3
LT1684
Note 1: Absolute Maximum Ratings are those values beyond which the life
of the device may be impaired.
Note 2: IC Supply current specification represents unloaded condition and
does not include external FET gate pull up/down currents (GATE
+
, GATE
–
pins). Actual total IC bias currents will be higher and vary with operating
conditions. See Applications Information.
Note 3: PWM inputs are high impedance through ±100mV beyond the
input thresholds.
Note 4: 10k resistor from pin AMPIN to ground.
Note 5: Guaranteed but not tested.
The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at T
A
= 25°C.
V
+
– V
–
= 20V, Voltages referenced to pin OUT, V
OUT
= V
ATREF
unless otherwise noted.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Supply and Protection
I
S
DC Supply Current (Note 2) IN A – IN B ≥ 1.6V ● 680 950 µA
|V
+
| Local Supply Voltages V
GATE
+ ≥ V
+
● 6.5 10 V
|V
–
|V
GATE
– ≤ V
–
V
GATE
+ Active Tracking Supply FET I
GATE
+ = –100µA, ● 13.2 14.0 14.8 V
Bias Voltage AT
REF
= 0V
V
GATE
– Active Tracking Supply FET I
GATE
– = 100µA, ● –14.8 –14.0 –13.2 V
Bias Voltage AT
REF
= 0V
PWM Receiver
f
PWM
Input Carrier Frequency 10 kHz
V
IN
Minimum Valid Differential Input IN A – IN B or IN B – IN A ● 1.6 V
Differential Input Threshold ● 0.50 0.70 1.00 V
| IN A – IN B |
R
IN
Differential Input Overdrive Impedance V
IN
> V
TH
+ 100mV ● 710 kΩ
(Note 3, 5)
R
INA,INB
Single-Ended Input Impedance To Pin OUT ● 50 kΩ
(Note 5)
BG Buffer
V
BGOUT
BG
OUT
Normalized Voltage Magnitude |V
BGOUT
| 1.235 1.250 1.265 V
● 1.225 1.250 1.275 V
V
BGOUTOS
Output Offset Voltage –7 7 mV
[(V
BGOUT
+) + (V
BGOUT
–)]/2 ● –10 10 mV
I
BGOUTSC
BG
OUT
Short-Circuit Current ● ±2 ±4.5 mA
R
BGOUT
BG
OUT
Output Impedance –2mA ≤ I
BGOUT
≤ 2mA 0.2 Ω
t
r
BG
OUT
Rise Time (10% to 90%) R
OUT
= 5k, C
OUT
= 10pF ● 160 300 ns
t
f
BG
OUT
Fall Time (10% to 90%) R
OUT
= 5k, C
OUT
= 10pF ● 260 400 ns
∆t
r-f
BG
OUT
RiseTime – Fall Time ● –200 –100 0 ns
t
pr
BG
OUT
Propagation Delay PWM Input R
OUT
= 5k, C
OUT
= 10pF ● 340 500 ns
Transition to 10% Output (Rising Edge)
t
pf
BG
OUT
Propagation Delay PWM Input R
OUT
= 5k, C
OUT
= 10pF ● 440 600 ns
Transition to 90% Output (Falling Edge)
∆t
p
BG
OUT
Propagation Delay ● –200 –100 100 ns
Rising Edge – Falling Edge
Output Amplifier
V
OUTOS
OUT Offset Voltage V
AMPIN
= 0v, I
OUT
= 0A –6 6 mV
R
AMPIN
= 10k (Note 4) ● –8 8 mV
R
OUT
OUT Output Impedance –10mA ≥ I
LIM
+ ≥ –100mA, LIM
+
Shorted to OUT 0.01 Ω
10mA ≤ I
OUT
≤ 100mA, LIM
–
Shorted to V
–
0.15 Ω
I
OUTSC
OUT Short-Circuit Current LIM
+
Shorted to OUT ● ±100 ±190 mA
LIM
–
Shorted to V
–
ELECTRICAL CHARACTERISTICS
