TI UC3175B

UC3175B
Full-Bridge Power Amplifier
FEATURES
•
•
•
•
•
DESCRIPTION
Precision Current Control
This full-bridge power amplifier is rated for continuous output current of 0.8 Amperes and is intended for use in demanding servo applications such as head
±800mA Load Current
positioning for high-density disk drives. The device includes a precision current
sense amplifier that provides accurate control of load current. Current is
1.25V Total VSAT at 800mA
sensed with a single resistor in series with the load. The power amplifier has a
Controlled Velocity Head Parking
very low output saturation voltage and will operate down to 4V supply levels.
Power output stage protection includes current limiting and thermal shutdown.
Precision Dual Supply Monitor
with Indicator
Auxiliary functions on this device include a dual-input under-voltage compara-
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Limit Input to Force Output
Extremes
•
Inhibit Input and UVLO
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4V to 15V operation
tor, which can monitor two independent supply voltages and force a built-in
head park function when either is below minimum. When activated by either the
UV comparator, or a command at the separate PARK input, the park circuitry
will override the amplifier inputs to convert the power outputs to a programmable constant voltage source which will hold regulation as the supply voltage
falls to below 3.0 Volts. Added features include a POWER OK flag output, a
LIMIT input to force the drive output to its maximum level in either polarity, and
a over-riding INHIBIT input to disable all amplifiers and reduce quiescent supply current.
This device is packaged in a power PLCC surface mount configuration which
maintains a standard 28-pin outline, but with 7 pins along one edge allocated to
ground for optimum thermal transfer. And is also available in a 24-pin surface
mount SOIC package.
BLOCK DIAGRAM
Note: Pin numbers refer to PLCC package.
10/94
UDG-92054-1
UC3175B
ABSOLUTE MAXIMUM RATINGS
Input Supply Voltage, (+VIN,+VC). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20V
UV Comparator, and Digital Inputs
Maximum forced voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to 10V
Maximum forced current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±10mA
C/S Inputs
Maximum forced voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to 20V
A and B Amplifier Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to +VIN
Open Collector Output Voltages. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20V
A and B Output Currents (continuous)
Source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Internally Limited
Sink . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.0A
Parking Drive Output Current
Continuous . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150mA
Pulsed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1A
Output Diode Current (pulsed) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1A
Power OK Output Current(continuous) . . . . . . . . . . . . . . . . . . . . . . . . . 30mA
Operating Junction Temperature . . . . . . . . . . . . . . . . . . . . . . -55°C to +150°C
Storage Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -65°C to +150°C
Note 1: Unless otherwise indicated, voltages are
referenced to ground and currents are positive
into, negative out of, the specified terminals.
"Pulsed" is defined as a less than 10% duty cycle
pulse with a maximum duration of 500µs.
Note 2: See Unitrode Integrated Circuits databook
for information regarding thermal specifications
and limitations of packages.
Thermal Data
QP Package:
Thermal Resistance Junction to Leads,
θJL . . . . . . . . . . . . . . . . . . . . . . . 15°C/W
Thermal Resistance Junction to Ambient,
θJA . . . . . . . . . . . . . . . . . . . . . . . 40°C/W
CONNECTION DIAGRAMS
SOIC-24 (Top View)
DW Package
PLCC-28 (Top View)
QP Package
PACKAGE PIN FUNCTION
FUNCTION
PIN
+VIN
1
INH
2
UV2
3
UV1
4
Limit
5
Park Volts
6
C/S7
A+/REF Input
8
A- In
9
A Output
10
A Cur Sen
11
Gnd (Heat Dissipation Pins) 12-18
B Cur Sen
19
B Output
20
21
+VC Supply
B- In
22
B+ In
23
C/S+
24
Pwr OK
25
Park
26
Park Drive
27
C/S Out
28
ELECTRICAL CHARACTERISTICS: Unless otherwise stated specifications apply for 0°C ≤ TA ≤ 70°C, +VIN = 12V, +VC
= +VIN, A+/REF Input = 6V. TA=TJ.
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
42
UNITS
INPUT SUPPLY
+VIN Supply Current
All Amplifier Outputs = 6V
35
+VC Supply Current
IOUT = 0A
1
+VIN UVLO Threshold
Low to High
2.8
UVLO Threshold Hysteresis
200
2
mA
mA
3.0
V
mV
UC3175B
ELECTRICAL
CHARACTERISTICS (cont.)
Unless otherwise stated specifications apply for 0°C ≤ TA ≤ 70°C, +VIN = 12V, +VC = +VIN,
A+/REF INPUT = 6V. TA=TJ.
PARAMETER
UNDER VOLTAGE (UV) COMPARATOR
TEST CONDITIONS
Input Bias Current
UV Thresholds
Low to High, Other Input = 5V
UV Threshold Hysteresis
MIN
TYP
-1.5
-0.5
1.48
1.50
15
25
MAX
UNITS
µA
1.52
V
40
mV
Pwr OK VSAT
IOUT = 5mA
0.45
V
Pwr OK Leakage
VOUT = 20V
5
µA
Input Offset Voltage
VCM = 6V, A Amplifier
B Amplifier
8
12
mV
mV
Input Offset Drift
Note 1, A Amplifier Only
25
µV/°C
Input Bias Current
VCM = 6V, except A+/REF Input
Input Offset Current
VCM = 6V, B Amplifier Only
200
nA
105
µA/V
POWER AMPLIFIERS A and B
-500
-150
nA
Input Bias Current at A+/Ref Input
(A+/Ref–C/S+)/12k, TJ = 25°C
60
84
CMRR
1V ≤ VCM ≤ 10V
70
90
dB
PSRR
+VIN = 4V to 15V, VCM = 1.5V
70
90
dB
Large Signal Voltage Gain
VOUT = 1V, Sinking 500mA to VOUT = 11V,
3.0
15.0
Sourcing 500mA
Slew Rate
Unity Gain Bandwidth
1 to 13V, 13 to 1V, TJ = 25°C
V/mV
2.1
V/µs
Note 1, A Amplifier
2
MHz
Note 1, B Amplifier
1
MHz
High-Side Current Limit
Output Saturation Voltage
1
1.0
A
High-Side, ISOURCE = 250mA
0.8
0.7
V
High-Side, ISOURCE = 800mA
0.85
V
Low-Side, ISINK = 250mA
0.3
0.4
V
V
Low-Side, ISINK = 800mA
Total, IOUT = 250mA
1.0
1.2
V
Total, IOUT = 800mA
1.25
1.6
V
High Side Diode VF
ID = 800mA, Inhibit Activated
1.0
V
Low Side Diode VF
ID = 800mA, Inhibit Activated
1.0
V
CURRENT SENSE AMPLIFIER
Input Offset Voltage
VCM = 6V
Input Offset Change with Common Mode
0V ≤ VCM ≤ 12V
Input
1500
µV/V
8
µV/°C
2.05
V
Low-Side, ISINK = 1.5mA
0.3
0.5
V
High-Side, ISOURCE = 1.5mA
0.4
0.7
V
2.6
3.0
V
1.1
1.7
V
Note 1
-1.0V ≤ VDIFF ≤ +1.0V, VCM = 6V
Maximum A+/Ref Input
mV
2.00
Input Offset Drift
Voltage Gain
Output Saturation Voltage
2.0
1.95
Volts Below +VIN, C/S+ & C/S- = BOUTPUT Max @
10mA Output Current, +VIN = 4.5V, C/S VIO ≤ 5mV
PARKING FUNCTION
Park Input Threshold
0.7
Park Input Current
Park Input = 1.7V
60
100
µA
Park Drive Saturation Voltage, PDVSAT
ISINK = 100mA
0.3
0.5
V
Parking Drive Leakage
VOUT = 20V
100
µA
Amplifier A Aux Input Bias Current
-500
3
-150
nA
UC3175B
ELECTRICAL
CHARACTERISTICS (cont.)
Unless otherwise stated specifications apply for 0°C ≤ TA ≤ 70°C, +VIN = 12V, +VC = +VIN,
A+/REF Input = 6V. TA=TJ.
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNITS
0.65
0.8
V
1.50
1.53
V
1.7
1.9
V
0.8
2.2
2.3
V
V
1.8
V
PARKING FUNCTIONS (cont.)
Amplifier A Saturation Voltage, AHVSAT
ISOURCE = 50mA, +VIN = 3V
Regulating Voltage at Park Volts
Minimum Parking Supply Voltage
1.47
AHVSAT + PDVSAT ≤ 1.3V @ 50mA
AUXILIARY FUNCTIONS
Limit Input Low Voltage
Limit Input High Voltage
A Output Forced Low
A Output Forced High
Limit Inactive
1.2
Limit Open Circuit Voltage
Limit Input Resistance
0.7
1.45
1.2V ≤ Limit Input ≤ 1.8V
Inhibit Input Threshold
Inhibit Input = 1.7V
Supply Current when Inhibited
The sum of +VIN and +VC currents
Thermal Shutdown Temperature
1.55
10
0.7
Inhibit Input Current
1.50
V
kΩ
1.1
1.7
V
400
700
µA
2
6
mA
165
°C
Note 1: This specification not tested in production.
UC3175B Series Current Sensing
UDG-92058
GO =
IL
Rfb
=
VS Rfa • 2 • RS
4
UC3175B
Parking Function
UDG-92059
1.5V • R1 + R2
R2 − (IL • RP)
RP is optional for current limiting.
Inhibit and Park Inputs are active high.
Pwr OK is low on power failure.
Notes: Parking voltage =
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