LTC1922-1
3
ELECTRICAL CHARACTERISTICS
The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at V
CC
= 9.5V, C
T
= 180pF, T
A
= T
MIN
to T
MAX
unless other wise noted.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Oscillator
OSCT Total Variation V
CC
= 6.5V to 9.5V ● 236 277 319 kHz
OSCV C
T
RAMP Amplitude Measured on C
T
3.6 3.85 4.2 V
OSYT SYNC Threshold Measured on SYNC 1.6 1.8 2.2 V
OSYW Minimum SYNC Pulse Width Measured at Outputs (Note 2) 6 ns
OSYWX Maximum SYNC Pulse Width Measured on Outputs, C
T
= 180pF 1.3 µs
OSOP SYNC Output Pulse Width Measured on SYNC, R
SYNC
= 5.1k 170 ns
Error Amplifier
V
FB
FB Input Voltage COMP = 2.5V (Note 3) 1.179 1.204 1.229 V
FBI FB Input Range Measured on FB (Note 4) –0.3 2.5 V
AVOL Open-Loop Gain COMP = 1V to 3V (Note 3) 70 90 dB
I
IB
Input Bias Current COMP = 2.5V (Note 3) 5 50 nA
V
OH
Output High Load on COMP = –100µA 4.7 4.92 V
V
OL
Output Low Load on COMP = 100µA 0.18 0.4 V
I
SOURCE
Output Source Current COMP = 2.5V – 400 –800 µA
I
SINK
Output Sink Current COMP = 2.5V 3 7 mA
Reference
V
REF
Initial Accuracy T
A
= 25°C, Measured on V
REF
4.925 5 5.075 V
REFTV Total Variation Line, Load and Temperature ● 4.9 5 5.1 V
REFLD Load Regulation Load on V
REF
= 100µA to 5mA 2 15 mV
REFLN Line Regulation V
CC
= 6.5V to 9.5V 0.1 10 mV
REFSC Short-Circuit Current V
REF
Shorted to GND 18 30 45 mA
Outputs
OUTH(X) Output High Voltage I
OUT(X)
= –50mA 7.9 8.4 V
OUTL(X) Output Low Voltage I
OUT(X)
= 50mA 0.6 1 V
R
HI(X)
Pull-Up Resistance I
OUT(X)
= –50mA to –10mA 22 30 Ω
R
LO(X)
Pull-Down Resistance I
OUT(X)
= –50mA to –10mA 12 20 Ω
t
r(X)
Rise Time C
OUT(X)
= 50pF 5 15 ns
t
f(X)
Fall Time C
OUT(X)
= 50pF 5 15 ns
Current Limit and Shutdown
CLPP Pulse-by-Pulse Current Limit Threshold Measured on CS 0.34 0.415 0.48 V
CLSD Shutdown Current Limit Threshold Measured on CS 0.55 0.64 0.73 V
SSI Soft-Start Current SS = 2.5V 7 12 17 µA
SSR Soft-Start Reset Threshold Measured on SS 0.7 0.4 0.1 V
FLT FAULT Reset Threshold Measured on SS 4.4 4.1 3.8 V
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: SYNC pulse width is valid from >20ns and <0.4 • (1/f
OSC
),
V
SYNC
= 0V to 5V.
Note 3: FB is driven by a servo loop amplifier to control V
COMP
for these
tests.
Note 4: Set FB to –0.3V, 2.5 and insure that COMP does not phase invert.
Note 5: The LTC1922-1E is guaranteed to meet performance specifications
from 0°C to 85°C. Specification over the –40°C to 85°C operating
temperature range are assured by design, characterization and correlation
with statistical process controls. The LTC1922-1I is guaranteed and tested
over the – 40°C to 85°C operating temperature range.
