XXRR7799110066
2222VV,, 66AA SSyynncchhrroonnoouuss SStteepp--DDoowwnn CCOOTT PPoowweerr MMoodduullee
April 2016 Rev. 1A
EEVVAALLUUAATTIIOONN BBOOAARRDD MMAANNUUAALL
GENERAL DESCRIPTION
The XR79106 is part of a family of 22V
synchronous step-down power modules
combining the controller, drivers, inductor,
passive components and MOSFETs in a single
package for point-of-load supplies. This
module requires very few external components
leading to ease of design and fast time to
market. The XR79106 has load current rating
of 6A. A wide 4.5V to 22V input voltage range
allows for single supply operation from
industry standard 5V, 12V and 19.6V rails.
With a proprietary emulated current mode
Constant On-Time (COT) control scheme, the
XR79106 provides extremely fast line and load
transient response using ceramic output
capacitors. It requires no loop compensation,
simplifying circuit implementation and
reducing overall component count. The control
loop also provides 0.2% load and 0.2% line
regulation and maintains constant operating
frequency. A selectable power saving mode,
FEATURES
allows the user to operate in Discontinuous
6A step-down power module
Current Mode (DCM) at light current loads
significantly increasing the converter
o 4.5V to 22V wide single input
efficiency. A host of protection features,
voltage
including overcurrent, over temperature,
o 0.6V adjustable output voltage
short-circuit and UVLO, helps achieve safe
Controller, drivers, inductor, passive
operation under abnormal operating
components and MOSFETs integrated in
conditions. The XR79106 is available in a
one package
RoHS-compliant, green/halogen-free space-
saving 8mm x 8mm x 4mm QFN package.
Proprietary constant on-time control
o No loop compensation required
o Stable with ceramic output
capacitors
o Programmable 100ns to 1s on-
time
o Constant 600kHz to 800kHz
frequency
o Selectable CCM or DCM/CCM
operation
Precision enable and power-good flag
Programmable soft-start
8mm x 8mm x 4mm QFN package
Exar Corporation www.exar.com
48720 Kato Road, Fremont CA 94538, USA Tel. +1 510 668-7000 Fax. +1 510 668-7001 XXRR7799110066
2222VV,, 66AA SSyynncchhrroonnoouuss SStteepp--DDoowwnn CCOOTT PPoowweerr MMoodduullee
April 2016 Rev. 1A
D1 MMSZ4685-TP
C A
R1 10k 1% R2 24.3k, 1%
VIN
2-3=DCM/CCM
SW
3 C13 0.22uF
2
1 R3 35.7k, 1%
RLIM
1-2=CCM
T3
1.65k
J1 CSS
EN
47nF
Lin VIN+
VIN = 4.5V - 12V
(short)
RON
VIN 1
SS 7.15k
2
CBST
PGOOD C1 C2 C3 C4 C5 C6
0.1uF 22uF 22uF VIN-
RPGOOD 10k
1
VCC
2
U1A
T4
AGND
1 41
SS PGND
2 40
PGood PGND
FB T1
3 AGND BST PVin 39
FB PGND
57 62 61
4 VOUT+
AGND
600kHz, 1.2V, 6A
5
AGND
VOUT 1
6 38 2
VIN VOUT
7 58 37
C7 C8 C9
VCC VOUT
8 SW VOUT 36 C10 C11 C12
PGND VOUT
60 35
VOUT 47uF 47uF 47uF
9 34 0.1uF VOUT-
RR 42.2k CR 2.2nF
SW VOUT
10 33
SW VOUT
11 32 1
SW VOUT
12 31 2
SW VOUT
PGND 30
VOUT CAC
13 59 29
PGND VOUT 22nF
T2
XR79106
SW
RFB1
CFF
2k, 1%
VOUT C14
VIN
VCC CSNB 0.1uF
VCC nF RFF
61 60
PVin VOUT
FB
RVIN R5VIN
RSNB
VIN FB
SW 58 59 Ohm
SW PGND
0k CIN CVCC
62
BST3 RFB2
57
0.1uF 4.7uF 2k, 1%
AGND
U2B XR79106
Fig. 1: XR79106 Evaluation Board Schematics
PIN CONFIGURATION
Fig. 2: XR79106 Pin Assignment
Exar Corporation www.exar.com
48720 Kato Road, Fremont CA 94538, USA Tel. +1 510 668-7000 Fax. +1 510 668-7001
14 56
PGND TON
15 55
PGND ENMode
16
PGND
17 54
PGND AGND
18 53
PGND AGND
19
PGND
52
ILIM
51
BST2
20 50
SW BST1
21
SW
22 49
SW PVin
23 48
SW PVin
47
PVin
24 46
VOUT PVin
25 45
VOUT PVin
26 44
VOUT NC
27
VOUT
28 43
VOUT PGND
42
PGND