5639 Pentode Vacuum Tube

Pentode6.3V / 0.45A8-lead subminiature (8DL)SPICE
SourceSylvania Engineering Data Service 1957 · Tung-Sol Premium Tube 1955-1957 · Raytheon CK5639WA 1959 · Tung-Sol 5639WA 1960Reviewed2026-05-29StatusDataModelCalcModelKoren pentode v1 (small-signal-at-bias)PDF

Small-signal pentode for low-noise voltage amplification

Datasheet ↗SPICE
Mode
50.0kΩ
9.0mA/V
9.0pF
0.2pF
8.00pF
GAIN0%
POWER10%
DRIVE50%
LINEARITY75%
SPECIFICATIONS
Heater6.3 V · 0.45 A
Max Plate Voltage165 V
Pa max4 W
Gain Factor
gm9 mA/V
rp50.0 kΩ
Inter-electrode capacitances
Cgk9 pF
Cgp0.18 pF
Cpk8 pF
Pinout8-lead subminiature (8DL)
Era1955
RaritySought-after
HEATER6.3V / 0.45A
MAX PLATE165V / 4W
BASEsubmini-8
Vhk max200V
Manufacturer datasheets (PDF downloads)
Datasheet limits (full)
Va max
165 V
Pa max
3.5 W
Pg max
1 W
Ik max
40 mA
Rg max
0.5 MΩ
Vhk max
200 V (f−/k+) · 200 V (f+/k−)
Bulb temp
220 °C
5639 standard: Vp max 165 V (peak fwd 330 V). 5639WA rating raised: Vp design-max 250 V (peak fwd 360 V) — but both Raytheon and Tung-Sol WA issues are maker-marked TENTATIVE. Plate dissipation: Sylvania 4.0 W, Tung-Sol & both WA issues 3.5 W — use 3.5 W for conservative work. Max screen voltage 155 V, screen dissipation 1.0 W. Max grid-1 resistance 0.5 MΩ self-bias / 0.1 MΩ fixed (Sylvania); Tung-Sol publishes 0.5 MΩ unified. Heater-cathode symmetric ±200 V. Ruggedness: 450 G impact, 1000 G uniform, 2.5 G fatigue per MIL-E-1.
Per-section / per-manufacturer capacitances
Capacitancesylvania5639tungsol5639tungsol5639WAraytheon5639WA
Cgp_unshielded0.18 pF0.18 pF0.13 pF0.13 pF
Cgp_shielded0.15 pF0.15 pF0.13 pF0.13 pF
Cin9 pF9 pF9 pF9 pF
Cout4.6 pF4.6 pF4.6 pF4.6 pF
SPICE variants per manufacturer
Each card below is a named subcircuit inside the downloadable .subckt file. Same physical tube, different manufacturer / measurement convention. The Ampera loadline calculator uses the Philips/1953 family; copy the Koren line from any card into your own simulator to bias the engine the same way.
5639_PENTODE_SYLVANIA_1957
Sylvania 5639 (calc default; Pa 4.0 W)
Va150 V
Vg-2.5 V
Ia21 mA
μ35.97
gm9 mA/V
rp50 kΩ
Cag0.18 pF
Koren fit
MU=35.97 EX=2.2 KG1=340.05361 KP=28.698 KVB=25.886
Default Ampera engine for 5639. Typical-point reproduces Ip 20.7 mA / gm 9.27 mA/V vs sheet 21 mA / 9.0.
5639_PENTODE_TUNGSOL_1957
Tung-Sol 5639 (Pa 3.5 W)
Va150 V
Vg-2.5 V
Ia21 mA
μ35.97
gm9 mA/V
rp50 kΩ
Cag0.18 pF
Koren fit
MU=35.97 EX=2.2 KG1=340.05361 KP=28.698 KVB=25.886
Use when conservative 3.5 W plate ceiling applies.
5639WA_PENTODE_RAYTHEON_1959
Raytheon CK5639WA (earliest WA, tentative)
Va150 V
Vg-2.5 V
Ia21 mA
μ35.97
gm9 mA/V
rp50 kΩ
Cag0.13 pF
Koren fit
MU=35.97 EX=2.2 KG1=340.05361 KP=28.698 KVB=25.886
Earliest WA issue. Validated against Raytheon's plotted gm-vs-Vg1 transfer curve at Eb=Ec2=100 V (model 8718 µmho vs sheet ~9000 µmho at the typical bias).
5639WA_PENTODE_TUNGSOL_1960
Tung-Sol 5639WA (tentative; Vp 250 V des.max)
Va150 V
Vg-2.5 V
Ia21 mA
μ35.97
gm9 mA/V
rp50 kΩ
Cag0.13 pF
Koren fit
MU=35.97 EX=2.2 KG1=340.05361 KP=28.698 KVB=25.886
Use for WA-grade designs needing the raised Vp design-max of 250 V.
5639_TRIODE_CONNECTED
5639 triode-connected (refit, Sylvania 1957 p.9)
Va200 V
Vg-6 V
Ia41 mA
μ15
gm7 mA/V
rp2.1 kΩ
Cag0.18 pF
Koren fit
MU=32 EX=1.4 KG1=380 KP=35 KVB=250 VCT=0.5
G2 strapped to plate. Hand-fitted to Sylvania 1957 p.9 Ib/Va triode-connected plate family (Vg=0..-26 V). Mean ~16 % residual vs traced curves; over-predicts at Vg≈0 / low Va and under-predicts near cutoff — inherent Koren-shape limit for sharp-cutoff video pentodes triode-strapped. Used by the calculator's triode mode when the user toggles it.
5639WA_TRIODE_CONNECTED
5639WA triode-connected (same fit; WA-grade Cgp 0.13 pF)
Va200 V
Vg-6 V
Ia41 mA
μ15
gm7 mA/V
rp2.1 kΩ
Cag0.13 pF
Koren fit
MU=32 EX=1.4 KG1=380 KP=35 KVB=250 VCT=0.5
Same fit as 5639_TRIODE_CONNECTED — Tung-Sol 5639WA p.8 and Raytheon CK5639WA p.6 tabulated triode curves converge on the Sylvania p.9 graph within reading tolerance. Use this subckt when the WA-grade tighter Cgp (0.13 pF) matters for HF / Miller analysis.
Transfer curve comparison

Ia vs Vg at Va = 250 V — each manufacturer Koren fit overlaid. The de-rated French families (μ=30) read lower than the Philips/1966 high-gm family (μ=32) at the same grid voltage.

051015-10-8-6-4-20Vg (V)Ia (mA)
Sylvania 5639 (calc default; Pa 4.0 W)5639 triode-connected (refit, Sylvania 1957 p.9)
Original descriptive texts

Verbatim excerpts from the four manufacturer datasheets. Expand each section to read the original text — the Philips technical article carries the richest application content.

Source datasheets

6 manufacturer datasheets cross-checked for 5639

6 verified
7 Koren fits
TYPICAL OPERATING POINT
Va90V
Ia19.47mA
Vg-3V
Pd1.75W
RL100kΩ
Av35dB
EXECUTIVE SUMMARY

The 5639 is a premium (JAN / MIL-E-1) subminiature sharp-cutoff video power pentode built in 8-lead flexible-lead button construction (8DL), produced by Sylvania and Tung-Sol in the mid-1950s for broadband radar, airborne and industrial video service under severe shock (450 G impact), vibration, high temperature and high altitude. It uses a 6.3 V / 0.45 A indirectly-heated coated unipotential cathode. The two original-issue manufacturer datasheets (Sylvania Feb 1957, Tung-Sol Oct 1955 / Jan 1957) are electrically the same tube and share an identical tabulated typical point: Vp = 150 V, Vg2 = 100 V, Rk = 100 Ω giving Ip = 21 mA, Ig2 = 4 mA, gm = 9000 µmho, rp = 50 kΩ. They differ only in stated limits — Sylvania rates plate dissipation at 4.0 W, Tung-Sol at 3.5 W — and in minor curve reference conditions; conservative work uses the 3.5 W ceiling and the 1.0 W screen ceiling. The Cgp = 0.18 pF unshielded (0.13 pF on the ruggedized 5639WA) makes it attractive as a low-Miller video / pulse stage even by modern standards. Triode-strapped operation (G2 to plate) is possible: μ ≈ 18, rp ≈ 1.6 kΩ from the 5639WA tabulated curve, μ ≈ 20, rp ≈ 2.5 kΩ from the indicative Sylvania p.9 graph. The 5639WA is the JAN/MIL ruggedized variant (Raytheon Mar 1959 earliest, Tung-Sol Jan 1960) with raised Vp design-max of 250 V (peak 360 V) but is maker-marked TENTATIVE on both issues. Note: the 5639 has NO relationship to the European RO4404 / RE604 / D404 family (which is a 1930 4 V directly-heated audio triode).

APPLICATIONS
Voltage amplifier
Generic pentode video / wideband (power) stage
HISTORY
Introduced1955ManufacturerSylvania·Tung-Sol
Golden Age
METRIX TESTER

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