isp1181 NXP Semiconductors, isp1181 Datasheet - Page 44

• Manufacturer Part Number: isp1181
• Description: Isp1181 Full-speed Universal Serial Bus Interface Device
• Manufacturer: NXP Semiconductors

Philips Semiconductors
14. Power supply
15. Crystal oscillator and LazyClock
9397 750 08938
Product data
Fig 10. ISP1181 with a 4.0 to 5.5 V supply.
ISP1181
V CC(3.3)
V reg(3.3)
V CC
V ref
The ISP1181 is powered from a single supply voltage, ranging from 4.0 to 5.5 V. An
integrated voltage regulator provides a 3.3 V supply voltage for the internal logic and
the USB transceiver. This voltage is available at pin V
external pull-up resistor on USB connection D . See
The ISP1181 can also be operated from a 3.0 to 3.6 V supply, as shown in
In that case the internal voltage regulator is disabled and pin V
connected to V
The ISP1181 has a crystal oscillator designed for a 6 MHz parallel-resonant crystal
(fundamental). A typical circuit is shown in
signal of 6 MHz can be applied to input XTAL1, while leaving output XTAL2 open.
The 6 MHz oscillator frequency is multiplied to 48 MHz by an internal PLL. This
frequency is used to generate a programmable clock output signal at pin CLKOUT,
ranging from 3 to 48 MHz.
In ‘suspend’ state the normal CLKOUT signal is not available, because the crystal
oscillator and the PLL are switched off to save power. Instead, the CLKOUT signal
can be switched to the LazyClock frequency of 115 kHz 10 %.
The oscillator operation and the CLKOUT frequency are controlled via the Hardware
Configuration Register, as shown in
•
•
•
MGS773
Fig 12. Typical oscillator circuit.
CLKRUN switches the oscillator on and off
CLKDIV[3:0] is the division factor determining the normal CLKOUT frequency
NOLAZY controls the LazyClock signal output during ‘suspend’ state.
4.0 to 5.5 V
CC
Rev. 04 — 30 October 2001
.
ISP1181
Fig 11. ISP1181 with a 3.0 to 3.6 V supply.
CLKOUT
XTAL2
XTAL1
Figure
Figure
13. The following bits are involved:
6 MHz
ISP1181
18 pF
18 pF
V reg(3.3)
V CC(3.3)
12. Alternatively, an external clock
V CC
V ref
Figure
MGS777
reg(3.3)
© Koninklijke Philips Electronics N.V. 2001. All rights reserved.
Full-speed USB interface
for connecting an
10.
MGS774
reg(3.3)
3.0 to 3.6 V
ISP1181
must be
Figure
44 of 71
11.