ISP1508AET NXP Semiconductors, ISP1508AET Datasheet - Page 16

• Manufacturer Part Number: ISP1508AET
• Description: RF Transceiver USB 2.0 ULPI TRNSCVR
• Manufacturer: NXP Semiconductors

Specifications of ISP1508AET

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 935283548118 ISP1508AET-T

NXP Semiconductors
ISP1508A_ISP1508B_1
Product data sheet
8.7.3 SRP charge and discharge resistors
8.10 Power-On Reset (POR)
8.8 Port power control
8.9 Band gap reference voltage
The ISP1508 provides on-chip resistors for short-term charging and discharging of V
These are used by the B-device to request a session, prompting the A-device to restore
the V
previous session by setting the DISCHRG_VBUS register bit to logic 1 and waiting for
SESS_END to be logic 1. Then the B-device charges V
register bit to logic 1. The A-device sees that V
threshold and starts a session by turning on the V
For an OTG or host application, the ISP1508 uses the PSW_N pin to control the external
power switch for the V
power switch can be connected to the FAULT pin of the ISP1508 to indicate to the ULPI
link the V
When the FAULT pin is not used, connect it to GND.
The band gap circuit provides a stable internal voltage reference to bias the analog
circuitry. This band gap circuit requires an accurate external reference resistor. Connect a
12 k
An internal POR is generated when REG1V8 rises above V
pulse will be generated whenever REG1V8 drops below V
t
To give a better view of the functionality,
internal POR starts with logic 0 at t0. At t1, the detector will see the passing of the trip
level so that POR pulse is generated to reset all internal circuits. If REG1V8 dips from t2 to
t3 for greater than t
less than t
w(REG1V8_L)
Fig 4. Digital overcurrent detection scheme
BUS
1 % resistor between the RREF pin and GND.
power. First, the B-device makes sure that V
BUS
w(REG1V8_L)
.
overcurrent status. For the connection scheme, see
w(REG1V8_L)
ISP1508
, the internal POR pulse will not be generated and will remain LOW.
BUS
Rev. 01 — 14 August 2007
5 V supply. The overcurrent detector output of the external
FAULT
PSW_N
V
, another POR pulse is generated. If the dip from t4 to t5 is
BUS
Figure 5
ISP1508A; ISP1508B
BUS
shows a possible curve of REG1V8. The
INDICATOR
BUS
is charged above the session valid
SWITCH
POWER
FAULT
+5 V
WITH
BUS
power.
BUS
is fully discharged from the
POR(trip)
by setting the CHRG_VBUS
POR(trip)
ULPI HS USB transceiver
004aaa864
Figure
for more than
V
. The internal POR
BUS
© NXP B.V. 2007. All rights reserved.
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BUS
.