DRV8426PWPR datasheet(11/49 Pages) TI1

11 / 49 page

AOUT

Step Input

BOUT

Full-scale current

RMS current

DRV8426

www.ti.com

SLOSE55 – MAY 2020

Product Folder Links: DRV8426

Submit Documentation Feedback

Feature Description (continued)

(1)

VCC is not a pin on the DRV8426 device, but a VCC supply voltage pullup is required for open-drain output nFAULT; nFAULT may be

pulled up to DVDD

Table 3. DRV8426 External Components

COMPONENT

PIN 1

PIN 2

RECOMMENDED

CVM1

GND

Two X7R, 0.01-µF, VM-rated ceramic capacitors

CVM2

GND

Bulk, VM-rated capacitor

CCP

VCP

X7R, 0.22-µF, 16-V ceramic capacitor

CSW

CPH

CPL

X7R, 0.022-µF, VM-rated ceramic capacitor

CDVDD

DVDD

GND

X7R, 0.47-µF to 1-µF, 6.3-V ceramic capacitor

RnFAULT

VCC (1)

nFAULT

>4.7-k

Ω resistor

RREF1

VREF

VCC

Resistor to limit chopping current. It is recommended that the value of parallel

combination of RREF1 and RREF2 should be less than 50-kΩ.

RREF2 (Optional)

VREF

GND

7.3.1 Stepper Motor Driver Current Ratings

Stepper motor drivers can be classified using three different numbers to describe the output current: peak, rms,

and full-scale.

7.3.1.1 Peak Current Rating

The peak current in a stepper driver is limited by the overcurrent protection trip threshold IOCP. The peak current

describes any transient duration current pulse, for example when charging capacitance, when the overall duty

cycle is very low. In general the minimum value of IOCP specifies the peak current rating of the stepper motor

driver. For the DRV8426 device, the peak current rating is 2.5A per bridge.

7.3.1.2 rms Current Rating

The rms (average) current is determined by the thermal considerations of the IC. The rms current is calculated

based on the RDS(ON), rise and fall time, PWM frequency, device quiescent current, and package thermal

performance in a typical system at 25°C. The actual operating rms current may be higher or lower depending on

heatsinking and ambient temperature. For the DRV8426 device, the rms current rating is 1.1 A per bridge.

7.3.1.3 Full-Scale Current Rating

The full-scale current describes the top of the sinusoid current waveform while microstepping. Because the

sinusoid amplitude is related to the rms current, the full-scale current is also determined by the thermal

considerations of the device. The full-scale current rating is approximately

√2 × IRMS. For the DRV8426 device,

the full-scale current rating is 1.5 A per bridge.

Figure 3. Full-Scale and RMS Current

DRV8426PWPR Datasheet(PDF) 11 Page - Texas Instruments

DRV8426PWPR Datasheet(HTML) 11 Page - Texas Instruments

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49

Datasheet Download

Link URL