Datasheet
LTC1857/LTC1858/LTC1859
19
185789fa
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representa-
tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.
PACKAGE DESCRIPTION
APPLICATIONS INFORMATION
1859 F13
ADC
+
LTC1857/LTC1858/LTC1859
DIGITAL
SYSTEM
OV
DD
DGND
24 21
ADC
–
10μF
DV
DD
20
10μF
AV
DD
19
AGND
14, 17, 18
10μF
REFCOMP
16
10μF
V
REF
15
12
MUXOUT
+
LTC1857/
LTC1858/
LTC1859
MUXOUT
–
10
CH0
CH1
CH2
CH3
CH4
CH5
CH6
CH7
COM
11
13
1μF
ANALOG GROUND PLANE
+
–
Figure 13. Power Supply Grounding Practice
LTC1858/LTC1859
can be tied to the analog ground plane.
Placing the bypass capacitor as close as possible to the
power supply pins, the reference and reference buffer out-
put is very important. Low impedance common returns for
these bypass capacitors are essential to low noise operation
of the ADC, and the foil width for these tracks should be
as wide as possible. Also, since any potential difference in
grounds between the signal source and ADC appears as
an error voltage in series with the input signal, attention
should be paid to reducing the ground circuit impedance
as much as possible. The digital output latches and the
onboard sampling clock have been placed on the digital
ground plane. The two ground planes are tied together at
the power supply ground connection.
G Package
28-Lead Plastic SSOP (5.3mm)
(Reference LTC DWG # 05-08-1640)
0.09 – 0.25
(.0035 – .010)
0° – 8°
0.55 – 0.95
(.022 – .037)
5.00 – 5.60**
(.197 – .221)
G28 SSOP 0204
7.40 – 8.20
(.291 – .323)
1234
5
6
7
8 9 10 11 12 1413
9.90 – 10.50*
(.390 – .413)
2526 22 21 20 19 18
17
16 1523242728
2.0
(.079)
MAX
0.05
(.002)
MIN
0.65
(.0256)
BSC
0.22 – 0.38
(.009 – .015)
TYP
MILLIMETERS
(INCHES)
DIMENSIONS DO NOT INCLUDE MOLD FLASH. MOLD FLASH
SHALL NOT EXCEED .152mm (.006") PER SIDE
DIMENSIONS DO NOT INCLUDE INTERLEAD FLASH. INTERLEAD
FLASH SHALL NOT EXCEED .254mm (.010") PER SIDE
*
**
NOTE:
1. CONTROLLING DIMENSION: MILLIMETERS
2. DIMENSIONS ARE IN
3. DRAWING NOT TO SCALE
0.42 ±0.03 0.65 BSC
5.3 – 5.7
7.8 – 8.2
RECOMMENDED SOLDER PAD LAYOUT
1.25 ±0.12