SLA7026M Ver la hoja de datos (PDF) - Allegro MicroSystems

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componentes Descripción

Fabricante

SLA7026M

HIGH-CURRENT PWM, UNIPOLAR STEPPER MOTOR CONTROLLER/DRIVERS

Allegro MicroSystems 

SLA7024M, SLA7026M, AND SMA7029M

HIGH-CURRENT PWM,

UNIPOLAR STEPPER MOTOR

CONTROLLER/DRIVERS

PACKAGE RATINGS/DERATING FACTORS

Thermal ratings/deratings for the multi-chip module packages vary

slightly. Normally, the SLA7024M and SMA7029M do not need heat

sinking when operated within maximum specified output current (≤1.0 A

with 2-phase drive) unless the design ambient temperature also ex-

ceeds +60°C. Thermal calculations must also consider the temperature

effects on the output FET ON resistance. The applicable thermal

ratings for the PMCM packages are:

SLA7024M and SLA7026M 18-Lead Power-Tab SIP

RΘJA = 28°C/W (no heat sink) or 4.5 W at +25°C and a derating

factor of -36 mW/°C for operation above +25°C. RΘJC = 5°C/W.

SMA7029M 15-Lead SIP

RΘJA = 31°C/W (no heat sink) or 4.0 W at +25°C and a derating

factor of -32 mW/°C for operation above +25°C. RΘJC = 6°C/W.

TEMPERATURE EFFECTS ON FET rDS(on)

Analyzing safe, reliable operation includes a concern for the

relationship of NMOS ON resistance to junction temperature. Device

package power calculations must include the increase in ON resistance

(producing higher output ON voltages) caused by higher operating

junction temperatures. Figure 8 provides a normalized ON resistance

curve, and all thermal calculations should consider increases from the

given +25°C limits, which may be caused by internal heating during

normal operation.

2.5

2.0

1.5

1.0

0.5

0

-40

0

+40

+80

+120

JUNCTION TEMPERATURE in °C

+160

Dwg. GK-017

FIGURE 8. NORMALIZED ON RESISTANCE

vs TEMPERATURE

115 Northeast Cutoff, Box 15036

™

Worcester, Massachusetts 01615-0036 (508) 853-5000

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