NXP Semiconductors TDA8752B manual

Philips Semiconductors TDA8752B
Triple high-speed Analog-to-Digital Converter 110 Msps
Product specification Rev. 03 — 21 July 2000 19 of 38
9397 750 07338 © Philips Electronics N.V. 2000. All rights reserved.
The default programmed value is: NFINE=0.
9.1.3 Control register
COAST and HSYNC signals can be inverted by setting the I2C-bus control bits
‘Vlevel’ and ‘Hlevel’ respectively. When ‘Vlevel’ and ‘Hlevel’ are set to zero
respectively, COAST and HSYNC are active HIGH.
The bit ‘Edge’ defines the rising or falling edge of CKREF to synchronize the PLL. It
will be on the rising edge if the bit is at logic 0 and on the falling edge if the bit is at
logic 1.
The bits ‘Up’ and ‘Do’ are used for the test, to force the charge pump current. These
bits have to be logic0 during nor mal use.
The bits ‘Ip0’, ‘Ip1’ and ‘Ip2’ control the charge pump current, to increase the
bandwidth of the PLL, as shown in Tabl e 8.
The default programmed value is as follows:
•Charge pump current = 100µA
•Test bits: no test mode; bits‘Up’ and ‘Do’ at logic 0
•Rising edge of CKREF: bit ‘Edge’ at logic 0
•COAST and HSYNC inputs are active HIGH: bits‘Vlevel’ and ‘Hlevel’ at logic 0.
9.1.4 VCO register
The bits ‘Z2’, ‘Z1’and ‘Z0’ enable the internal resistance for the VCO filter to be
selected.
Table 7: Gain correspondence (FINE)
NFINE Gain Vi to be full-scale (V)
0 0.825 1.212
31 0.878 1.139
Table 8: Charge pump current control
Ip2 Ip1 Ip0 Current (µA)
0 0 0 6.25
0 0 1 12.5
01025
01150
100100
101200
110400
111700