MAX1747EUP 查看數據表（PDF） - Maxim Integrated

零件编号

产品描述 (功能)

生产厂家

MAX1747EUP

Triple Charge-Pump TFT LCD DC-DC Converter

Maxim Integrated 

Triple Charge-Pump TFT LCD

DC-DC Converter

Pin Description

PIN

NAME

FUNCTION

1, 2

TGND Must be connected to ground.

3

RDY

Active-Low Open-Drain Output. Indicates all outputs are ready. The RON is 125Ω (typ).

4

FB

Main Charge-Pump Feedback Input. Regulates to 1.25V nominal. Connect to the center of a

feedback resistive divider between the main output (OUT) and analog ground (GND).

5

INTG

Main Charge-Pump Integrator Output. If used, connect 1500pF to analog ground (GND). To disable

the integrator, connect to GND.

6

IN

Supply Input. +2.7V to +4.5V input range. Powers only the logic and reference. Bypass to analog

ground (GND) with a 0.1µF capacitor as close to the pin as possible.

7

GND

Analog Ground. Connect to power ground (PGND) underneath the IC.

8

REF

Internal Reference Bypass Terminal. Connect a 0.22µF capacitor from this terminal to analog

ground (GND). External load capability to 50µA. REF is disabled in shutdown.

9

FBP

Positive Charge-Pump Feedback Input. Regulates to 1.25V nominal. Connect feedback resistive

divider to analog ground (GND).

10

FBN

Negative Charge-Pump Regulator Feedback Input. Regulates to 0V nominal. Connect feedback

resistive divider to the reference (REF).

Shutdown Input. Drive SHDN through an external resistor. When SHDN is pulled low, the device

turns off and draws only 0.1µA. OUT is also pulled low through an internal 10Ω resistor in shutdown

11

SHDN

mode. When current is sourced into SHDN through RFREQ, the device activates, and the SHDN

input current sets the oscillator’s switching frequency:

RFREQ (kΩ) = 45.5 (MHz / mA) ✕ (VON - 0.7V) / fOSC (MHz)

12

DRVN

Negative Charge-Pump Driver Output. Output high level is VSUPN, and low level is PGND.

13

SUPN

Negative Charge-Pump Driver Supply Voltage. Bypass to power ground (PGND) with a 0.1µF

capacitor.

14

DRVP

Positive Charge-Pump Driver Output. Output high level is VSUPP and low level is PGND.

15

SUPP

Positive Charge-Pump Driver Supply Voltage. Bypass to power ground (PGND) with a 0.1µF

capacitor.

16

PGND Power Ground. Connect to analog ground (GND) underneath the IC.

17

CXN

Negative Terminal of the Main Charge-Pump Flying Capacitor

18

SUPM Main Charge-Pump Supply Voltage Input

19

CXP

Positive Terminal of the Main Charge-Pump Flying Capacitor

Main Charge-Pump Output. Bypass to power ground (PGND) with 10µF for a 1MHz application

20

OUT

(see Output Capacitor Selection). An internal 10Ω resistor discharges the output when the device

is shut down.

Detailed Description

The MAX1747 is an efficient triple-output power supply

for TFT LCD applications. The device contains one

high-power charge pump and two low-power charge

pumps. The MAX1747 charge pumps switch continu-

ously at a constant frequency, so the output noise con-

tains well-defined frequency components, and the

circuit requires much smaller external capacitors for a

given output ripple. The adjustable switching frequency

is set by the current into the shutdown pin (see

Frequency Selection and Shutdown).

The main charge pump uses internal MOSFETs with

low RON to provide high output current. The adjustable

output voltage of the main charge pump can be set up

to 5.5V with external resistors. The dual low-power

charge pumps independently regulate a positive output

8 _______________________________________________________________________________________

Share Link: