Stepper driver input voltage: A4988, DRV8825 and TMC2209 limits

An A4988 stepper driver takes 8 to 35 V on its motor supply, a DRV8825 takes 8.2 to 45 V, and a TMC2209 takes 5.5 to 29 V. Any of them runs a 12 V or 24 V printer. None is rated for 48 V. That takes a driver that switches external MOSFETs (power transistors), such as the TMC2160 or TMC5160.

What input voltage does an A4988 stepper driver take?

An A4988 takes a motor supply (VBB, labeled VMOT on Pololu-style carrier boards) of 8 to 35 V, per Allegro’s datasheet, plus a separate 3 to 5.5 V logic supply on VDD. 12 V and 24 V printers sit comfortably inside that range. The 35 V figure is also its absolute maximum, with zero headroom.

Below 8 V the A4988 is outside its operating range. Allegro rates the outputs for 35 V and ±2 A per coil. Pololu’s carrier needs a heat sink or other cooling above about 1 A per coil, so 2 A assumes good cooling.

What is the A4988’s maximum voltage?

35 V. Allegro lists 35 V both as the top of the operating range and as the absolute maximum rating for the load supply. The DRV8825 has 2 V between its 45 V operating limit and its 47 V absolute maximum; the A4988 has none. Pololu warns that LC spikes at power-up (ringing between lead inductance and capacitance) “can exceed the 35 V maximum voltage rating for the A4988 and permanently damage the board, even when the motor supply voltage is as low as 12 V.”

Does the A4988 work with 3.3 V and 5 V boards?

Yes. The VDD logic supply accepts 3 to 5.5 V, so 3.3 V and 5 V controller boards both work. One catch: the reference voltage that sets the A4988’s current limit follows VDD. Pololu says to set the limit again whenever the logic voltage changes, so moving an A4988 from a 5 V board to a 3.3 V board changes its motor current.

What voltage can a DRV8825 stepper driver handle?

A DRV8825 runs on a motor supply of 8.2 to 45 V, according to Texas Instruments’ datasheet, with 47 V as its absolute maximum. It needs no logic supply: it makes its own 3.3 V internally, and its inputs accept 3.3 V or 5 V signals. Its main voltage advantage over an A4988 is 10 V more operating range.

TI’s undervoltage lockout keeps the outputs off until the motor supply rises past about 7.8 V (8.2 V at most). TI rates the outputs for 2.5 A per coil at 24 V and 25°C with a proper heat sink. Pololu’s carrier caps that at 2.2 A through its sense resistors and needs a heat sink above about 1.5 A per coil.

Does a DRV8825 need a logic voltage?

No. The DRV8825 takes everything it needs from VM. Inputs read high from 2.2 V up to 5.25 V, which covers 3.3 V and 5 V controller boards. On Pololu’s pin-compatible carrier, the A4988’s logic-power pin becomes the DRV8825’s FAULT output. A 1.5 kΩ resistor protects it, so the board drops into A4988 sockets that feed logic power to that pin.

Voltage limits for common stepper drivers

Driver	Motor supply, operating	Absolute maximum	Logic supply	Current per coil
A4988 (Allegro)	8 to 35 V	35 V	3 to 5.5 V	±2 A
DRV8825 (TI)	8.2 to 45 V	47 V	none (inputs 2.2 to 5.25 V)	2.5 A at 24 V
TMC2208 (Trinamic)	4.75 to 36 V	see datasheet	3 to 5 V (module)	1.4 A RMS
TMC2209 (Trinamic)	5.5 to 29 V	32 V	3.0 to 5.25 V	2.0 A RMS, 2.8 A peak
TMC2130 (Trinamic)	5.5 to 46 V (module)	see datasheet	3 to 5 V (module)	1.2 A RMS (module)
TMC2160 (Trinamic)	10 to 55 V	60 V	3.0 to 5.25 V	up to 20 A, external MOSFETs
TMC5160 (Trinamic)	8 to 60 V	see datasheet	see datasheet	up to 20 A, external MOSFETs

The A4988, DRV8825, TMC2209 and TMC2160 figures come from the chip datasheets. The TMC2208 range and current come from its datasheet’s feature list; Digi-Key lists the chip at 5.5 to 36 V. The TMC5160 range is from Digi-Key’s product highlight. Rows marked “(module)” are Watterott’s SilentStepStick module ratings, which put the TMC2209 module at 5.5 to 28 V, slightly under the chip.

The TMC2209’s first page says 4.75 to 29 V. The 4.75 V floor applies only with its internal 5 V regulator bridged. With the regulator in use, the operating range starts at 5.5 V. Its continuous current guideline is 1.4 A RMS (root mean square), and 2.0 A RMS is allowed with a duty-cycle limit such as 1 s on, 1 s standby.

How much voltage margin should a stepper driver have?

Keep the supply a few volts under the operating maximum, not just under the absolute maximum. The real rail swings above its nominal value for three reasons:

1. Power-up spikes. In Pololu’s test, a 12 V bench supply on 36-inch leads into a 10 µF ceramic capacitor produced a spike of almost 40 V, more than three times the set voltage.
2. Switching ringing. Trinamic’s datasheet warns that “even small trace inductivities” can “easily generate a few volts of ringing,” and says to consider this when working near the maximum voltage.
3. Motor regeneration. The same datasheet says “significant energy can be fed back from motor coils to the power supply in the event of quick deceleration, or when the driver becomes disabled,” and asks for overvoltage protection if a motor could be turned by hand at high speed.

The power supply’s own adjustment matters too. MEAN WELL’s 24 V LRS-350-24 supply adjusts from 21.6 to 28.8 V:

24 V supply turned to its maximum: 28.8 V

TMC2209 operating max   29 V − 28.8 V = 0.2 V headroom
A4988 maximum           35 V − 28.8 V = 6.2 V headroom
DRV8825 operating max   45 V − 28.8 V = 16.2 V headroom

At a nominal 24 V a TMC2209 has 5 V of room. Turning the supply’s trim pot up to chase speed uses almost all of that margin.

How do you protect a driver from voltage spikes?

Put a large electrolytic capacitor across motor power and ground, close to the driver. Pololu’s carriers call for at least 47 µF. Trinamic recommends at least 100 µF of low-ESR electrolytic capacitance near a TMC2209 (ESR is equivalent series resistance).

In Pololu’s test, the fix for the 40 V spike was a 100 µF electrolytic in parallel with the ceramic capacitor. The electrolytic’s higher ESR damps the ringing. Long supply leads and ceramic-only filtering make spikes worse. Power off before you plug or unplug a driver or motor.

Can stepper drivers handle a 12 V to 24 V printer conversion?

Yes. The A4988, DRV8825, TMC2208, TMC2209 and TMC2130 all run inside their operating ranges at 24 V. Prusa’s 24 V, 240 W replacement supply fits its printers from the MK3S to the CORE One. The TMC2209 sits closest to its limit, so leave its supply at 24 V rather than turning it up.

In a conversion the risk sits elsewhere: heaters, fans and the board’s own input rating. A 12 V heater cartridge on 24 V draws four times its rated power:

P = V² ÷ R
Double the voltage, same resistance: (2 × V)² ÷ R = 4 × power

Swap every heater for a 24 V part and check the fans and mainboard. The heater resistance calculator gives the resistance a 24 V heater needs, and the power supply calculator sizes the new supply.

Which stepper drivers can run on 48 V?

Only drivers rated well above 48 V. The A4988 (35 V), DRV8825 (45 V), TMC2208 (36 V), TMC2209 (29 V) and TMC2130 (46 V) all fall short. The TMC2160 operates up to 55 V and the TMC5160 is rated 8 to 60 V. Both drive external MOSFETs.

The module matters as much as the chip. Watterott rates its TMC5160 SilentStepStick at 10 to 35 V and only its high-voltage version at 50 V, so read the module’s rating as well as the chip’s. A 48 V supply can also sit above 48 V: MEAN WELL’s LRS-350-48 adjusts from 43.2 to 52.8 V.

The 24 V vs 48 V guide covers what the higher rail buys.

Does a higher supply voltage push more current into the motor?

No. These drivers chop the supply to hold the coil current at a set limit. You set that limit at the driver: with the Vref potentiometer on an A4988 or DRV8825, or in firmware over the serial UART link on a TMC2209 or the SPI bus on a TMC2160.

Pololu explains that active current limiting is what lets a motor run on a supply above its rated voltage, for higher step rates. The extra voltage does not raise the set current. Stepper motor voltage covers the motor side.