Pin description (continued) – Rainbow Electronics MAX1885 User 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