ls7260 LSI Computer Systems, Inc., ls7260 Datasheet - Page 2

• Manufacturer Part Number: ls7260
• Description: Brushless Dc Motor Commutator/controller
• Manufacturer: LSI Computer Systems, Inc.

7260-072503-2
MAXIMUM RATINGS:
Input Specifications:
BRAKE, ENABLE, CS1, CS2
S1, S2, S3, FWD/REV
Voltage (Logic 1)
OVERCURRENT SENSE (See Note)
Threshold Voltage
BRAKE (Pin 9) (Cont’d)
An internal pull-down resistor holds the input low when left
open. (Center- tapped motor configuration requires a power
supply disconnect transistor controlled by the BRAKE signal
- See Figure 2A).
ENABLE (Pin 10)
A high level at this input permits the output to sequence as
in Table 3, while a low disables all external output drivers.
An internal pull-up resistor holds the input high when left
open. Positive edges at this input will reset the overcurrent
flip-flop.
OVERCURRENT SENSE (Pin 12)
This input provides the user a way of protecting the motor
winding, drivers and power supply from an overload condi-
tion. The user provides a fractional-ohm resistor between
the negative supply and the common emitters of the NPN
drivers or common sources of N-Channel FET drivers. This
point is connected to one end of a potentiometer (e.g. 100k
ohms), the other end of which is connected to the positive
supply. The wiper pickoff is adjusted so that all outputs are
disabled for currents greater than the limit. The action of the
input is to disable all external output drivers. When BRAKE
exists, OVERCURRENT SENSE will be overridden. The
overcurrent circuitry latches the overcurrent condition. The
latch may be reset by the positive edge of either the saw-
tooth OSCILLATOR or the ENABLE input. When using the
ENABLE input as a chopped input, the OSC input should be
held at V
must be used to reset the overcurrent latch.
VTRIP (Pin 13)
This input is used in conjunction with the sawtooth OSC in-
put. When the voltage level applied to VTRIP is more neg-
ative than the waveform at the OSC input, the Outputs will
be enabled as shown in Table 3. When VTRIP is more pos-
itive than the sawtooth OSCILLATOR waveform the external
output drivers are disabled.
DC ELECTRICAL CHARACTERISTICS:
(All Voltages Referenced to V
Supply Voltage
Supply Current (Outputs not loaded)
Any Input Voltage to Vss
Storage Temperature
Operating Temperature
PARAMETER
DC Supply Voltage
(Logic 0)
SS
. When the ENABLE input is held high, the OSC-
DD
,
T
A
= 25°C unless otherwise specified)
SYMBOL
SYMBOL
Vss - V
T
V
V
R
V
V
T
V
STG
I
DD
TH
SS
A
IN
IH
in
IL
DD
(V
SS
V
SS
/2) - 0.25
MIN
0
5
-
-
-
The sawtooth waveform at the OSC input typically varies
from 0.4Vss to Vss - 2V. The purpose of the VTRIP input in
conjunction with the OSCILLATOR is to provide variable
speed adjustment for the motor by means of PWM for Vss
greater than 7V. Below Vss = 7V, the IC may only be used
as a commutator (See Note).
Note: Below Vss = 7V, the OSC sawtooth amplitude is too
small to allow proper operation of the PWM circuitry.
OSCILLATOR (Pin 14)
An R and C connected to this input (see Figure 6) provide
the timing components for a sawtooth OSCILLATOR. The
signal generated is used in conjunction with VTRIP to pro-
vide PWM for variable speed applications and to reset the
overcurrent condition.
OUTPUTS 1, 2, 3 (Pins 2, 3, 4)
For the LS7262, these open drain Outputs are enabled as
shown in Table 2 and provide base current to PNP tran-
sistors or gate drive to P-Channel FET drivers when COM-
MON is floating. If COMMON is held at Vss, these Outputs
can provide drive to NPN transistors or N-Channel FET
drivers. For the LS7260, these Outputs provide drive to
P-Channel FET drivers if COMMON is held at V
OUTPUTS 4, 5, 6 (Pins 6, 7, 8)
These open drain Outputs are enabled as in Table 2 and
provide base current to NPN transistors or gate drive to
N-Channel FET drivers.
COMMON (Pin 5)
The COMMON may be connected to Vss when using a
center-tapped motor configuration or when using all NPN
or N-Channel drivers. For the LS7260, the COMMON is
tied to V
Vss, V
Supply voltage positive and negative terminals.
1.5
DD
SS
(Pins 11, 18)
.
-30 to +0.5
-65 to +150
-40 to +125
VALUE
+35
150
TYP
4.5
-
-
-
-
(V
SS/
V
SS
MAX
V
2) + 0.25 V
28
SS
6
-
- 4.0
UNIT
UNIT
°C
°C
k
V
V
V
V
V
mA
SS
.