Rainbow Electronics MAX1885 - Manual (Page 18)

MAX1778/MAX1880–MAX1885
Quad-Output TFT LCD DC-DC
Converters with Buffer
18 ______________________________________________________________________________________
Pin Description (continued)
PIN
MAX1778
MAX1881 MAX1880
MAX1882 MAX1883
MAX1884
MAX1885
NAME FUNCTION
14 − 12 − LDOOUT
Linear Regulator Output. Sources up to 40mA. Bypass to GND with
a ceramic capacitor determined by:
15 − 13 − FBL
Voltage Setting Input. Connect a resistive divider from the linear
regulator output (V LDOOUT ) to FBL to analog ground (GND).
16 16 14 14 FLTSET
Fault Trip-Level Set Input. Connect to a resistive divider between
REF and GND to set the main step-up converter’s and positive
charge pump’s fault thresholds between 0.67 x V
REF
and 0.85 x
V REF . Connect to GND for the preset fault threshold (0.9 x V REF ).
17 17 − − SUPN
Negative Charge-Pump Driver Supply Voltage. Bypass to power
ground (PGND) with a 0.1µF capacitor.
18 18 − − DRVN
Negative Charge-Pump Driver Output. Output high level is V SUPN
and low level is PGND.
19 19 − − SUPP
Positive Charge-Pump Driver Supply Voltage. Bypass to power
ground (PGND) with a 0.1µF capacitor.
20 20 − − DRVP
Positive Charge-Pump Driver Output. Output high level is V SUPP
and low level is PGND
21 21 17 17 PGND
Power Ground. Connect to analog ground (GND) underneath the
IC.
22 22 18 18 LX
Main Step-Up Regulator Power MOSFET N-Channel Drain. Place
output diode and output capacitor as close to PGND as possible.
23 23 19 19 TGND Must be connected to ground.
24 24 20 20 RDY
Active-Low, Open-Drain Output. Indicates all outputs are ready.
On-resistance is 125
Ω (typ).
− 13, 14, 15 15, 16
11, 12, 13,
15, 16
N.C. No Connection. Not internally connected.
C ms X
I
V
LDOOUT
LDOOUT MAX
LDOOUT
.
( ) ≥

 

0 5