FAN5070 Datasheet, PDF (2/14 Pages) Fairchild Semiconductor – High Performance Programmable Synchronous DC-DC Controller

FAN5070
Pin Assignments
HIDRV
SW
GNDA
VID4
VID3
VID2
VID1
VID0
VREF
NC
1
20
2
19
3
18
4
17
5
6
16
FAN5070 ₁₅
7
14
8
13
9
12
10
11
VCCP
LODRV
GNDP
VCCA
VFB
DROOP
ILIM
PWRGD
SS/ENABLE
NC
Pin Definitions
Pin Number Pin Name
Pin Function Description
1
HIDRV High Side FET Driver. Connect this pin to the gate of an N-channel MOSFET. The
trace from this pin to the MOSFET gate should be <0.5".
2
SW
High Side Driver Source and Low Side Driver Drain Switching Node. Together
with DROOP and ILIM pins allows FET sensing for V_CC current.
3
GNDA Analog Ground. Return path for low power analog circuitry. This pin should be
connected to a low impedance system ground plane to minimize ground loops.
4-8
VID4-0 Voltage Identification Code Inputs. These open collector/TTL compatible inputs
will program the output voltage over the ranges specified in Table 1.
9
VREF DAC Output for Test Only. Do not load externally.
10, 11
NC
NC. No Connect.
12
ENABLE/SS Output Enable. A logic LOW on this pin will disable all outputs. An internal current
source allows for open collector control. This pin also doubles as soft start for all
outputs.
13
PWRGD Power Good Flag. An open collector output that will be logic LOW if any output
voltage is not within ±14% of the nominal output voltage setpoint.
14
ILIM
V_CC Current Feedback. Pin 11 is used in conjunction with pin 2 as the input for the
V_CC current feedback control loop. Layout of these traces is critical to system
performance. See Application Information for details.
15
DROOP Droop Set. Use this pin to set magnitude of active droop.
16
VFB
Vcc Voltage Feedback. Pin 13 is used as the input for the V_CC voltage feedback
control loop. See Application Information for details regarding correct layout.
17
VCCA Analog V_CC. Connect to system 5V supply and decouple with a 0.1µF ceramic
capacitor.
18
GNDP Power Ground. Return pin for high currents flowing in pin 17 (V_CCP).
19
LODRV V_CC Low Side FET Driver. Connect this pin to the gate of an N-channel MOSFET
for synchronous operation. The trace from this pin to the MOSFET gate should be
<0.5".
20
VCCP Power V_CC. For all FET drivers. Connect to system 12V supply through a 33Ω, and
decouple with a 1µF ceramic capacitor.
2
REV. 1.0.1 8/7/01