APPLICATION INFORMATIONS

Figure 1 shows the L6242 configurated as a tran-

sconductance amplifier, in order to drive linear

motors as Voice Coil (VCM). The L6242 provides

the power section of the Transconductance Am-

plifier. The two OP AMP are configurated one as

inverting and the other as noninverting amplifier,

with the same gain. Working in push-pull, they

can be configurated as a bridge. The motor cur-

rent can be controlled by means of the sense re-

sistor (typical 1

Ω) in series with the motor. The

current sense amplifier provides the feedback sig-

nal, which is summed to the driving signal at the

node which is the inverting input of the Error Am-

plifier. R1 closes the control loop. R2 converts the

input voltage signal, into a current signal.

The snubber network provides the system stabil-

ity, always required by the application. The net-

work is directly connected to the output pins of

the IC, OUT1 and OUT2, and in parallel with the

load. R4 and C2 could be of different values, de-

pending on the p.c.b. configuration and on the

motor characteristics.

The DC transfer function may be expressed as:

gm = Iout/Vin = k

• (R1/R2)

where k = 1/(Rsense

• Ad)

and Ad = gain of the current sense amplifier.

ABSOLUTE MAXIMUM RATINGS

Symbol

Parameter

Value

Unit

Supply Voltage

28

V

Input Voltage

VS

V

Differential Input Voltage

V

DC Output Current

1

A

Peak Output Current (non repetitive)

1.5

A

°C

°C

1

5

W

W

Storage and Junction Temperature Range

-40 to 150

°C

°C unless otherwise specified)

Symbol

Parameter

Test Condition

Min.

Typ.

Max.

Unit

Supply Voltage

4

28

V

Quiescent Drain Current

10

15

mA

Input Bias Current

0.2

1

µA

Input Offset Voltage

15

mV

Input Offset Current

10

50

nA

Slew Rate

1.5

V/

µs

Input Resistance

500

K

Ω

Open Loop Voltage Gain

f = 100Hz

70

80

dB

CMR

Common Mode Rejection

f = 100Hz

66

84

dB

SVR

Supply Voltage Rejection

Ω

54

dB

High Drop Voltage

I = 100mA

I = 500mA

0.7

1

1.5

V

V

Low Drop Voltage

I = 100mA

I = 500mA

0.3

0.6

1

V

V

Thermal Shutdown Junction Temperature

145

°C

Internal Pull-up Resistor of the Enable Input

50

K

Ω

Enable Low Voltage

°C

-0.3

1.2

V

Quiescent Drain Current

En = L

2

5

mA

Enable Delay

50

µs

Output Leakage Current

10

µA

L6242

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