EN23F0QI
©Enpirion 2012 all rights reserved, E&OE Enpirion Confidential www.enpirion.com, Page 3
Pin Description
I/O Legend: P=Power G=Ground NC=No Connect I=Input O=Output I/O=Input/Output
PIN NAME I/O FUNCTION
1-24,
36, 81
NC NC
NO CONNECT – These pins may be internally connected. Do not connect them to each
other or to any other electrical signal. Failure to follow this guideline may result in device
damage.
25-35 VOUT O
Regulated converter output. Connect these pins to the load and place output capacitor
between these pins and PGND pins 40-42.
37-39,
83-92
NC(SW) NC
NO CONNECT – These pins are internally connected to the common switching node of the
internal MOSFETs. They are not to be electrically connected to any external signal, ground,
or voltage. Failure to follow this guideline may result in damage to the device.
40-46 PGND G
Input/Output power ground. Connect these pins to the ground electrode of the input and
output filter capacitors. See VOUT and PVIN pin descriptions for more details.
47-63 PVIN P
Input power supply. Connect to input power supply. Decouple with input capacitor to PGND
pins 43-46.
64 AVINO O
Internal 3.3V linear regulator output. Connect this pin to AVIN (Pin 73) for applications
where operation from a single input voltage (PVIN) is required. If AVINO is being used,
place a 1µF, X5R/X7R, capacitor between AVINO and AGND as close as possible to
AVINO.
65 PG I/O Place a 0.1µF, X7R, capacitor between this pin and BTMP.
66 BTMP I/O See pin 65 description.
67 VDDB O
Internal regulated voltage used for the internal control circuitry. Place a 1µF, X7R, capacitor
between this pin and BGND.
68 BGND G See pin 67 description.
69 S_IN I
Digital Input. This pin accepts either an input clock to phase lock the internal switching
frequency or a S_OUT signal from another EN23F0QI. Leave this pin floating if not used.
70 S_OUT O Digital Output. PWM signal is output on this pin. Leave this pin floating if not used.
71 POK O
Power OK is an open drain transistor (pulled up to AVIN or similar voltage) used for power
system state indication. POK is logic high when VOUT is -10% of VOUT nominal. Leave
this pin floating if not used.
72 ENABLE I
Input Enable. Applying a logic high to this pin enables the output and initiates a soft-start.
Applying a logic Low disables the output. Do not leave this pin floating.
73 AVIN P
3.3V Input power supply for the controller. Place a 0.1µF, X7R, capacitor between AVIN
and AGND.
74 AGND G
Analog Ground. This is the ground return for the controller. Needs to be connected to a
quiet ground.
75 M/S I
A logic level low configures the device as Master and a logic level high configures the
device as a Slave. Connect to ground in standalone mode.
76 VFB I/O
External Feedback Input. The feedback loop is closed through this pin. A voltage divider at
VOUT is used to set the output voltage. The mid-point of the divider is connected to VFB. A
phase lead capacitor from this pin to VOUT is also required to stabilize the loop.
77 EAIN O
Optional Error Amplifier Input. Allows for customization of the control loop for performance
optimization. Leave this pin floating if unused.
78 SS I/O
Soft-Start node. The soft-start capacitor is connected between this pin and AGND. The
value of this capacitor determines the startup time. See Soft-Start Operation in the
Functional Description section for details.
79 RCLX I/O
Programmable over-current protection. Placement of a resistor on this pin will adjust the
over-current protection threshold. See Table 2 for the recommended RCLX Value to set
OCP at the nominal value specified in the Electrical Characteristics table. No current limit
protection when this pin is left floating.
80 FADJ I/O
Adding a resistor (R
FS
) to this pin will adjust the switching frequency of the EN23F0QI. See
Table 1 for suggested resistor values on R
FS
for various PVIN/VOUT combinations to
maximize efficiency. Do not leave this pin floating.
82 CGND G Connect to GND plane at all times.
93 PGND G
Not a perimeter pin. Device thermal pad to be connected to the system GND plane for heat-
sinking purposes.
