10/94
Note: Pin numbers refer to PLCC package.
BLOCK DIAGRAM
Precision Current Control
800mA Load Current
1.25V Total V
SAT
at 800mA
Controlled Velocity Head Parking
Precision Dual Supply Monitor
with Indicator
Limit Input to Force Output
Extremes
Inhibit Input and UVLO
4V to 15V operation
This full-bridge power amplifier is rated for continuous output current of 0.8 Am-
peres and is intended for use in demanding servo applications such as head
positioning for high-density disk drives. The device includes a precision current
sense amplifier that provides accurate control of load current. Current is
sensed with a single resistor in series with the load. The power amplifier has a
very low output saturation voltage and will operate down to 4V supply levels.
Power output stage protection includes current limiting and thermal shutdown.
Auxiliary functions on this device include a dual-input under-voltage compara-
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 programma-
ble 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 sup-
ply 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.
UC3175B
Full-Bridge Power Amplifier
FEATURES
DESCRIPTION
UDG-92054-1
CONNECTION DIAGRAMS
UC3175B
PACKAGE PIN FUNCTION
FUNCTION
PIN
+V
IN
1
INH
2
UV2
3
UV1
4
Limit
5
Park Volts
6
C/S-
7
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
+V
C
Supply
21
B- In
22
B+ In
23
C/S+
24
Pwr OK
25
Park
26
Park Drive
27
C/S Out
28
PLCC-28 (Top View)
QP Package
ABSOLUTE MAXIMUM RATINGS
Input Supply Voltage, (+V
IN
,+V
C
). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 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 +V
IN
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 500
s.
Note 2: See Unitrode Integrated Circuits databook
for information regarding thermal specifications
and limitations of packages.
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNITS
INPUT SUPPLY
+V
IN
Supply Current
All Amplifier Outputs = 6V
35
42
mA
+V
C
Supply Current
I
OUT
= 0A
1
mA
+V
IN
UVLO Threshold
Low to High
2.8
3.0
V
UVLO Threshold Hysteresis
200
mV
ELECTRICAL CHARACTERISTICS:
Unless otherwise stated specifications apply for 0
C
T
A
70
C, +V
IN
= 12V, +V
C
= +V
IN
, A+/REF Input = 6V. T
A
=T
J
.
SOIC-24 (Top View)
DW Package
Thermal Data
QP Package:
Thermal Resistance Junction to Leads,
JL
. . . . . . . . . . . . . . . . . . . . . . . 15
C/W
Thermal Resistance Junction to Ambient,
JA
. . . . . . . . . . . . . . . . . . . . . . . 40
C/W
2
ELECTRICAL
CHARACTERISTICS (cont.)
Unless otherwise stated specifications apply for 0
C
T
A
70
C, +V
IN
= 12V, +V
C
= +V
IN
,
A+/REF INPUT = 6V. T
A
=T
J
.
UC3175B
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNITS
UNDER VOLTAGE (UV) COMPARATOR
Input Bias Current
-1.5
-0.5
A
UV Thresholds
Low to High, Other Input = 5V
1.48
1.50
1.52
V
UV Threshold Hysteresis
15
25
40
mV
Pwr OK V
SAT
I
OUT
= 5mA
0.45
V
Pwr OK Leakage
V
OUT
= 20V
5
A
POWER AMPLIFIERS A and B
Input Offset Voltage
V
CM
= 6V, A Amplifier
8
mV
B Amplifier
12
mV
Input Offset Drift
Note 1, A Amplifier Only
25
V/C
Input Bias Current
V
CM
= 6V, except A+/REF Input
-500
-150
nA
Input Offset Current
V
CM
= 6V, B Amplifier Only
200
nA
Input Bias Current at A+/Ref Input
(A+/RefC/S+)/12k, T
J
= 25C
60
84
105
A/V
CMRR
1V
V
CM
10V
70
90
dB
PSRR
+V
IN
= 4V to 15V, V
CM
= 1.5V
70
90
dB
Large Signal Voltage Gain
V
OUT
= 1V, Sinking 500mA to V
OUT
= 11V,
Sourcing 500mA
3.0
15.0
V/mV
Slew Rate
1 to 13V, 13 to 1V, T
J
= 25
C
1
2.1
V/
s
Unity Gain Bandwidth
Note 1, A Amplifier
2
MHz
Note 1, B Amplifier
1
MHz
High-Side Current Limit
0.8
1.0
A
Output Saturation Voltage
High-Side, I
SOURCE
= 250mA
0.7
V
High-Side, I
SOURCE
= 800mA
0.85
V
Low-Side, I
SINK
= 250mA
0.3
V
Low-Side, I
SINK
= 800mA
0.4
V
Total, I
OUT
= 250mA
1.0
1.2
V
Total, I
OUT
= 800mA
1.25
1.6
V
High Side Diode V
F
I
D
= 800mA, Inhibit Activated
1.0
V
Low Side Diode V
F
I
D
= 800mA, Inhibit Activated
1.0
V
CURRENT SENSE AMPLIFIER
Input Offset Voltage
V
CM
= 6V
2.0
mV
Input Offset Change with Common Mode
0V
V
CM
12V
Input
1500
V/V
Input Offset Drift
Note 1
8
V/C
Voltage Gain
-1.0V
V
DIFF
+1.0V, V
CM
= 6V
1.95
2.00
2.05
V
Output Saturation Voltage
Low-Side, I
SINK
= 1.5mA
0.3
0.5
V
High-Side, I
SOURCE
= 1.5mA
0.4
0.7
V
Maximum A+/Ref Input
Volts Below +V
IN
, C/S+ & C/S- = B
OUTPUT
Max @
10mA Output Current, +V
IN
= 4.5V, C/S VIO
5mV
2.6
3.0
V
PARKING FUNCTION
Park Input Threshold
0.7
1.1
1.7
V
Park Input Current
Park Input = 1.7V
60
100
A
Park Drive Saturation Voltage, PD
VSAT
I
SINK
= 100mA
0.3
0.5
V
Parking Drive Leakage
V
OUT
= 20V
100
A
Amplifier A Aux Input Bias Current
-500
-150
nA
3
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNITS
PARKING FUNCTIONS (cont.)
Amplifier A Saturation Voltage, A
HVSAT
I
SOURCE
= 50mA, +V
IN
= 3V
0.65
0.8
V
Regulating Voltage at Park Volts
1.47
1.50
1.53
V
Minimum Parking Supply Voltage
A
HVSAT
+ PD
VSAT
1.3V @ 50mA
1.7
1.9
V
AUXILIARY FUNCTIONS
Limit Input Low Voltage
A Output Forced Low
0.7
0.8
V
Limit Input High Voltage
A Output Forced High
2.2
2.3
V
Limit Inactive
1.2
1.8
V
Limit Open Circuit Voltage
1.45
1.50
1.55
V
Limit Input Resistance
1.2V
Limit Input
1.8V
10
k
Inhibit Input Threshold
0.7
1.1
1.7
V
Inhibit Input Current
Inhibit Input = 1.7V
400
700
A
Supply Current when Inhibited
The sum of +V
IN
and +V
C
currents
2
6
mA
Thermal Shutdown Temperature
165
C
UC3175B
ELECTRICAL
CHARACTERISTICS (cont.)
Unless otherwise stated specifications apply for 0
C
T
A
70
C, +V
IN
= 12V, +V
C
= +V
IN
,
A+/REF Input = 6V. T
A
=T
J
.
Note 1: This specification not tested in production.
UDG-92058
UC3175B Series Current Sensing
G
O
=
I
L
V
S
=
Rfb
Rfa
2
R
S
4
UNITRODE INTEGRATED CIRCUITS
7 CONTINENTAL BLVD.
MERRIMACK, NH 03054
TEL. (603) 424-2410
FAX (603) 424-3460
UC3175B
Notes: Parking voltage
=
1.5V
R1
+
R2
R2
-
(
I
L
RP
)
RP is optional for current limiting.
Inhibit and Park Inputs are active high.
Pwr OK is low on power failure.
Parking Function
UDG-92059
5
IMPORTANT NOTICE
Texas Instruments and its subsidiaries (TI) reserve the right to make changes to their products or to discontinue
any product or service without notice, and advise customers to obtain the latest version of relevant information
to verify, before placing orders, that information being relied on is current and complete. All products are sold
subject to the terms and conditions of sale supplied at the time of order acknowledgement, including those
pertaining to warranty, patent infringement, and limitation of liability.
TI warrants performance of its semiconductor products to the specifications applicable at the time of sale in
accordance with TI's standard warranty. Testing and other quality control techniques are utilized to the extent
TI deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily
performed, except those mandated by government requirements.
CERTAIN APPLICATIONS USING SEMICONDUCTOR PRODUCTS MAY INVOLVE POTENTIAL RISKS OF
DEATH, PERSONAL INJURY, OR SEVERE PROPERTY OR ENVIRONMENTAL DAMAGE ("CRITICAL
APPLICATIONS"). TI SEMICONDUCTOR PRODUCTS ARE NOT DESIGNED, AUTHORIZED, OR
WARRANTED TO BE SUITABLE FOR USE IN LIFE-SUPPORT DEVICES OR SYSTEMS OR OTHER
CRITICAL APPLICATIONS. INCLUSION OF TI PRODUCTS IN SUCH APPLICATIONS IS UNDERSTOOD TO
BE FULLY AT THE CUSTOMER'S RISK.
In order to minimize risks associated with the customer's applications, adequate design and operating
safeguards must be provided by the customer to minimize inherent or procedural hazards.
TI assumes no liability for applications assistance or customer product design. TI does not warrant or represent
that any license, either express or implied, is granted under any patent right, copyright, mask work right, or other
intellectual property right of TI covering or relating to any combination, machine, or process in which such
semiconductor products or services might be or are used. TI's publication of information regarding any third
party's products or services does not constitute TI's approval, warranty or endorsement thereof.
Copyright
1999, Texas Instruments Incorporated
PDF 
ZIP