TI UC3177

UC3176
UC3177
Full Bridge Power Amplifier
FEATURES
DESCRIPTION
•
Dual Power Operational Amplifiers
•
±2A Output Current Guaranteed
•
Precision Current Sense Amplifier
•
Two Supply Monitoring Inputs
•
Parking Function and Under-Voltage
Lockout
The UC3176/7 family of full bridge power amplifiers is rated for a continuous output current of 2A. Intended for use in demanding servo applications
such as disk head positioning, the onboard current sense amplifier can be
used to obtain precision control of load current, or where voltage mode
drive is required, a standard voltage feedback scheme can be used. Output stage protection includes foldback current limiting and thermal shutdown, resulting in a very rugged device.
•
Safe Operating Area Protection
•
3V to 35V Operation
Auxiliary functions on this device include a dual input under-voltage comparator that can be programmed to respond to low voltage conditions on
two independent supplies. In response to an under-voltage condition the
power Op-Amps are inhibited and a high current, 100mA, open collector
drive output is activated. A separate Park/Inhibit command input.
The devices are operational over a 3V to 35V supply range. Internal under-voltage lockout provides predictable power-up and power-down characteristics.
BLOCK DIAGRAM
10/94
UC3176
UC3177
CONNECTION DIAGRAM
ABSOLUTE MAXIMUM RATINGS (Note 1)
Input Supply voltage, (+VIN) . . . . . . . . . . . . . . . . . . . . . . . 40V
Park/Inhibit, UV1 and UV2 inputs (zener clamped)
Maximum forced voltage . . . . . . . . . . . . . . . . -0.3V to 10V
Maximum forced current. . . . . . . . . . . . . . . . . . . . . ±10mA
Other Input Voltages. . . . . . . . . . . . . . . . . . . . . -0.3V to +VIN
AlSINK and BlSINK Voltages . . . . . . . . . . . . . . . . . . -0.3V to 6V
Open Collector Output Voltages. . . . . . . . . . . . . . . . . . . . 40V
A and B Output Currents (Continuous)
Source . . . . . . . . . . . . . . . . . . . . . . . . . . Internally Limited
Sink. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5A
Total Supply Current (Continuous). . . . . . . . . . . . . . . . . . . 4A
Parking Drive Output Current (Continuous) . . . . . . . . 200mA
Supply OK Output Current, UC3177 (Continuous) . . . 30mA
Operating Junction Temperature . . . . . . . . -55°C to +150°C
Power Dissipation at TC = +75°C
QP package. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4W
Storage Temperature . . . . . . . . . . . . . . . . . -65°C to +150°C
Note 1: Unless otherwise indicated, voltages are reference to
ground and currents are positive into, negative out of, the
specified terminals.
PLCC-28 (Top View)
QP Package
THERMAL DATA
QP package:
Thermal Resistance Junction to Leads, θJL . . . . . . 15°C/W
Thermal Resistance Junction to Ambient, θJA . . . . 50°C/W
PACKAGE PIN FUNCTION
FUNCTION
PIN
+VIN
B Output
BISINK (Sense)
BISINK
N/C
B- Input
*
Park/Inhibit
Parking Drive
Gnd (Heat Flow Pins)
UV1
UV2
Current Feedback
A+ Input
A- Input
N/C
AISINK
AISINK (Sense)
A Output
Gnd
1
2
3
4
5-7
8
9
10
11
12-18
19
20
21
22
23
24
25
26
27
28
*Pin 9: UC3176, B+ Input
UC3177, Supply OK
ELECTRICAL CHARACTERISTICS: Unless otherwise stated, specifications hold for TA = 0 to 70°C, +VIN = 12V, TA = TJ.
PARAMETER
TEST CONDITIONS
MIN.
TYP.
MAX. UNITS
Input Supply
Supply Current
UVOL Threshold
+VIN = 12V
18
25
mA
+VIN = 35V
21
30
mA
+VIN low to high
2.8
3.0
V
Threshold Hysteresis
220
300
mV
8
mV
Power, Amplifier, A and B
Input Offset Voltage
VCM = 6V, VOUT = 6V
Input Bias Current
VCM = 6V, Except A+ Input
Input Bias Current at A+/Reference Input
(A+/Ref - BISINK)/36kohms; TJ = 25°C
-500
-100
23
28
Input Offset Current B Amp (UC3176 Only) VCM = 6V
nA
35
µA/V
200
nA
CMRR
VCM = 1 to 33V, +VIN =35V, VOUT = 6V
70
100
PSRR
Large Signal Voltage Gain
+VIN = 5 to 35V, VCM = 2.5V
VOUT = 3V, w/IOUT = 1A to VOUT = 9V, w/IOUT = -1A
70
100
dB
1.5
4
V/mV
Thermal Feedback
+VIN = 20V, Pd = 20W at opposite output
25
Saturation Voltage
IOUT = -2A, High Side, TJ = 25°
1.9
CIOUT = 2A, Low Side, TJ = 25°C
1.6
Total VSAT at 2A, TJ = 25°C
3.5
dB
200
µV/W
V
V
3.7
V
Unity Gain Bandwidth
1
MHz
Slew Rate
1
V/µs
Differential IOUT Sense Error Current
in Bridge Configuration
High Side Current Limiting
IOUT(A) = -IOUT(B), /IOUT/- /AISINK - BISINK/
IOUT ≤200mA
3.0
6.0
mA
IOUT ≤ 2A
5.0
10
mA
=VIN - VOUT < 12V
-2.7
-2.0
A
2
UC3176
UC3177
ELECTRICAL CHARACTERISTICS: Unless otherwise stated, specifications hold for TA = 0 to 70°C, +VIN = 12V, TA = TJ.
PARAMETER
TEST CONDITIONS
MIN.
TYP.
MAX. UNITS
Current Sense Amplifier
Input Offset Voltage
VCM = 0V, A+/Ref at 6V
3
mV
600
µV/V
75
µV/W
Ref = 2V to 20V, +VIN = 35, change with Ref
input voltage
Thermal Gradient Sensitivity
+VIN = 20V, Ref = 10V Pd = 20W @ A or B
output
5.0
PSRR
Ref = 2.5V, +VIN = 5 to 35V
70
Gain
/AISINK - BISINK/ ≤ 0.5V
7.8
Slew Rate
3dB Bandwidth
Max Output Current
Output Saturation Voltage
Under-Voltage Comparator
Threshold Voltage
ISOURCE = +VIN - VOUT = 0.5V
2.5
100
8
dB
8.1
V/V
2
V/µS
1
MHz
3.5
mA
ISOURCE = 1.5mA, High Side
0.15
0.30
V
ISINK = 5mA, Low Side
1.4
1.7
V
1.50
1.56
V
80
mV
Low to High, other input at 5V
1.44
Threshold Hysteresis
50
70
Input Current
Input = 2V, other input at 5V
-2
-.05
Supply OK VSAT (UC3177 Only)
IOUT = 5mA
0.45
V
Supply OK Leakage (UC3177 Only)
VOUT = 35V
5
µA
1.3
1.7
V
60
100
µA
0.3
0.7
V
15
µA
µA
Park/Inhibit
Park/Inhibit Thl’d
1.1
Park/Inhibit Input Current
Parking Drive Saturation Voltage
At threshold
IOUT = 100mA
Parking Drive Leakage
VOUT = 35V
Thermal Shutdown
Shutdown Temperature
Output Saturation Voltage
vs Current
165
Maximum Source Current
vs +VIN - VOUT
3
Crossover Current Error
Characteristic
°C
UC3176
UC3177
APPLICATION AND OPERATION INFORMATION
WAVEFORMS FOR ABOVE APPLICATION
DESIGN EQUATIONS
Transconductance (GO) =
IL RF2  1 
=
×
VS RF1  8RS 
with: RSA = RSB and RF3 = RF4
VIN − 1.5
RP + RL
where: RL = load resistance
Parking Current (IP) =
Under-Voltage Thresholds, at Supplies
High to Low Threshold, (VLH) = 1.425 (RA + RB)/RB
Low to High Threshold, (VHL) = 1.5 (RA + RB)/RB
UNITRODE INTEGRATED CIRCUITS
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4
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