MP8126 – LNB POWER SUPPLY AND CONTROL VOLTAGE REGULATOR

MP8126 Rev. 1.03

www.MonolithicPower.com

5

5/27/2013

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PIN FUNCTIONS

Pin #

TSSOP-16

Pin #

QFN24

Name

Description

1

22

SGND

Analog ground.

2

23, 24

BYPASS

Connect a bypass capacitor for the internal regulator.

3

2

VDD

Input supply.

4

4

COMP

Compensation pin for Boost regulator (47nF& 4.7k & 470pF is

suggested).

5

5

EN

Regulator On/Off Control Input. The output is disabled when this pin

goes low. The converter turns on when this pin goes high. Connect EN

to the input source (through a 100kΩ pull-up resistor if VIN > 6V) for

automatic startup. Do not leave EN floating.

6

6

LINEDROP

VOUT compensation selection. For voltage drops on the long coaxial

cable. The LDO output increases by 1V when LINEDROP is high,. Do

not leave LINEDROP floating.

7

7

POK

Power OK. A high output indicates that LDO output is within ±12% of

nominal value. A low output means that LDO output is outside this

window.

8

8

13V/18V

Select 13V or 18V. For output voltage. Select logic HIGH for 18V and

LOW for 13V. Do not leave this pin floating.

9

10

EXTM

External Modulation Input. For 22kHz signaling that is internally shaped

and transferred to the output. Tie it to ground if not used.

10

11

TCAP

Internal voltage reference for LDO output, A soft-start capacitor can be

connected to this pin to set rise time of the output voltage. The

capacitor should be very close to this pin and SGND, and the route

should keeps far away from any noise like SW copper.

11

12

ILIMIT

Output Current Limit Set. Sets the LDO output current limit of LDO.

Program using a resistor from ILIMIT to GND.

12

13, 14

VOUT

Output Voltage.

13

15, 16

VBOOST

Internal LDO Input.

14

17

BST

Internal LDO Driver Supply.

15

19

SW

Switching Input. Drain of the internal boost-stage MOSFET. Connect

the power inductor and output rectifier to SW.

16

20, 21

PGND

Power Ground.

1, 3, 9, 18

NC

Not Connect.

EP

Exposed Pad

Heatsink. Not connected internally. Connect to a metal GND pad for

best results. Do not connect to other pins.