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PRELIMINARY
FEATURES
• DELIVERS UP TO 5A CONTINUOUS OUTPUT
• OPERATES AT SUPPLY VOLTAGES UP TO 55V
• TTL AND CMOS COMPATIBLE INPUTS
• NO “SHOOT-THROUGH” CURRENT
• THERMAL SHUTDOWN (OUTPUTS OFF) AT 160°C
• INTERNAL CLAMP DIODES
• SHORTED LOAD PROTECTION (to VS or PGND or
SHORTED LOAD)
• NO BOOTSTRAP CAPACITORS REQUIRED
• 100KHZ ONBOARD PWM
APPLICATIONS
• DC AND STEPPER MOTOR DRIVES
• POSITION AND VELOCITY SERVOMECHANISMS
• FACTORY AUTOMATION ROBOTS
• NUMERICALLY CONTROLLED MACHINERY
• COMPUTER PRINTERS AND PLOTTERS
• AUDIO AMPLIFICATION
FIGURE 1. BLOCK DIAGRAM
DESCRIPTION
The SA56 is a 5A PWM Amplifier designed for motion con-
trol applications. The device is built using a multi-technology
process which combines bipolar and CMOS control circuitry
with DMOS power devices in the same monolithic structure.
Ideal for driving DC and stepper motors; the SA56 accom-
modates peak output currents up to 10A. An innovative circuit
which facilitates low-loss sensing of the output current has
been implemented. On board PWM oscillator and comparator
are used to convert an analog signal into PWM direction and
magnitude for motor control applications, or to amplify audio
signals using class D amplification.
23 PIN SIP
PACKAGE STYLE EX
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ABSOLUTE MAXIMUM RATINGS
SPECIFICATIONS
SA56
ABSOLUTE MAXIMUM RATINGS SUPPLY VOLTAGE, VCC 6V
SUPPLY VOLTAGE, VS 55V
PEAK OUTPUT CURRENT (200mS) 10A
CONTINUOUS OUTPUT CURRENT 5A
POWER DISSIPATION 25W
POWER DISSIPATION (TA = 25°C, Free Air) 3W
JUNCTION TEMPERATURE, TJ(MAX) 150°C
ESD SUSCEPTIBILITY 1500V
STORAGE TEMPERATURE, TSTG –40°C to +150°C
LEAD TEMPERATURE (Soldering, 10 sec.) 300°C
JUNCTION TEMPERATURE, TJ –40°C to +150°C
NOTE: These specifications apply for VS = 50V and Vcc = 5V at 25°C, unless otherwise specified.
SPECIFICATIONS
PARAMETER TEST CONDITIONS MIN TYP MAX UNITS
VS 12 60 V
Vcc 4.5 5.5 V
SWITCH ON RESISTANCE, RDS(ON) Output Current = 5A 0.33 0.6 Ω
CLAMP DIODE FORWARD DROP, VCLAMP Clamp Current = 5A 2.4 3.0 V
LOGIC LOW INPUT VOLTAGE, VIL -0.5 0.8 V
LOGIC LOW INPUT CURRENT, IIL VIN = –0.1V -10 +10 µA
LOGIC HIGH INPUT VOLTAGE, VIH 2 Vcc V
LOGIC HIGH INPUT CURRENT, IIH VIN = 5.5V -10 10 µA
CURRENT SENSE OUTPUT IOUT = 1A 200 250 µA
IOUT = 5A 1 1.2 MA
CURRENT SENSE LINEARITY 1A ≤ IOUT ≤ 5A ±2 ±5 %
SHUTDOWN TEMPERATURE, TJSD Outputs Turn OFF 160 175 °C
QUIESCENT SUPPLY CURRENT, IS All Logic Inputs Low 13 25 mA
Icc 13 25 mA
OUTPUT TURN-ON DELAY TIME, tDon Sourcing Outputs, IOUT = 1A 300 ns
Sinking Outputs, IOUT = 1A 300 ns
OUTPUT TURN-ON SWITCHING TIME, ton Sourcing Outputs, IOUT = 1A 100 ns
Sinking Outputs, IOUT = 1A 80 ns
OUTPUT TURN-OFF DELAY TIMES, tDoff Sourcing Outputs, IOUT = 1A 200 ns
Sinking Outputs, IOUT = 1A 200 ns
OUTPUT TURN-OFF SWITCHING TIME, toff Sourcing Outputs, IOUT = 1A 75 ns
Sinking Outputs, IOUT = 1A 70 ns
MINIMUM INPUT PULSE WIDTH, tp 1 µs
APWM FREQUENCY (DIGITAL MODE) 500 Kc
REFERENCE VOLTAGE
3.8 4 4.1 V
Vref OUTPUT CURRENT (Vref 4V)
1 mA
ANALOG INPUT RANGE FOR Load Current = 400µA 1 Ref Voltage V
FULL MODULATION
HIGH CURRENT SHUTDOWN RESPONSE Output shorted 400 500 1000 ns
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OPERATING
CONSIDERATIONS SA56
GENERAL
Please read Application Note 1 "General Operating Consid-
erations" which covers stability, power supplies, heat sinking,
mounting, and specification interpretation. Visit www.apexmi-
crotech.com for design tools that help automate tasks such as
calculations for stability, internal power dissipation, current limit,
heat sink selection, Apex's complete Application Notes library,
Technical Seminar Workbook and Evaluation Kits.
GROUND PINS
The main ground for the SA56 is the package tab. In ad-
dition, there are 3 GND pins. Pin 12 is for input signal GND
and pins 1 and 23 are provided for production test only. The
package TAB should be connected so the load current flows
through the TAB.
POWER SUPPLY BYPASSING
Bypass capacitors to power supply terminals Vs and Vcc
must be connected physically close to the pins to prevent
erratic, low efficiency operation and excessive ringing at the
outputs. Electrolytic capacitors, at least 10µF per output amp,
are required for suppressing Vs to PGND noise. High qual-
ity ceramic capacitors (X7R) 1µF or greater should also be
used. Only capacitors rated for switching applications should
be considered.
The bypass capacitors must located as close to the power
supply pins as possible (due to the very fast switching times
of the outputs, the inductance of 1 inch of circuit trace could
cause noticeable degradation in performance). The bypassing
requirements of Vcc are less stringent, but still necessary. A
0.1µF to 0.47µF capacitor connected directly between the Vcc
and GND (SIG) pins will suffice.
PIN DESCRIPTIONS
Insert pin numbers and arrange in proper order later
Vs: High voltage supply
Aout, Bout: Half bridge outputs
PGND: Power ground, high current ground return path of the
motor.
SC: Short circuit detect logic output, CMOS, typically connected
to SCin. Will be "HIGH" when output current exceeds the
internal current threshold.
SCin: Short circuit detect input, CMOS, typically connected
to SC. SCin has a 100KΩ resistor that pulls the input low
when not driven. This input pin can be left open when Short
Circuit Protection is not used.
TLIM: Temperature limit output, CMOS, typically connected to
TLIMin. Will be "HIGH" when output MOSFET temperature
exceeds the internal temperature threshold.
TLIMin: Temperature limit in, input CMOS. Typically connected
to TLIMout. TLIMin has a 100KΩ resistor that pulls the
input low when not driven. This input pin can be left open
when not used.
Vcc: 5V supply for input logic and analog circuitry.
DIR: Direction logic input, CMOS/TTL. Determines the active
output MOSFETs in 2 quadrant digital control mode.
DIS: Disable logic input, CMOS/TTL. Disables all four output
MOSFETs. Also resets a latched fault condition caused by
short circuit or over temperature.
FAULT: Protection circuit flag output, CMOS. Goes "HIGH"
when the output MOSFETs have been automatically latched
"OFF" because of short circuit or excessive temperature.
APWM: Digital or analog duty cycle input, CMOS/TTL or 1-
4V analog.
VREF: 4V reference voltage. Can be used at low current for
biasing analog loop circuits. Internally used for generating
the ramp signal in analog input mode.
CPWM: PWM timing capacitor connection in analog mode.
Set below 1V for digital input mode.
GND (SIG): Analog ground connection for all internal low
current circuitry.
Iout: Analog output representing the forward output current.
Typically connected to ISEN and a resistor to ground.
ISEN: Analog voltage input used for programmable current
limit. Typically connected to Iout and a resistor to program
the current limit.
MODES OF OPERATION
The following chart shows the four modes of operation.
Mode CPWM PWM DIR Aout Bout
2
Quad
Digital
GND Modu-
lation
In
High High PWM
2
Quad
Digital
GND Modu-
lation
In
Low PWM High
4
Quad
Digital
GND High Modu-
lated
In
DIR DIR
4
Quad
Analog
Add
Cap. to
set
Fre-
quency
Drive
with
analog
signal
Not
used
but
GND
Greater
than 50%
high for a
positive
input
Greater
than 50%
high for a
negative
input
ANALOG INPUT OPERATION
The SA56 can operate with analog or digital inputs. In the
analog mode, the capacitor from CPWM to GND (SIG) sets
the frequency of an internal triangular ramp signal. An analog
input at the APWM pin is compared to the ramp to generate
the duty cycle of the output. In Analog mode, the digital input
on the DIR pin is ignored, though this pin should never be
left floating.
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OPERATING
CONSIDERATIONS
SA56
OPERATING WITH DIGITAL INPUTS
Two and 4 quadrant operation are possible with the SA56
when driven with a digital PWM signal from a microcontroller or
DSP. When using a digital modulation signal, tie the CPWM pin
to GND to disable the internal oscillator and ramp generator.
When operating in the digital mode, pulse widths should be
no less than 100ns and the switching frequency should remain
less than 500KHz. This will allow enough time for the output
MOSFETs to reach their full on/off state before receiving a
command to reverse state.
2 QUADRANT DIGITAL MODE
For sign/magnitude (2 quadrant) operation, two digital input
signals are required. A digital PWM signal to the APWM pin can
control the output duty cycle at one output pin with the other
output pin held "HIGH". The digital input on the DIR pin will
control direction by selecting the outputs that switch according
to the APWM input. If DIR is a logic "HIGH", the A output will
be held high and the B output will be switched as the inverse of
the PWM input signal and the average output of A will always
be greater than B. If DIR is logic "LOW", the B output will be
held "HIGH" and the A output will be switched. Operating in 2
quadrant mode reduces switching noise and power dissipation,
but limits the control of the motor at very low speed.
A braking function can be achieved by holding the PWM input
"LOW", which will turn both of the upper MOSFETs on, rapidly
reducing the circulating current of the motor winding.
4 QUADRANT DIGITAL MODE
During 4 quadrant operation a single digital PWM input in-
cludes magnitude and direction information. The digital PWM
input signal is applied to the DIR pin and the PWM/INPUT pin
is tied to "HIGH". Both pairs of output MOSFETs will switch
in a locked anti-phase fashion from 0-100% duty cycle. With
a 50% duty cycle the average voltage of each output will be
half of Vs, and the differential voltage applied to the load will
be zero. Four quadrant operation allows smooth transitions
through zero current for position servos and low speed ap-
plications. Power dissipation is slightly higher since all four
output MOSFETs switch every cycle.
PROTECTION CIRCUITS
Thermal and short circuit protection are included in the
SA56 to prevent damage during fault conditions. High cur-
rent protection circuits will sense a direct short from either
output to GND or Vs as well as across the load. The thermal
protection will engage when the temperature of the MOSFETs
reach approximately 160°C. The FAULT output pin will latch
"HIGH" if either protection circuits engages and will place all
MOSFETs in the "OFF" state (high impedance output). The
SC or TLIM output will also go "HIGH" though not be latched, to
indicate which of the protection features has been triggered.
If the TLIMIN is connected to TLIM and SSIN is tied to SSOUT
the fault output will latch high whenever either SC or TLIM go
high. The fault going high tristates the 4 output transistors. To
reset the tristate condition, cycle the Vcc power or bring the
DISABLE pin "HIGH" then "LOW".
The most severe condition for any power device is a direct,
hard-wired ("screwdriver") short from an output to ground.
While the short circuit protection will latch the output MOSFETs
within 500ns (typical) the die and package may be required
to dissipate up to 500 Watts of power until the protection is
engaged. This energy can be destructive, particularly at higher
operating voltages, so good thermal design is critical if such
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This data sheet has been carefully checked and is believed to be reliable, however, no responsibility is assumed for possible inaccuracies or omissions. All specifications are subject to change without notice.
SA56U REV 6 DECEMBER 2004 © 2004 Apex Microtechnology Corp.
fault tolerance is required of the system. The Vs and PGND
pins may become very hot during this period of high current.
PROGRAMMABLE CURRENT LIMIT
The ISEN pin sources a current proportional to the forward
output current of the active P channel output MOSFET. The
proportionality is 200µA (nom) per ampere of output current.
The ISEN output is blocked during the switching transitions
when current spikes can be significant.
OPERATING
CONSIDERATIONS SA56
To create a programmable current limit, connect a resis-
tor from ISEN out to GND. When the voltage across this
resistor exceeds internally generated 2.75V threshold, all 4
output MOSFETs will be turned off for the remainder of the
switching cycle. A 2.75KΩ resistor will set the current limit to
approximately 5 Amps.
The ISEN output can also be used for maintaining a current
control loop in torque motor applications.
