UCC1972/3
UCC2972/3
UCC3972/3
ELECTRICAL CHARACTERISTICS:
Unless otherwise specified these specifications hold for T
A
=0°C to +70°C for the
UC3972/3, –40°C to +85°C for the UC2972/3, and –55°C to +125°C for the UC1972/3; T
A
=T
J
; VDD=VBAT=VBUCK=12V;
MODE=OPEN. For any tests with VBAT>17V, place a 1k resistor from VBAT to VDD.
PARAMETER
Oscillator Section
Synchronizable Frequency (See Note 2.)
BUCK = VBAT– 2, V
BAT
= 12V to 25V,
T
A
= –40°C to +85°C
BUCK = VBAT–2, V
BAT
= 12V to 25V
T
A
= –55°C to +125°C
Maximum Duty Cycle
Minimum Duty Cycle
BUCK Input Bias Current
Zero Detect Threshold
FB = 1V, T
A
< 0°C
FB = 1V, T
A
= 0°C to 70°C
FB = 2V
BUCK = VBAT = 12V
BUCK = VBAT = 25V
Measured at BUCK w/respect to VBAT,
VBAT=12V to 25V, T
A
< 0°C
Measured at BUCK w/respect to VBAT,
VBAT=12V to 25V, T
A
= 0°C to 70°C
Error Amplifier
Input Voltage
Line Regulation
Input Bias Current
Open Loop Gain
Output High Voltage
Output Low Voltage
Output Source Current
Output Sink Current
Output Source Current
Output Sink Current
Unity Gain Bandwidth
Mode Select
Output Enable Threshold
Open Lamp Detect Enable Threshold
Mode Output Current
MODE Clamp Voltage
Open Lamp
Open Lamp Detect Threshold
Measured at BUCK with respect to VBAT,
VBAT=12V to 25V
–8
–10.3
–7
–9
–6
–7.7
V
V
MODE = 0.5V
MODE = OPEN
0.85
2.75
15
3.3
1
3
20
3.7
1.15
3.25
25
4
V
V
COMP = 0.5V to 3.0V
FB = 1V
FB = 2V
FB = 1V, COMP = 2V
FB = 2V, COMP = 2V
FB = 1V, COMP = 2V, MODE = 0.5V
FB = 2V, COMP = 2V, MODE = 0.5V
T
J
= 25C, Note 1
2
–1
–1
2
COMP = 2V, T
A
= 0°C to +70°C
COMP = 2V
1.465
1.455
–2
–500
60
3.3
2
–100
80
3.7
0.15
–1.2
4
1
1
4.1
0.35
–0.4
1.5
1.535
1.545
10
V
V
mV
nA
dB
V
V
mA
mA
–2.4
–2.0
40
80
–1
–1
80
80
84
90
95
0
90
110
–0.3
–0.3
-
-
160
145
kHz
kHz
%
%
%
mA
mA
V
V
TEST CONDITIONS
MIN
TYP
MAX
UNITS
m
A
m
A
MHz
m
A
V
Over-voltage Clamp Threshold (UCC3973) Measured at BUCK with respect to VBAT,
VBAT=12V to 25V, I
FB
= 100µA
Note 1. Ensured by design. Not 100% tested in production.
Note 2. Oscillator operates at 2x transformer switching frequencey.
3
TI [ TEXAS INSTRUMENTS ]
