CSR8615A04-IQQF-R View Datasheet(PDF) - Unspecified
Part Name
Description
MFG CO.
'CSR8615A04-IQQF-R' PDF : 114 Pages View PDF
L1
4.7µH
C1
2.2µF
VBAT
3V3_USB
C2
2.2µF
LX
1.35V Switch-
mode Regulator
SENSE
LX_1V35
SMPS_1V35_SENSE
VSS_SMPS_1V35
1.35V Supply Rail
C3
4.7µF
To 1.8V Switch-mode
10.3 1.8V and 1.35V Switch-mode Regulators Combined Regulator Input
, 2013 Figure 10.4: 1.35V Switch-mode Regulator Output Configuration
r 16 Minimise the series resistance of the tracks between the regulator input, VBAT and 3V3_USB, ground terminals, the
be filter and decoupling components, and the external voltage source to maintain high-efficiency power conversion and
tem low supply ripple.
ep Ensure a solid ground plane between C1, C2, C3 and VSS_SMPS_1V35.
y, S Also minimise the collective parasitic capacitance on the track between LX_1V35 and the inductor L1, to maximise
da efficiency.
Mon For the regulator to meet the specifications in Section 13.3.2.1 requires a total resistance of <1.0Ω (<0.5Ω
- recommended) for the following:
.cn â– The track between the battery and VBAT.
om â– The track between LX_1V8 and the inductor.
.c â– The inductor, L1, ESR.
mm â– The track between the inductor, L1, and the sense point on the 1.35V supply rail.
co The following enable the 1.35V switch-mode regulator:
che â– VREGENABLE pin
pa â– The CSR8615 QFN firmware with reference to PSKEY_PSU_ENABLES
- a â– VCHG pin
sao The switching frequency is adjustable by setting an offset from 4.00MHz using PSKEY_SMPS_FREQ_OFFSET,
T which also affects the 1.80V switch-mode regulator.
mes When the 1.35V switch-mode regulator is not required, leave unconnected:
r ja â– The regulator input VBAT and 3V3_USB
fo â– The regulator output LX_1V35
Prepared For applications that require a single 1.80V supply rail with higher currents CSR recommends combining the outputs
of the integrated 1.80V and 1.35V switch-mode regulators in parallel to power a single 1.80V supply rail, see Figure
10.5.
Figure 10.5 shows that an external LC filter circuit of a low-resistance series inductor L1 (4.7µH), followed by a low
ESR shunt capacitor, C3 (2.2µF), is required between the LX_1V8 terminal and the 1.80V supply rail. Connect the
1.80V supply rail and the VDD_AUX_1V8 pin and ground the SMPS_1V35_SENSE pin.
Pre-production Information
© Cambridge Silicon Radio Limited 2013
Confidential Information - This Material is Subject to CSR's Non-disclosure Agreement
Page 65 of 114
CS-303726-DSP3
www.csr.com
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