CSR8615A04-IQQF-R View Datasheet(PDF) - Unspecified
Part Name
Description
MFG CO.
'CSR8615A04-IQQF-R' PDF : 114 Pages View PDF
10.1 1.8V Switch-mode Regulator
CSR recommends using the integrated switch-mode regulator to power the 1.80V supply rail.
Figure 10.3 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.
er 16, 2013 C1
ptemb 2.2µF
VBAT
3V3_USB
C2
2.2µF
LX
1.8V Switch-mode
Regulator
SENSE
To 1.35V Switch-mode
Regulator Input
LX_1V8
SMPS_1V8_SENSE
VSS_SMPS_1V8
L1
4.7µH
1.8V Supply Rail
C3
2.2µF
ay, Se Figure 10.3: 1.8V Switch-mode Regulator Output Configuration
ond Minimise the series resistance of the tracks between the regulator input, VBAT and 3V3_USB, ground terminals, the
- M filter and decoupling components, and the external voltage source to maintain high-efficiency power conversion and
n low supply ripple.
om.c Ensure a solid ground plane between C1, C2, C3 and VSS_SMPS_1V8.
m.c Also minimise the collective parasitic capacitance on the track between LX_1V8 and the inductor L1, to maximise
m efficiency.
eco For the regulator to meet the specifications in Section 13.3.1.1 requires a total resistance of <1.0Ω (<0.5Ω
ach recommended) for the following:
ap â– The track between the battery and VBAT.
- â– The track between LX_1V8 and the inductor.
sao â– The inductor, L1, ESR.
T â– The track between the inductor, L1, and the sense point on the 1.80V supply rail.
es The following enable the 1.80V switch-mode regulator:
jam â– VREGENABLE pin
for â– The CSR8615 QFN firmware with reference to PSKEY_PSU_ENABLES
ed â– VCHG pin
par The switching frequency is adjustable by setting an offset from 4.00MHz using PSKEY_SMPS_FREQ_OFFSET,
Pre which also affects the 1.35V switch-mode regulator.
When the 1.80V switch-mode regulator is not required, leave unconnected:
â– The regulator input VBAT and 3V3_USB
â– The regulator output LX_1V8
10.2 1.35V Switch-mode Regulator
CSR recommends using the integrated switch-mode regulator to power the 1.35V supply rail.
Figure 10.4 shows that an external LC filter circuit of a low-resistance series inductor L1 (4.7µH), followed by a low
ESR shunt capacitor, C3 (4.7µF), is required between the LX_1V35 terminal and the 1.35V supply rail. Connect the
1.35V supply rail and 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 64 of 114
CS-303726-DSP3
www.csr.com
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