Si8250/1/2
D
I G I TA L
P
O W E R
C
O N T R O L L E R
Features
Single-chip, Flash-based digital
power controller
Supports isolated and non-isolated
applications
Enables new system capabilities
such as:
- Adaptive dead-time control for
higher efficiency
- Nonlinear control for faster
transient response
- Self diagnostics for higher
reliability
- SMBus port
Highly-integrated control solution:
High-speed digital hardware
control loop
In-system programmable
supervisory processor
Programmable system protection
functions
Hardware cycle-by-cycle current
limiting and OCP
External clock and frame
synchronization inputs
Performs system management
functions, such as external power
supply sequencing and fan
control/monitoring
In-system Flash programmable
Flash can also be used as NV
memory for data storage
Low-cost, comprehensive
development tool kit includes:
Graphical, easy-to-use system
design tools
Integrated development
environment
In-system, on-line debugger
Turnkey isolated 35 W digital
half-bridge target board
Typical Applications
Isolated and non-isolated DC/DC
converters
AC/DC converters
Fully Pb-free and ROHS compliant
packages
32-pin LQFP
28-pin 5x5 mm QFN
Temp Range: –40 to +125 °C
Pin Assignments:
See page 23
32-pin LQFP
GND
VDD
PH1
PH2
PH3
PH4
PH5
32
31
30
29
28
27
26
RST/C2CK
IPK
VSENSE
GNDA
VDDA
VREF
P1.0/VIN/AIN0
P1.1/AIN1
1
2
3
4
5
6
7
8
25
PH6
24
23
22
P0.0
P0.1
P0.2
P0.3 / XCLK
P0.4
P0.5
P0.6
P0.7
Si8250/1/2
Top View
21
20
19
18
17
10
11
12
13
14
15
P1.6/AIN6
GND
VDD
28-pin QFN
28
27
26
25
24
23
GND
RST / C2CK
IPK
VSENSE
GND
VDD
VREF
P1.0/VIN/AIN0
1
2
3
4
5
6
GND
7
15
P0.7
22
P0.0
PH1
PH2
PH3
PH4
PH5
PH6
P1.7/AIN7/C2D
P1.2/AIN2
P1.3/AIN3
P1.4/AIN4
P1.5/AIN5
16
9
21
20
19
P0.1
P0.2
P0.3/XCLK
P0.4
P0.5
P0.6
Si8250/1/2
Top View
18
17
16
10
11
12
13
P1.6/AIN6
P1.1/AIN1
P1.2/AIN2
P1.3/AIN3
P1.4/AIN4
P1.5/AIN5
Description
The Si8250/1/2 provides all control and protection functions necessary to
implement highly-intelligent, fast-response power delivery and
management control systems for isolated and non-isolated power
supplies. Onboard processing capability enables intelligent control
optimization for improved system performance and new capabilities, such
as serial connectivity via the SMBus or onboard UART. The Si8250/1/2
family is in-system Flash programmable, enabling control and protection
parameters, such as system regulation and protection settings, startup
and shutdown modes, loop response, and modulation timing, to be readily
modified. The built-in, high-speed control path provides loop updates
every 100 ns and provides pulse-by-pulse current limiting and overcurrent
protection, even while the internal CPU is disabled.
The Si825x family is supported by the Si8250DK development kit, which
contains everything required to develop and program power supply
applications with the Si825x family of digital controllers.
Patents pending
Rev. 1.0 6/07
Copyright © 2007 by Silicon Laboratories
P1.7/AIN7/C2D
14
8
9
Si8250/1/2
Si8250/1/2
T
A B L E
Section
OF
C
O N T E N TS
Page
1. Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
2. Benefits of Digital Power Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
3. Product Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.1. System Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
3.2. Control Processor Functional Block Descriptions (Figure 1) . . . . . . . . . . . . . . . . . . . 16
3.3. System Management Processor Functional Block Descriptions . . . . . . . . . . . . . . . . 17
4. Design Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
5. Example Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
5.1. Isolated DC/DC Converter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
5.2. Single-Phase Point of Load (POL) Converter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
6. Layout Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
7. Pin Descriptions: Si8250/1/2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
7.1. Pin Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
8. Ordering Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
9. Package Outline: 32LQFP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
10. Package Outline: 28QFN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Document Change List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30
Contact Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32
Rev. 1.0
3
Si8250/1/2
1. Electrical Specifications
Table 1. Absolute Maximum Ratings*
Parameter
Ambient temperature under bias
Storage temperature
Voltage on any Port0 Pin with respect to GND
Voltage on all other pins with respect to GND
Voltage on V
DD
with respect to GND
Maximum total current through V
DD
or GND
Maximum output current sunk by RST or any
port pin
Conditions
Min.
–55
–65
–0.3
–0.3
–0.3
—
—
Typ.
—
—
—
—
—
—
—
Max.
+135
+150
5.5
4.0
4.0
400
80
Units
°C
°C
V
V
V
mA
mA
*Note:
Stresses above those listed in this table may cause permanent device damage. This is a stress rating only, and
functional operation of the devices at those or any conditions above those indicated in the operation listings of this
specification is not implied. Exposure to maximum rating conditions for extended periods may affect device reliability.
Table 2. DC Electrical Specifications
T
A
= –40 to +125 °C, V
DD
= 2.5 V, SYSCLK = 25 MHz, PLLCLK = 200 MHz unless otherwise specified.
Parameter
Supply voltage
Supply current (all peripherals enabled)
Lockout mode supply current
Digital supply current (shutdown)
Digital supply RAM data retention voltage
Conditions
Min
2.25
Typ
—
26
300
—
1.5
Max
2.75
—
—
500
—
Units
V
mA
µA
µA
V
Analog + Digital Supply Current.
Analog + Digital Supply Current.
(See Table 1)
Oscillator not running,
V
DD
monitor disabled
—
—
—
—
4
Rev. 1.0
Si8250/1/2
Table 3. Reference DAC Electrical Specifications
T
A
= –40 to +125 °C, V
DD
= 2.5 V, SYSCLK = 25 MHz, PLLCLK = 200 MHz unless otherwise specified.
Parameter
Resolution
LSB size
Integral nonlinearity (INL)
Differential nonlinearity (DNL)
Settling time
Turn-on time
Noise
Power supply rejection
Supply current
Shutdown supply current
Conditions
Min
—
—
–2
–1.0
Typ
—
2.44
—
—
2
20
1
70
220
0.1
Max
9
—
+2
+1.0
—
—
—
—
—
—
Units
Bits
mV
LSB
LSB
µs
µs
mV
PP
db
µA
µA
1/2 LSB change from
0 to full scale
—
—
2 MHz BW
—
—
—
—
Rev. 1.0
5
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