Specifications

Altera Corporation 31
EPXA1 Development Board Hardware Reference Manual
A voltage regulator regulates the main supplies for the board. The input
supply is unregulated 12 V (±5%), which is reduced to 3.3 V for the I/O
pins and to 1.8 V for the processor core. Voltage regulator U5 reduces the
input to 5 V and distributes it to a pin on the expansion headers. The
unregulated input is also routed to a pin on the expansion headers.
The maximum current permitted on the expansion headers depends on
the input voltage: for 3.3 V, it is 500 mA, and for 5 V, it is 50 mA. If the
input supply is 12 V, the maximum current per header depends on how
much power is consumed by the rest of the board, but should not exceed
100 mA.
Three function-specific status LEDs indicate the presence of 1.8 V, 3.3 V,
and 5 V to the board, as listed in Table 18 on page 31.
Tables 19 through 22 list the estimated maximum power-supply
requirements for the development board modules.
 The typical power-supply requirement for the development
board is 250 mA/500 mA.
Table 18. Power Supply LEDs
Board Reference Signal Description
D14 VCC_1V8 Indicates the presence of 1.8 V
D13 VCC_3V3 Indicates the presence of 3.3 V
D12 VCC_5V Indicates the presence of 5 V
Table 19. 12-V Supply Requirements
Module Max mA
Expansion headers 100 per header
Table 20. 5-V Supply Requirements
Module Max mA
CLK_REF Alternative crystal oscillator—75
Expansion headers
50 per header