UCC2915, UCC3915

15V PROGRAMMABLE HOT SWAP POWER MANAGER

SLUS198C – FEBUARY 2000 - REVISED - JUNE 2001

5

POST OFFICE BOX 655303

• DALLAS, TEXAS 75265

pin descriptions

B0 – B3: These pins provide digital input to the DAC, which sets the fault-current threshold. They can be used

to provide a digital soft-start and adaptive-current limiting.

CT: A capacitor connected to ground sets the maximum-fault time. The maximum-fault time must be more than

the time required to charge the external capacitance in one cycle. The maximum-fault time is defined as

TFAULT = 16.1 × 103 × CT. Once the fault time is reached the output will shutdown for a time given by

TSD = 833 × 103 × CT, this equates to a 1.9% duty cycle.

FAULT: Open-drain output, which pulls low upon any fault or interrupt condition, or thermal shutdown.

IMAX: When this pin is set to a logic low, the maximum-sourcing current will always be 1 A above the

programmed-fault level. When set to a logic high, the maximum-sourcing current will be a constant 4 A for

applications which require fast charging of load capacitance.

SHTDWN: When this pin is brought to a logic low, the IC is put into a sleep mode drawing typically less than

100

µA of ICC.The input threshold is hysteretic, allowing the user to program a startup delay with an external

RC circuit.

VIN: Input voltage to the UCC3915. The recommended voltage range is 7 V to 15 V. Both VIN pins should be

connected together and connected to the power source.

VOUT: Output voltage from the UCC3915. Both VOUT pins should be connected together and connected to

the load. When switched the output voltage will be approximately VIN – (0.15 Ω × IOUT). VOUT must not exceed

VIN by greater than 0.3 V.

APPLICATION INFORMATION

UDG-99175

6

7

8

9

11

10

B0

B1

B2

B3

IMAX

16

3

2

4

12

13

5

14

15

1

SHTDWN

VOUT

VIN

FAULT

CT

GND

HEAT SINK

GND PINS

UCC3915

RL

COUT

VOUT

CSD

RSD

VIN

CIN

D1

CT

S1

S2

S3

S4

S5

DIP

SWITCH

S6

VIN

VIN

R1

LED

5 V

Figure 1. Evaluation Circuit