Datasheet AD7740 (Analog Devices) - 5

AD7740 PIN CONFIGURATIONS 8-Lead MSOP 8-Lead SOT-23 1 8 CLKOUT BUF 1 8 BUF CLKOUT AD7740 AD7740 2 7 CLKIN FOUT 2 7 CLKIN microSOIC FOUT SOT-23 GND 3 TOP VIEW 6 VDD VDD 3 TOP VIEW 6 GND (Not to Scale) (Not to Scale) REFIN/OUT 4 5 VIN 4 VIN 5 REFIN/OUT PIN FUNCTION DESCRIPTIONS 8-LEAD MSOP PIN NUMBERS* Pin No. Mnemonic Function
1 CLKOUT The crystal/resonator is tied between this pin and CLKIN. In the case of an external clock driving CLKIN, an inverted clock signal appears on this pin and can be used to drive other circuitry provided it is buffered first. 2 CLKIN The master clock for the device may be in the form of a crystal/resonator tied between this pin and CLKOUT. An external CMOS-compatible clock may also be applied to this input as the clock for the device. If CLKIN is inactive low for 1 ms (typ), the AD7740 automatically enters power-down. 3 GND Ground reference for all the circuitry on-chip. 4 REFIN/OUT Voltage Reference Input. This is the reference input to the core of the VFC and defines the span of the VFC. If this pin is left unconnected, the internal 2.5 V reference is the default reference. Alternatively, a precision external reference may be used to overdrive the internal reference. The internal reference has high output impedance in order to allow it to be overdriven. 5 VIN The analog input to the VFC. It has a nominal input range from 0 V to VREF which corresponds to an output frequency of 10% fCLKIN to 90% fCLKIN. It has a ± 150 mV overrange. If buffered, it draws virtually no current from whatever source is driving it. 6 VDD Power Supply Input. These parts can be operated at 3.3 V ± 10% or 5 V ± 5%. The supply should be adequately decoupled with a 10 µF and a 0.1 µF capacitor to GND. 7 FOUT Frequency Output. FOUT goes from 10% to 90% of fCLKIN, depending on VIN. 8 BUF Buffered Mode Select Pin. When BUF is tied low, the VIN input is unbuffered and the range on the VIN pin is –0.15 V to VDD + 0.15 V. When it is tied high, VIN is buffered and the range on the VIN pin is restricted to 0.1 V to VDD – 0.2 V. *Note that the SOT-23 and MSOP packages have different pinouts.
ORDERING GUIDE Model1 Temperature Range Package Description Package Option Branding Information
AD7740KRM 0°C to +85°C 8-Lead MSOP RM-8 V0K AD7740KRMZ 0°C to +85°C 8-Lead MSOP RM-8 V0K AD7740KRMZ-REEL 0°C to +85°C 8-Lead MSOP RM-8 V0K AD7740KRMZ-REEL7 0°C to +85°C 8-Lead MSOP RM-8 V0K AD7740YRM −40°C to +105°C 8-Lead MSOP RM-8 V0Y AD7740YRMZ −40°C to +105°C 8-Lead MSOP RM-8 V0Y AD7740YRMZ-REEL −40°C to +105°C 8-Lead MSOP RM-8 V0Y AD7740YRMZ-REEL7 −40°C to +105°C 8-Lead MSOP RM-8 V0Y AD7740YRTZ-REEL7 −40°C to +105°C 8-Lead SOT-23 RJ-8 C41 1 Z = RoHS Compliant Part. –4– REV. C