Rainbow Electronics MAX1585 - Manual (Page 10)

MAX1584/MAX1585
5-Channel Slim DSC Power Supplies
10 ______________________________________________________________________________________
Pin Description
PIN NAME FUNCTION
1 CC1
AUX1 Controller Compensation Node. Connect a series resistor-capacitor from CC1 to GND to
compensate the converter control loop. This pin is actively driven to GND in shutdown, overload, and
thermal limit. See the AUX Compensation section.
2 FB1
AUX1 Controller Feedback Input. The feedback threshold is 1.25V. This pin is high impedance in
shutdown.
3 PGSD
Step-Down Power Ground. Connect all PG_ pins together and to GND with short traces as close as
possible to the IC.
4 LXSD
Step-Down Converter Switching Node. Connect to the inductor of the step-down converter. LXSD is high
impedance in shutdown.
5 PVSD
Step-Down Converter Input. PVSD can connect to PVSU, effectively making OUTSD a boost-buck output
from the battery. Bypass to GND with a 1µF ceramic capacitor if connected to PVSU. PVSD can also be
connected to the battery but should not exceed PVSU by more than a Schottky diode forward voltage.
Bypass PVSD with a 10µF ceramic capacitor when connecting to the battery input. A 10k
Ω internal
resistance connects PVSU and PVSD.
6 ONSD
Step-Down Converter On/Off Control Input. Logic high = on; however, turn-on is locked out until the step-
up has reached regulation. This pin has an internal 330k
Ω pulldown resistance to GND.
7 CCSD
Step-Up Converter Compensation Node. Connect a series resistor-capacitor from CCSD to GND to
compensate the converter control loop. This pin is actively driven to GND in shutdown, overload, and
thermal limit. See the Step-Down Compensation section.
8 FBSD
Step-Down Converter Feedback Input. Connect a resistive voltage-divider from OUTSD to FBSD to GND.
The FBSD feedback threshold is 1.25V. This pin is high impedance in shutdown.
9 ON1
AUX1 Controller On/Off Input. Logic high = on; however, turn-on is locked out until 1024 OSC cycles after
the step-up has reached regulation. This pin has an internal 330k
Ω pulldown resistance to GND.
10 ON2
AUX2 Controller On/Off Input. Logic high = on; however, turn-on is locked out until 1024 OSC cycles after
the step-up has reached regulation. This pin has an internal 330k
Ω pulldown resistance to GND.
11 ON3
AUX3 Controller On/Off Input. Logic high = on; however, turn-on is locked out until 1024 OSC cycles after
the step-up has reached regulation. This pin has an internal 330k
Ω pulldown resistance to GND.
12 ONSU
Step-Up Converter On/Off Control. Logic high = on. All other ON_ pins are locked out until 1024 OSC
cycles after the step-up DC-DC converter output has reached its final value. This pin has an internal
330k
Ω pulldown resistance to GND.
13 REF
Reference Output. Bypass REF to GND with a 0.1µF or greater capacitor. The maximum allowed load on
REF is 200µA. REF is actively pulled to GND when all converters are shut down.
14 FBSU
Step-Up Converter Feedback Input. Connect a resistive voltage-divider from PVSU to FBSU to GND. The
FBSU feedback threshold is 1.25V. This pin is high impedance in shutdown.
15 CCSU
Step-Up Converter Compensation Node. Connect a series resistor-capacitor from CCSU to GND to
compensate the converter control loop. This pin is actively driven to GND in shutdown, overload, and
thermal limit. See the Step-Up Compensation section.