monitoring / Detector, RF Test and Measurement Attenuator.
Broadband RF Switch (SPST/SPDT)
The UM9301's thick intrinsic I region and 75 V reverse-voltage rating make it well suited for broadband SPST and SPDT RF switches spanning HF, VHF, and UHF. In SPST use, the diode is forward-biased at 10-50 mA for the low-loss ON state and held at 0 V reverse for the high-isolation OFF state. Its 1 W dissipation rating handles continuous-wave RF power typical of shortwave and low-power microwave links. Compared to a Schottky switch diode, the UM9301 offers lower distortion and higher reverse-voltage tolerance at the cost of higher bias current, which is acceptable for transmit/receive switching in HF transceivers and instrumentation.
Recommandé
PIN-Diode AGC Attenuator
In automatic gain control (AGC) attenuator circuits the UM9301 operates in its linear-resistance region between 1-10 mA forward current, presenting a controllable RF resistance. The thick I-region geometry specified in the Microchip datasheet is optimized for low intermodulation distortion at high RF power, critical for receiver AGC loops where harmonics and IMD products would otherwise leak through. The 75 V VR rating absorbs RF voltage swings in 50 ohm and 75 ohm systems up to roughly +20 dBm without breakdown. This makes the UM9301 a strong choice for HF/VHF receiver front ends, signal generators, and spectrum analyzer input protection/leveling stages.
Recommandé
Transmit/Receive (T/R) Switch
T/R switching in half-duplex radios and radar transceivers places a 75 V, 1 W PIN diode such as the UM9301 between the antenna, transmit amplifier, and receive LNA. During transmit the diode is reverse-biased to isolate the LNA; during receive it is forward-biased to route incoming signals to the LNA. The thick I-region keeps carrier lifetime long enough for fast switching (sub-microsecond transitions in practice) while the 1 W dissipation rating sustains the DC bias plus any reflected RF heating during the receive window. UM9301's low series resistance in forward bias keeps receive-path insertion loss below 0.5 dB in a properly designed bias network.
Recommandé
Antenna Switching Matrix
Multi-antenna systems (phased arrays, MIMO test beds, diversity receivers) use matrices of PIN diodes to route any antenna to any receiver chain. The UM9301's 75 V VR withstands the open-circuit RF voltage that appears on unselected ports when a high-power transmitter drives a common feed, while 1 W dissipation supports continuous forward bias for static configuration matrices. Its thick I-region geometry reduces insertion-loss variation across the bias range, important when calibrating the matrix. Multiple UM9301 diodes can be cascaded in PI or T attenuator sections to build programmable step attenuators with 1-2 dB per bit resolution.
Recommandé
RF Power Monitoring / Detector
Coupled-line RF power monitors place a PIN diode such as the UM9301 at the detector tap of a directional coupler, biased at a few milliamps in its linear-resistance region. The detected DC voltage across the diode tracks the RF power on the main line. The thick I region minimizes harmonic re-radiation that could otherwise corrupt the measurement, and the 75 V VR rating handles peak voltage at the tap without breakdown. This configuration is used in transmitter power control loops, antenna tuner VSWR monitors, and laboratory RF power meters where flat frequency response and low distortion matter more than absolute detector sensitivity.
Recommandé
RF Test and Measurement Attenuator
Bench-cal step attenuators and laboratory programmable attenuators rely on PIN diode sections with predictable resistance-vs-bias curves. The UM9301's thick I-region geometry specified by Microchip delivers flat attenuation-versus-frequency response from HF through low microwave bands, with low harmonic distortion under high RF drive. Designers cascade UM9301 sections to construct 1 dB, 2 dB, 5 dB, and 10 dB steps, and the 75 V VR rating tolerates the open-circuit RF voltage when a step is bypassed. 1 W power dissipation allows continuous bias without thermal issues in laboratory instruments that remain powered for hours.
Recommandé
Récapitulatif des produits recommandés
Données de référence d'ingénierie pour UM9301 — comparaison, recommandations de conception et informations de conformité.
Guide de sélection
Comparaison avec les alternatives
| Paramètre | Ce produit | UM9301SM | UM9300 | UM9401 |
|---|---|---|---|---|
| Package | Axial (glass-leaded, DO-35 style) | Surface-Mount (different footprint) | Axial (glass-leaded, DO-35 style) - same | Axial (glass-leaded, DO-35 style) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Diode Type | PIN Diode (thick I region) | PIN Diode (thick I region) | PIN Diode (thick I region) | PIN Diode (thick I region) |
| Power Dissipation | 1 W | 1 W | 1 W | 1 W |
| Mounting Type | Through-Hole (axial) | Surface Mount | Through-Hole (axial) | Through-Hole (axial) |
| Switch / Attenuator Optimized | Both (low bias switch + low-distortion attenuator) | Both (same die) | Both | Both |
| RoHS Compliance | Compliant | Compliant | Compliant | Compliant |
Principaux différenciateurs
- Dual-purpose optimized: switch at low/no bias AND attenuator with low distortion (vs UM9300)
- Same die as the SMT UM9301SM (vs UM9301SM)
- 75 V reverse voltage rating for medium-voltage RF switch use (vs UM9401)
Notes de conception
Estimated: at 50 mA forward bias and 0.9 V Vf, the UM9301 dissipates approximately 45 mW DC, well below the 1 W rating. However, RF heating during high-power switch operation (e.g., passing 100 W peak through the diode in ON state) can push junction temperature beyond the limit even with low DC bias. For high-power switch use, calculate total dissipation = DC bias + (RF voltage squared / R_ON) and derate linearly to zero at the maximum junction temperature.
Use short lead lengths and a continuous ground plane when prototyping the UM9301 in through-hole form. The axial glass-leaded package has lead inductance around 5 nH per cm of lead; keeping leads under 5 mm total preserves RF performance above 100 MHz. For through-hole prototypes, bend leads flush to the board and solder directly to a 50 ohm microstrip or coplanar waveguide structure with via-fenced ground returns to avoid parasitic modes.
Place the DC bias network (RF choke + bias resistor) as close as possible to the UM9301 cathode lead, and use a small RF bypass capacitor (100 pF to 1 nF) at the choke-to-ground junction to prevent RF leakage into the bias supply. Bias resistor values of 100 ohm to 1 kohm are typical for 5-50 mA bias current from a 5 V supply. For attenuator mode, use a current source rather than a bias resistor to set a stable operating point independent of supply voltage variation.
Informations de conformité
RoHS compliant per Microchip product page. Not AEC-Q100 qualified - this part targets commercial/industrial RF applications, not automotive. Lifecycle: last-time-buy per Microchip PCN MFOL-19MRQH667 effective 2025-06-26, no further supply.
