SC1110 Datasheet, PDF (1/7 Pages) Semtech Corporation – SINK AND SOURCE DC/DC CONTROLLER FOR TERMINATION POWER SUPPLY APPLICATIONS

SINK AND SOURCE DC/DC CONTROLLER FOR _SC1110
TERMINATION POWER SUPPLY APPLICATIONS
PRELIMINARY - October 9, 2000
TEL:[phone] FAX:[phone] WEB:http://www.semtech.com
DESCRIPTION
The SC1110 is a low-cost, full featured, synchronous
voltage-mode controller designed to generate termina-
tion voltage in double data rate (DDR) memory sys-
tems and other applications where wide data bus need
to be actively terminated. Synchronous control of the
MOSFET half bridge allows power flowing bi-
directionally. The termination voltage can be tightly
regulated to track the chipset voltage, i.e. to be exactly
50% of that at all times.
The SC1110 is ideal for low cost implementation of ter-
mination voltage supplies. SC1110 features include
temperature compensated voltage reference, triangle
wave oscillator and current sense comparator circuitry,
and allows the use of inexpensive N-channel power
switches.
The SC1110 operates at a fixed 250kHz, providing an
optimum compromise between efficiency, transient
performance, external component size, and cost.
FEATURES
•= Generates termination voltages for active termina-
tion schemes
•= 1% set point accuracy
•= For ±7A output current, transient regulation is bet-
ter than ±80mV
•= V_REFIN pin available
•= Buffered V_REFOUT for system usage
•= R_DSON sensing for over current protection in hiccup
mode
•= Soft start and logic input enabling
•= 250kHz switching for best transient and efficiency
performance
•= Gate drive capable for 0.5A sourcing and sinking
APPLICATIONS
•= For DDR memory systems
•= For active termination schemes in high speed logic
systems
TYPICAL APPLICATION CIRCUIT
ORDERING INFORMATION
DEVICE⁽¹⁾ PACKAGE
SC1110CSTR SO-14
TEMP. RANGE (T_J)
0 - 125°C
Note:
(1) Only available in tape and reel packaging. A reel
contains 2500 devices.
REFOUT
R1 C1
5k
0.01
SS/ENBL
C3
0.1
PWRGD
C25
0.1
+5Vcc
R2
1.24k
C2
0.1
R3
10
U1
R4
SC1110
1k
1 _VCC
REFOUT ¹⁴
C4
0.022
+
C7
C8,9
C10,11
Vin 2.5V
1.0
2 x 10uF
2 x 560uF
_
2 _SS/ENBL
3 _OCSET
4 _PWRGD
REFIN ¹³
SENSE ¹²
COMP ¹¹
R5
1k
C5
R6
0.047
4.7k
5 _GND
6 _PHASE
7 _DL
BSTL ¹⁰
BSTH ⁹
DH ⁸
D1
MBRM120
R7
2.2
R8
2.2
Q1
Si9426DY
Q2
Si9426DY
C6
1.0
L1
800 nH
C12-14
C15-24
3 x 560uF 10 x 10uF
C10-14: Sanyo, 4SP560M
C8,9,15-24: TDK, CC3216AX5R0J106K
L1: Panasonic, ETQP6F0R8L or Falco, QPIP1205-809-3
Q1,Q2 options: Si9426DY, FDS6890A, IRF7401
D1: ON Semi (Motorola)
+
Vout = 1.25V @ 7A
_
1
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