UNITRODE UC1638, UC2638, UC3638 Technical data

UC2638

UC1638

UC2638

UC3638

Advanced PWM Motor Controller

FEATURES

∙Single or Dual Supply Operation

∙Accurate High Speed Oscillator

∙Differential X5 Current Sense Amplifier

∙Bidirectional Pulse-by-Pulse Current Limiting

∙Programmable Oscillator Amplitude and PWM Deadband

∙Dual 500mA Totem Pole Output Drivers

∙Dual 60V, 50mA Open Collector Drivers

∙Undervoltage Lockout

DESCRIPTION

The UC1638 family of integrated circuits are advanced pulse width modulators intended for a variety of PWM motor drive and amplifier applications requiring either uni-directional or bi-directional drive circuits. Similar in architecture to the UC1637, all necessary circuitry is included to generate an analog error signal and modulate two bi-directional pulse train outputs in proportion to the error signal magnitude and polarity.

Key features of the UC1638 include a programmable high speed triangle oscillator, a 5X differential current sensing amplifier, a high slew rate error amplifier, high speed PWM comparators, and two 50mA open collector as well as two ±500mA totem pole output stages. The individual circuit blocks are designed to provide practical operation to switching frequencies of 500kHz.

Significant improvements in circuit speed, elimination of many external programming components, and the inclusion of a differential current sense amplifier, allow this controller to be specified for higher performance applications, yet maintain the flexibility of the UC1637. The current sense amplifier in conjunction with the error amplifier can be configured for average current feedback. The additional open collector outputs provide a drive signal

continued

BLOCK DIAGRAM

UDG-95048-4

1/98

DESCRIPTION (cont.)

for the highside switches in a full bridge configuration. The programmable AREFIN pin allows for single or dual supply operation. Oscillator ramp amplitude and PWM deadband are programmable by tapping a voltage divider off the 5V reference to the appropriate programming input (PVSET or DB).

Additional features include a precision externally available 5V reference, undervoltage lockout, pulse-by-pulse peak current limiting, and a remote shutdown port. The UC1638 family is available in the 20 pin N, DW and J packages. Consult the factory for other packaging options.

CONNECTION DIAGRAMS

DIL-20 (Top View)

N or J Package

UC1638

UC2638

UC3638

ABSOLUTE MAXIMUM RATINGS

Supply Voltage VCC (referenced to VEE) . . . . . . . . . . . . . 40V Output Drivers (AOUT2, BOUT2)

Currents (continuous) . . . . . . . . . . . . . . . . . . . . . . . . ±0.25A Currents (peak) . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±500mA REF Output Current . . . . . . . . . . . . . . . . . . . . Internally Limited PVSET, DB, RT, INV, REF, CSOUT . . . . . . . . . . . . . 0.3 to 10V CS+, CS- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . VEE–1V to VCC CT, AREF, AREFIN, COMP, SD . . . . . . . . . . . . . . . . VEE − 0.3 Output Voltage (AOUT1, BOUT1) . . . . . . . . . . . . . . . . . . . . 60V Storage temperature. . . . . . . . . . . . . . . . . . . . −65°C to +150°C Junction Temperature . . . . . . . . . . . . . . . . . . . −55°C to +150°C Lead temperature (soldering, 10 sec.) . . . . . . . . . . . . . . +300°C

Currents are positive into, negative out of the specified terminal. Consult packaging section of data book for thermal limitation considerations of packages.

SOIC-20 (Top View)

DW Package

PLCC-20 (Top View)

Q Package

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UC1638

UC2638

UC3638

	ELECTRICAL CHARACTERISTICS	Unless otherwise specified; VCC = 15V, VEE =–15V, CT = 680pF, RT = 3k,
		VPVSET = 1.5V, VCOMP = 0V, VCSOUT = 0V, VDB = REF, VEXTREF = 0V, VSD =
		VCC – 3V, TA = −55°C to 125°C for the UC1638, −25°C to 85°C for the UC2638,
		0°C to 70°C for the UC3638. T A = TJ.
	PARAMETER	TEST CONDITIONS	MIN	TYP	MAX	UNITS
	Overall
	Supply Current, Operating			15	23	mA
	UVLO Threshold	Reference to VEE		9	10	V
	UVLO Hysteresis	Reference to VEE		1		V
	Voltage Amplifier
	Input Offset Voltage	COMP = 0V	−15	0	15	mV
	VSENSE Bias Current		0	0.5	2	mA
	Open Loop Gain	COMP = −5V to +5V	75	100		dB
	CMRR	VCM = −5V to +5V	70	100		dB
	PSRR	VCM = 0V, VCC − VEE = 10V to 36V	70	90		dB
	VOUT High	INV = −0.1V, RL = 10k	13	13.6		V
	VOUT Low	INV = +0.1V, RL = 10k		−13.8	–13	V
	Slew Rate Rising and Falling	Overdrive = ±1V		12		V/μs
	Output Source Current	COMP Shorted to VEE	5	15		mA
	Output Sink Current	COMP Shorted to VCC	15	40		mA
	Gain Bandwidth Product	FIN = 100kHz, 10mV p-p	1	5		MHz
	5V Reference
	Output Voltage	IREF = −1mA, TA = 25°C	4.925	5	5.075	V
	Output Voltage	IREF = −1mA	4.875	5	5.125	V
	Load Regulation	IREF = −1mA to −10mA	−15	2	15	mV
	Line Regulation	VCC - VEE = 10V to 36V	−15	2	15	mV
	Short Circuit Current	VREF = 0V	15	70		mA
	Oscillator
	Initial Accuracy	TA = 0°C – 70°C	86	98	110	kHz
	Voltage Stability	VCC − VEE = 10V to 36V		2		%
	Total Variation	Line, Temperature	76	98	120	kHz
	PVSET Input Bias Current			0.5	3	μA
	PVSET Input Voltage Range	(Note 1)	0.5		VREF	V
	Amplitude Limit	(Note 1)	VEE+3		VCC−3	V
	AOUT1, BOUT1 Output Drivers
	Output Low Voltage	IOUT = 1mA, Ref. to PVE, PVE = 0V		0.9	1.3	V
		IOUT = 50mA		1.2	1.8	V
	Leakage Current	Output Voltage = 50V		0.1	50	μA
	AOUT2, BOUT2 Output Drivers
	Output High Voltage	IOUT = −20mA, Ref. to PVE, PVE = 0V	12.2	13.5		V
		IOUT = −100mA, Ref. to PVE, PVE = 0V	12	13.5		V
	Output High Clamp Level	IOUT = −20mA, Ref. to PVE, PVE = VEE		14.4	16.5	V
	Output Low Voltage	IOUT = 20mA, Ref. to PVE, PVE = 0V		0.4	1	V
		IOUT = 100mA, Ref. to PVE, PVE = 0V		0.6	2.2	V
	Output Rise Time	COUT = 1nF		50	100	ns
	Output Fall Time	COUT = 1nF		50	100	ns

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