tb436

EL5825 Rev A. Demo Board
®
Technical Brief
December 22, 2004
Description
The EL5825 REV A demo board is designed for
demonstrating the operation of Intersil's high precision
reference voltage generator, the EL5825. For a detailed
description, please refer to the data sheet. A parallel port
Visual Basic program is used to drive the SDI, SCLK, and
ENA pins for the channel and voltage selection.
8-Channel Circuit Description
Please refer to Figure 1 and the single demo board circuit.
On the board, VS is the supply voltage (5V to 16V). VSD is
the digital supply (3.3V to 5V). REFH is the high reference
output voltage (REFL < REFH ≤ VS). REFL is the low
reference output voltage (0 ≤ REFL < REFH). REFH and
REFL voltage are supplied by EL5220 and can be adjusted
by the 10K Trim POT.
R20 to R23, R26, R28 to R30 are 1.5k load resistors. C6, C11,
and C21 are the 0.1µF local bypass capacitors.
C1 to C10 are 180pF load capacitors. If bigger capacitors are
required, then, a serial resistor (20Ω to 100Ω) must be used
between the output and the capacitor.
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"Send" button outputs a 16-bit single channel data. The
"SendAll" button outputs 8-channel data. The "Write to File"
button can save the setup to a file and the "Read From File"
button can load the setup from the file.
Dual Board Control (16-Channel)
When you click the EL5825dual.exe icon on your Windows
desktop, a dual board control panel shows up (See Figure 4).
On the panel, you can set your reference high and reference
low voltage for board one and board two. You can set the
voltage for each channel. On our 16-channel configuration,
the reference high on board two is shorted to reference low
in board one. So, the VREF Low 1-8 must have the same
value as VREF High 9-16. The "Send" button outputs a 32 bit
dual channel data. The "SendAll" button outs 16 channel
data. The "Write to File" button can save the setup to a file
and the "Read From File" button can load the setup from the
file. For the dual board connection, the OSC pins are shorted
together. If no external oscillator is used, then board one can
set to the external oscillator mode and use the internal
oscillator output in board two.
16-Channel Circuit Description
A 16-channel voltage reference generator can be simply
formed by connecting two single boards together (See
Figure 2). The resistors and capacitors connections are the
same as the 8-channel connection for each board. Board
one contains channel 1 to channel 8 and board two contains
channel 9 to channel 16. The parallel port on board two
drives the logic signals. The SDO pin on board two is
shorted to SDI pin on board one. The REFL pin in board one
is shorted to REFH in board two. Those make the channels
in board one, high voltage references, and the channels in
board two, low voltage references.
Control Software
For 8-channel and 16-channel configuration, two separated
Visual Basic programs are used to drive the parallel port to
output the data stream for SDI, SCLK, and ENA inputs. To
install the software, just copy the EL5825.exe and
EL5825dual.exe to your Windows desktop. If your operating
system is Win98, copy the files "ntport.dll and zntport.sys" to
the directory: C:\windows\system. If your operating system is
NT or Win2000, copy the files "ntport.dll and zntport.sys" to
the directory: C:\winnt\system32.
Single Board Control (8-Channel)
Click the EL5825.exe icon on your windows desktop, a
single board control panel shows up (See Figure 3). On the
panel, you can set your reference high and reference low
voltage. You can set the voltage for each channel. The
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 321-724-7143 | Intersil (and design) is a registered trademark of Intersil Americas Inc.
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Technical Brief 436
EL5825IL Rev A. Demo Board Circuit
C16
REFL
VSD
GND
VS
SDI
SCLK
NC
LOAD
NC
EXT OSC
J1
VSD
D4
4.7µF
BAT42
VS
C17
4.7µF
REFL
EXT OSC
LOAD
C24
C22
OPEN
OPEN
REFH
SDI
C25
OPEN
SCLK
0Ω
180pF
R3
20
21
22
24
1
VSD
R5
19
C3
0Ω
C6
0.1µF
2
18
3
17
C6 4
16
5
15
6
14
7
13
180pF
C11
0.1µF
0Ω
180pF
R23
1.5kΩ
C5
R26
180pF 1.5kΩ
R9
0Ω
180pF
R11
0Ω
BG
REFL
OUTC
VS
OUTD
VSD
OUTF
OUTH
R28
180pF 1.5kΩ
C9
C21
0.1µF
OUTB
NC
C8
R10
0Ω
REFH
OUTG
0Ω
12
C20
10pF
11
REFL
10
C9
10pF
J2
OUTA
OUTE
C4
R8
REFH
1K
2 R24
14 1K
LOAD
1
R22
1.5kΩ
R7
VS
8
22
9
21
8
20
7
19
6
18
5
17
SCLK
4 R27
16 1K SDI
3 R25
23
180pF
9
24
11
23
R21
1.5kΩ
C2
0Ω
JUMPER
S1
25
OPEN
R20
1.5kΩ
C1
R1
C19
NC
NC
R29
1.5kΩ
NC
EXT_OSC
C10
180pF
R30
1.5kΩ
SDO
SDI
NC
D1
LOAD
D2
VSD
D3
2
REFH
VSD
GND
VS
SDO
SCLK
NC
LOAD
NC
EXT OSC
BAT42
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Technical Brief 436
C16
4.7µF
REFL
VSD
GND
VS
SDI
SCLK
NC
LOAD
J1
VSD
NC
EXT OSC
EL5825IRE Rev A. Demo Board Circuit
D4
BAT42
VS
C17
4.7µF
REFL
EXT OSC
C24
C22
OPEN
LOAD
OPEN
REFH
SDI
C25
C19
OPEN
OPEN
SCLK
1 SCLK
SDI 24
2 SDO
ENA 23
3 OSC
OUTA 22
4 VSD
OUTB 21
5 NC
OUTC 20
JUMPER
S1
25
C6
22
9
21
8
20
7
19
6
18
5
17
4 R27 SCLK
16 1K
SDI
3 R25
1K
2 R24 LOAD
14 1K
1
R20
1.5K
C2
R21
180pF
1.5K
C3
R22
180pF
1.5K
C4
R23
R1
VSD
24
11
23
C1
180pF
0.1µF
0
R5
6 VS
0.1µF
GND 18
R7
8 REFL
OUTE 17
9 GND
OUTF 16
180pF
R9
C9 10pF
R10
REFL
C20
10pF
10 NC
OUTG 15
11 BG
OUTH 14
12 NC
NC 13
REFL
OUTC
VS
OUTD
VSD
OUTF
OUTG
C5
R26
180pF
1.5K
C7
R28
180pF
1.5K
C8
R29
180pF
1.5K
OUTH
0
0
NC
NC
0
R11
0
NC
NC
EXT_OSC
BG
C21
1.5K
0
R8
REFH
OUTB
OUTE
OUTD 19
7 REFH
REFH
0
0
VS
C11
R3
J2
OUTA
0.1µF
C10
R30
180pF
1.5K
SDI
SDO
SCLK
NC
D1
LOAD
D2
VSD
D3
BAT42
3
REFH
VSD
GND
VS
SDO
SCLK
NC
LOAD
NC
EXT OSC
J4
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Technical Brief 436
EL5825IY Rev A. Demo Board Circuit
EL5220IY (MSOP-8)
VS+
JP1
REFH
R16
0Ω
10kΩ
1
JP1
2
R18
10kΩ
BG
8
7
-
REFL
0Ω
+
3
-
6
+
4
VS-
5
R17
R19
10kΩ
10kΩ
CONTROLS REFH AND REFL FOR EL5825I
J1
Connector supplies Power, reference voltages
and daisy chained control signals for a second
board
Test Points or Power Connections
J2
Output Voltages
connector may also be
used for Power, High &
Low Reference
Voltages, also serial
control Interface.
J3
Connector to PC,
connects to Parallel
port
REFH and REFL
provided by EL5220.
J4
Connector For second
board
FIGURE 1. 8-CHANNEL
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Technical Brief 436
EL5825I Rev A. Demo Board Circuit
VS and VSD for BOTH
Board One and Board
Two
Board Two
Channel 9 to Channel 16
J1
PC Connector to Parallel
Port
J2
Output Voltages, connector may
also be used for Power, High &
Low Reference Voltages, also
Serial Control Interface
Power Inputs REFH and
REFL, for Board Two Only.
Supplied by EL5220
Board One
Channel 1 to Channel 8
J1
PC Connector not used
for Board One
J2
Output Voltages, connector may
also be used for Power, High &
Low Reference Voltages, also
Serial Control Interface
Power Input REFH for
Board One Only Provide
by EL5220
FIGURE 2. 16-CHANNEL
5
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Technical Brief 436
FIGURE 3.
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Technical Brief 436
FIGURE 4.
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Intersil products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without
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reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result
from its use. No license is granted by implication or otherwise under any patent or patent rights of Intersil or its subsidiaries.
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