10/94
Note: Pin numbers refer to PLCC packag e.
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 Amperes and is intended for use in demanding servo applications such as head
positioning for high-d ensi ty disk drives. The device includes a precision current
sense amplifier that provides accurate control of load current. Current is
sensed with a single resi s tor in seri es 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 l imiting and thermal shutdown.
Auxiliary functions on this device include a dual-input under-voltage comparator, which can monitor two independent supply voltages and force a built-in
head park function when either is below minimum. When activated by e ither the
UV comparator, or a command at the separate PARK input, the park circuitry
will override the amplifier i nputs to convert the power outputs to a programmable constant voltage source which will h old regula tion as th e 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 al l 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.
UC3175B
Full-Bridge Power Amplifier
FEATURES DESCRIPTION
UDG-92054-1
CONNECTION DIAG RAMS
UC3175B
PACKAGE PIN FUNCTION
FUNCTION PIN
+VIN 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 Dissipat io n 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 Vo ltag e, (+VIN,+VC). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20V
UV Comparator, and Digital Input s
Maximum forced vo ltag e. . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to 10V
Maximum forced cu rrent. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±10mA
C/S Inputs
Maximum forced vo ltag e. . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to 20V
A and B Amplifier Inpu ts . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to +V
IN
Open Collector Out put Voltages. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20V
A and B Output Curren ts (continu ous)
Source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Internally Limited
Sink . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.0A
Parking Drive Output Curr ent
Continuous . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150mA
Pulsed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1A
Output Diode Current (pulsed). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1A
Power OK Output Cu rrent (c ont inuou s) . . . . . . . . . . . . . . . . . . . . . . . . . 30mA
Operating Jun ctio n Tem per atur e. . . . . . . . . . . . . . . . . . . . . . -55°C to +150 °C
Storage Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -65°C to +150°C
Note 1: Unless other w ise indicat ed, volt age s are
reference d to grou nd and current s are pos itive
into, negat ive out of, the sp ecif ied te rminals.
"Pulsed" is defined as a less than 10% duty cycle
pulse with a maximum dur ation of 500µs.
Note 2: See Unitrode Int egr at ed Circ uits databoo k
for informat ion regarding thermal specif ic atio ns
and limitat ions of packages.
PARAMETER TEST CONDITION S MIN TYP MAX UNITS
INPUT SUPPLY
+V
IN Supply Current All Amplifier Outpu ts = 6V 35 42 mA
+V
C Supply Current IOUT = 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 spec ifications apply for 0°C ≤ TA ≤ 70°C, +VIN = 12V, +VC
= +VIN, A+/REF Inp ut = 6 V. TA=TJ.
SOIC-24 (Top View)
DW Package
Thermal Data
QP Package:
Thermal Resistance Junction to Leads,
θ
JL . . . . . . . . . . . . . . . . . . . . . . . 15°C/W
Thermal Resistance Junction to Ambient,
θ
JA . . . . . . . . . . . . . . . . . . . . . . . 40°C/W
2
ELECTRICAL
CHARACTERISTICS (cont.)
Unless other wise stat ed sp ecif ic atio ns app ly for 0°C ≤ TA ≤ 70°C, +VIN = 12V, + VC = +VIN,
A+/REF INPUT = 6V. T
A=TJ.
UC3175B
PARAMETER TEST CONDITION S MIN TYP MAX UNITS
UNDER VOLTAGE (UV) COM PARATOR
Input Bias Current -1.5 -0.5 µA
UV Thresholds Low to High, Other Input = 5V 1.48 1.50 1.52 V
UV Threshold Hyst eresis 15 25 40 mV
Pwr OK V
SAT IOUT = 5mA 0.45 V
Pwr OK Leakage V
OUT = 20V 5 µA
POWER AMPLI FI ERS A and B
Input Offset Voltage V
CM = 6V, A Amplifie r 8 mV
B Amplifier 12 mV
Input Off set Drift No te 1, A Amp lifier Only 25 µV/°C
Input Bias Current V
CM = 6V, except A+ /REF Input -500 -150 nA
Input Offset Current V
CM = 6V, B Amplifier O nly 200 nA
Input Bias Cu rrent at A+/Ref Inpu t (A+/Ref–C/S+)/12k, T
J = 25°C 60 84 105 µA/V
CMRR 1V ≤ V
CM ≤ 10V 70 90 dB
PSRR +V
IN = 4V to 15V, VCM = 1.5V 70 90 dB
Large Signal Volta ge G ai n V
OUT = 1V, Sinking 500mA to VOUT = 11V,
Sourcin g 500m A 3.0 15.0 V/mV
Slew Rate 1 to 13V, 13 to 1V, T
J = 25°C12.1V/µs
Unity Gain Bandwidt h Note 1, A Amplifier 2 MHz
Note 1, B Am p l ifi er 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, ISINK = 800m A 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 ID = 800mA, Inhibit Ac tivated 1.0 V
Low Side Diode V
F ID = 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 µV/V
Input Offset Drift Note 1 8 µV/°C
Voltage Gain -1.0V ≤ V
DIFF ≤ +1. 0V, VCM = 6V 1.95 2.00 2.05 V
Output Satu ration Volt age 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- = BOUTPUT 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 µA
Park Drive Satura tion Voltag e, PD
VSAT ISINK = 100mA 0.3 0.5 V
Parking Drive Leakage V
OUT = 20V 100 µA
Amplifier A Aux Input Bias Curren t -500 - 150 nA
3
PARAMETER TEST CONDITION S MIN TYP MAX UNITS
PARKING FUNCTIONS (cont .)
Amplifier A Satura tion Voltag e, A
HVSAT ISOURCE = 50mA, +VIN = 3 V 0.65 0.8 V
Regulating Volt age at Park Volts 1.47 1.50 1.53 V
Minimum Parking Supply Voltage A
HVSAT + PDVSAT ≤ 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 O utpu t Forced H igh 2.2 2.3 V
Limit In active 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 kΩ
Inhibit Input Threshold 0.7 1.1 1.7 V
Inhibit Input Current I n hibit Input = 1. 7V 400 700 µA
Supply Curren t whe n Inhibite d The sum of +V
IN and +VC current s 2 6 mA
Thermal Shutdown Tempe ratur e 165 °C
UC3175B
ELECTRICAL
CHARACTERISTICS (cont.)
Unless other wise stat ed sp ecif ic atio ns app ly for 0°C ≤ TA ≤ 70°C, +VIN = 12V, + VC = +VIN,
A+/REF Input = 6V. T
A=TJ.
Note 1: This specifica tion not teste d in prod uct ion.
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 −
(IL • RP)
RP is optional for current limiting.
Inhibit and Park Input s are active high.
Pwr OK is low on power failure.
Parking Function
UDG-92059
5
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