{"type_number":"E280F","canonical_url":"https://tubeofile.com/tubes/E280F","manufacturer":"Philips","tube_type_key":"ss_pentode","tube_type_display_name":"Small Signal Pentode","base_name":"Noval","description":"Special quality (SQ) wideband pentode. Frame-grid construction for high transconductance (26 mA/V), low noise (Req = 220 Ω), and good gain-bandwidth product (S/2πCges = 180 MHz). Designed for RF, IF, video, and wideband amplifiers up to 300 MHz, cathode followers, oscillators, and frequency multipliers. Life tested to 10,000 hours. Gold-plated pins.","is_directly_heated":false,"completeness":"high","notes":["Operating point uses a positive g1 supply rail (+8 V, Philips; +9 V, Siemens) rather than connecting g1 to ground. The cathode resistor (Rk = 370 Ω) sets the actual bias: Vk ≈ 9.6 V, giving an effective Vg1-k ≈ −1.6 V. This topology allows a higher Rk for improved RF noise performance.","Pin 8 (g3, shield): NOT internally connected to cathode — must be tied to cathode externally in pentode operation. In triode connection (method A: g2 → anode, g3 → cathode) it also connects to cathode. A second triode method (g2 and g3 both to anode) is sometimes used; it increases feedback capacitance.","Both cathode pins (1 and 3) should be connected in parallel. The Siemens datasheet recommends parallel connection for lowest noise (both cathode leads connected).","When using a cathode bypass capacitor > 10 µF, the grid resistor must be at least 1 kΩ (Siemens specification).","CV10775 is the British military equivalent designation.","7722 is the CBS-Hytron (US) equivalent designation — identical tube, different trade name.","D3a (Siemens) shares the same Noval pinout and is the closest Western equivalent by application, but has significantly higher gm (35 mA/V) and μg2g1 (80). E180F and E186F share the same pinout with lower gm.","S/C ratio (transconductance-to-capacitance) = 2.2 mA/V/pF; gain-bandwidth figure S/2πCges = 180 MHz (Cges = Ce + Ca + 5 pF stray capacitance)."],"references":["https://frank.pocnet.net/sheets/009/e/E280F.pdf","https://frank.pocnet.net/sheets/190/e/E280F.pdf"],"source_urls":{"r_type":null,"tdsl":"https://tdsl.duncanamps.com/show.php?des=E280F","radiomuseum":"https://www.radiomuseum.org/tubes/tube_e280f.html"},"raw_equivalents":["7722","CV10775"],"equivalents":[],"similar":[{"type_number":"6J11P","reason":"Electrically related wideband pentode but different Noval pinout (anode on pin 2, g1 on pin 7) — not pin-compatible","has_detail_page":true},{"type_number":"D3a","reason":"Same Noval pinout; higher gm (35 vs 26 mA/V) and higher μg2g1 (80 vs 60) — not a neutral drop-in for RF circuits","has_detail_page":true},{"type_number":"E180F","reason":"Same Noval pinout family; lower gm (16.5 vs 26 mA/V); pin 6 differs (k on E180F vs ic on E280F) — not a pin-for-pin drop-in","has_detail_page":true},{"type_number":"E186F","reason":"Same Noval pinout; lower gm (16.5 vs 26 mA/V); Philips SQ low-microphonics sibling","has_detail_page":true}],"pins":[{"pin_number":"1","function":"Cathode","function_code":"k","notes":null},{"pin_number":"2","function":"Control Grid (g1)","function_code":"g1","notes":null},{"pin_number":"3","function":"Cathode (connected to pin 1)","function_code":"k","notes":null},{"pin_number":"4","function":"Heater","function_code":"h","notes":null},{"pin_number":"5","function":"Heater","function_code":"h","notes":null},{"pin_number":"6","function":"Internal Connection (shield)","function_code":"ic","notes":null},{"pin_number":"7","function":"Anode","function_code":"a","notes":null},{"pin_number":"8","function":"Suppressor Grid (g3, shield — connect to cathode externally)","function_code":"g3","notes":null},{"pin_number":"9","function":"Screen Grid (g2)","function_code":"g2","notes":null}],"specs":[{"key":"Vh","display_name":"Heater Voltage","value":"6.3","numeric_value":"6.3","unit":"V","param_group":"heater"},{"key":"Ah","display_name":"Heater Current","value":"0.315","numeric_value":"0.315","unit":"A","param_group":"heater"}],"sections":[{"section_number":1,"section_label":"Pentode","tube_type_key":"ss_pentode","specs":[{"key":"Va_max","display_name":"Anode Voltage (max)","value":"220","numeric_value":"220","unit":"V","param_group":"absolute_max"},{"key":"Vs_max","display_name":"Screen Voltage (max)","value":"180","numeric_value":"180","unit":"V","param_group":"absolute_max"},{"key":"Pa_max","display_name":"Anode Dissipation (max)","value":"4","numeric_value":"4","unit":"W","param_group":"absolute_max"},{"key":"Ps_max","display_name":"Screen Dissipation (max)","value":"1.1","numeric_value":"1.1","unit":"W","param_group":"absolute_max"},{"key":"Ik_max","display_name":"Cathode Current (max)","value":"30","numeric_value":"30","unit":"mA","param_group":"absolute_max"},{"key":"Vhk_max","display_name":"Heater-to-Cathode Voltage (max)","value":"120","numeric_value":"120","unit":"V","param_group":"absolute_max"},{"key":"Rg_max","display_name":"Max Grid Resistor","value":"0.5","numeric_value":"0.5","unit":"MΩ","param_group":"absolute_max"},{"key":"Va","display_name":"Anode Voltage (typical)","value":"190","numeric_value":"190","unit":"V","param_group":"typical_operating"},{"key":"Vs","display_name":"Screen Voltage (typical)","value":"160","numeric_value":"160","unit":"V","param_group":"typical_operating"},{"key":"Vg","display_name":"Grid 1 Bias Voltage","value":"-1.6","numeric_value":"-1.6","unit":"V","param_group":"typical_operating"},{"key":"mAa","display_name":"Anode Current","value":"20","numeric_value":"20","unit":"mA","param_group":"typical_operating"},{"key":"mAs","display_name":"Screen Current","value":"6","numeric_value":"6","unit":"mA","param_group":"typical_operating"},{"key":"ra","display_name":"Anode Resistance","value":"100000","numeric_value":"100000","unit":"Ω","param_group":"typical_operating"},{"key":"gm","display_name":"Transconductance","value":"26","numeric_value":"26","unit":"mA/V","param_group":"typical_operating"},{"key":"Rk","display_name":"Cathode Resistor (self-bias)","value":"370","numeric_value":"370","unit":"Ω","param_group":"typical_operating"},{"key":"Cgp","display_name":"Grid-to-Plate Capacitance","value":"0.035","numeric_value":"0.035","unit":"pF","param_group":"capacitances"},{"key":"Cin","display_name":"Input Capacitance","value":"9.3","numeric_value":"9.3","unit":"pF","param_group":"capacitances"},{"key":"Cout","display_name":"Output Capacitance","value":"2.6","numeric_value":"2.6","unit":"pF","param_group":"capacitances"},{"key":"Rn","display_name":"Equivalent Noise Resistance","value":"220","numeric_value":"220","unit":"Ω","param_group":"noise_rf"},{"key":"NF","display_name":"Noise Figure","value":"6.6","numeric_value":"6.6","unit":"dB","param_group":"noise_rf"},{"key":null,"display_name":"Amplification factor (μg2g1)","value":"60","numeric_value":"60","unit":"—","param_group":null}]},{"section_number":2,"section_label":"Triode Strapped","tube_type_key":"small_signal_triode","specs":[{"key":"Va_max","display_name":"Anode Voltage (max)","value":"220","numeric_value":"220","unit":"V","param_group":"absolute_max"},{"key":"Pa_max","display_name":"Anode Dissipation (max)","value":"4","numeric_value":"4","unit":"W","param_group":"absolute_max"},{"key":"Ik_max","display_name":"Cathode Current (max)","value":"30","numeric_value":"30","unit":"mA","param_group":"absolute_max"},{"key":"Va","display_name":"Anode Voltage (typical)","value":"160","numeric_value":"160","unit":"V","param_group":"typical_operating"},{"key":"Vg","display_name":"Grid 1 Bias Voltage","value":"-1.6","numeric_value":"-1.6","unit":"V","param_group":"typical_operating"},{"key":"mAa","display_name":"Anode Current","value":"24","numeric_value":"24","unit":"mA","param_group":"typical_operating"},{"key":"ra","display_name":"Anode Resistance","value":"1800","numeric_value":"1800","unit":"Ω","param_group":"typical_operating"},{"key":"gm","display_name":"Transconductance","value":"33","numeric_value":"33","unit":"mA/V","param_group":"typical_operating"},{"key":"mu","display_name":"Amplification Factor (μ)","value":"60","numeric_value":"60","unit":"—","param_group":"typical_operating"},{"key":"Rk","display_name":"Cathode Resistor (self-bias)","value":"400","numeric_value":"400","unit":"Ω","param_group":"typical_operating"},{"key":"Rn","display_name":"Equivalent Noise Resistance","value":"100","numeric_value":"100","unit":"Ω","param_group":"noise_rf"}]}],"synced_at":"2026-04-22T14:43:06.032Z"}