NJM3777 New Japan Radio, NJM3777 Datasheet
NJM3777
Available stocks
Related parts for NJM3777
NJM3777 Summary of contents
Page 1
... GENERAL DESCRIPTION The NJM3777 is a switch-mode (chopper), constant-current driver with two channels: one for each winding of a two-phase stepper motor. The NJM3777 is equipped with a Disable input to simplify half-stepping operation. The NJM3777 contains a clock oscillator, which is common for both driver channels, a set of comparators and flip-flops implementing the switching control, and two output H-bridges, including recirculation diodes ...
Page 2
... and V MM1 MM2 and M A1 and a 4 700 pF capacitor to ground to obtain CC and M A2 and V MM1 MM2 NJM3777 when Phase is HIGH ground. S when Phase is HIGH should be connected together. . Motor current flows from M ...
Page 3
... FUNCTIONAL DESCRIPTION Each channel of the NJM3777 consists of the following sections: an output H-bridge with four transistors and four recirculation diodes, capable of driving up to 800 mA continuous current to the motor winding, a logic section that controls the output transistors, an S-R flip-flop, and a comparator. The clock-oscillator is common to both channels. ...
Page 4
... Logic – 18 GND NJM3777 Symbol Min -0 -0 -900 Symbol Min Typ V 4 ...
Page 5
... M V =41 V, Dis = Dis 500 mA 700 pF kohm 700 pF. Note Symbol Conditions Rth J-GND Rth Note 2. J-A 2 PCB copper area with free air convection 23.0 kHz. s NJM3777 Min Typ - 2 mA 160 - 1.1 2 -0.2 -0.1 480 500 - 500 - 5 - ...
Page 6
... For accurate current regulation, the sensing resistor should be a 0.5 - 1.0 W precision resistor less than 1% tolerance and low temperature coefficient 700 pF GND (V CC Figure 6. Typical stepper motor driver application with NJM3777 V (+ ...
Page 7
... I MA1 140% 100% 24-pin EMP –100% –140% I MA2 140% 100% –100% –140% Full step mode Figure 9. Stepping modes NJM3777 and C at the RC-pin sets the digital limited kohm. The Half step mode Modified half step mode T ...
Page 8
... V (Reference) inputs R The Vref inputs of the NJM3777 have a voltage divider with a ratio reduce the external reference voltage to an adequate level. The divider consists of closely matched resistors. Nominal input reference voltage Interference Due to the switching operation of NJM3777, noise and transients are generated and might be coupled into adjacent circuitry. To reduce potential interference there are a few basic rules to follow: • ...
Page 9
... Modifying the current levels must be done by bringing the reference voltage up (or down) from its nominal value correspondingly. This can be done by using DACs or simple resistor divider networks. The NJM3777 is designed to handle about 1.4 times higher current in one channel on mode, for example 2 x 600 mA in the full-step position, and 1 x 800 mA in the half-step position ...
Page 10
... All ground pins soldered onto PCB copper area with free air convection. Figure 11. Maximum allowable power dissipation V (V) CE Sat 1.2 1.0 0.8 0.6 0.4 0 0.20 0.40 0.60 0.80 I (A) M Figure 14. Typical upper transistor saturation voltage vs. output current NJM3777 V (V) CE Sat 1.2 1.0 0.8 0.6 0.4 0 0.20 0.40 0.60 0.80 I (A) M Figure 12. Typical lower transistor saturation voltage vs. output current V ( 1.2 1.0 ...