Datasheet

UCC2897A
SLUS829D -- AUGUST 2008 -- REVISED JULY 2009
4
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ELECTRICAL CHARACTERISTICS
V
DD
=12V
(1)
,1-μF capacitor from VDD to GND, 0.01-μF capacitor from VREF to GND, R
ON
=R
OFF
=75kΩ,R
DEL
=10kΩ,
R
SLOPE
=50kΩ,--40°C ≤ T
A
=T
J
≤ 125°C (unless otherwise noted)
PARAMETER
TEST CONDITIONS MIN TYP MAX UNIT
OVERALL
I
STARTUP
Start-up current V
DD
<V
UVLO
300 500 μA
I
DD
Operating supply current
(1)(2)
V
FB
=0V, V
CS
=0V,
Outputs not switching
2 3 mA
HIGH-VOLTAGE BIAS SECTION
I
DD--ST
VDD startup current
Current available from VDD during start-
up, T
A
=--40°Cto85°C, VIN = 36 V,
(3)
4 11 mA
I
VIN
JFET leakage current VIN = 120 V; VDD = 14 V 75 μA
UNDERVOLTAGE LOCKOUT
UVLO Start threshold voltage 12.2 12.7 13.2
Minimum operating voltage after start 7.6 8.0 8.4
V
Hysteresis 4.4 4.7 5.0
V
LINE MONITOR
V
LINEUV
Line UV voltage threshold 1.243 1.268 1.294 V
I
LINEUVHYS
Line UV hysteresis current -- 11 . 5 --13.0 --14.5 μA
V
LINEOV
Line OV voltage threshold 1.243 1.268 1.294 V
I
LINEOVHYS
Line OV hysteresis current -- 11 . 5 --13.0 --14.5 μA
SOFT-START
I
SSC
SS charge current R
ON
=75kΩ
(4)
--10.5 --14.5 --18.5
A
I
SSD
SS discharge current R
ON
=75kΩ
(4)
10.5 14.5 18.5
μ
A
V
SS/SD
Discharge/shutdown threshold voltage 0.4 0.5 0.6 V
VOLTAGE REFERENCE
V
REF
Reference voltage T
J
=25°C 4.85 5.00 5.15
V
V
REF
Reference voltage 0A<I
REF
< 5 mA, over temperature 4.75 5.00 5.25
V
I
SC
Short circuit current REF = 0 V, T
J
=25°C -- 2 0 -- 11 -- 8 mA
INTERNAL SLOPE COMPENSATION
m Slope FB = High -10%
R
CS
R
SLOPE
+10%
OSCILLATOR
f
O
s
c
i
l
l
a
t
o
r
f
r
e
q
u
e
n
c
y
T
J
=25°C 237 250 265
k
H
z
f
OSC
Oscillator
f
requency
-- 4 0 °C<T
J
< 125°C; 8.5V < VDD < 14.5V 225 270
kHz
V
P_P
Oscillator amplitude (peak -to-peak) 2 V
(1)
Set VDD above the start threshold before setting at 12 V.
(2)
Does not include current of the external oscillator network.
(3) The power supply starts with I
DD--ST
load on VDD, part will start up with no load up to 125°C. For more information see the Detailed Pin
Description section for VIN and VDD.
(4) I
SSC
and I
SS/SD
are directly proportional to I
RON
. See equation 7.