UNITRODE UC1725, UC2725, UC3725 Technical data

UC1725

UC1725

UC2725

UC3725

Isolated High Side FET Driver

FEATURES

∙Receives Both Power and Signal Across the Isolation Boundary

∙9 to 15 Volt High Level Gate Drive

∙Under-voltage Lockout

∙Programmable Over-current Shutdown and Restart

∙Output Enable Function

DESCRIPTION

The UC1725 and its companion chip, the UC1724, provide all the necessary features to drive an isolated MOSFET transistor from a TTL input signal. A unique modulation scheme is used to transmit both power and signals across an isolation boundary with a minimum of external components.

Protection circuitry, including under-voltage lockout, over-current shutdown, and gate voltage clamping provide fault protection for the MOSFET. High level gate drive is guaranteed to be greater than 9 volts and less than 15 volts under all conditions.

Uses include isolated off-line full bridge and half bridge drives for driving motors, switches, and any other load requiring full electrical isolation.

The UC1725 is characterized for operation over the full military temperature range of -55°C to +125°C while the UC2725 and UC3725 are characterized for -25°C to +85°C and 0°C to +70°C respectively.

BLOCK DIAGRAM

UDG-92051-1

1/94

ABSOLUTE MAXIMUM RATINGS

Supply Voltage (pin 3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30V Power inputs (pins 7 & 8) . . . . . . . . . . . . . . . . . . . . . . . . . . . 30V Output current, source or sink (pin 2)

DC. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.5A Pulse (0.5 us) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.0A Enable and Current limit inputs (pins 4 & 6). . . . . . . . -0.3 to 6V Power Dissipation at TA ≤ 25°C (DIL-8) . . . . . . . . . . . . . . . . 1W Power Dissipation at TA ≤ 25°C (SO-14) . . . . . . . . . . . . 725mW Lead Temperature (Soldering, 10 Seconds) . . . . . . . . . . 300°C

Note 1: Unless otherwise indicated, voltages are referenced to ground and currents are positive into, negative out of, the specified terminals (pin numbers refer to DIL-8 package).

Note 2: See Unitrode Integrated Circuits databook for information regarding thermal specifications and limitations of packages.

UC1725

UC2725

UC3725

CONNECTION DIAGRAMS

	PLCC-20 (Top View)	PACKAGE PIN FUNCTION
		FUNCTION	PIN
	Q Package
		N/C	1
		ISENSE	2
		N/C	3-5
		Timing	6
		Enable	7
		N/C	8-9
		Input A	11
		N/C	12-14
		Input B	15
		Gnd	16
		VCC	17
		N/C	18-19
		Output	20

DIL-8 (Top View)

J Or N Package

SOIC-16 (Top View)

DW Package

DIL-16 (Top View)

JE Or NE Package

ELECTRICAL CHARACTERISTICS: (Unless otherwise stated, these specifications apply for -55°C≤TA≤+125°C for UC1725; -25°C≤TA≤+85°C for UC2725; 0°C≤TA≤+70°C for UC3725; VCC (pin 3) =

0 to 15V, RT=10k, CT=2.2nf, TA =TJ, pin numbers refer to DIL-8 package.)

PARAMETER	TEST CONDITIONS	MIN	TYP	MAX	UNITS
POWER INPUT SECTION (PINS 7 & 8)
Forward Diode Drop, Schottky Rectifier	IF = 50ma		.55	.7	V
	IF = 500ma		1.1	1.5	V
CURRENT LIMIT SECTION (PIN 4)
Input bias current	VPIN4 = OV		-1	-10	μA
Threshold voltage		0.4	0.5	0.6	V
Delay to outputs	VPIN4 = 0 to 1V		100	250	ns
TIMING SECTION (PIN 5)
Output Off Time		27	30	33	μs
Upper Mono Threshold		6.3	7.0	7.7	V
Lower Mono Threshold		1.9	2.0	2.3	V
HYSTERESIS AMPLIFIER (PINS 7 & 8)
Input Open Circuit Voltage	Inputs (pins 7 & 8), Open Circuited, TA= 25°C	7.0	Vcc/2	8.0	V
Input Impedance	TA = 25°C	23	28	33	kΩ
Hysteresis		26.5	2*Vcc	30.5	V
Delay to Outputs	VPIN7 - VPIN8 = VCC + 1V		100	300	ns

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