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 ind ependent 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 m 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, q jl . . . . . . . . . . . . . . . . . . . . . . . 15 c/w thermal resistance junction to ambient, q 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 m 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 m 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 m 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+/refCc/s+)/12k, t j = 25c 60 84 105 m 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 c12.1v/ m 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 m v/v input offset drift note 1 8 m 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 m a park drive saturation voltage, pd vsat i sink = 100ma 0.3 0.5 v parking drive leakage v out = 20v 100 m 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 w inhibit input threshold 0.7 1.1 1.7 v inhibit input current inhibit input = 1.7v 400 700 m 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
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