Datasheet
ABSOLUTE MAXIMUM RATINGS
(1)
UCC2817-EP
UCC2818-EP
SLUS716 – DECEMBER 2008 ...........................................................................................................................................................................................
www.ti.com
VCC: Positive supply voltage. Connect to a stable source of at least 20 mA between 10 V and 17 V for normal
operation. Bypass V
CC
directly to GND to absorb supply current spikes required to charge external MOSFET gate
capacitances. To prevent inadequate gate drive signals, the output devices are inhibited unless V
VCC
exceeds
the upper under-voltage lockout voltage threshold and remains above the lower threshold.
VFF: Feed-forward voltage. The RMS voltage signal generated at this pin by mirroring 1/2 of the I
IAC
into a single
pole external filter. At low line, the VFF voltage should be 1.4 V.
VSENSE: Voltage amplifier inverting input. This is normally connected to a compensation network and to the
boost converter output through a divider network.
VREF: Voltage reference output. V
REF
is the output of an accurate 7.5-V voltage reference. This output is
capable of delivering 20 mA to peripheral circuitry and is internally short-circuit current limited. VREF is disabled
and remains at 0 V when V
VCC
is below the UVLO threshold. Bypass VREF to GND with a 0.1- µ F or larger
ceramic capacitor for best stability. Please refer to Figure 8 and Figure 9 for VREF line and load regulation
characteristics.
over operating free-air temperature range (unless otherwise noted)
MIN MAX UNIT
V
CC
Supply voltage 18 V
I
CC
Supply current 20 mA
Gate drive current, continuous 0.2 A
Gate drive current 1.2 A
CAI, MOUT, SS 8
Input voltage PKLMT 5 V
VSENSE, OVP/EN 10
RT, IAC, PKLMT 10
Input current mA
V
CC
(no switching) 20
Maximum negative voltage DRVOUT, PKLMT, MOUT – 0.5 V
Power dissipation 1 W
θ
JA
Package thermal impedance ° C/W
T
J
Junction temperature – 55 150 ° C
T
stg
Storage temperature range – 65 150 ° C
T
sol
Lead temperature Soldering, 10 s 300 ° C
(1) Stresses beyond those listed under " absolute maximum ratings " may cause permanent damage to the device. These are stress ratings
only, and functional operation of the device at these or any other conditions beyond those indicated under " recommended operating
conditions " is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
THERMAL RESISTANCE
PACKAGE θ
JC
( ° C/W) θ
JA
( ° C/W)
SOIC-16 (D) 22 40 to 70
(1)
(1) Specified θ
JA
(junction to ambient) is for devices mounted to 5-in
2
FR4 PC board with 1-oz copper, where noted. When resistance range
is given, lower values are for 5-in
2
aluminum PC board. Test PWB was 0.062-in thick and typically used 0,635-mm trace widths for
power packages and 1,3-mm trace widths for nonpower packages with a 100-mil × 100-mil probe land area at the end of each trace.
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