Datasheet

LTC1051/LTC1053
10
10513fa
SYSTEM BUSY, ONLY ABORT COMMANDS ALLOWED
RANGE: 11dBV
STATUS: PAUSED
20dBV
15dB
/DIV
–100
CENTER: 10 000Hz
X: 5475Hz
BW: 95.485Hz
Y: –58.05dBV
SPAN: 10 000Hz
f
IN
=10kHz6f
CLK
– f
IN
68dB
–
+
1/2
LTC1051
1051/53 F07
R1
100Ω
R2
10k
90mV
P-P
10kHz
0.1µF
0.1µF
50pF
5V
–5V
V
OUT
R
L
(LOAD RESISTANCE,Ω)
V
OUT
± SWING (±V)
1051/53 G08
01k2k3k
4k
5k
6k 7k 8k 9k 10k
NEGATIVE SWING
POSITIVE SWING
V
S
= ±8V, T
A
≤85°C
V
S
= ±5V, T
A
≤85°C
V
S
= ±2.5V, T
A
≤85°C
10
9
8
7
6
5
4
3
2
1
0
INVERTING CLOSED-LOOP GAIN
1
OUTPUT SIGNAL TO ALIAS SIGNAL(S) RATIO (dB)
10010
1051/53 G09
90
80
70
60
50
40
30
20
10
V
S
= ±5V
f
IN
≤10kHz
5. For unity-gain inverting configuration, all the alias
frequencies are 80dB to 84dB down from the output signal
(Figures 6a, 6b). Combined with excellent THD under wide
swing, the LTC1051/LTC1053 op amps make efficient
unity gain inverters.
For gain higher than –1, the “signal to alias” ratio de-
creases at an approximate rate of –6dB per decade of
closed-loop gain (Figure 9).
6. For closed-loop gains of –10 or higher, the “signal to
alias” ratio degrades when the value of the feedback gain
setting resistor increases beyond 50k. For instance, the
68dB value of Figure 7 decreases to 56dB if a (1k, 100k)
resistor set is used to set the gain of –100.
7. When the LTC1051/LTC1053 are used as noninverting
amplifiers, all the previous approximate rules of thumb
apply with the following exceptions: when the closed-loop
gain is 10(V/V) and below, the “signal to alias” ratio is 1dB
to 3dB less than the inverting case; when the closed-loop
gain is 100(V/V), the degradation can be up to 9dB,
especially when the input signal is much higher than the
clock frequency (i.e. f
IN
= 10kHz).
8. The signal/alias ratio performance improves when the
op amp has bandlimited loop gain.
Figure 7. Output Voltage Spectrum of 1/2 LTC1051 Operating as an Inverting Amplifier with a Gain of –100 and
Amplifiying a 90mV
P-P
, 10kHz Input Signal. With a 9V
P-P
Output Swing the Measured 2nd Harmonic (20kHz)
was 75 Down from the 10kHz Input Signal
Figure 8. Output Voltage Swing vs Load Figure 9. Signal to Alias Ratio vs
Closed-Loop Gain
APPLICATIO S I FOR ATIO
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