Maxim MAX12527 manual Interchannel Characteristics, Internal Reference Refout, Vcom

MAX12527

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

ELECTRICAL CHARACTERISTICS (continued)

(VDD = 3.3V, OVDD = 2.0V, GND = 0, REFIN = REFOUT (internal reference), CL ≈ 10pF at digital outputs, VIN = -0.5dBFS (differen- tial), DIFFCLK/SECLK = OVDD, PD = GND, SHREF = GND, DIV2 = GND, DIV4 = GND, G/T = GND, fCLK = 65MHz, TA = -40°C to

+85°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1)

PARAMETER	SYMBOL	CONDITIONS	MIN	TYP	MAX	UNITS
Overdrive Recovery Time		±10% beyond full-scale		1		Clock
						cycle
INTERCHANNEL CHARACTERISTICS
Crosstalk Rejection		fINA or fINB = 70MHz at -0.5dBFS		90		dB
		fINA or fINB = 175MHz at -0.5dBFS		85
Gain Matching				±0.01	±0.1	dB
Offset Matching				±0.01		%FSR
INTERNAL REFERENCE (REFOUT)
REFOUT Output Voltage	VREFOUT		2.000	2.048	2.080	V
REFOUT Load Regulation		-1mA < IREFOUT < +1mA		35		mV/mA
REFOUT Temperature Coefficient	TCREF			±50		ppm/°C
REFOUT Short-Circuit Current		Short to VDD—sinking		0.24		mA
		Short to GND—sourcing		2.1
BUFFERED REFERENCE MODE (REFIN is driven by REFOUT or an external 2.048V single-ended reference source;
VREFAP/VREFAN/VCOMA and VREFBP/VREFBN/VCOMB are generated internally)
REFIN Input Voltage	VREFIN			2.048		V
REFIN Input Resistance	RREFIN			>50		MΩ
COM_ Output Voltage	VCOMA	VDD / 2	1.60	1.65	1.70	V
	VCOMB
REF_P Output Voltage	VREFAP	VDD / 2 + (VREFIN x 3/8)		2.418		V
	VREFBP
REF_N Output Voltage	VREFAN	VDD / 2 - (VREFIN x 3/8)		0.882		V
	VREFBN
Differential Reference Voltage	VREFA	VREFA = VREFAP - VREFAN	1.440	1.536	1.590	V
	VREFB	VREFB = VREFBP - VREFBN
Differential Reference	TCREF			±25		ppm/°C
Temperature Coefficient

UNBUFFERED EXTERNAL REFERENCE (REFIN = GND, VREFAP/VREFAN/VCOMA and VREFBP/VREFBN/VCOMB are applied externally, VCOMA = VCOMB = VDD / 2)

REF_P Input Voltage	VREFAP	VREF_P	- VCOM	+0.768	V
	VREFBP
REF_N Input Voltage	VREFAN	VREF_N	- VCOM	-0.768	V
	VREFBN
COM_ Input Voltage	VCOM	VDD / 2		1.65	V
Differential Reference Voltage	VREFA	VREF_ = VREF_P - VREF_N = VREFIN x 3/4		1.536	V
	VREFB

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