1F4G Fast Recovery Rectifier: 400 V Ratings and Replacement Checks

The Good-Ark 1F4G fast recovery rectifier is a 1 A, 400 V silicon diode in an R-1 axial package. Its maximum reverse…

The Good-Ark 1F4G fast recovery rectifier is a 1 A, 400 V silicon diode in an R-1 axial package. Its maximum reverse recovery time is 150 ns under the manufacturer’s specified test conditions. The 400 V blocking rating distinguishes it from lower-voltage members of the family, but does not guarantee suitability for every circuit operating below 400 V.

This guide focuses on voltage stress and replacement decisions. The important question is what happens across the diode during normal operation, switching transitions and relevant startup or fault conditions.

Last updated: October 16, 2026

What does the 1F4G data sheet actually specify?

It specifies conditional electrical and thermal limits.

The reference is Good-Ark’s 1F1G–1F7G data sheet, Rev. B, with November 13, 2023 shown in the revision history. Other manufacturers using similar names need their own documents.

Parameter	1F4G value	Condition or interpretation
Repetitive reverse voltage	400 V	Maximum V_RRM
RMS reverse voltage	280 V	Published V_RMS rating
DC blocking voltage	400 V	Maximum V_DC
Average rectified current	1 A	Specified mounting/thermal conditions apply
Forward surge current	30 A	Single 8.3 ms half-sine on rated load
Maximum recovery time	150 ns	I_F = 0.5 A, I_R = 1 A, I_RR = 0.25 A
Forward drop	1.30 V	Listed at 1 A
Reverse leakage	5 μA / 100 μA	Rated reverse voltage, junction 25°C / 125°C
Typical junction capacitance	12 pF	4 V, 1 MHz
Junction range	−55°C to +150°C	Rated operating range

The electrical table explicitly calls recovery time maximum and capacitance typical. It lists forward drop and leakage without a separate min/typ/max column, so the wording above follows the original labels.

The family’s mounting note specifies leads kept at ambient temperature 9.5 mm from the case. A current label read without that condition can overstate what a compact enclosed assembly can sustain.

Does 400 V make the 1F4G suitable for mains?

Only a topology-specific stress check can answer that.

A 230 V RMS sine wave has an ideal peak of 230 × √2 = 325.27 V. With an assumed +10% variation, that becomes 253 × √2 = 357.80 V. These calculations describe the source peak, not every diode’s reverse voltage.

In an ideal capacitor-input bridge, a blocked diode sees approximately the source peak. Against 400 V, the second example leaves about 42.2 V before considering overshoot, surges or other design allowances. That arithmetic is not an approval of the device for an offline supply.

In an ideal capacitor-input half-wave rectifier, the negative source peak adds to the charged capacitor voltage, giving reverse stress near twice the source peak. At the same assumed high line, that is about 715.6 V, which exceeds 400 V even before additional transients.

This is why “280 V RMS” cannot be used as a universal AC input rating. The topology, filtering and transient environment determine the stress. Rectification also does not provide galvanic isolation.

The same AC source can produce different reverse stress — PIV means peak inverse voltage. These idealized relationships depend on the stated topology and are not complete mains-design requirements.

How does the 1F4G compare with the rest of the family?

Higher blocking voltage can come with a different recovery limit.

Within the referenced Good-Ark document, all seven members share the 1 A average-current rating and R-1 package. The voltage and recovery rows differ as shown below; these shared labels do not guarantee identical operation in every circuit.

Model	V_RRM	Maximum t_rr
1F1G	50 V	150 ns
1F2G	100 V	150 ns
1F3G	200 V	150 ns
1F4G	400 V	150 ns
1F5G	600 V	250 ns
1F6G	800 V	500 ns
1F7G	1,000 V	500 ns

The recovery values use the shared published test conditions. Moving from a 1F4G to a 1F5G raises the blocking label but changes maximum recovery time from 150 to 250 ns. That is a reason to check commutation, not a basis for predicting an exact efficiency change.

A higher-voltage replacement may be acceptable if all required conditions fit. Conversely, a 1F3G cannot substitute where the application relies on the 1F4G’s 400 V blocking capability. See the 1F3G identification guide and the 1F5G parameter guide for those members.

Can a 1N4004 replace a 1F4G?

Do not assume equivalence from the voltage and current labels.

A 1N4004-class device is a general-purpose rectifier designation, whereas the 1F4G specifies fast recovery. Check both manufacturers’ documents and the actual circuit. In forced commutation, different stored-charge behavior can change switch stress, ringing and loss.

For a low-frequency circuit, recovery may not be the dominant constraint, but that still leaves voltage, surge, forward loss, leakage, package and thermal checks. A repair needs an approved replacement, not a conclusion based only on a matching “400 V, 1 A” description.

Likewise, an ultrafast diode is not automatically superior. Compare the stated test conditions and the effect on the surrounding circuit. A different forward drop or recovery shape can matter even when the headline recovery time is shorter.

What does 150 ns tell you about switching suitability?

It describes one recovery measurement, not a frequency ceiling.

The diode must remove stored charge when it changes from forward conduction to reverse blocking. Vishay’s rectifier fundamentals describes that mechanism. How much stress it creates depends on the diode and the switch forcing commutation.

The 150 ns result does not describe recovery charge at every junction temperature or forward current. Nor does it establish a broad “medium-frequency” operating range. Such labels are less useful than the circuit’s voltage, current slew rate and measured switching behavior.

When recovery is critical, compare information at representative conditions and inspect the switching node on hardware. If the available data cannot support the required loss or stress analysis, request additional information or consider a device with more relevant characterization.

What package and temperature checks are needed?

Check polarity, physical fit and the complete heat path.

The cathode band identifies the cathode; the opposite lead is the anode. Use the actual outline drawing for body and lead dimensions. A schematic diode direction and a physical axial orientation must agree.

A constant-drop conduction example makes the thermal issue concrete. Assume 0.6 A during 50% of each cycle and a constant 1.1 V drop while conducting. Average current is 0.3 A, and estimated average forward loss is 0.6 × 0.5 × 1.1 = 0.33 W. Multiplying by an assumed assembly resistance of 90°C/W gives a 29.7°C rise.

This is an illustrative estimate, not a measured 1F4G result. It excludes recovery and leakage loss and does not establish that the assumed thermal resistance applies. Temperature changes the electrical behavior; use an appropriate model and verify the installed assembly.

Review a 1F4G replacement in four steps: A higher blocking rating is only one part of compatibility — Replacement review sequence. Match the conditions behind each value, not just the part name.

Keep the 400 V family member distinct

For this part, record the exact manufacturer and the 1F4G document revision before comparing a replacement. A shared 1 A label does not establish the same recovery or mounting behavior. The fast-recovery guide covers the common waveform principles; this page keeps the 1F4G ratings and family comparison.

FAQ

Is the 1F4G a single diode or a bridge?

It is a single two-terminal axial diode. A full-wave bridge requires a different connected arrangement of junctions.

Can a 1F5G automatically replace a 1F4G?

No. The referenced family has a higher voltage rating for the 1F5G but a different maximum recovery time. Verify dynamic behavior, losses, package and the application requirements.

Does 400 V mean the diode can rectify any 400 V supply?

No. It is a reverse-blocking rating. The voltage across the diode depends on the waveform, topology, filtering and transients.

Use the rating as a boundary, not a recommendation

The 1F4G offers a defined 400 V blocking and 150 ns recovery specification. Selection still requires the circuit’s worst-case conditions. Use the rectifier selection guide to compare those conditions with candidate devices.

Continue through this engineering topic

For the complete selection, design, verification, and troubleshooting path, explore the Rectifier Selection and Ratings.