Datasheet

LT1249
3
ELECTRICAL CHARACTERISTICS
Maximum operating voltage (V
MAX
) = 25V, V
CC
= 18V, I
AC
= 100µA, CA
OUT
= 3.5V, VA
OUT
= 5V, no load on any outputs,
unless otherwise noted.
The ● denotes specifications which apply over the operating temperature
range.
Note 1: Current amplifier is in linear mode with 0V input common mode.
Note 2: Multiplier Gain Constant: K =
Note 3: Maximum GTDR output voltage is internally clamped for higher
V
CC
voltages.
TYPICAL PERFORMANCE CHARACTERISTICS
U
W
FREQUENCY (Hz)
10
GAIN (dB)
100
80
60
40
20
0
–20
100
1k 10k 100k
1249 G01
1M 10M
0
–20
–40
–60
–80
–100
–120
PHASE (DEG)
PHASE
GAIN
Voltage Amplifier Open-Loop
Gain and Phase
FREQUENCY (Hz)
1k
TRANSCONDUCTANCE (µmho)
400
350
300
250
200
150
100
50
0
20
0
–20
–40
–60
–80
–100
–120
–140
100k10k
1249 G02
1M
PHASE (DEG)
10M
g
m
θ
Transconductance of
Current Amplifier
I
M
I
AC
(VA
OUT
– 1.5)
2
PARAMETER CONDITIONS MIN TYP MAX UNITS
Reference
Reference Output Voltage T
A
= 25°C, Measured at V
SENSE
Pin 7.39 7.5 7.6 V
Reference Output Voltage Worst Case All Line, Temperature ● 7.32 7.5 7.68 V
Reference Output Voltage Line Regulation V
LOCKOUT
< V
CC
< V
MAX
● –20 5 20 mV
Multiplier
Multiplier Output Current I
AC
= 100µA, VA
OUT
= 5V 35 µA
Multiplier Output Current Offset R
AC
= 1M from I
AC
to GND ● –0.05 –0.5 µA
Multiplier Max Output Current (I
M(MAX)
)I
AC
= 450µA, VA
OUT
= 7V (Note 1) ● – 375 –250 –150 µA
Multiplier Max Output Voltage (I
M(MAX)
× R
MOUT
)I
AC
= 450µA, VA
OUT
= 7V (Note 1) ● –1.25 –1.1 –0.96 V
Multiplier Gain Constant (Note 2) 0.035 V
–2
I
AC
Input Resistance I
AC
from 50µA to 1mA 15 25 35 kΩ
Oscillator
Oscillator Frequency ● 75 100 125 kHz
Control Pin (CA
OUT
) Threshold Duty Cycle = 0 ● 1.3 1.8 2.3 V
Synchronization Frequency Range Synchronizing Pulse Low ≤ 0.35V on CA
OUT
● 127 160 kHz
Gate Driver
Max GTDR Output Voltage 0mA Load, 18V < V
CC
< V
MAX
(Note 3) ● 12 15 17.5 V
GTDR Output High –200mA Load, 11.5V ≤ V
CC
≤ 15V ● V
CC
– 3.0 V
GTDR Output Low (Device Unpowered) V
CC
= 0V, 50mA Load (Sinking) ● 0.9 1.5 V
GTDR Output Low (Device Active) 200mA Load (Sinking) ● 0.5 1 V
Peak GTDR Current 10nF from GTDR to GND 2 A
GTDR Rise and Fall Time 1nF from GTDR to GND 25 ns
GTDR Max Duty Cycle 90 96 %