Rainbow-electronics MAX19515 Manual do Utilizador descarregar pdf (Página 30)

MAX19515

Dual-Channel, 10-Bit, 65Msps ADC

30 ______________________________________________________________________________________

Integrated Voltage Regulator

The MAX19515 includes an integrated self-sensing lin-

ear voltage regulator on the analog supply (AVDD). See

Figure 17. When the applied voltage on AVDD is below

2V, the voltage regulator is bypassed, and the core

analog circuitry operates from the externally applied

voltage. If the applied voltage on AVDD is higher than

2V, the regulator bypass switches off, and voltage reg-

ulator mode is enabled. When in voltage regulation

mode, the internal-core analog circuitry operates from a

stable 1.8V supply voltage provided by the regulator.

The regulator provides an output voltage of 1.8V over a

2.3V to 3.5V AVDD input-voltage range. Since the

power-supply current is constant over this voltage

range, analog power dissipation is proportional to the

applied voltage.

Power-On and Reset

The user-programmable register default settings and

other factory-programmed settings are stored in non-

volatile memory. Upon device power-up, these values are

loaded into the control registers. This operation occurs

after application of supply voltage to AVDD and applica-

tion of an input clock signal. The register values are

retained as long as AVDD is applied. While AVDD is

applied, the registers can be reset, which will overwrite all

user-programmed registers with the default values. This

reset operation can be initiated by software command

through the serial-port interface or by hardware control

using the SPEN and SHDN inputs. The reset time is pro-

portional to the ADC clock period and requires 130µs at

65Msps. Table 9 summarizes the reset methods.

SAMPLING RATE (Msps) V

OVDD

= 3.3V

FROM TO DA_BYPASS DLY_HALF_T DTIME<2:0> DCLKTIME<2:0>

30 63 1 0 000 000

63 65 1 0 101 101

Table 7. Recommended Timing Adjustments (V

OVDD

= 3.3V)

DTIME<2:0> ALLOWED DCLKTIME<2:0> SETTINGS

111 (-3T/16) 111 (-3T/16)

110 (-2T/16) 110 (-2T/16); 111 (-3T/16)

101 (-1T/16) 101 (-1T/16); 110 (-2T/16); 111 (-3T/16)

000 (nominal) 000 (nominal); 101 (-1T/16); 110 (-2T/16); 111 (-3T/16)

001 (+1T/16) 001 (+1T/16); 000 (nominal); 101 (-1T/16); 110 (-2T/16); 111 (-3T/16)

010 (+2T/16) 010 (+2T/16); 001 (+1T/16); 000 (nominal); 101 (-1T/16); 110 (-2T/16); 111 (-3T/16)

011 (+3T/16) 011 (+3T/16); 010 (+2T/16); 001 (+1T/16); 000 (nominal); 101 (-1T/16); 110 (-2T/16); 111 (-3T/16)

Table 8. Allowed Settings of DCLKTIME and DTIME for DA_BYPASS = 1

RESET MODE DESCRIPTION

Power-On Reset

Upon power-up (AVDD supply voltage and clock signal applied), the POR (power-on-reset) circuit initiates a

Software Reset Write data 5Ah to address 0Ah to initiate register reset.

Hardware Reset A register reset is initiated by the falling edge on the SHDN pin when SPEN is high.

Table 9. Reset Methods

1 2 ... 25 26 27 28 29 30 31 32 33 34

MAX19515 1

Comentários a estes Manuais

Sem comentários

Rainbow-electronics MAX19515 Manual do Utilizador Página 30

Comentários a estes Manuais

Manuais e produtos relacionados com Sensores Rainbow-electronics MAX19515