UNITRODE UC1702, UC2702, UC3702 Technical data

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UNITRODE UC1702, UC2702, UC3702 Technical data

UC2702

UC1702

UC2702

UC3702

Quad PWM Relay Driver

FEATURES

Maintains Constant Average Relay Voltage With Varying Supply Voltages

VBUS Voltages up to 42.5V

Up to 50mA per Relay

Integrated Schottky Flyback Diodes

Individual Relay Control Inputs

Short Circuit Protection

User Selectable Operating Center Frequency and Relay Voltage

Global Reset

DESCRIPTION

The UC3702 Quad Relay Driver is intended to drive up to four relays from logic inputs using an unregulated relay voltage supply. The relays are driven from the Bus supply in a power efficient PWM converter fashion. The relay coil is used as the inductive element. (See the application's section concerning the relay selection.) VBUS must be higher then the rated relay voltage. Short circuit protection is provided on chip with periodic retry.

The UC3702 requires a +5V logic supply as a reference. Two external resistors program the effective relay voltage and a capacitor sets the nominal operating frequency. Internal Schottky diodes eliminate the need for any external power components.

In typical applications, the UC3702 grants the user the flexibility to choose the most cost effective relay without the added burden of generating a separate relay supply voltage. The UC3702 will even function with a poorly regulated supply VBUS, containing significant 100Hz or 120Hz ripple.

BLOCK DIAGRAM

UDG-96009-1

SLUS368 - APRIL 1997

ABSOLUTE MAXIMUM RATINGS

VBUS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +50V VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +9V Input Voltage . . . . . . . . . . . . . . . . . . . . . . –0.3V to VCC + 0.3V Average Current per Relay. . . . . . . . . . . . . . . . . . . . . . . . 50mA Total Output Capacitance. . . . . . . . . . . . . . . . . . . . . . . . . 25pF 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 Databook for thermal limitations and considerations of packages.

UC1702

UC2702

UC3702

CONNECTION DIAGRAM

DIL-16, SOIC-16 (Top View)

J or N, D Package

ELECTRICAL CHARACTERISTICS: Unless otherwise stated these specifications apply for TA = –55°C to +125°C for UC1702; –25°C to +85°C for UC2702; 0°C to +70°C for UC3702; VBUS = 34V, VCC = 5V, RESET = VCC, R2 = 43.2k;

R1 = 203k; CT = 220pF, TA = TJ.

 

 

PARAMETER

 

 

TEST CONDITIONS

MIN

TYP

MAX

UNITS

 

Supply Voltage Section

 

 

 

 

 

 

 

VCC

 

 

 

4.5

5

8

V

 

 

 

 

 

 

 

 

 

 

 

VCC Supply Current

 

RESET, INA, INB, INC, IND = VCC

 

4

6

mA

 

VBUS

 

 

 

 

 

42.5

V

 

Oscillator Section

 

 

 

 

 

 

 

NOMINAL Operating Frequency

 

R1 = 203k , R2 = 43.2k , CT = 220pF

150

175

200

kHz

 

R1

 

 

 

100

202

500

k

 

R2

 

 

 

20

42.5

80

k

 

CT

 

 

 

100

 

 

pF

 

Output Driver VBUS = 20V

 

 

 

 

 

 

 

Rated Relay Current

 

 

 

 

 

50

mA

 

Short Circuit Current

 

 

 

100

175

 

mA

 

Diode Leakage Current

 

Control Input Low, VOUTX = VBUS

 

0.05

5

A

 

Diode Forward Voltage

 

 

 

 

500

 

mV

 

Averaged Output Voltage Error

 

UC2702, UC3702 (Note 1)

–10

 

10

%

 

 

 

 

UC1702

–20

 

20

%

 

Control Inputs (INA, INB, INC, IND)

 

 

 

 

 

 

 

Logic Low

 

 

 

 

 

0.5

V

 

Logic High

 

 

 

3

 

VCC

V

 

TON / TOFF Delay

 

 

 

 

 

250

ns

 

Input Current

 

 

 

–1

0

1

A

 

Input Current

 

VIN = 5V

 

70

120

A

 

 

 

 

 

 

 

 

 

 

 

RESET

 

 

 

 

 

 

 

TON / TOFF Delay

 

 

 

 

 

2

s

 

Input Current

 

VIN = 0.3V

–8

–5

 

A

 

Input Current

 

VIN = 5V

–10

0

10

A

Note 1: Programmed Average Voltage = 106. R1VCC – 400mV

2 R2

2

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