CMX971 Datasheet, PDF (5/25 Pages) CML Microcircuits – Small 16-lead VQFN Package

Quadrature Modulator
CMX971
3 Pin and Signal List
3.1 Main Functions
Pin Name
1 TXIP
2 RFOUT
3 RFGND
4 VCC
5 LO
6 LOGND
7 CDATA / FREQ1*
8 VDD
9 SCLK / RESETN*
10 RDATA / DIVSET*
11 CSN / FREQ2*
12 VSS
13 CBUSOFFN
14 TXQN
15 TXQP
16 TXIN
~ EXPOSED METAL PAD
Type
IP
OP
PWR
PWR
IP
PWR
IP
PWR
IP
OP or
IP*
IP
PWR
IP
IP
IP
IP
PWR
Signal Description
Input for baseband transmit I signal (positive)
RF output
Analogue and RF ground
Analogue and RF supply
Input for local oscillator
LO Buffer ground
C-BUS data-in
C-BUS and digital supply
C-BUS clock input
C-BUS data output
C-BUS chip select
C-BUS and digital ground
Disable pin for C-BUS operation. If held low, direct
control pin functions are selected as described in
Table 2 and it enables modulator sections (equivalent
to General Control Register b4 and b0 = ‘1’, see
section 6.2.1). Internal ≈1MΩ pullup resistor.
Input for baseband transmit Q signal (negative)
Input for baseband transmit Q signal (positive)
Input for baseband transmit I signal (negative)
Substrate. Connect to Analogue and RF ground
* Direct control functions for these pins selected if CBUSOFF pin = ‘0’, see Table 2.
Notes: IP
=
OP =
PWR =
NC =
Table 1 Main Pin Functions
Input
Output
Power Connection
No connection – should NOT be connected to any signal
3.2 Direct Control Functions
When C-BUS is held disabled, pins 7, 9, 10 and 11 have the following functions (Table 2). Every time the
CBUSOFFN pin is held low the registers of the device are placed in the RESET state (section 6.1.1)
except ENBIAS and TXEN (see section 6.2.1) which are active. The functions listed in Table 2 are then
controlled by the appropriate pins.
Pin Function
7 FREQ1 – in combination with FREQ2 sets frequency range (see bit 0 of Tx Control
register, section 6.3.1 and section 7.))
9 RESETN – When low puts the device into low power mode. No internal pullup resistor.
10 DIVSET – if low sets mixer input to local oscillator divide by two, if high sets mixer input
to local oscillator divide by four (equivalent to the inverse of bit 6 of General Control
Register, section 6.2.1)
11 FREQ2 – in combination with FREQ1 sets frequency range (see bit 1 of Tx Control
register, section 6.3.1 and section 7.)
Note: local oscillator divide by two and local oscillator divide by four will hereafter be referred to as LO/2
and LO/4 respectively.
Table 2 Direct Control Pin Functions
 2015 CML Microsystems Plc
5
D/971/4