ISP1109BS Просмотр технического описания (PDF) - Philips Electronics

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ISP1109BS

Universal Serial Bus transceiver with carkit support

Philips Electronics 

Philips Semiconductors

ISP1109

USB transceiver with carkit support

8. Modes of operation

The ISP1109 supports four types of modes:

• Power modes

• Serial control modes

• USB modes

• Transparent modes.

8.1 Power modes

8.1.1 Normal mode

In this mode, both VCC and VCC(I/O) are connected and their voltage levels are within the

operation range (VCC ≥ 3.0 V, VCC(I/O) ≥ 1.65 V, VCC(I/O) ≤ VCC).

There are three levels of power saving schemes in the ISP1109:

• Active power mode: Power is on; all circuits are active.

• USB suspend mode: To reduce power consumption, the USB differential receiver is

powered off.

• Power-down mode: Set by writing logic 1 to bit PWR_DN of the Mode Control 2

register. The clock generator and all biasing circuits are turned off to reduce power

consumption to the minimum possible; typically ICC is less than 20 µA. For details on

waking up the clock, see Section 10.

8.1.2 Disable mode

In disable mode, VCC(I/O) is cut-off and VCC is powered. In this mode, the ISP1109 is in

Power-down state, if VBUS is below SESS_VLD threshold (0.8 V to 2.0 V).

When VCC is below threshold Vth(ISET), pin ISET will remain at the LOW level.

When VBUS > Vth(svc) and VCC rises above Vth(ISET), the ISP1109 will output HIGH on

pin ISET, if any of the following conditions is detected:

• Voltage on pin ID is greater than Vth(ID_FM)

• DP and DM are single-ended one (SE1).

If the preceding condition is detected, pin ISET will be asserted within 1.5 ms when VCC

rises above Vth(ISET).

The USB differential driver will be set in three-state as long as VCC(I/O) is lost. The DP

pull-up resistor (RUP(DP)) will be disconnected from the DP line. The DP weak pull-up

resistor (RweakUP(DP)) will be connected if the VBUS voltage is above Vth(svc).

8.1.3 Isolate mode

In isolate mode, VCC is cut-off and VCC(I/O) is powered. In this mode, the ISP1109 will drive

stable level to all digital output pins, and all bidirectional digital pins will be set in

three-state.

Table 10 shows a summary of power modes.

9397 750 13355

Product data sheet

Rev. 01 — 14 July 2005

© Koninklijke Philips Electronics N.V. 2005. All rights reserved.

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