CDK1307 EXAR | Alldatasheet
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Technical content
CDK1307 Ultra Low Power, 20/40/65/80MSPS, 12/13-bit ADCs Rev 1B CDK1307 Ultra Low Power, 20/40/65/80MSPS, 12/13-bit Analog-to-Digital Converters (ADCs) Exar Corporation www.exar.com 48720 Kato Road, Fremont CA 94538, USA Tel. +1 510 668-7000 - Fax. +1 510 668-7001
FEATURES
n 20/40/65/80MSPS max sampling rate n Ultra-Low Power Dissipation: 19/33/50/60mW n 72.4dB SNR at 80MSPS and 8MHz FIN n Internal reference circuitry n 1.8V core supply voltage n 1.7 – 3.6V I/O supply voltage n Parallel CMOS output n 40-pin QFN package n Pin compatible with CDK1308
APPLICATIONS
The CDK1307 is a high performance ultra low power Analog-to-Digital Converter (ADC). The ADC employs internal reference circuitry, a CMOS control interface and CMOS output data, and is based on a proprietary struc- ture. Digital error correction is employed to ensure no missing codes in the complete full scale range. Two idle modes with fast startup times exist. The entire chip can either be put in Standby Mode or Power Down mode. The two modes are optimized to allow the user to select the mode resulting in the smallest possible energy consumption during idle mode and startup. The CDK1307 has a highly linear THA optimized for frequencies up to Nyquist. The differential clock interface is optimized for low jitter clock sources and supports LVDS, LVPECL, sine wave, and CMOS clock inputs. Functional Block Diagram
Ordering Information
Part Number Speed Package Pb-Free RoHS Compliant Operating Temperature Range Packaging Method CDK1307AILP40 20MSPS QFN-40 Yes Yes -40°C to +85°C Tray CDK1307BILP40 40MSPS QFN-40 Yes Yes -40°C to +85°C Tray CDK1307CILP40 65MSPS QFN-40 Yes Yes -40°C to +85°C Tray CDK1307DILP40 80MSPS QFN-40 Yes Yes -40°C to +85°C Tray Moisture sensitivity level for all parts is MSL-2A.
CDK1307 Ultra Low Power, 20/40/65/80MSPS, 12/13-bit ADCs Rev 1B ©2009-2013 Exar Corporation 2/15 Rev 1B Pin Assignments Pin No. Pin Name Description 0 VSS Ground connection for all power domains. Exposed pad 1, 11, 16 DVDD Digital and I/O-ring pre driver supply voltage, 1.8V
2 CM_EXT Common Mode voltage output
3, 4, 7 AVDD Analog supply voltage, 1.8V 5, 6 IP, IN Analog input (non-inverting, inverting) 8 DVDDCLK Clock circuitry supply voltage, 1.8V
9 CLKP Clock input, non-inverting (format: LVDS, LVPECL, CMOS/TTL, Sine Wave)
10 CLKN Clock input, inverting. For CMOS input on CLKP, Connect CLKN to ground 12 CLK_EXT_EN CLK_EXT signal enabled when low (zero). Tristate when high. 13 DFRMT Data format selection. 0: Offset Binary, 1: Two's Complement 14 PD_N Full chip Power Down mode when Low. All digital outputs reset to zero. After chip power up always apply Power Down mode before using Active Mode to reset chip. 15 OE_N Output Enable. Tristate when high 17, 18, 25, 26, 36, 37 OVDD I/O ring post-driver supply voltage. Voltage range 1.7 to 3.6V
19 D_0 Output Data (LSB, 13-bit output or 1Vpp full scale range)
20 D_1 Output Data (LSB, 12-bit output 2Vpp full scale range)
21 D_2 Output Data
22 D_3 Output Data
2CM_EXT 4AVDD 3AVDD 1DVDD 6IN 8DVDDCLK 7AVDD 10CLKN 9CLKP 5IP
29 D_6
27 CLK_EXT
28 D_5
30 D_7
25 OVDD
23 D_4
24 ORNG
21 D_2
22 D_3
26 OVDD
12CLK_EXT_EN 14PD_N 13DFRMT 11DVDD 16DVDD 18OVDD 17OVDD 20D_1 19D_0 15OE_N
39 CM_EXTBC_0
37 OVDD
38 CM_EXTBC_1
40 SLP_N
35 D_12
33 D_10
34 D_11
31 D_8
32 D_9
36 OVDD
CDK1307 Ultra Low Power, 20/40/65/80MSPS, 12/13-bit ADCs Rev 1B ©2009-2013 Exar Corporation 3/15 Rev 1B Pin No. Pin Name Description
23 D_4 Output Data
24 ORNG Out of Range flag. High when input signal is out of range 27 CLK_EXT Output clock signal for data synchronization. CMOS levels
28 D_5 Output Data
29 D_6 Output Data
30 D_7 Output Data
31 D_8 Output Data
32 D_9 Output Data
33 D_10 Output Data
34 D_11 Output Data (MSB for 1Vpp full scale range, see Reference Voltages section)
35 D_12 Output Data (MSB for 2Vpp full scale range)
38, 39 CM_EXTBC_1, CM_EXTBC_0 Bias control bits for the buffer driving pin CM_EXT 00: OFF 01: 50μA 10: 500μA 11: 1mA
40 SLP_N Sleep Mode when low
Pin Assignments (Continued)
CDK1307 Ultra Low Power, 20/40/65/80MSPS, 12/13-bit ADCs Rev 1B ©2009-2013 Exar Corporation 4/15 Rev 1B Absolute Maximum Ratings The safety of the device is not guaranteed when it is operated above the “Absolute Maximum Ratings”. The device should not be operated at these “absolute” limits. Adhere to the “Recommended Operating Conditions” for proper device function. The information contained in the Electrical Characteristics tables and Typical Performance plots reflect the operating conditions noted on the tables and plots. Parameter Min Max Unit AVDD -0.3 +2.3 V DVDD -0.3 +2.3 V AVSS, DVSSCK, DVSS, OVSS -0.3 +0.3 V OVDD, OVSS -0.3 +3.9 V CLKP, CLKN -0.3 +3.9 V Analog inputs and outpts (IPx, INx) -0.3 +2.3 V Digital inputs -0.3 +3.9 V Digital outputs -0.3 +3.9 V Reliability Information Parameter Min Typ Max Unit Junction Temperature TBD °C Storage Temperature Range -60 +150 °C Lead Temperature (Soldering, 10s) J-STD-020 ESD Protection Product QFN-40 Human Body Model (HBM) 2kV Recommended Operating Conditions Parameter Min Typ Max Unit Operating Temperature Range -40 +85 °C
CDK1307 Ultra Low Power, 20/40/65/80MSPS, 12/13-bit ADCs Rev 1B ©2009-2013 Exar Corporation 5/15 Rev 1B
Electrical Characteristics
(AVDD = 1.8V, DVDD = 1.8V, DVDDCLK = 1.8V, OVDD = 2.5V, 20/40/65/80MSPS clock, 50% clock duty cycle, -1dBFS 8MHz input signal, 13-bit output, unless otherwise noted) Symbol Parameter Conditions Min Typ Max Units DC Accuracy No Missing Codes Guaranteed Offset Error Midscale offset 1 mV Gain Error Full scale range deviation from typical -6 6 %FS DNL Differential Non-Linearity 12-bit level ±0.2 LSB INL Integral Non-Linearity 12-bit level ±0.6 LSB VCMO Common Mode Voltage Output VAVDD/2 V Analog Input VCMI Input Common Mode Analog input common mode voltage VCM -0.1 VCM +0.2 V VFSR Full Scale Range, Normal Differential input voltage range, 2.0 Vpp Full Scale Range, Option Differential input voltage range, 1V (see section Reference Voltages)
1.0 Vpp
Input Capacitance Differential input capacitance 2 pF Bandwidth Input bandwidth, full power 500 MHz Power Supply AVDD, DVDD Core Supply Voltage Supply voltage to all 1.8V domain pins. See Pin Configuration and Description 1.7 1.8 2.0 V OVDD I/O Supply Voltage Output driver supply voltage (OVDD). Must be higher than or equal to Core Supply Voltage (VOVDD ≥ VOCVDD) 1.7 2.5 3.6 V
CDK1307 Ultra Low Power, 20/40/65/80MSPS, 12/13-bit ADCs Rev 1B ©2009-2013 Exar Corporation 6/15 Rev 1B (AVDD = 1.8V, DVDD = 1.8V, DVDDCLK = 1.8V, OVDD = 2.5V, 20MSPS clock, 50% clock duty cycle, -1dBFS 8MHz input signal, 13-bit output, unless otherwise noted) Symbol Parameter Conditions Min Typ Max Units Performance SNR Signal to Noise Ratio FIN = 2MHz 72.5 dBFS FIN = 8MHz 71.5 72.2 dBFS FIN ≃ FS/2 72.1 dBFS FIN = 20MHz 71.6 dBFS SINAD Signal to Noise and Distortion Ratio FIN = 2MHz 72.4 dBFS FIN = 8MHz 71 72.0 dBFS FIN ≃ FS/2 71.7 dBFS FIN = 20MHz 71.3 dBFS SFDR Spurious Free Dynamic Range FIN = 2MHz 87 dBc FIN = 8MHz 75 85 dBc FIN ≃ FS/2 80 dBc FIN = 20MHz 80 dBc HD2 Second order Harmonic Distortion FIN = 2MHz -90 dBc FIN = 8MHz -85 -95 dBc FIN ≃ FS/2 -95 dBc FIN = 20MHz -95 dBc HD3 Third order Harmonic Distortion FIN = 2MHz -87 dBc FIN = 8MHz -75 -85 dBc FIN ≃ FS/2 -80 dBc FIN = 20MHz -80 dBc ENOB Effective number of Bits FIN = 2MHz 11.7 bits FIN = 8MHz 11.5 11.7 bits FIN ≃ FS/2 11.6 bits FIN = 20MHz 11.6 bits Power Supply AIDD Analog Supply Current 7.8 mA DIDD Digital Supply Current Digital core supply 1.0 mA OIDD Output Driver Supply 2.5V output driver supply, sine wave input, FIN = 1MHz, CLK_EXT enabled 1.7 mA 2.5V output driver supply, sine wave input, FIN = 1MHz, CLK_EXT disabled 1.3 mA Analog Power Dissipation 14.0 mW Digital Power Dissipation OVDD = 2.5V, 5pF load on output bits, FIN = 1MHz, CLK_EXT disabled 5.1 mW Total Power Dissipation OVDD = 2.5V, 5pF load on output bits, FIN = 1MHz, CLK_EXT disabled 19.1 mW Power Down Dissipation 9.9 µW Sleep Mode Power Dissipation, Sleep mode 9.2 mW Clock Inputs Max. Conversion Rate 20 MSPS Min. Conversion Rate 15 MSPS
CDK1307 Ultra Low Power, 20/40/65/80MSPS, 12/13-bit ADCs Rev 1B ©2009-2013 Exar Corporation 7/15 Rev 1B (AVDD = 1.8V, DVDD = 1.8V, DVDDCLK = 1.8V, OVDD = 2.5V, 40MSPS clock, 50% clock duty cycle, -1dBFS 8MHz input signal, 13-bit output, unless otherwise noted) Symbol Parameter Conditions Min Typ Max Units Performance SNR Signal to Noise Ratio FIN = 2MHz 72.5 dBFS FIN = 8MHz 71.9 72.7 dBFS FIN ≃ FS/2 72 dBFS FIN = 30MHz 70.8 dBFS SINAD Signal to Noise and Distortion Ratio FIN = 2MHz 71.7 dBFS FIN = 8MHz 71 72.1 dBFS FIN ≃ FS/2 71.5 dBFS FIN = 30MHz 71.2 dBFS SFDR Spurious Free Dynamic Range FIN = 2MHz 81 dBc FIN = 8MHz 75 81 dBc FIN ≃ FS/2 80 dBc FIN = 30MHz 80 dBc HD2 Second order Harmonic Distortion FIN = 2MHz -90 dBc FIN = 8MHz -85 -95 dBc FIN ≃ FS/2 -95 dBc FIN = 30MHz -90 dBc HD3 Third order Harmonic Distortion FIN = 2MHz -81 dBc FIN = 8MHz -81 dBc FIN ≃ FS/2 -75 -80 dBc FIN = 30MHz -80 dBc ENOB Effective number of Bits FIN = 2MHz 11.6 bits FIN = 8MHz 11.5 11.7 bits FIN ≃ FS/2 11.6 bits FIN = 30MHz 11.4 bits Power Supply AIDD Analog Supply Current 13.4 mA DIDD Digital Supply Current Digital core supply 1.7 mA OIDD Output Driver Supply 2.5V output driver supply, sine wave input, FIN = 1MHz, CLK_EXT enabled 3.3 mA 2.5V output driver supply, sine wave input, FIN = 1MHz, CLK_EXT disabled 2.4 mA Analog Power Dissipation 24.1 mW Digital Power Dissipation OVDD = 2.5V, 5pF load on output bits, FIN = 1MHz, CLK_EXT disabled 9.1 mW Total Power Dissipation OVDD = 2.5V, 5pF load on output bits, FIN = 1MHz, CLK_EXT disabled 33.2 mW Power Down Dissipation 9.7 µW Sleep Mode Power Dissipation, Sleep mode 14.2 mW Clock Inputs Max. Conversion Rate 40 MSPS Min. Conversion Rate 20 MSPS
CDK1307 Ultra Low Power, 20/40/65/80MSPS, 12/13-bit ADCs Rev 1B ©2009-2013 Exar Corporation 8/15 Rev 1B (AVDD = 1.8V, DVDD = 1.8V, DVDDCLK = 1.8V, OVDD = 2.5V, 65MSPS clock, 50% clock duty cycle, -1dBFS 8MHz input signal, 13-bit output, unless otherwise noted) Symbol Parameter Conditions Min Typ Max Units Performance SNR Signal to Noise Ratio FIN = 8MHz 71.6 72.6 dBFS FIN = 20MHz 71.8 dBFS FIN ≃ FS/2 71.5 dBFS FIN = 40MHz 70.4 dBFS SINAD Signal to Noise and Distortion Ratio FIN = 8MHz 70.5 71.7 dBFS FIN = 20MHz 71.7 dBFS FIN ≃ FS/2 71.1 dBFS FIN = 40MHz 70 dBFS SFDR Spurious Free Dynamic Range FIN = 8MHz 75 81 dBc FIN = 20MHz 84 dBc FIN ≃ FS/2 79 dBc FIN = 40MHz 77 dBc HD2 Second order Harmonic Distortion FIN = 8MHz -85 -95 dBc FIN = 20MHz -95 dBc FIN ≃ FS/2 -95 dBc FIN = 40MHz -95 dBc HD3 Third order Harmonic Distortion FIN = 8MHz -75 -81 dBc FIN = 20MHz -84 dBc FIN ≃ FS/2 -79 dBc FIN = 40MHz -79 dBc ENOB Effective number of Bits FIN = 8MHz 11.4 11.6 bits FIN = 20MHz 11.6 bits FIN ≃ FS/2 11.5 bits FIN = 40MHz 11.3 bits Power Supply AIDD Analog Supply Current 20.4 mA DIDD Digital Supply Current Digital core supply 2.3 mA OIDD Output Driver Supply 2.5V output driver supply, sine wave input, FIN = 1MHz, CLK_EXT enabled 5.1 mA 2.5V output driver supply, sine wave input, FIN = 1MHz, CLK_EXT disabled 3.5 mA Analog Power Dissipation 36.7 mW Digital Power Dissipation OVDD = 2.5V, 5pF load on output bits, FIN = 1MHz, CLK_EXT disabled 12.9 mW Total Power Dissipation OVDD = 2.5V, 5pF load on output bits, FIN = 1MHz, CLK_EXT disabled 49.6 mW Power Down Dissipation 9.3 µW Sleep Mode Power Dissipation, Sleep mode 20.4 mW Clock Inputs Max. Conversion Rate 65 MSPS Min. Conversion Rate 40 MSPS
CDK1307 Ultra Low Power, 20/40/65/80MSPS, 12/13-bit ADCs Rev 1B ©2009-2013 Exar Corporation 9/15 Rev 1B (AVDD = 1.8V, DVDD = 1.8V, DVDDCLK = 1.8V, OVDD = 2.5V, 80MSPS clock, 50% clock duty cycle, -1dBFS 8MHz input signal, 13-bit output, unless otherwise noted) Symbol Parameter Conditions Min Typ Max Units Performance SNR Signal to Noise Ratio FIN = 8MHz 70.4 72 dBFS FIN = 20MHz 71.7 dBFS FIN = 30MHz 71.2 dBFS FIN ≃ FS/2 70.7 dBFS SINAD Signal to Noise and Distortion Ratio FIN = 8MHz 69.5 70.5 dBFS FIN = 20MHz 70.5 dBFS FIN = 30MHz 70.5 dBFS FIN ≃ FS/2 70.3 dBFS SFDR Spurious Free Dynamic Range FIN = 8MHz 74 77 dBc FIN = 20MHz 78 dBc FIN = 30MHz 78 dBc FIN ≃ FS/2 78 dBc HD2 Second order Harmonic Distortion FIN = 8MHz -80 -95 dBc FIN = 20MHz -90 dBc FIN = 30MHz -90 dBc FIN ≃ FS/2 -85 dBc HD3 Third order Harmonic Distortion FIN = 8MHz -74 -77 dBc FIN = 20MHz -78 dBc FIN = 30MHz -78 dBc FIN ≃ FS/2 -78 dBc ENOB Effective number of Bits FIN = 8MHz 11.3 11.4 bits FIN = 20MHz 11.4 bits FIN = 30MHz 11.4 bits FIN ≃ FS/2 11.4 bits Power Supply AIDD Analog Supply Current 24.5 mA DIDD Digital Supply Current Digital core supply 2.9 mA OIDD Output Driver Supply 2.5V output driver supply, sine wave input, FIN = 1MHz, CLK_EXT enabled 6.1 mA 2.5V output driver supply, sine wave input, FIN = 1MHz, CLK_EXT disabled 4.1 mA Analog Power Dissipation 44.1 mW Digital Power Dissipation OVDD = 2.5V, 5pF load on output bits, FIN = 1MHz, CLK_EXT disabled 15.5 mW Total Power Dissipation OVDD = 2.5V, 5pF load on output bits, FIN = 1MHz, CLK_EXT disabled 59.6 mW Power Down Dissipation 9.1 µW Sleep Mode Power Dissipation, Sleep mode 24.1 mW Clock Inputs Max. Conversion Rate 80 MSPS Min. Conversion Rate 65 MSPS
CDK1307 Ultra Low Power, 20/40/65/80MSPS, 12/13-bit ADCs Rev 1B ©2009-2013 Exar Corporation 10/15 Rev 1B Digital and Timing Electrical Characteristics (AVDD = 1.8V, DVDD = 1.8V, DVDDCLK = 1.8V, OVDD = 2.5V, 20/40/65/80MSPS clock, 50% clock duty cycle, -1 dBFS input signal, 5pF capacitive load, unless otherwise noted) Symbol Parameter Conditions Min Typ Max Units Clock Inputs Duty Cycle 20 80 % high Compliance CMOS, LVDS, LVPECL, Sine Wave Input Range Differential input swing -200 200 mVpp Differential input swing, sine wave clock input -800 800 mVpp Input Common Mode Voltage Keep voltages within ground and voltage of OVDD 0.3 VOVDD -0.3 V Input Capacitance Differential 1.7 pF Timing TPD Start Up Time from Power Down From Power Down Mode to Active Mode References has reached 99% of final value 900 clk cycles TSLP Start Up Time from Sleep From Sleep Mode to Active Mode 0.5 µs TOVR Out Of Range Recovery Time 1 clk cycles TAP Aperture Delay 0.8 ns εRMS Aperture Jitter <0.5 ps TLAT Pipeline Delay 12 clk cycles TD Output Delay 5pF load on output bits (see timing diagram) 4 ns 10pF load on output bits (see timing diagram) TBD ns TDC Output Delay Relative to CLK_EXT See timing diagram 2 ns Logic Inputs VIH High Level Input Voltage VOVDD ≥ 3.0V 2 V VOVDD = 1.7V – 3.0V 0.8 • VOVDD V VIL Low Level Input Voltage VOVDD ≥ 3.0V 0 0.8 V VOVDD = 1.7V – 3.0V 0 0.2 • VOVDD V IIH High Level Input Leakage Current -10 10 µA IIL Low Level Input Leakage Current -10 10 µA CI Input Capacitance 3 pF Logic Outputs VOH High Level Output Voltage -0.1 +VOVDD V VOL Low Level Output Voltage 0.1 V CL Max Capacitive Load Post-driver supply voltage equal to pre-driver supply voltage VOVDD = VOCVDD 5 pF Post-driver supply voltage above 2.25V (1) 10 pF Note: (1) The outputs will be functional with higher loads. However, it is recommended to keep the load on output data bits as low as possible to keep dynamic currents and resulting switching noise at a minimum.
CDK1307 Ultra Low Power, 20/40/65/80MSPS, 12/13-bit ADCs Rev 1B ©2009-2013 Exar Corporation 13/15 Rev 1B The quality of the input clock is extremely important for high-speed, high-resolution ADCs. The contribution to SNR from clock jitter with a full scale signal at a given frequency is shown in the equation below: SNRjitter = 20 • log (2 • π • FIN • εt) where FIN is the signal frequency, and εt is the total rms jitter measured in seconds. The rms jitter is the total of all jitter sources including the clock generation circuitry, clock distribution and internal ADC circuitry. For applications where jitter may limit the obtainable per - formance, it is of utmost importance to limit the clock jitter. This can be obtained by using precise and stable clock references (e.g. crystal oscillators with good jitter specifications) and make sure the clock distribution is well controlled. It might be advantageous to use analog power and ground planes to ensure low noise on the supplies to all circuitry in the clock distribution. It is of utmost im - portance to avoid crosstalk between the ADC output bits and the clock and between the analog input signal and the clock since such crosstalk often results in harmonic distortion. The jitter performance is improved with reduced rise and fall times of the input clock. Hence, optimum jitter per - formance is obtained with LVDS or LVPECL clock with fast edges. CMOS and sine wave clock inputs will result in slightly degraded jitter performance. If the clock is generated by other circuitry, it should be re- timed with a low jitter master clock as the last operation before it is applied to the ADC clock input. Digital Outputs Digital output data are presented on parallel CMOS form. The voltage on the OVDD pin set the levels of the CMOS outputs. The output drivers are dimensioned to drive a wide range of loads for OVDD above 2.25V, but it is rec - ommended to minimize the load to ensure as low transient switching currents and resulting noise as possible. In ap - plications with a large fanout or large capacitive loads, it is recommended to add external buffers located close to the ADC chip. The timing is described in the Timing Diagram section. Note that the load or equivalent delay on CK_EXT always should be lower than the load on data outputs to ensure sufficient timing margins. The digital outputs can be set in tristate mode by setting the OE_N signal high. The CDK1307 employs digital offset correction. This means that the output code will be 4096 with shorted inputs. However, small mismatches in parasitics at the input can cause this to alter slightly. The offset correction also re - sults in possible loss of codes at the edges of the full scale range. With no offset correction, the ADC would clip in one end before the other, in practice resulting in code loss at the opposite end. With the output being centered digitally, the output will clip, and the out of range flags will be set, before max code is reached. When out of range flags are set, the code is forced to all ones for over-range and all zeros for under-range. Data Format Selection The output data are presented on offset binary form when DFRMT is low (connect to OV SS). Setting DFRMT high (connect to OV DD) results in 2’s complement output format. Details are shown in Table 1 on page 14. The data outputs can be used in three different configurations. Normal mode: All 13-bits are used. MSB is D_12 and LSB is D_0. This mode gives optimum performance due to reduced quanti- zation noise. 12-bit mode: The LSB is left unconnected such that only 12 bits are used. MSB is D_12 and LSB is D_1. This mode gives slightly reduced performance, due to increased quantization noise. Reduced full scale range mode: The full scale range is reduced from 2Vpp to 1Vpp which is equivalent to 6dB gain in the ADC frontend. MSB is D_11 and LSB is D_0. Note that the codes will wrap around when exceeding the full scale range, and that out of range bits should be used to clamp output data. See section Reference Voltages for details. This mode gives slightly reduced performance.
CDK1307 Ultra Low Power, 20/40/65/80MSPS, 12/13-bit ADCs Rev 1B ©2009-2013 Exar Corporation 14/15 Rev 1B Table 2: Data Format Description for 1Vpp Full Scale Range Differential Input Voltage (IP - IN) Output data: D_11: D_0 (DFRMT = 0) (2’s Complement) Out of Range (Use Logical AND Function for &) Output Data: D_11: D_0 (DFRMT = 1) (2’s Complement) Out of Range (Use Logical AND Function for &) > 0.5V 0111 1111 1111 D_12 = 1 & D_11 = 1 0111 1111 1111 D_12 = 0 & D_11 = 1 0.5V 0111 1111 1111 0111 1111 1111 +0.24mV 0000 0000 0000 0000 0000 0000 -0.24mV 1111 1111 1111 1111 1111 1111 -0.5V 1000 0000 0000 1000 0000 0000 < -0.5V 1000 0000 0000 D_12 = 0 & D_11 = 0 1000 0000 0000 D_12 = 1 & D_11 = 0 Reference Voltages The reference voltages are internally generated and buff- ered based on a bandgap voltage reference. No external decoupling is necessary, and the reference voltages are not available externally. This simplifies usage of the ADC since two extremely sensitive pins, otherwise needed, are removed from the interface. If a lower full scale range is required the 13-bit output word provides sufficient resolution to perform digital scaling with an equivalent impact on noise compared to adjusting the reference voltages. A simple way to obtain 1.0V pp input range with a 12-bit output word is shown in the Table 2 below. Note that only 2‘s complement output data are available in this mode and that out of range conditions must be determined based on a two bit output. The output code will wrap around when the code goes outside the full scale range. The out of range bits should be used to clamp the output data for overrange conditions. Operational Modes The operational modes are controlled with the PD_N and SLP_N pins. If PD_N is set low, all other control pins are overridden and the chip is set in Power Down mode. In this mode all circuitry is completely turned off and the internal clock is disabled. Hence, only leakage current contributes to the Power Down Dissipation. The startup time from this mode is longer than for other idle modes as all references need to settle to their final values before normal operation can resume. The SLP_N bus can be used to power down each channel independently, or to set the full chip in Sleep Mode. In this mode internal clocking is disabled, but some low band - width circuitry is kept on to allow for a short startup time. However, Sleep Mode represents a significant reduction in supply current, and it can be used to save power even for short idle periods. The input clock could be kept running in all idle modes. However, even lower power dissipation is possible in Power Down mode if the input clock is stopped. In this case it is important to start the input clock prior to en - abling active mode. Table 1: Data Format Description for 2Vpp Full Scale Range Differential Input Voltage (IP - IN) Output data: D_12 : D_0 (DFRMT = 0, offset binary) Output Data: D_12 : D_0 (DFRMT = 1, 2’s complement)
1.0 V 1 1111 1111 1111 0 1111 1111 1111
+0.24mV 1 0000 0000 0000 0 0000 0000 0000 -0.24mV 0 1111 1111 1111 1 1111 1111 1111 -1.0V 0 0000 0000 0000 1 0000 0000 0000
CDK1307 Ultra Low Power, 20/40/65/80MSPS, 12/13-bit ADCs Rev 1B For Further Assistance: Exar Corporation Headquarters and Sales Offices 48720 Kato Road Tel.: +1 (510) 668-7000 Fremont, CA 94538 - USA Fax: +1 (510) 668-7001 www.exar.com NOTICE EXAR Corporation reserves the right to make changes to the products contained in this publication in order to improve design, performance or reliability. EXAR Corporation assumes no responsibility for the use of any circuits described herein, conveys no license under any patent or other right, and makes no representation that the circuits are free of patent infringement. Charts and schedules contained here in are only for illustration purposes and may vary depending upon a user’s specific application. While the information in this publication has been carefully checked; no responsibility, however, is assumed for inaccuracies. EXAR Corporation does not recommend the use of any of its products in life support applications where the failure or malfunction of the product can reasonably be expected to cause failure of the life support system or to significantly affect its safety or effectiveness. Products are not authorized for use in such applications unless EXAR Corporation receives, in writing, assurances to its satisfaction that: (a) the risk of injury or damage has been minimized; (b) the user assumes all such risks; (c) potential liability of EXAR Corporation is adequately protected under the circumstances. Reproduction, in part or whole, without the prior written consent of EXAR Corporation is prohibited. ©2009-2013 Exar Corporation 15/15 Rev 1B Mechanical Dimensions NOTE: Package dimensions in millimeter unless otherwise noted. Symbol Min Typ Max Min Typ Max A 2 – 0.023 0.028 – 0.65 0.7 A 3 0.008 REF 0.2 REF D 0.236 BSC 6.00 BSC D 1 0.226 BSC 5.75 BSC e 0.020 BSC 0.50 BSC R 0.004 0.008 – 0.1 0.2 – Inches Millimeters Pin 1 ID - Dia. 0.5 (Top Side) Pin 1 ID - Dia. R Pin 0 Exposed Pad F G A /uni03B81 L be 1.14 0.45 D D D2 D1