SU753

Block diagram

Power supply

The internal DC-DC Converter can deliver max about 80 mA. If more needed, please use the external power supply.

The MAX14900E chip can drive up to 100 mA per channel, the operational amplifier about 50 mA (but there are serial resistors of 100 Ohm there!). Use the MAX channels for more current.

The voltage supply of the MAX14900E chip can be either from the DC-DC Converter or from the external power supply input and should not exceed 36V!

The voltage supply of the 2 operational amplifier channels can be different from the rest -> either DC-DC-Converter or External -> direct or through the own voltage regulator. The max voltage supply of the operational amplifier is 32V! The max input voltage of its voltage regulator is 30V!

Current consumption without load

Current consumption from the external power supply without load is: Op Ampl 2-6 mA, MAX14900E <0.5 mA. The internal DC-DC converter consumes about 50 mA unloaded. In total, when configured to use the internal DC-DC converter, unloaded about 57 mA. Fully loaded, the DC-DC converter consumes about 0.5 A.

SPI Interface and diagnostics

The MAX chip has a SPI interface, which is used to read back the status (on | off | failure), see the datasheet for more details. The status of the Op Ampl channels can not be read back!

Pinout

SU753 pin table (direction shown for the SU board!)

 power    in            +5V  2    1 +5V             in     power
    NC     -              -  4    3 -               -      NC
    NC     -              -  6    5 -               -      NC
    NC     -              -  8    7 -               -      NC
    NC     -              - 10    9 -               -      NC
    NC     -              - 12   11 -               -      NC
 LVTTL    in       DATA<10> 14   13 -               -      NC
 LVTTL    in        DATA<9> 16   15 -               -      NC
 LVTTL    in             EN 18   17 -               -      NC
 LVTTL    in          SRIAL 20   19 -               -      NC
 LVTTL    in        DATA<8> 22   21 FAULT           out    LVTTL
 LVTTL    in        DATA<6> 24   23 DATA<7>         in     LVTTL
 LVTTL    in            CSn 26   25 DATA<5>         in     LVTTL
 LVTTL    in            SDI 28   27 SCLK            in     LVTTL
 LVTTL    in        DATA<4> 30   29 SDO             out    LVTTL
 LVTTL    in        DATA<2> 32   31 DATA<3>         in     LVTTL
 LVTTL    in         PUSHPL 34   33 DATA<1>         in     LVTTL
 power    in            GND 36   35 GND             in     power

Channels 9..10

The two Op Ampl channels 9..10 use only pins DATA<9> and DATA<10>. The other pins control the MAX14900E chip and thus only channels 1..8!

Channels 1..8

Some pins have different meaning in SERIAL mode. The present LogicBox designs use the parallel mode (SRIAL=0).

FAULT is open drain and active low, global for the MAX chip.

PSUSHPL is global for the MAX chip and should be 1 for normal operation. Otherwise the MAX outputs will only pull high!

EN is a global pin and should be 1 for normal operation. Single channels can not be enabled/disabled.

The SPI interface in parallel mode is used only to read back the status (on|off|fail) of channels 1..8.

Measurements

Note: the operational amplifier was supplied with 18.5V from its voltage regulator in these tests. The MAX14900E chip was supplied directly from the DC-DC-converter.

One channel per group, no load

Rising edge

Falling edge

MAX14900E (1..8), comparison with/without load of 10k || 100pF

Rising edge

Falling edge

Op Ampl (9..10), comparison with/without load of 10k || 100pF

Rising edge

Falling edge