LB11948T-TLM-E SANYO, LB11948T-TLM-E Datasheet - Page 12

• Manufacturer Part Number: LB11948T-TLM-E
• Description: IC MTR DVR PWM STEP TSSOP30
• Manufacturer: SANYO

Specifications of LB11948T-TLM-E

• Applications: Stepper Motor Driver, 1 - 2 Phase
• Number Of Outputs: 1
• Voltage - Load: 3 V ~ 15 V
• Voltage - Supply: 3 V ~ 15 V
• Operating Temperature: -20°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 30-TSSOP (0.220", 5.6mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Output: -
• Other names: 869-1219-2

(2) Constant current settings
(3) VREF pins
(4) Notes on the Ground Pins
The reference voltages of the VREF1 and VREF2 pins can be set by dividing the resistance voltage from the 1V
regulator output pin (1VREG).
The output current is set using the VREF reference voltage applied to the VREF1 and VREF2 pins and the Re resistor
connected between the E1 and E2 pins and ground. The bias current of the output transistor also flows from the E pins
so that the Iout output current flowing to the motor is reduced by an amount equivalent to the bias current. In addition,
in controlling the constant current, the voltage is sensed by the E pins (pad area on IC chip) so that the amount
equivalent to the wire bonding resistance (rw) from the pad to the package pins is added to the current sensing
resistance (Re).
Therefore, the formula for calculating the current setting is as shown below. (Refer to Fig. 2)
The VREF pins are the reference voltage input pins for the preset current, so take special care to ensure that they are
not affected by noise. If these pins will be affected by noise, connect a capacitor to VREF1 and VREF2 pins.
Since this IC switches large currents, the following notes on ground lines must be observed.
• The PCB pattern lines in areas that handle large currents must be as wide as possible so as to have low impedances,
• The ground terminals on the sensing resistors Re connected to the E pins (E1 and E2) must be connected as close as
• The capacitors between V CC and ground and between V BB and ground must be as close as possible to the
and must be kept as far as possible from the small signal systems.
possible to the IC GND (pin 21), PGND (pin 22), or DGND (pins 5 and 26) pins as possible.
corresponding V CC and V BB pin in the pattern.
I OUT = VREF / (Re + rw) - Ibias
Re : Sensing resistance of resistor connected between E pins and ground
rw : Amount equivalent to wire bonding resistance from pad to pins
Ibias : Output transistor bias current
The Ibias current corresponds to the current setting reactive current (IE) in the specifications for the electrical
characteristics.
Current setting reactive current IE ratings : Min : -22mA Typ : -17mA
Sense current : Ie = I O +Ibias
Ibias
Wire (rw)
[A]
IC E1 pin
I O
LB11948T
Re
Fig. 2
VREF
rw = 50 - 100mΩ
IC VREF1 pin
Max : -10.5mA
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