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Q: Can I replace an LM393 with an LM2903 directly?

Yes - same pinout, same specs, wider temperature range. The LM2903 is the industrial-grade version of the LM393. Drop it in and the circuit won't know the difference.

Q: Can I use an LM358 op-amp in place of an LM393 comparator?

Not as a direct replacement. The LM358 shares the same pinout but has a push-pull output. The LM393 has an open-collector output that requires a pull-up resistor. Swapping them will cause incorrect logic levels.

Q: What's the difference between LM393 and LM339?

Channel count and package. LM393 = 2 comparators, 8-pin. LM339 = 4 comparators, 14-pin. Same silicon, same electrical specs. The LM339 won't fit in an 8-pin LM393 footprint.

Q: Should I worry about the TI LM393 PCN die changes?

If your design depends on specific behavior at input common-mode limits, yes. TI has been transitioning to new die processes since 2021. Check the CSO/CCO label on your reel: SHE=classic, CU3=Ji3, RFB=TiB. The B-versions use the TiB process.

Q: LM393 vs LM393B - is the B-version worth switching?

Yes, for almost every new design. The LM393B gives ±4mV offset (vs ±9mV), 3.5nA bias, 0.8mA supply, 1µs response, and 2kV ESD - all pin-compatible with the classic LM393.

Q: What's the lowest-power drop-in replacement for the LM393?

The TS393 from ST at 9µA per channel - 20× less than the classic LM393. For 5V-only, the LMV393 at 50µA is also a drop-in. For sub-2V, the LM393LV operates down to 1.65V with 25µA per channel.

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LM393 Equivalent, Alternative & Replacement Guide | ICMASS

2026/8/4 11:19:58

LM393 Equivalent, Alternative & Replacement Guide | ICMASS

The LM393 is a dual low-power voltage comparator — open-collector outputs, 2V–30V supply, 0°C to 70°C. When you need a replacement, the choice depends on three questions: wider temperature range? better specs? or lower power?

The most common drop-in is the LM2903 (−40°C to +125°C, same specs). The best upgrade is the LM393B (tighter offset, lower power, better ESD). For battery power, the LMV393 draws just 50µA. And if you need four comparators, the LM339 is functionally identical in a 14-pin package.

LM393 vs LM2903 vs LM393B: Full Comparison

Parameter	LM393	LM2903	LM393B
Channels	2	2	2
Supply Voltage	2V–30V	2V–30V (32V for V ver)	2V–36V
Temperature Range	0°C to 70°C	−40°C to +125°C	−40°C to +85°C
Offset Voltage (max)	±9mV	±7–15mV	±4mV
Input Bias Current (typ)	25nA	25nA	3.5nA
Supply Current (max, dual)	2.5mA	2.5mA	0.8mA
Response Time (typ)	1.3µs	1.3µs	1.0µs
ESD (HBM)	1000V	1000V	2000V
Output Type	Open-collector	Open-collector	Open-collector
Package (SOIC-8)	Yes	Yes	Yes
Package (TSSOP-8)	Yes	Yes	Yes
Pin-Compatible	—	Yes	Yes
Automotive Qualified	No	Yes (AEC-Q100)	Optional (Q1)

When to Use LM2903

If your design needs to survive −40°C cold starts or +125°C engine-compartment temperatures. The LM2903 is the same silicon as the LM393, screened to the wider temperature range. For any industrial or outdoor design, default to the LM2903 — the price difference is negligible and you won't have to re-qualify later.

When to Use LM393B

If you want better specs without a PCB change. The B-version gives you half the offset voltage, one-third the bias current, one-third the supply current, and double the ESD — same footprint. The 36V supply adds margin on 24V rails where transients push past 30V.

When NOT to Use Any LM393-Class Comparator

If you're running from a single Li-ion cell below 2V, the LM393 won't work — minimum supply is 2V. Use the LM393LV (1.65V–5.5V) instead.

If you're comparing signals near the positive rail, the LM393's common-mode range stops at V_CC−1.5V. Use a rail-to-rail input comparator like the TLV7021.

If you need push-pull output (no pull-up resistor), the TS3702 gives you push-pull in the same pinout. The LM393's open-collector always needs an external pull-up.

Supply Current Comparison

Max supply current (dual, both channels), lower is better

LMV393

50µA

TS393

18µA

LM393B

0.8mA

LM393 / LM2903

2.5mA

The LM393B cuts supply current by two-thirds vs the classic LM393. For battery-powered designs needing the full 30V supply range, the TS393 draws just 9µA per channel. The LMV393 is the lowest-power drop-in but limits you to 5.5V max supply.

Pinout: All Drop-In Replacements Share the 8-Pin Layout

_CC 72OUT 62IN− 52IN+ LM393, LM2903, LM393B, LM393A, LMV393 all use this identical pinout. Drop-in.

All dual comparators in the LM393 family share this pinout. The LM339 (quad) uses a 14-pin package and is NOT a drop-in replacement. The LM358 (dual op-amp) shares the same pinout but is an amplifier, not a comparator — using it as a comparator without a pull-up resistor on the output will not work correctly.

LM393 Replacement Decision Flow

Other Alternatives Worth Knowing

Model	Type	Key Difference	Best For
LM339	Quad Comparator	4 channels, 14-pin, same silicon	New designs needing more channels
LMV393IDR	Low-Voltage Dual	2.7V–5.5V, 50µA supply	Battery-powered, 3.3V/5V systems
LM393LV	Low-Voltage Dual	1.65V–5.5V, 25µA/ch, RRI	Sub-2V supplies, rail-to-rail input
TS393	Micropower CMOS Dual	9µA/ch, 2.7V–16V	Ultra-low power, wide voltage
LM2901	Quad Comparator	14-pin, −40° to +125°C	Quad version of LM2903
KA393 / BA393	Second-Source Dual	Same specs, KEC/ROHM manufacturing	Procurement diversity

Frequently Asked Questions

Q1: Can I replace an LM393 with an LM2903 directly?

A: Yes — same pinout, same specs, wider temperature range. The LM2903 is the industrial-grade version of the LM393. Drop it in and the circuit won't know the difference. The only change: your design now works from −40°C to +125°C instead of 0°C to 70°C.

Q2: Can I use an LM358 op-amp in place of an LM393 comparator?

A: Not as a direct replacement. The LM358 shares the same pinout and can sometimes be used as a slow comparator, but the LM393 is purpose-built for fast switching with an open-collector output that requires a pull-up resistor. The LM358 has a push-pull output. If your circuit expects an open-collector output with a pull-up, the LM358 will drive against the pull-up and may oscillate or fail to reach valid logic levels.

Q3: What's the difference between LM393 and LM339?

A: Channel count and package. LM393 = 2 comparators, 8-pin. LM339 = 4 comparators, 14-pin. Same silicon, same electrical specs. If you need four comparators in a new design, use the LM339. If you're replacing an LM393 on an existing board, the LM339 won't fit in the 8-pin footprint.

Q4: Should I worry about the TI LM393 PCN die changes?

A: If your design depends on specific behavior at the common-mode limits, yes. TI has been transitioning LM393 production to new die since 2021. The Ji3 die (PCN#1) changed output state when both inputs exceed the common-mode range. The TiB die (PCN#2) restored classic behavior with a V_CM clamp. Check CSO/CCO on your reel: SHE=classic, CU3=Ji3, RFB=TiB. B-versions use the TiB process. For safety-critical designs, qualify the specific die revision.

Q5: LM393 vs LM393B — is the B-version worth switching?

A: Yes, for almost every new design. The LM393B gives ±4mV offset (vs ±9mV), 3.5nA bias, 0.8mA supply, 1µs response, and 2kV ESD — all pin-compatible. The only reason to stay with classic is if you've already qualified a specific die revision.

Q6: What's the lowest-power drop-in replacement for the LM393?

A: The TS393 from ST, at 9µA per channel. It's CMOS, pin-compatible, and works from 2.7V to 16V — 20× less current than the classic LM393. For 5V-only systems, the LMV393 at 50µA total is also a drop-in. For sub-2V supplies, the LM393LV operates down to 1.65V with 25µA per channel.