MP8125 – LNB POWER SUPPLY AND CONTROL VOLTAGE REGULATOR

MP8125 Rev. 1.11

www.MonolithicPower.com

5

5/9/2013

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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 pin.

4

4

COMP

Compensation pin for Boost regulator (47nF & 19.6kΩ is suggested).

5

5

EN

Regulator On/Off Control Input. When this pin is low, the output is

disabled. A high level at EN turns on the converter. Connect EN to the

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

automatic startup. EN cannot be left floating.

6

6

LINEDROP

long coaxial cable. When the LINEDROP is high, the LDO output is 1V

increased. LINEDROP cannot be left 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. High level for 18V while low level

for 13V. This pin cannot be left floating.

9

10

EXTM

External modulation input for 22kHz signaling. A high level at EXTM

turns on 22kHz signal and a low level disables it. EXTM cannot be left

floating.

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

The ILIMIT is used to set the value of the output current limit of LDO. A

resistor from ILIMIT to GND programs the limit.

12

13, 14

VOUT

Output voltage.

13

15, 16

VBOOST

Input of the internal LDO.

14

17

BST

Supply for the internal LDO driver.

15

19

SW

SW is the drain of the internal MOSFET switch of Boost stage.

Connect the power inductor and output rectifier to SW.

16

20, 21

PGND

Power ground.

1, 3, 9, 18

NC

Not Connect.