8
LTC1273
LTC1275/LTC1276
127356fa
CCHARA TERIST
ICS
UW
AT
Y
P
I
CA
LPER
F
O
R
C
E
PI FU CTIO S
UU U
A
IN
(Pin 1): Analog Input. 0V to 5V (LTC1273), ±2.5V
(LTC1275) or ±5V (LTC1276).
V
REF
(Pin 2): +2.42V Reference Output. Bypass to
AGND (10µF tantalum in parallel with 0.1µF ceramic).
AGND (Pin 3): Analog Ground.
D11-D4 (Pins 4 to 11): Three-State Data Outputs.
DGND (Pin 12): Digital Ground.
D3/11-D0/8 (Pins 13 to 16): Three-State Data Outputs.
NC (Pins 17 and 18): No Connection.
HBEN (Pin 19): High Byte Enable Input. This pin is used
to multiplex the internal 12-bit conversion result into
the lower bit outputs (D7-D0/8). See Table 1. HBEN also
disables conversion start when HIGH.
RD (Pin 20): READ Input. This active low signal starts
a conversion when CS and HBEN are low. RD also
enables the output drivers when CS is low.
CS (Pin 21): The CHIP SELECT Input must be low for
the ADC to recognize RD and HBEN inputs.
BUSY (Pin 22): The BUSY Output shows the converter
status. It is low when a conversion is in progress.
S/(N + D) vs Input Frequency and
Amplitude
Acquisition Time
vs Source Impedance
Intermodulation Distortion Plot
R
SOURCE
(Ω)
10
2500
ACQUISITION TIME (ns)
3000
3500
4000
4500
100 1k 10k
LTC1273/75/76 • TPC10
2000
1500
500
0
1000
INPUT FREQUENCY (Hz)
20
SIGNAL/(NOISE + DISTORTION) (dB)
40
50
70
80
10k 100k 10M
LTC1273/75/76 • TPC11
0
1k
60
30
10
1M
V
IN
= –60dB
V
IN
= –20dB
V
IN
= 0dB
f
SAMPLE
= 300kHz
Spurious Free Dynamic Range
vs Input Frequency
Reference Voltage
vs Load Current
LOAD CURRENT (mA)
–5
2.405
REFERENCE VOLTAGE (V)
2.410
2.415
2.420
2.425
2.430
2.435
–4 –2 –1 2
LTC1273/75/76 • TPC13
–3 0 1
INPUT FREQUENCY (Hz)
10k
–60
SPURIOUS FREE DYNAMIC RANGE (dB)
–50
–40
–30
–20
100k 1M 10M
LTC1273/75/76 • TPC12
–70
–80
–90
–100
–10
0
f
SAMPLE
= 300kHz
FREQUENCY (kHz)
0
–120
AMPLITUDE (dB)
–100
–80
–60
–40
40 80
120
160
LTC1273/75/76 • F05
–20
0
20 60 100
140
f
SAMPLE
= 300kHz
f
IN1
= 29.37kHz
f
IN2
= 32.446kHz
