Datasheet

3
LT1339
sn1339 1339fas
12V
IN
= V
BOOST
= 12V, V
C
= 2V, TS = 0V, V
FB
= V
REF
= 1.25V, C
TG
= C
BG
= 3000pF, T
A
= 25°C unless otherwise noted.
E
LECTR
IC
AL C CHARA TERIST
ICS
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Error Amplifier
V
FB
Error Amplifier Reference Voltage Measured at Feedback Pin 1.242 1.250 1.258 V
● 1.235 1.250 1.265 V
I
FB
Feedback Input Current V
FB
= V
REF
● 0.1 0.5 1.0 µA
g
m
Error Amplifier Transconductance ● 1200 2000 3200 µmho
A
V
Error Amplifier Voltage Gain ● 1500 3000 V/V
I
VC
Error Amplifier Source Current ● 200 275 µA
Error Amplifier Sink Current V
FB
– V
REF
= 500mV ● 280 400 µA
V
VC
Absolute V
C
Clamp Voltage Measured at V
C
Pin 3.5 V
V
SENSE
Peak Current Limit Threshold Measured at Sense Inputs ● 170 190 mV
Average Current Limit Threshold (Note 4) Measured at Sense Inputs
● 110 120 130 mV
V
IAVG
Average Current Limit Threshold Measured at I
AVG
Pin 2.5 V
Current Sense Amplifier
A
V
Amplifier DC Gain Measured at I
AVG
Pin 15 V/V
V
OS
Amplifier Input Offset Voltage 2V < V
CMSENSE
< 60V, ● 0.1 mV
SENSE
+
– SENSE
–
= 5mV
I
B
Input Bias Current Sink (V
CMSENSE
> 5V) ● 45 75 µA
Source (V
CMSENSE
= 0V) ● 700 1200 µA
Oscillator
f
O
Operating Frequency, Free Run ● 150 kHz
Frequency Programming Error (Note 3) f
O
≤ 150kHz ● –5 5 %
I
CT
Timing Capacitor Discharge Current LT1339C ● 2.20 2.50 2.75 mA
LT1339I
● 2.10 2.50 2.75 mA
V
SYNC
SYNC Input Threshold Rising Edge ● 0.8 2.0 V
f
SYNC
SYNC Frequency Range f
SYNC
≤ 150kHz ● f
O
1.4f
O
Output Drivers
V
TG,BG
Undervoltage Output Clamp 12V
IN
≤ 8V ● 0.4 0.7 V
Standby Mode Output Clamp V
RUN
< 0.5V ● 0.1 V
V
TG
Top Gate On Voltage ● 11.0 11.9 12.0 V
Top Gate Off Voltage
● 0.4 0.7 V
t
TGR
Top Gate Rise Time ● 130 200 ns
t
TGF
Top Gate Fall Time ● 60 140 ns
V
BG
Bottom Gate On Voltage ● 11.0 11.9 12.0 V
Bottom Gate Off Voltage
● 0.4 0.7 V
t
BGR
Bottom Gate Rise Time ● 70 200 ns
t
BGF
Bottom Gate Fall Time ● 60 140 ns
Note 2: Supply current specification does not include external FET gate
charge currents. Actual supply currents will be higher and vary with
operating frequency, operating voltages and the type of external FETs
used. See Application Information section.
Note 3: Test condition: R
CT
= 16.9k, C
CT
= 1000pF.
Note 4: Test Condition: V
CMSENSE
= 10V.
The ● denotes specifications which apply over the full operating
temperature range.
Note 1: Absolute maximum ratings are those values beyond which the life
of a device may be impaired.