Datasheet
LT1991
6
1991fh
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
PSRR Power Supply Rejection Ratio V
S
= ±1.35V to ±18V (Note 8)
l
105 135 dB
Minimum Supply Voltage
l
2.4 2.7 V
V
OUT
Output Voltage Swing (to Either Rail) No Load
V
S
= 5V, 0V
V
S
= 5V, 0V
V
S
= ±15V
l
l
40
55
75
120
mV
mV
mV
1mA Load
V
S
= 5V, 0V
V
S
= 5V, 0V
V
S
= ±15V
l
l
150
225
300
340
mV
mV
mV
I
SC
Output Short-Circuit Current (Sourcing) Drive Output Positive;
Short Output to Ground
l
8
4
12 mA
mA
Output Short-Circuit Current (Sinking) Drive Output Negative;
Short Output to V
S
or Midsupply
l
8
4
21 mA
mA
BW –3dB Bandwidth G = 1
G = 3
G = 9
110
78
40
kHz
kHz
kHz
GBWP Op Amp Gain Bandwidth Product f = 10kHz 560 kHz
t
r
, t
f
Rise Time, Fall Time G = 1; 0.1V Step; 10% to 90%
G = 9; 0.1V Step; 10% to 90%
3
8
µs
µs
t
s
Settling Time to 0.01% G = 1; V
S
= 5V, 0V; 2V Step
G = 1; V
S
= 5V, 0V; –2V Step
G = 1; V
S
= ±15V, 10V Step
G = 1; V
S
= ±15V, –10V Step
42
48
114
74
µs
µs
µs
µs
SR Slew Rate V
S
= 5V, 0V; V
OUT
= 1V to 4V
V
S
= ±15V; V
OUT
= ±10V; V
MEAS
= ±5V
l
l
0.06
0.08
0.12
0.12
V/µs
V/µs
I
s
Supply Current V
S
= 5V, 0V
l
100 110
180
µA
µA
V
S
= ±15V
l
130 160
250
µA
µA
ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the operating
temperature range of –40°C to 125°C for H-grade parts, otherwise specifications are at T
A
= 25°C. Difference amplifier configuration,
V
S
= 5V, 0V or ±15V; V
CM
= V
REF
= half supply, unless otherwise noted.
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for
extended periods may affect device
reliability and lifetime.
Note 2: The P3/M3 and P9/M9 inputs should not be taken more than 0.2V
beyond the supply rails. The P1/M1 inputs can withstand ±60V if P9/M9
are grounded and V
S
= ±15V (see Applications Information section about
“High Voltage CM Difference Amplifiers”).
Note 3: A heat sink may be required to keep the junction temperature
below
absolute maximum ratings.
Note 4: Both the LT1991C and LT1991I are guaranteed functional over the
–40°C to 85°C temperature range. The LTC1991H is guaranteed functional
over the –40°C to 125°C temperature range.
Note 5: The LT1991C is guaranteed to meet the specified performance
from 0°C to 70°C and is designed, characterized and expected to meet
specified performance from –40°C to 85°C but is
not tested or QA sampled
at these temperatures. The LT1991I is guaranteed to meet specified
performance from –40°C to 85°C. The LT1991H is guaranteed to meet
specified performance from –40°C to 125°C.
Note 6: This parameter is not 100% tested.
Note 7: Input voltage range is guaranteed by the CMRR test at V
S
= ±15V.
For the other voltages, this parameter is guaranteed by design and through
correlation
with the ±15V test. See the Applications Information section to
determine the valid input voltage range under various operating conditions.
Note 8: Offset voltage, offset voltage drift and PSRR are defined as
referred to the internal op amp. You can calculate output offset as follows.
In the case of balanced source resistance, V
OS,OUT
= V
OS
• NOISEGAIN
+ I
OS
• 450k + I
B
• 450k • (1– R
P
/R
N
) where R
P
and R
N
are the total
resistance at the op amp positive and negative terminal respectively.
Note 9: Applies to resistors that are connected to the inverting inputs.
Resistor matching is not tested directly, but is guaranteed by the gain
error test.
Note 10: Input impedance is tested by a combination of direct
measurements and correlation to the CMRR and gain error tests.
Note 11: I
B
and I
OS
are tested at V
S
= 5V, 0V only.