Maxim MAX12527 manual Equivalent Binary, Dor, D11A-D0A D11B-D0B CODE10

REF_P

Dual, 65Msps, 12-Bit, IF/Baseband ADC

externally isolates it from heavy capacitive loads. Refer to the MAX12527 EV Kit schematic for recommendations of how to drive the DAV signal through an external buffer.

Data Out-of-Range Indicator The DORA and DORB digital outputs indicate when the analog input voltage is out of range. When DOR_ is high, the analog input is out of range. When DOR_ is low, the analog input is within range. The valid differential input range is from (VREF_P - VREF_N) x 2/3 to (VREF_N -

V ) x 2/3. Signals outside of this valid differential range cause DOR_ to assert high as shown in Table 1.

DOR is synchronized with DAV and transitions along with the output data D11–D0. There is an 8 clock-cycle latency in the DOR function as is with the output data (Figure 5). DOR_ is high impedance when the MAX12527 is in power-down (PD = high). DOR_ enters a high-impedance state within 10ns after the rising edge of PD and becomes active 10ns after PD’s falling edge.

Digital Output Data and Output Format Selection The MAX12527 provides two 12-bit, parallel, tri-state output buses. D0A/B–D11A/B and DORA/B update on

the falling edge of DAV and are valid on the rising edge of DAV.

The MAX12527 output data format is either Gray code or two’s complement depending on the logic input G/T. With G/T high, the output data format is Gray code. With G/T low, the output data format is set to two’s com- plement. See Figure 8 for a binary-to-Gray and Gray-to- binary code conversion example.

The following equations, Table 3, Figure 6, and Figure 7 define the relationship between the digital output and the analog input.

Gray Code (G/T = 1):

VIN_P - VIN_N = 2/3 x (VREF_P - VREF_N) x 2 x

(CODE10 - 2048) / 4096

Two’s Complement (G/T = 0):

VIN_P - VIN_N = 2/3 x (VREF_P - VREF_N) x 2 x CODE10 / 4096

where CODE10 is the decimal equivalent of the digital output code as shown in Table 3.

MAX12527

Table 3. Output Codes vs. Input Voltage

GRAY-CODE OUTPUT CODE				TWO’S COMPLEMENT OUTPUT CODE
		(G/T = 1)				(G/T = 0)
		HEXADECIMAL	DECIMAL			HEXADECIMAL	DECIMAL	VIN_P - VIN_N
			EQUIVALENT				EQUIVALENT
BINARY		EQUIVALENT		BINARY		EQUIVALENT		VREF_P = 2.418V
D11A–D0A	DOR	OF	OF	D11A–D0A	DOR	OF	OF	VREF_N = 0.882V
			D11A–D0A				D11A–D0A
D11B–D0B		D11A–D0A		D11B–D0B		D11A–D0A
			D11B–D0B				D11B–D0B
		D11B–D0B				D11B–D0B
			(CODE10)				(CODE10)
								>+1.0235V
1000 0000 0000	1	0x800	+4095	0111 1111 1111	1	0x7FF	+2047	(DATA OUT OF
								RANGE)
1000 0000 0000	0	0x800	+4095	0111 1111 1111	0	0x7FF	+2047	+1.0235V
1000 0000 0001	0	0x801	+4094	0111 1111 1110	0	0x7FE	+2046	+1.0230V
1100 0000 0011	0	0xC03	+2050	0000 0000 0010	0	0x002	+2	+0.0010V
1100 0000 0001	0	0xC01	+2049	0000 0000 0001	0	0x001	+1	+0.0005V
1100 0000 0000	0	0xC00	+2048	0000 0000 0000	0	0x000	0	+0.0000V
0100 0000 0000	0	0x400	+2047	1111 1111 1111	0	0xFFF	-1	-0.0005V
0100 0000 0001	0	0x401	+2046	1111 1111 1110	0	0xFFE	-2	-0.0010V
0000 0000 0001	0	0x001	+1	1000 0000 0001	0	0x801	-2047	-1.0235V
0000 0000 0000	0	0x000	0	1000 0000 0000	0	0x800	-2048	-1.0240V
								<-1.0240V
0000 0000 0000	1	0x000	0	1000 0000 0000	1	0x800	-2048	(DATA OUT OF
								RANGE)

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