L298

Part: L298 from STMicroelectronics

Type: Dual full-bridge driver

Description: High-voltage, high-current dual full-bridge driver designed to accept standard TTL logic levels and drive inductive loads, with operating supply voltage up to 46 V and 2 A DC output current per channel.

Operating Conditions:

• Supply voltage (power stage, V_S): V_IH +2.5 to 46 V
• Supply voltage (logic, V_SS): 4.5 to 7 V
• Operating temperature (T_op): -25 to 130 °C
• Max commutation frequency: 40 KHz (at I_L = 2A)

Absolute Maximum Ratings:

• Max power supply voltage (V_S): 50 V
• Max logic supply voltage (V_SS): 7 V
• Max continuous output current (each channel, I_O DC operation): 2 A
• Max junction/storage temperature (T_stg, T_j): -40 to 150 °C

Key Specs:

• Power supply voltage (V_S): V_IH +2.5 to 46 V (operative condition)
• Logic supply voltage (V_SS): 4.5 to 7 V
• Input low voltage (V_iL): -0.3 to 1.5 V
• Input high voltage (V_iH): 2.3 to V_SS V
• Total voltage drop (V_CEsat): 1.80 V (min) to 3.2 V (max) at I_L = 1A
• Total voltage drop (V_CEsat): up to 4.9 V (max) at I_L = 2A
• Quiescent supply current (I_S): 13 mA (typ) to 70 mA (max)
• Commutation frequency (f_C): 25 KHz (typ) to 40 KHz (max) at I_L = 2A

Features:

• Operating supply voltage up to 46 V
• Total dc current up to 4 A
• Low saturation voltage
• Overtemperature protection
• Logical "0" input voltage up to 1.5 V (high noise immunity)

Applications:

• Dual brush DC motors
• Stepper motors

Package:

• Multiwatt15L V (15-lead)
• Multiwatt15L H (15-lead)
• PowerSO-20 (20-lead)

• Operating supply voltage up to 46 V.
• Total dc current up to 4 A.
• Low saturation voltage.
• Overtemperature protection.
• Logical "0" input voltage up to 1.5 V (high noise immunity).

Figure 8 shows a bidirectional DC motor control schematic diagram for which only one bridge is needed.

The external bridge of diodes D1 to D4 is made by four fast recovery elements (t rr ≤ 200 ns) that must be chosen of a V F as low as possible at the worst case of the load current.

An external bridge of diodes are required when inductive loads are driven and when the inputs of the IC are chopped; Schottky diodes would be preferred.

The sense output voltage can be used to control the current amplitude by chopping the inputs, or to provide overcurrent protection by switching low the enable input.

The brake function (Fast motor stop) requires that the Absolute Maximum Rating of 2 A must never be exceeded.

When the repetitive peak current needed from the load is higher than 2 A, a paralleled configuration can be chosen (See Figure 9).

This solution can drive up to 3 A in dc operation and until 3.5 A of a repetitive peak current.

On Figure 10 it is shown the driving of a two phase bipolar stepper motor; the needed signals to drive the inputs of the L298 are generated, in this example, by the IC L297.

Figure 11 shows an example of P.C.B. designed for the application of Figure 10.

Figure 12 shows a second two phase bipolar stepper motor control circuit where the current is controlled by the IC L6506.

Figure 10. Two phase bipolar stepper motor circuit

Note: RS1 = RS2 = 0.5 Ω.

Figure 11. Suggested printed circuit board layout for the circuit of fig. 10 (1:1 scale)

Figure 12. Two phase bipolar stepper motor control circuit by using the current controller L6506.

Figure 2. Pin configuration

Table 3. Pin function

Table 3. Pin function

(VS = 42 V; V SS = 5 V, T j = 25 °C; unless otherwise specified)

1. 'Sense A' and 'Sense B' pins connected to GND.
2. Sensing voltage can be -1 V for t ≤ 50 μsec; in steady state V sens min ≥ - 0.5 V.
3. See Figure 4.
4. See Figure 6.
5. The load must be a pure resistor.

Note:

For INPUT switching, set EN = H

For ENABLE switching, set IN = H

Figure 5. Source current delay times vs. input or enable switching

Figure 6. Switching times test circuits

Note: For INPUT Switching, set EN = H For ENABLE Switching, set IN = L

Figure 7. Sink current delay times vs. input 0 V enable switching

Figure 8. Bidirectional dc motor control

Table 5. Values of bidirectional dc motor control

Note: L = Low, H = High, X = Do not care

Figure 9. For higher currents, outputs can be paralleled. Take care to parallel channel 1 with channel 4 and channel 2 with channel 3

Table 5. Values of bidirectional dc motor control

Figure 9. For higher currents, outputs can be paralleled. Take care to parallel channel 1 with channel 4 and channel 2 with channel 3

Absolute maximum ratings are those values beyond which damage to the device may occur. These are stress ratings only and functional operation of the device at these conditions is not implied. Operating outside maximum recommended conditions for extended periods of time may impact product reliability and result in device failures.

Table 1. Absolute maximum ratings

Table 2. Thermal data

Table 2. Thermal data

In order to meet environmental requirements, ST offers these devices in different grades of ECOPACK packages, depending on their level of environmental compliance. ECOPACK specifications, grade definitions and product status are available at: www.st.com. ECOPACK is an ST trademark.