Cirrus Logic AN35 User Manual

Application Note

The CS5504 Family Characteristics

AN35

The CS5504/5/6/7/8/9 are a series of A/D converters all derived from a high performance

∆Σ architecture. The CS5504 family members are based on a core architecture including both an analog modulator and a digital filter, with only subtle differences between the individual products. The digital filter has been optimized to attenuate ac line interference (50/60 Hz and their harmonics) when the devices are operated from a low-cost 32.76 8kHz crystal.

The use of a low-cost 32.768kHz clock provides 20 samples per second from the family. The CS5505/6/7/8 can achieve up to 100 samples/second with a 163kHz system clock, while the CS5504/9 can achieve up to 200

samples/second when operated from it’s maximum input clock of 330 kHz. In achieving higher conversion rates, the CS5504 requires slightly higher operating currents than the CS5505/6/7/8. The CS5509 achieves the same high conversion rate as the CS5504 with lower power consumption, but pays a slight penalty in linearity.

Resolution #Channels

CS5504 20-bits 2 CS5505 16-bits 4 CS5506 20-bits 4 CS5507 16-bits 1 CS5508 20-bits 1 CS5509 16-bits 1

Max.

1 2 2 1 1 1

Speed

200 0.0007% No 4.4 mW No SEC 20 100 0.0015% Yes 3 mW Yes SEC, SSC 24 100 0.0007% Yes 3 mW Yes SEC, SSC 24 100 0.0015% Yes 3 mW Yes SEC, SSC 20 100 0.0007% Yes 3 mW Yes SEC, SSC 20 200 0.0015% No 1.7 mW No SEC 16

Linearity

(Typical) Sleep Power

Table 1 summarizes the similarities and differences of the C S5504 family.

The CS5504/9 come in smaller packages than the CS5505/6/7/8, however, the CS5505/6/7/8 have more functionality and flexibility. The CS5505/6/7/8 offer a sleep function, an on-chip voltage reference, and multiple serial communication mode s.

Table 2 shows the CS5504 family’s wide array of power supply options. Note: the CS5509 is single supply, however, the VA+ supply for all devices must always be the most positive operating voltage under all operating conditions, including start -up.

VA+ VA- VD+

CS5504/5/

6/7/8

CS5509

+5 to +10V 0V +5V

+5V0 to -5V+5V +5V 0 to - 5V +3.3V +5V - +5V +5V - +3. 3V

Table 2. Power Supply Arrangements

On-chip

VREF

Serial Port

Modes5Pin Count

Notes: 1. Fully-differential

2. Pseudo-differential

3. CS5509 is production tested at 330 kHz (200 samples/second) All others are production tested at 32.768 kHz for the best 50/60 Hz rejection.

4. These linearity specifications are based on a 20Hz output rate using a 32.768kHz crystal.

5. SEC is synchronous external clocking of the data out while SSC is synchronous self-clocking.

Crystal Semiconductor Corporation

P.O. Box 17847, Austin, TX 78760 (512) 445-7222 FAX 445-7581 http://www.crysta l.com

Table 1. CS5504 Family Characteristics

JAN ’95

AN35REV2